geology from 1991
TRANSCRIPT
Plainview Prospect
T2S R70W
Jefferson Co., Colorado
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February 25, 1991 .R. Randy RayGeologist/Geophysicist
Copy No. 10
Table of Contents
Page
Appendix I - Summary of P-Lyons Fields .
Appendix II - Oil Seeps .
Executive Summary .
Introduction .
Regional Structure .
Golden Thrust Fault .
Lyons Sandstone .
Dakota and Muddy "J" Sandstones .
Niobrara Chalk .
Thermal Maturity .
Conclusions .
References .......................................................
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Illustrations
List of Fi2;ures
1) Denver Basin after Tainter, 1984
2) Generalized stratigraphic column after Leroy, 19553) Generalized tectonic map after Warner, 19804) Golden Fault Structural Models after Domoracki, 19865) Geologic cross-section at Soda Lakes, Berg, 19626) Golden Fault Seismic Line - Final Stack, Domoracki, 19867) Interpreted Golden Fault Seismic Line - Migrated Modified from
Domoracki, 1986, Interpreted by R.R. Ray8) State Highway 72 - Seismic Line - Final Stack from Domoracki, 19869) Interpreted State Highway 72 - Seismic Line - Final Stack from
Domoracki, 1986, Interpreted by R.R. Ray10) Typical electric log Pierce Field Area and geologic cross-section after
Sonnenberg, 198411) "Pierce-Black Hollow" right-wrench zone after Stone, 198512) Seismic structure map on the Lyons Formation of the Pierce-Black
Hollow-New Windsor oil field complex, Weld Co., Colorado afterStone, 1985
13) East-West electric log section from Eldorado Springs outcrop to eastSide of Wattenberg Field after Weimer & Sonnenberg, 1989
14) Index map of thermally mature and oil productive Niobrara formationafter Rice, 1984
15) Geothermal gradients in the northern portion of Denver Basin afterWeimer & Sonnenberg, 1989
16) Photograph of fractured Ft. Hayes Limestone in outcrop north ofMorrison, Co.
Plates
Plate 1 - Structural Cross-section A-A'Plate 2 - Geologic Map, I" = 2000'Plate 3 - Stratigraphic Well-log Cross-section E-E'Plate 4 - Muddy "J" Structure Map, 1:100,000Plate 5 - Fox Hills Structure Map, 1:100,000Plate 6 - Prospect Leases, I" = 2000' showing pipelines and proposed
seismic program
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Plainview ProspectT2S R70W
Jefferson County, Colorado
Executive Summary
Plainview Oil and Gas holds leases on a prospect 15 miles west of the center ofdowntown Denver. It is a combination gas and oil prospect located very close tomarket. An 8 inch intrastate pipeline passes across the lease.
Plainview Prospect is a structural trap formed at the intersection of regional faulttrends along the Front Range. The eastward thrusted Golden Fault is the dominantstructural element and hides the underlying basinal structure. It overlaps the IdahoSprings-Ralston shear zone which formed the Colorado Mineral belt and creates aregional fracture trend in the Denver Basin. Potential primary productive zonesinclude fractured Niobrara chalks, Dakota Sandstones and Lyons Sandstones.Secondary productive zones may include the Terry, Hygiene and Muddy-J Sandstones.Potential reserves of up to 10 million barrels of oil are possible based on analog fields.
Further seismic definition of the prospect will be needed to confirm the presence andsize of a structure underneath the northern extension of the Golden Fault. An acreageblock of 3088 acres is presently held over the prospect and could be enlarged afterseismic definition.
Introduction
Plainview Oil and Gas acquired leases over an area that is attractive for oil and gasexploration. The acreage is located northwest of Denver, between the towns of Goldenand Boulder, along the Colorado Front Range (figs. 1 & 3).
The acreage lies at the western margin of the Denver Basin as it abutts the structurallyuplifted Front Range. The Denver Basin covers most of the eastern half of Coloradowith the deepest part of the basin lying next to the mountains near Denver (fig. 1).Because of its long producing history, the stratigraphy of the basin is well known, bothfrom subsurface and outcrop control. A diagrammatic, generalized stratigraphicsection prepared by Leroy, 1955, is shown in figure 2. Additional information has beenadded which helps clarify the following discussions.
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the
The northern extent of the Golden Fault is unclear from outcrop information. Inoutcrop, the Paleozoic and Mesozoic rocks continue to have steep east dip all along themountain front. However, at Superior the vertical to 60° E dipping beds at the FoxHills sandstone flatten out and head off to the northeast. The change in trend iscoincident with the projection of the Idaho Springs-Ralston shear zone as it emergesfrom the mountain front.
The Superior area has several NE trending faults exposed in outcrop. The area hasbeen mined for coal in the Laramie and Fox Hills zones since the late 1800's. Thefaulting has been interpreted to be listric normal faults caused by sediment loadingassociated with prograding Fox Hills deltas (Weimer, 1973; Davis, 1974; Davis, 1985).This is probably a secondary structure created by the underlying wrenching associatedwith the Idaho Springs-Ralston shear zone.
New seismic data acquired by the Colorado School of Mines (Domoracki, 1986) helps toillustrate the geometry of the Golden fault as a low angle (30°) thrust fault (fig. 5).Displacement on the Precambrian surface is about 10,000 ft. Using this new model ofthe faulting, it becomes clear that the Golden Thrust Fault is a low angle thrust which islosing throw and dying out to the north where it is overtaken by the wrenchingassociated with the Idaho Springs-Ralston shear zone. The intersection of these trendsis an excellent area to generate structural folding. faulting and fracturing.
Even though the seismic evidence of the Golden fault zone is clear, the resolution of thefootwall structure is more difficult (fig. 6). There is a large reflection time distortioncaused by overthrusted, high velocity Precambrian rocks. This causes velocity pull-upwhich makes the reflections appear to be rising to the west. When properly correctedto depth, the basinal dips would be flat lying to slightly eastward dipping.
With this new model in mind, the Colorado School of Mines seismic line down Highway72 can be interpreted. This data was shot as 12 fold vibroseis in 1977 (Davis andYoung, 1977), but has been reprocessed by Domoracki, 1986 (fig. 7 & 8). When a 30°thrust fault is placed on the section, it becomes clear that reflections underneath thefault are probably associated with fault blocks in the basin. Of particular interest is anarching reflection just underlying the leading edge of the thrust which appears to be ahigh fault block. At this position, there is not much velocity pull-up created since thethrust carries Pierre shale over the Pierre shale in the basin. Velocity pull-up will beginto increase west of SP 15 where the Niobrara limestone is present in the overthrustblock (see Plate 1).
Lvons Sandstone
The Permian Lyons Sandstone is one of the primary objectives in the PlainviewProspect since it is an oil producing zone in several large fields. The outcrop of LyonsSandstone in the Boulder to Morrison area has two major facies which interfinger witheach other. The first is the white to red, fine to medium grained, cross-stratified,quartzose sandstone recognized as eolian dunes at the type section in Lyons, Colorado.
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number
As previously discussed, the seismic indicates a basement fault block on the Plainviewacreage. This basement structure could be created by the wrench faulting of the IdahoSprings-Ralston shear zone analogous to the Pierce or Black Hollow fields. Based onoutcrop and subsurface control, the Lyons Sandstone is present and could be trapped ina low relief anticline under the leading edge of the Golden Fault.
Dakota and Muddv "J" Sandstones
Potential for an extension of the Superior Gas Field is possible in the prospect area.Production is primarily oil and wet gas-condensate from Dakota channel sandstones(see stratigraphic cross-section E-E'). The Muddy "J" Sandstone is generally thin andtight, but does produce in a couple of the wells.
The Dakota interval is comprised of two to four channel sandstones in this area. Basedon correlation to outcrop three miles to the west, the lower channel is Lytle Sandstone.It generally is not productive, testing wet. The middle channel is the PlainviewSandstone and it appears to be the most continuous channel across the prospect area.It is productive and reaches a maximum of over 60 feet thick in wells closest to thePlainview Prospect area. The upper most channel is the El Dorado Springs Sandstoneand it is also productive. It appears to be pinching out to the south across the prospectarea.
Gas production from the Dakota channels is at a rate of 250-650 MCFPD per well. Thesandstones completions generally include fracing and acidizing treatments. The wellsclosest to the prospect are all shut in and have no completion test information.
The Muddy "J" Sandstone is productive to the north and south. Wattenberg Field withreserves in the order of 1 TCFG from the Muddy "J" Sandstone is about 15 miles to thenortheast. To the southeast, the Teton Energy Co. Church Estate #22-1 well tested oiland gas from the "J", even though it is currently shut-in. Most Muddy "J" productionis classed as from stratigraphic traps, but subtle paleo-structure and unconformitieshave also controlled the petroleum accumulations (Weimer and Sonnenberg, 1989).
A structure map on the Muddy "J" Sandstone (Plate 4) indicates a prominent NW-SEtrending nose on the south end of Superior Field. The nosing may be related to a NWSE trending fault as seen in the Precambrian outcrop. The structural discontinuity isshown in the shallow Fox Hills structure map also (Plate 5). A second NW-SE trendingstructural nose is also contoured by Van Horn, 1976, through the Teton Energy ChurchEstate #22-1 well. This structural trend could be part of the trapping mechanism for"J" in the well, even though it is structurally much lower than wells in the SuperiorField. This structural trend may also be indicating a basement flexural trend thatwould create closure under the Golden Thrust.
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Niobrara Chalk
The Cretaceous age Niobrara Chalk interval is the other primary objective in thePlainview Prospect. It is an attractive oil and gas producing target when developedusing horizontal drill holes to intersect vertical fractures. The brittle chalks in theNiobrara have a tendency to naturally fracture due to compaction and burial, as well aslocal tectonics. As articulated in the Ree:ional Structure and Golden Thrust Faultsections, preceding, the Idaho Springs-Ralston SW-NE trending basement shear zoneintersects the north-south trending Golden Thrust Fault underneath the PlainviewProspect acreage block. This should enhance the fracturing at depth.
Figure 16 illustrates the intersecting vertical fracture pattern of the Fort HayesLimestone member of the Niobrara as exposed in outcrop north of Morrison (Sec. 26,T4S, R70W). The outcrop dips about 45° east and shows prominent north trendingfractures spaced on average about one foot apart. These are intersected by crossfractures trending NW-SE spaced every 2-6 feet apart.
Oil produced from the Niobrara chalks is sourced from the surrounding organicallyrich shales. The shales, like the chalks, were deposited in shallow to deep marineenvironments. When thermally mature, the Niobrara shales generate hydrocarbonsthat migrate into the fractured chalks. The Plainview prospect is in the thermallymature, oil-generating part of the Denver Basin (Tainter, 1982) and is in the areawhere wells produce oil and wet gas condensate from the Niobrara (Rice, 1985). (seefig. 14) Weimer and Sonnenberg, 1989, has noted higher geothermal gradientsassociated with an extension of the Colorado Mineral Belt trend (fig. 15). The deepburial depths and higher heat flow associated with the Idaho Springs-Ralston shearzone create thermally mature rocks in the Niobrara.
The Soda Lakes oil field produced 13,000 BO and flared untold quantities of associatedgas after its discovery in 1955. It was trapped in a structure along the Golden Thrustsimilar to the Plainview Prospect. The S.D. Johnson #' Lillie Pallaoro well (see Plate 3)indicates the production was from the Fort Haves Limestone interval in the basalNiobrara chalk formation.
Immediately adjacent to the Plainview Prospect, the vertically drilled MartinExploration Carrucci #1-33 well blew out three times; twice while drilling the top 120feet interval in the Niobrara and once while drilling the basal Fort Hayes member. Inaddition, several wells (Sec. 13 & 25), in the Superior Field, produce from the Codellinterval immediately underlying the Ft. Hayes Limestone. Electric logs run on wells inthe vicinity show high electrical resistivities through a large part of the Niobraraformation. High resistivity readings like these correspond to producing areas in theAustin Chalk trend of south-central Texas (Hinds & Berg, 1990) and in the Silo Field ofsouthwest Wyomine:.
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Thermal Maturity
The Plainview Prospect is located in a part of the Denver Basin which has oil and gasgenerating source rocks present (fig. 14). The mountain front between Boulder, Goldenand Morrison lies juxtaposed to the deepest part of the Denver Basin (Tainter, 1982,fig.1). Marine shales of the Benton, Niobrara and Pierre formations are thermallymature and source hydrocarbons for oil production in the Denver Basin. Numerous oilseeps and shows have been reported (Stewart, 1955, see Appendix 11) along the FrontRange. These are undoubtedly sourced from the shales underlying the Golden fault.
The geometrical gradients mapped by Weimer and Sonnenberg, 1989 (fig. 15), indicatean extension of the Colorado Mineral Belt (Idaho Springs-Ralston Creek) trend into thebasin across the Plainview Prospect. This should enhance oil generation and fracturingover the prospect.
Conclusions
The Plainview Prospect is a potential structural and stratigraphic trap in the deepportion of the Denver Basin. A review of available surface geology, well control, seismicand published articles shows it has potential for trapping petroleum in multiplereservoirs. It will require further seismic definition using modern high fold Vibroseisdata. A program of about 13 miles should be acquired to detail the structural strikeand dip orientations (see Plate 6). The lines should be designed to accommodate theexpected structural complexity and still be able to get good data.
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References
Geologic Maps
LeRoy, L.W., 1955, Summary of Surface Stratigraphy: in Field Conference onGeology of Front Range Foothills West of Denver; Rocky MountainAssociation of Geologists, p. 15-24.
Scott, G.R. and Cobban, W.A., 1965, Geologic and Biostratigraphic Map of thePierre Shale Between Jarre Creek and Loveland, Colorado: U.S. Geol.Survey Map 1-439
Scott, G.R., 1972, Geologic Map of the Morrison Quadrangle, Jefferson County,Colorado: United States Geological Survey Map 1-790A, Scale 1:24,000
Sheridan, D.M., Maxwell, CH. And Albee, A.L., 1967, Geology and UraniumDeposits of the Ralston Buttes District, Jefferson County, Colorado:U.S. Geological Survey Prof. Paper
Stewart, W.A., 1953, Structure and oil possibilities of the west flank of the DenverBasin north-central, Colorado: PhD thesis, Colorado School of Mines,T-777,121p.
Stewart, W.A., 1955, Structure of the Foothills Area West of Denver, Colorado;in Field Conference Guidebook: Rocky Mountain Association ofGeologists, p. 25-30.
Van Horn, R., 1957, Bedrock Geology of the Golden Quadrangle, Colorado:U.S. Geological Survey Map GQ 103.
Van Horn, R., 1972, Surfical and Bedrock Geologic Map of the Golden Quadrangle,Jefferson County, Colorado: U.S. Geological Survey Map 1-761-A
Structure
Berg, R.R., 1962a, Subsurface Interpretation of the Golden Fault at Soda Lakes,Jefferson County, Colorado: Am. Assoc. Petroleum Geologists Bull., v. 46,p. 704-707.
Berg, R.R., 1962b, Mountain Flank Thrusting in Rocky Mountain Foreland,Wyoming and Colorado: Am. Assoc. Petroleum Geologists Bull., v. 46,n. 11, p. 2019-2032.
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Davis, T.L., and Young, T.K., 1977, Seismic Investigation of the Colorado FrontRange Zone of Flank Deformation Immediately North of Golden, Colorado;in Veal, H.K., ed., Exploration Frontiers in the Central and SouthernRockies: Rocky Mountain Association of Geologists, p. 77-88.
Davis, T.L., 1985, Seismic Evidence of Tectonic Influence on Development ofCretaceous Listric Normal Faults, Boulder-Wattenberg-Greeley Area,Denver Basin, Colorado: The Mountain Geologist, v. 22, n. 2, p. 47-53.
Gries, R, 1983, Oil and Gas Prospecting Beneath Precambrian Foreland ThrustPlates in Rocky Mountains: Am. Assoc. Petroleum Geologists Bull., v. 67,n. 1, p. 1-28.
Stone, D.S., 1969, Wrench Faulting and Rocky Mountain Tectonics: The MountainGeologist, v. 6, n. 2, p.67-79.
Stone, D.S., 1985, Seismic profiles in the area of the Pierce and Black Hollow fields,Weld Co., Colorado: Seismic Exploration of the Rocky Mountain Region,RMAG & DGS 1985 Atlas, p. 79-87.
Warner, L.A., 1980, The Colorado Lineament; in Kent, H.C. and Porter, K.W. eds.,Colorado Geology: Rocky Mountain Association of Geologists, p. 11-21.
Weimer, RJ., and Davis, T.L., 1977, Stratigraphic and Seismic Evidence for LateCretaceous Growth Faulting, Denver Basin, Colorado; in Payton, C.E. ed.,Seismic Stratigraphy - Applications to Hydrocarbon Exploration:American Association of Petroleum Geologists, Memoir 26, p. 277-300.
Lyons Sandstone
Blood, W.A., 1970, Upper Portion of the Fountain Formation and the LyonsFormation at Morrison, Colorado: Mtn. Geol., v. 7, no. 1, p.33-48.
Dimelow, T.E., 1972, Stratigraphy and petrology, Lyons Sandstone, northeasternColorado: Colo. Sch. Of Mines, unpub. M.S. thesis #1158.
Levandowski, D.W., Kaley, M.E., Silverman, S.R, and Smalley, RG., 1973,Cementation in 'Lyons Sandstone and its role in oil accumulation, Denver,Basin, Colorado: Am. Assoc. Petroleum Geologists Bull., v. 57, p. 2217-2244.
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Momper, J.A., 1963, Nomenclature, Lithofacies and Genesis of PermoPennsylvanian Rocks, Northern Denver Basin: Rocky MountainAssociation Geologists Guidebook, 14th Ann. Field Conf., p. 41-67.
Sonnenberg, S.A., 1984, The Pierce Field Structure: The Mtn. Geologist,v. 21, no. 1, Jan., 1984, p. 1-4.
Thompson, W.O., 1949, Lyons Sandstone of Colorado Front Range:Am. Assoc. Petroleum Geologists Bull., v. 33, p. 52-72.
Weimer, RJ., and Land, c.B., 1973, Lyons Formation (Permain), JeffersonCounty, Colorado: A Fluvial deposit: The Mountain Geologist, v. 9,Nos. 2-3, p. 289-297.
Muddy J. Sandstone and Dakota Sandstone
Weimer, RJ., and Sonnenberg, S.A., 1989, Sequence Stratigraphic Analysis ofMuddy (J) Sandstone Reservoir, Wattenberg Field, Denver Basin,Colorado: Rocky Mountain Association of Geologists, 1989 Guidebook,p. 197-220.
Niobrara Formation
Smagala, T.M., Brown, C.A. and Nydegger, G.L., 1984, Log-derived indicatorof thermal maturity, Niobrara Formation, Denver Basin, Colorado,
Nebraska, Wyoming: Hydrocarbon Source Rocks of the Greater RockyMtn. Region, RMAG 1984 Guidebook, p. 355-363.
Upper Cretaceous
Weimer, RJ., 1973, Guide to Uppermost Cretaceous Stratigraphy, CentralFront Range, Colorado: Deltaic Sedimentation, Growth Faulting andEarly Laramie Crustal Movement: The Mountain Geologist, v. 10,no. 3, p. 53-97.
Hinds, G.S. and Berg, RR, 1990, Estimating organic maturity from well logs,upper Cretaceous Austin Chalk, Texas Gulf Coast: Gulf Coast Assoc.Geol. Soc. Trans. - 40th Annual Mtg., p. 295-300.
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Rice, D.D., 1989, Relation of hydrocarbon occurrence to thermal maturity ofOrganic matter in the Upper Cretaceous Niobrara Formation, easternDenver Basin: Evidence of biogenic versus thermogenic origin ofHydrocarbons; in J. Woodward, F.F. Meissner and J.L. Clayton, eds.,Hydrocarbon Source Rocks of the Greater Rocky Mountain Region,RMAG 1984 Guidebook, p. 365-368.
Tainter, P.A., 1984, Stratigraphic and Paleostructural Controls on HydrocarbonMigration in Cretaceous D and J Sandstones of the Denver Basin; in J.Woodward, F.F. Meissner and J.L. Clayton, eds., Hydrocarbon SourceRocks of the Greater Rocky Mountain Region, RMAG: p.330-354.
Seismic Data
Davis, T.L., 1974, Seismic Investigation of Late Cretaceous Faulting Along theEast Flank of the Central Front Range, Colorado: Ph.D. thesis,Colorado School of Mines, T-1681, p. 65.
Money, N.R, 1977, A Seismic Investigation of the North Golden Area, JeffersonCounty, Colorado: M.S. thesis, Colorado School of Mines, T-1849, p. 56.
Nelson, K.J., 1977, A Reflection Seismic Investigation of the Golden QuadrangleArea, Jefferson County, Colorado: M.S. thesis, Colorado School of Mines,T-1990, p. 55.
Ray, RR, Gries, R, and Babcock, J,W., 1983, Acoustic Velocities, SyntheticSeismograms, and Lithologies of Thrusted Precambrian Rocks, RockyMountain Foreland; in Lowell, J.D., ed., Conference on Rocky MountainForeland Basins and Uplifts: Rocky Mountain Association of Geologists,p. 125-135,
Shuck, E.L., 1976, A Seismic Survey of the Ralston Area, Jefferson County,Colorado: M.S. thesis, Colorado School of Mines, T-1835, p. 45.
Young, T.K., 1977, A Seismic Investigation of North and South Table MountainsNear Golden, Jefferson County, Colorado: M.S. thesis, Colorado SchoolOf Mines, T-1947, p. 54.
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Allliendix I
Summary of P-Lvons FieldsField Name
No. WellsCum. Prod.
Black Hollow
1110,648,846New Windsor
3896,621Pierce
1511,207,343Fort Collins
6327,321Lake Canal
12,717Loveland
15,939Keota
112,816LaPorte
3141Berthoud
1306,820Douglas Lake
112,548
TOTALS
4323,421,112
All Wells Avg. 535,092 BOIW ell
Status of Wells
11 PR1 PR14PR1 PR 1 S.I.o PRo PRo PRo PR3 PRo PR 1 S.I.
30 PR, 2 S.I., 11 P&A
Summary (Prod. Wells)
Field Name
Black HollowNew WindsorPierceFort CollinsBerthoud
TOTALS
No. Wells Cum. Prod.
11
10,648,8461
896,62115
11,207,3431
6,7183
306,820
31
23,066,348
Producing Wells Avg. 752,944 BOIWELL
The two largest fields only
Black Hollow& Pierce 25 21,856,186
Best Wells Avg. 874,971 BOIWELL
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Appendix IINOTE: This is a list of the oil seeps compiled by W. Alan Stewart, 1953, Structure
and Oil Possibilities of the West Flank of the Denver Basin North
Central, Colorado: Colo. Sch. Mines Ph.D. Thesis #777, 121 p. Mycomments are added in brackets {*}. Oil seeps are plotted on Plate 5.
Direct Indications of Natural Hvdrocarbons
There are at least nine known occurrences of bituminous material in the foothills belt
between the Ralston Reservoir and Dutch Creek. They consist of live oil seeps, dead oilresidues, asphaltic sandstones, solid, brittle bitumens and shows in oil and water wells.An index map recording these localities is shown in Figure 19. The nature of theindividual occurrences is discussed by index number below:
Locality
1)
This locality is a live oil seep occurring in a gulch emptying into Golden Gate Canyonabout 1-112 miles northwest of Golden. The seep occurs in metamorphic rocks and islocated one-half mile west of the crystalline-sedimentary contact. The stream gravels inthe bottom of the gulch are locally cemented by asphaltic residue. In summer, when thestream has nearly dried up, pockets of live, green, high-gravity oil accumulate in thegravels. It is believed that this oil rises through fractures in the crystallines fromsedimentary rocks underthrust below them in the crystallines from sedimentary rocksunderthrust below them in the footwall of the Golden Fault. {* Probably sourced fromCretaceous age rocks. Cretaceous oil is generally green, 44-48° F pour point.}
2)
About 1-1/4 miles northeast of the locality, a live green oil seep was encountered whenthe Denver Fire Clay Company drove an adit into the Dakota sandstones to open up afire clay seam (Van Tuyl, p. 744, 1932).
3)
Van Tuyl (oral communication) reports an occurrence of high gravity petroleum in awater well drilled near the Fountain-Basement contact, west of Morrison and south ofRed Rocks Park.
4)An oil show in the Dakota sandstone is recorded inn the driller's log of the Midas Oiland Gas Company, No.2 well, near Morrison in T5S, R69W (Barb, p. 134, 1946).
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5)
Van Tuyl oral communication) states that a construction crew driving the pilot tunnelfor the first tunnel on U.S. Highway 40 in Clear Creek Canyon, encountered a pocket ofheavy, black, dead oil in the joints of the metamorphic rocks. This locality is aboutthree-fourths of a mile west of the Fountain-Basement contact. {*Probably sourced byPaleozoic rocks. Paleozoic oil is generally black, 36-410 API gravity, paraffinic, 00 Fpour point.}
6)LeRoy (p. 31, 1946) describes occurrences of a black, brittle, bituminous substance inthe shales and limestones of the basal Lykins formation in Glennon Canyon south ofMorrison.
7)LeRoy (p. 31, 1946) reports a similar occurrence in a limestone, 15 feet above theLyons-Lykins contact on Ralston Creek.
8)Heavy, black, brittle bituminous material was observed by Van Tuyl (personalcommunication) in a road cut near the parking lot behind the amphitheater at RedRocks Park. This material was found in the four to five feet of the basal Fountain andin joints of the underlying crystallines.
9)South of the Turkey Creek water gap in the Dakota hogback, there is an old quarrydeveloped in an occurrence of bituminous sandstone at the top of the Dakota formation.An attempt was made once to extract the bitumen by a hot water or steam process.
All of the foregoing occurrences are located in the hanging wall of the Golden Fault.The source of many of these hydrocarbons could be the 9,000 foot section of marinelimestones and shales of the Benton, Niobrara and Pierce formations in the footwall ofthe fault. Trap possibilities are almost negligible in the upthrown block andcommercial accumulations, if present, are expected on the downthrown side of the fault.
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Plainview Oil and Gas ProspeCt
Multiple Reservoirs) Nahlral F:ractured SettingDenver Basin
T2S R70W
Jefferson CountY, Colorado
The Plainview Oil and Gas Prospect is comprised of 2,123 acres located in Sections 8, 16,
17,18, and 20 of Township 2 South Range 70 West Jefferson County, Colorado. The prospect lies
on the very Western Edge of the Denver Basin near the upJift of the Rocky Mountains. The Denver. '
Basin has been and continues to be a high!y productive basin for both oil and gas iTom numerous
reservoirs. The potential reservoirs for thls prospect are ,simil,ar to the reservoirs that produce in the
Denver Basin. These reservoirs are primarily Cretaceous-age ~ndstones but, reservoirs of Permian
age are also productive. This prospect, beC<.use of its ideal location, has a high probability of
encountering oil and gas reservoirs with high concentrations, of natural fi-actures. The natural
fractures greatly enhance the producing C<lpabilities of the reservoirs. The key essentials for this
prospect are based upon seismk data and the location of the Church #22;.1 well which was drilled
a1id then completed in January, 1983. The seismic data 'indi'cates structural potential for highly, ,
fractured reservoirs and deeper structural c1osure, whereas the Church wen shows the presence of
reservoirs comparable to other productive reservoirs in the Denver Basin. The Church we\! is
, locattd only :2 miles southeast of the prospect.
GEOLOGY
The prospect is locat~ on the very western edge of the Denver Basi n, just northwest of the
city of Denver (Figure 1). The location of the prospect is in an area of the basin where the deeper
reservoirs are void of mobile water. It is a basin.centeredhydroC<lrbon accumulation based on data
from the nearby giant Wattenberg Field. Arty reservoir that has sufficient porosity and permeability
will contain' hydrocarbons without significant quantities of water
Structurally, this prospect Jies near the intersection of two major fault trends. The Golden
Fault is a north-south trending thrust fault tha.~ separates the Rocky Mountain Uplift &om the
Denver Basin. The vertical displacement of this fault is on the order of 6,000 feet. The second
major fault 20ne is the Idaho Springs-Ra!ston Shear zone, a northeast trending high angle shear
zone. The intersection of these two faults is an idea! location to generate structural folding, faulting
Plainview Oil and Gas ProspeCtMultiple Reservoirs, Natural ~ractured Setting
Denver BasinT2S R70W
Jefferson CountY, Colorado
The Pla.inview Oil and G3s Prospect is comprised of 2,123 acres located in Sec~ioos 8, 16,
17, 18, and :2.0of Township 2 South Range 70 West Jefferson County, Colorado. The prospect lies
on the very Western Edge of the Denver Basin near the uplift of the Rocky Mountains. The Denver. '
Basin has been and continues to be a highly productiye basin for both oil and gas from numerous
reservoirs. The potential reservoirs for this prospect are ,similar to the reservoirs that produce in the
Denver Basin. These reservoirs are primarily Cretaceous-age sandstones but, reserY'oirs of Permian
age are also productive. This prospect, because of its ideal 1ocation, has a high probability of
encountering oil and, gas reserY'oirs with high concentrations of natural fractures. The natural
fra.ctures greatly enhance the producing capabilities of the reservoirs. The key essentials for this
prospect are based upon seismic data and the Iocation of the ,Church #22-1 weB which was drilled
and then completed in January, 1983. The seismic data'indi'cates structural potential for highly
fractured reservoirs and deeper structural closure, whereas the Church wel1 shows the presence of
reservoirs comparable to other productive reservoirs in the Denver Basin. The Church well is
located only 2 miles southeast of the prospect.
,GEOLOGY
The prospect is located on the very western edge of the Denver Basin, just northwest of the
city of Denver (FigUre 1). The location of the prospect is in an area of the basin where the deeper
reservoirs are void of mobile water. It is a basin~centeredhydrocarbon accumulation based on data
from the nearby giant Wattenberg Field. My reservoir that has sufficient porosity and permeability-....
will contain' hydrocarbons without significant quantities of water
StruCturally, this prospect lies near the intersection of two major fault trends. The Golden
Fault is a north-south trending thrust fault that, separates the Rocky Mountain Uplift from the
Denver Basin. The vertical displacement of this fault is on the order of 6,000 feet. The second
major fault zone is the Idaho Springs-Ralston Shear zone, a northeast trending high angle shear
zone. The intersection of these two faults is an ideal1ocation to generate structural folding, faulting
and fracturing. Figure 2 is a schematic of the location of these two faults along with other regional
features. Figure 3 is a seismic line which shows the structure and potential reservoirs for this
prospect. The deeper Cretaceous reservoirs in the footwall (subthrust block of the Golden fault)
demonstrate dip reversal against ·the fault, which may form structl.1ral or structural-stratigraphic
traps. However, structural closure is not necessary for the Cretaceous reservoirs to be productive.
Also shown is a "triangular" zone that is believed to be highly fractured and could c.ontain an
unusually large amount of hydrocarbons. This zone is comprised of Pierre Shale, which is the
major source bed for the deeper Cretaceous reservoirs, and it is oil productive in several areas of the
basin.
RESER YOIRS
Lvons Sandstone
The Lyons Sandstone is the deepest potential reservoir. This reservoir has produced
hydrocarbons from several anticlinal structures along the west flank of the basin. The geologic
setting of this prospect is very simila.r to that at Black Hollow Field. To date the Lyons has not been
a large contributor to the overall hydrocarbon production in the Denver Basin, however, the Black
Hallow and Pierce Fields to the north in T8N and R66W have cumulative production of slightly less
than 1,000,000 barrels of oil per well. If structural closure is present in the subthrust fault block of
this prospect, the Lyons Sandstone could be a significant reservoir.
Dakota Sandstones
The Dakota begins just below the base of the J formation. In the Church wel1 the first
Dakota Sandstone reservoir penetrated below the J Sandstone is the Plainview Sandstone (See
Figure 4a). The Plainview Sandstone is approximately 60 feet thick. Log analysis indicated this
2~one should be productive in the Church well. Below the Plainview Sandstone is the Lytle
Sandstone. The Lytle Sandston~ is not considered productive in the Church well. Both of these
sandstone reservoirs are interpreted to be channel sandstone deposits. A third reservoir known in
the area as the El Dorado Springs Sandstone, which is above the Plainview Sandstone, is not present
in the Church well. It has been interpreted that the El Dorado Springs Sandstone has been faulted
out in the Church well but it should be present in most other locations in the prospect. The mudlog
ITam the Church well had oil shows within the Plainview Sandstone. There were no drill-stem or·
production tests of the Dakota reservoirs in the Church well.
The Dakota interval was proven productive in the Superior Field 6 miles north of the Church
well. According to the Colorado Oil and Gas Conservation Commission (COGCC) records a total
of 6 wells in the Superior Field were completed only in the Dakota interval during the early 1980' s.
These six wells produced an average of only 1,100 barrels of oil and 79.0 mil1ion cubic feet of ga$
due to inadequate fracture treatments in the early 1980' s. The log characteristics of the Church well
are similar to the wells in the Superior Field, and therefore, the Church well should be capabJe of
producing hydrocarbons, especially considering the advancement of fracture technoJogy and
completion pra.ctices currently utilized. In addition to comparing the log characteristics (thickness,
resistivity profiles, and rracture indications) of the Church well with welts in the Superior Field,
computed porosity and water saturation values ITom log data displayed very similar results.
"J" Sandstone
The J Sandstone is the most prolific producing formation in the Denver Basin. The J
Sandstone reservoirs are at a depth ,of approximately 9,500 feet or about 400 feet below the Codell
formation (See Figures 4a and 4b). The gross interval exceeds 50 feet of thickness. Log analysis
indicated 32 Teet of hydrocarbon bearing sandstones. In the Denver Basin the J Sandstone interval
can have three producing intervals, known as the J1, J2 and J3 reservoirs, The J1 is generally a
channel or barrier bar sandstone. The 12 is identified as a valley fill channel sandstone. The 32 feet
of hydrocarbon bearing sandstones are located within the 11 and 12 sections. The 13 reservoir, a
shaly deltaic sandstone, is the poorer of the three reservoirs. The J3 is not present in the Church
#22-1 well.
The J1 Sandstone is credited with having the most prolific gas well in the Denver Basin.
The Monaghan State #1-16 well located within the boundary of Denver International Airport (DlA)
property, approximately 30 miles east of this prospect, produced more than 250,000 barrels of oil
and 12 billion cubic feet of gas. More recently the J2 interval has also been a primary reservoir in
wells drilled within the airport boundary. These newer wells continued a development trend
established by earlier fields, such as Radar, on the eastern boundary of DIA extending westward
onto the DIA property. From DlA the J2 val1ey-fill sequence continues westward through the
.prospect area,
Shown in Figure 5 is a well Jog cross~section from the Church #22-1 weB to the West
Ambush #23-11 weJllocated wi"thi'n the boundary ofDIA. This ~ew.DIA well, completed in 1998,
>.>
has a comparable 11 and J2 section. This new Ambush #23·11 well has already produced more than
60,000 barrels of oil and 400 million cubic feet of gas.
The Church #22-1 well was originally completed in January 1983. A gross interval of 48
feet was perforated with a total of 11 perforations in the J1 and J2 reservoirs. By today' s standards
t~is was an inadequate number of perforations to cover an interval of this thickness. The
perforations were fracture treated with 45,00 gallons of 2% KCL water. The COGCC records do
not reflect the amount of sand used in the fracture treatment. The well produced at a rate of 326
thousand cubic feet of gas per day, 10 barrels of oi] per day, and a water production rate of 75
barrels per day. The water production is believed to be fluid used in the fracture treatment. >This
wel1 is located in an area of the Denver Basin where free water production does not exist. The
records indicate the well was shut-in and was never connected to a gas sales Jine. In August 1984 a
bottom-hole pressure bomb was run in the well to a depth of 9,500 feet. The pressure bomb
indicated a reservoir pressure of approximately 3,360 psig. A fluid level was indicated at a depth of
approximately 8,850 feet (658 feet above the upper-most perforation). The gradient of the fluid
appears to be that of oil and not of water. Considering the advancements of fracture technology and
completion techniques used today versus the 1983 practices, it is highly likely tha.t the well could
have produced at much higher rates.
The J1 and J2 reservoirs should be low risk at the prospect location. Due to its location in
the basin there should only be hydrocarbons if sufficient reservoir quality is found. Also there is a
high probability of natural fractures at this location which would greatly enhance productivity. At
the prospect location the J is likely to have two benches. The Jl and J2 reservoirs in the prospect
area should encounter a net thickness of approximately 20 feet for the 11 and J2 reservoirs.
Niobrara.. F~.Hayes~and CodeJl
The Niobrara/Ft. Hayes/Codell interval is approximately 340 feet thick, and it lies at a depth
of approximately 8,800 feet. Of this total section the Niobrara is approximately 280 feet thick, the
Ft. Hayes limestone is approximately 30 feet thick, and the Cadell is approximately 30 feet thick.
The Niobrara formation is comprised mainly of brittle chalky limestone that has a tendency to
fracture. This prospect is located in an area of high tectonic activity, and therefore, the Niobrara has
:ahigh probability of being naturally fractured. The Ft. Hayes is a limest~ne that is usually natura,l[y>
>fTactured, and numerous wells dri11ed in the Denver Basin have recorded oil shows iTom this
formation. The Codell reservoir located just below the F( Hayes limestone is a shaly sandstone that
generally requires hydraulic fracture treatments in order to produce. Figure 4b shows a log section
over this interval. It is quite common for wens to be completed in all three intervals with the
production commingled.
The combination of these reservoirs is very prolific in the Denver Basin. The Wattenberg
Field located in the vicinity of the city of Greeley, Colorado and northeast of the Church #22-1 well,
has produced ITom these zones in 100's of we!1s. Also, these reservoirs have produced in the
Superior Field approximately 6 miles north of the Church well location
In southeast Wyoming the Silo Field produ'ces. from t~e Niobrara formation. Both
horizontal and vertical weIls were utilized in completions. This prospect location is in an idea!
location for natural fractures to occur within this zone, which would greatly enhance production
, capability.
At the base of the Niobrara is the 30 foot thick Ft. Hayes limestone. To date the Ft. Hayes
has not been a large contributor to the regions' oil and gas production. But the geologic setting of
th1S prospect is ,similar to the structural trap found in the Lillie Pal1aoro #1 well in Section 6 T5S
R69W. This wen, disco~ered in 1955, produced more than 13,000 barrels of 011 and a significant
but unknown amount of associated gas. '
The Codel1 sandstone is located just below the Ft. Hayes limestone. It is a shaley 30 foot
thick sandstone that generally requires hydrauJic fracturing to produce. The Codell has been the
main recompletion candidate for"many of th,e J wells dri!1ed in the Denver Basin. For this prospect
these zones are considered secondary objec.tives but should provide supplemental reserves.
The Church #22-1 well has comparable reservoir characteristics in this interval compared to,
other wells in the area that have produced iTom these reservoirs. Also, it is in an area very favorable'
for natural fracturing, which would enhance production ca.pability.
Pierre Shale
The Pierre Shale is a.n organically rich shaie that is thought to be the main source rock of
hydroc.3rbons fot'the deeper Cretaceous reservoirs. The Pierre Shale is not normally considered a
conventional hydr0c.:u:bon res~oir .. However, the unique location of this prospect has enhanced
the possibility of a very thick., natural1y fractured section of the Pierre Shale. If this formation
proves to be highly tracrured as indicated by seismic data, trapped hydrocarbon reserves could be
more than 75 million barrels of oil under the prospect area. Even though the probability for this
large reserve is not certain, it is a very attractive section that must be driHed prior to reaching the
deeper CretaC-..""0us reservoirs. It is a zone with an extremely hig~ potentia.l which deserv'es
immediate attention.
ECONOJv11CS
Three economic scenarios were run for this prospect. Ca.se A projected reserves and cash
Oow from al1 potential reservoirs for 50 productive wells within the prospect ana. Case B projected
reserves and cash flows from the J, Dakota and Lyons reservoirs for 2S productive wells wltrun the
productive area. Case C projected reserves and cash £lows for a single well completed in the J and
Dakota reservoirs, The economic output for the tnree cases is sr.o'Wn in Fig\li'es 6a, 6b, and 6c.· The
following table summarizes the economic proje.ctions for the 3 cases.
GrossGrossOil
G2..sDiscounted .Investment
Reserves·ReservesCash FlowNumber
(Thousand(Thousand. (Million(ThousandCase
ReservoirsOfWe11sDollars)Barrels)SCFJDo11ars)
I
Pierre., J, Dakota,I IA
Lvons, Code!lINiobrara 5042.00036,800131.600258,300B
J Dakota., LyonsI25 I25.500 14,70059 20098,700IC
I J, Dakota 157525850297.
MARKETS
When the Church #22-1 weB was dri!1ed there was no convenient pipeline at that time for
the gas production. Currently, an electrical generating plant is being built nearby which will burn
natura! gas and is therefore a r~dy market for the ga.s production from the prospect we!!. The oil
market remains strong due to the refineries loc.ated just north of the city of Denver.
Authored by:Van Kirk & Associates'
November, 2001
Plainview Oil & Gas Inc.8134 Logan StreetDenver, CO 80229..5840
Phone: 303-289-6300E-mail: L<;:.~[[email protected]! ..
December 30, 2005
POTENTIAL IDGH PROBABILITY MJNIMUM RES.ERVES AND ECONOMICSROCKY FLATS VENTURE
JEFFERSON COUNIT, COLORADO
INTRODUCTION:
Plainview Oil & Gas, Inc, (pOG!), has an acreage block in the Front Range Zone of FlankDeformation _.<\rea,located generally in the westerly portion ofT2S-R70 \V, 6th PM, JeffersonCounty, Colorado, that has the potential of encountering commercial accumulations ofhydrocarbon liquids in up to seven (7) intervals from in the Pierre shale formation, down throughthe Lyons sandstone formation. This "Critique" only covers the possibility of a high probabilityoccurrence of the basal Crmceous interval, known to be present in the subsurface under POGI's#1 State 16-4 suspended test we\!, located 460 feet snl and 460 feet ewl of Sec. 16, T2S-R70W,6th P:M, Jefferson County, Colorado, from a depth of approximately 8,600 feet below ground levelto a depth of approximately 9,550 feet below ground leveL
LOGIC:
The "Logic" developed for use in this "Critique" contains two (2) components; theprobabil1ty of the actual occurrence of the projected intervals in question in the basal Cretaceousformation (the subsurface rocks under the well site) and the probability of what kinds-offluid(s)may be in the potential void space that will be found within these reservoir intervals. An ancillarycomponent in this discussion will be "how" these potential hydrocarbon reservoir fluids will reactto depletion mechanisms involved in their subsequent production histories.
POTENTIAL FORMATION AND RESERVOIR INTERVAL OCCURRENCES:
It is logical to predict, before the fact, that the gross, approximately one-thousand (1,000).foot thick, basal Cretaceous formation, with up to five (5), projected void space hydrocarbonintervals, is present, based on the following three (3) bits of information:
1. An approximate thirty (30) mile long Electric Log Cross Section, from theSouthwest portion of the Wattenberg Field, under the Rocky Flats Area inquestion and on to the Soda Lakes Field (discovered in 1952 - nowabandoned), located southeast of Morrison, Colorado.
2. The physical, surface presence of this Formation, occurring in the"Hogback"outcrop, located about two (2) miles West of the POGI block of acreage.
3.. The reflective presence of this FOffilation in the DOE's, 2-D, dip-configuredSeismic Line, traced in a southwest-northeast azimuth, directly across thePOGI block of acreage.
1
The five (5), potential, high degree of occuning, reservoir intervals, within the basalCretaceous formation and their projected gross ultimate hydrocarbon reserve, are as [ollows:
Basal Cretaceous Formation
(40 Acre Spacing)
Est. Depth "Footprint"(GL meas.- ft.) .
Zone
Niobrara chalk
Ft. Hays Is/Coden 55.'T' sandDakota (Plainview) ss.Lakota (Lytle) ss.Morrison formationRTMD
Totals
Est. Oil Rec.(gr. bbls.)150,000 , ..
7,50025,00050,00025,000
257,500
Est. Gas Rec.(gr. mcf)150,000225,000750,000
1,500,000750,000
3,375,000
8,6008,8509,2009,3509,5009,5509,600
Silo Field, WYWattenberg Field
"
""
NATURAL FRACTURING EFFECT(S) ON RESERVOlR PERFORMANCE:
The POGI acreage block is located in the Front Range Zone of Flank. Deformation Area,at the intersection ofthe Golden Thrust Fault Complex with the Idaho Springs ~ Ralston ShearZone (the Colorado Mineral Belt Trend). The Golden Thrust Fault Complex, primarily resultedfrom the tectonics involved with the Laramide Orogeny; ie; the Rocky Mountains, mountainbuilding process. At the approximate same time, the deeper, pre-Cambrian, Idaho Springs Ralston Shear Zone Feature was "r~uvenated", resulting in massive crustal movement in thisgeneral Area., in three dimensions (lengthlwidthlheight). This resulted in a well defined, fracturezone trend area, in a "fairway" con:figuratio~ trending almost straight North-South, parallelingthe ''toe''ofthe Mountain Front; a fTacture "location luxury", not often found in the "Oil Patch" ingeneral!
This directed, massive, natural fracture Continental Event, with attendant pattern, winhave great positive effect on reservoir performance in. aJl of the potenttaJ hydrocarbon intervalsexpected to be penetrated in the deepening operation in POGI's #1 State 16-4 suspended testwel!.
This massive and eX1ensive, natural fracturing will create, by its' very nature,
permeabiJities that will be in the d 'Any's, with reservoir aniostropy's of considerably < J. Thiswill advantageously affect gross ultimate recoveries and aHow for high, "steady state"hydrocarbon production rates for wells completed in these intervals. The reservoir mechanismswill be gas cap e.xpansion, gravity and solution gas drive(s). In this Area of the D/J Basin, therewill be no free water productiqn_ Therefor, the productive scenario will allow for depletion ofthese hydrocarbon reserves to be programmed to a twenty (20) year productive life.
2
GENERAL ECONOMICS:
All ofPOGl's properties are eighty (80)% NRI leases. POGI prescntly owns or controls2,123.04 acres, more or less, in the Area. The Venture Property will be developed on forty (40)
acre spacing. The mixed, associated and free gas production, will have ,an heating value ~hat willvary from 1100 to 1300 btu's.lst'd. cu. ft. and contain four point five (4.5) gpm of LPG products.
In order to produce free hydrocarbon liquids from this Property win require theconstruction and installation of a cryogenic gasoline plant to produce a required "tailgate"product with a heating value of865 btu's/st'd. cu. ft., to be fungible with the gas in Xcel's, 6",town gas line market outlet. The "shrinkage factor" through the gasoline plant process will befifteen (15) %. The gravity of the produced, free hydrocarbon liquids recovered at atmosphericconditions from the wells in this Project, will be 44° API, at sf d. condo Therefor:
2.123.0440
= 53,075 productive forty (40) acre locations
all Recoveries:
257,500 (0.80) (53) = 10,918,000 net gross bbls.Plant "Tai1gate" Gas Recoveries:
3,375,000 (0.80) (0.85) (53) = ·121,635,000 net gross mef.LPG Product( s) Recoveries:
3,375,000 (0.80) (53) (4.5/42) = 15,332,143 net gross bbls.
The net gross (to the WI) cash flow stream (assuming $60 oil and $) 0 gas, unescalated undiscounted and before all taxes and operating expenses), would be:
Oil Revenues:
10,918,000 ($60) =Plant "Tailgate Gas" Revenues:
12],635,000 ($10)LPG Product(s) Revenues:
15,332,143 ($60)
$ 659,080,000
1,2] 6,350,000
919.928.580
TOT ALS =
The estimated gross capital costs to develop this total Venture Property may be:
Gross Capital Costs of Producing Wens. complete:$1,500,000 (53) = $ 79,500,000
Gross Capital Costs of Cryogenic Gasoline Plant:6,000,000
Contingency & Misc. EXRenses (15%)::
TOTALS
3
12.825.000
$ 98,325,000
Therefor:
Net Gross ROI;;;;;$ 2,795,358.580$ 98,325,000
28.44/1
Assuming a twenty year productive life and "steady state" production rates, the net grossPay-Out would be:
$ 98.325.000 = 255.94 days Of 8.42 months$ 2,795,358,580/7,305
The gross daily average production rates would be:
Oil:
10.918.000/0.80 = 1,869 gr. bbls.lday7,305
:Plant "Tailgate" Gas:12L635.000/0.80 = 20,814 gr. mcfi'day
7,305LPG Products:
15,332.143/0.80 ~ 2,625 gr. bbls.lday7,305
COMMENTS:
It is interesting to note that there will be more LPG liquids recovered ITom the cryogenicgasoline Plant through-put gas flow stream, than will be produced as free oil production ITom allof the fifty three (53) productive wens in this "Critique", in tms Venture Area! This demonstratesthe "cash cow" potential ofthis installation and further demonstrates the ''value'' of the UPRRrailroad spur line that is contiguous to the driIl pad location for POGl's #1 State 16-4 test well.Also, Xce1's 6" Market line is located a.bout five-hundred (500) feet, North of the drill pad. Thefree oil production could either be trucked to Suncor's, 90,000 bbllday through-put Refinery,located about :fifteen (15) air miles, East of the location. or shipped by rail to Market.
It should be remembered tMt this "Critique" does not take into account the fact that there1S a very excellent chance of obtaining major hydrocarbon reserves in the shallower PieITe shaleinterval (that will be penetrated in the deepening operation of testing the basal Cretaceous section)and in the deeper Permo-Pennsylvanian Age, Lyons sandstone formation, which occursapproximately eight-hundred (800) feet deeper, in the section; ie: at a RTVMD of 10,450 ft.
db~./~
4
Exhibit "A"
Plainview Oil & Gas; Inc.
Rocky Flats Block
T2S - R70W Jefferson County, Colorado
Lease DescriptionAcreageExpiresRemarks
City of Boulder Open Space
E/2 See,S & NE/4 NE/41,483,04May 21, 2009Preferential Right to Lease
Sec. 17 SW/4Sec, 5; El2
Document, Rec. No,
WI2 Sec. 8; part ofEl2
F0876970 - Surface
SWf4 Sec. 8; Sec. 17 (less
access denied
part ofW/2 NW/4) ; part of Sec. 18, part ofNW/4 &
'.,
part ofN/2 NF/4 Sec. 20State of Colorado
Section 16 (aU)640,00August 12, 2006Oil & gas lease, Rec, No,F0003599 State Lease No.OG 93/I140-S. Surfaceaccess restricted
Total
2,123.04
(2) Area Of Mature Source RocksC.1. = 500'
Figure 14. Structure on J Sandstone at present, datum Is sea level.after Tainter, 1984
POG fig. 1
ERAAGE1-1 FORMATION.. '.0_. "u 00 LOWERo~ GREEN MOUNT AIN
N lD ~fJ~ .:-. ~._. ,_
~>
0TERTI ARYz w
.- c: uEa>
O~
alCI o .'-::7'~-==:,'kdaDENVER-ARAPAHOE~ 0 t:\J •aI ~ - " .•. - ................JO
o __
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R,ALSTONCREEK0 ~ b>, 'y 1 PLL YKI N S
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U
z<z<>,..J>I/)
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uoNo\/1
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uoNou.:
after Leroy 1955 POG fig. 2
THE COLORADO LINEAMENT
30 hi I20!
40!
\1
1\
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~00
fI,
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o •..
4'
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0
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~
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~
~OIL FIELD
PRECAMBRIAN
...- -",...-""""
HIGH ANGLE FAULT
I ".~-:,;.-;-I"B A S E OF FOX HI L L S
THRUST FAULT
(TEETH ON UP SIDE)
EXPLANATION
'BASE OF"CENOZOIC
r:::=::J
'L-1-'PRE-UPPER CRETACEOUS
® SKIN GULCH SHEAR ZONE
(~MOOSE MT. SHEAR ZONE
o IDAHO SPRINGS-RALSTON SHEAR ZONE
CD DIABASE
Figure 4. Generalized tectonic map of northeast Front Range foothills and adjacent Denver basin, Colorado. Compiled from varioussources, Including Burbank and others (1935)•. Fisher (1946), Lovering and Goddard (1950), Hunter (1955), Parker (1961),
Spencer (1961),Abbott (1970), Punongbayan (1972), Nesse (1977). ft W 1980a er arner,POG fig. 3
E. jE~~~~~~_-_5_0_0_0Figure 5. Golden fault structural models: A-Ziegler(1917, Fig. 6), through Golden; B-Stewart (1953, Plate10), near Golden Gate Canyon, SP indicates shotpoint; CBirdsall (1956, Fig. 19), along Golden Gate Canyon; DBieber (1983, Fig. 5), near Ralston Creek; E-Money(1977, Fig. 14C), one mile north of Golden Gate Canyon.Ty=Tertiary; Mz=Mesozoic; Pz=Paleozoic; pC=Precambrian.
pz
6000
~a Level
EAST+APPROXIt0.4ATE SCALE
1" '" 10.000'
after Domoracki, 1986
POG fig. 4
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JOHNSON ITO 9655'
-1-
GREAT BASINSTO 9587'
\j /
NE
Kp
-Yi- _
+:5000 FT.
SEA LEVEL
-5000
-(Q
01
Figure 6. Geologic cross-section at Soda Lakes (fromBerg, 1962a, Fig. 4)
...
Triangle
Dakota
Lyons
~Golden Gate Canyon. HorizontalMF-mountain front; GF-surface trace
bend. after Domoracki, 1986
__ [A:..J.
~Figure ~7. Final stacKscale is compressed 2:1.of Golden fault; LB-line
MF OF
-\~: \~17(q ~.,: -\
I.., J •. :.
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POG fig. 6
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Higrated stackwith 80 ~ or stacking velocities.Interpretation by R.R.Ray
Figure 18. Golden Gate Canyon. Higrationafter Domoracki, 1986
POG fig. 7
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Figure 21. Final stacks - state Highway 72.is'near 1:1. after Domoracki, 1986
Display scale
Figure 21. Final stacks - state Highway 72. Display scaleis near 1: 1. after Domoracki, 1986. Interpretation by R.R.Ray. See also Plate 4."Uo
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76° E dip Fox Hillsoutcrop
~
K pierre
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-.c 000 n
-5000 It
-4000 ft
-5000 ft
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I ,I.'- /
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/'\ P-C BASEUENT , \. ,. '\ ,. " " '" /' " /",. " '" ,,/ \ ~ •. "" .•. \ ,/ '\
TRUE SCALE
z<x: :.:.:.LYON5 55:":-: : ...:,- .
~ SAT ANKA FMwa.,
\NGLES\DE FM
A8 to 1
NW VERTICAL EXAGGERATION
~ Member--.- -park creek La
L YK\NS FM
~I PENN CARBONATESz<x:>
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poudra Mbr
Park Crk Mbr
Forel/a Mbr
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10 mv
Pf 9201-9210, Pumped 317 BOPD
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Figure 2. Typical electric log Pierce field area showing Lykinsand Lyons Formations (California Co. # 1 Priddy, NW SWSec. 23, T8N, R66W).
after Sonnenberg, 1984
o 11.41I
Figure 5. Structural cross section through Pierce structure. Notehow subtle the structure is on true scale cross section.
o
:••••WY.i
..•.......................-1- 41-
301
tNI
10 20I I
mi
ol
[D
~tn-2
c o.ARE A of
~F IG.12
9DENVER
o 10 20 30 40 50I I I I I I
km
Figure 1: Index map showing area of Figure 2 from Stone, 1969, Pl. 1, with New Windsor anticlinal
axis added. R,12 is the "Pierce,Black Hollow" right-wrench zone, here called the Windsor Fault. R-ll IS
the "Colorado Mineral Belt." after Stone, 1985
POG fig. 11
Figure 2: Seismic structure map on the Lyons Formation of the Pierce-Black Hollow-New Windsor oil
field complex, Weld County, Colorado. after Stone, 1985
POG fig.12
Weimer and Sonnenberg
TETON ENERGY CONTINENT AL MARTIN BRYAN
Sequences Formations Members HE SE 13; is - 70W SE HE SW 5; is - 69W SENE2; 1S-69W NE NW 13; is - 68W
- Ft. Hays
~ CARLILE
THLH
TnLsr
-~-~•.. -
>-5
W AHEN
4
3Smok yHill
Lincoln Ls.
Hartland Sh.
Bridge Creek Ls.
x - BENTONITE
za:oJ:Zwwa:c
PIERRE
NIOBRARA
GRANEROS
5
4
3
Tn::::::MOWRY
MUDDY (J)LSr:2SKULL
CREEKTSa:~PLAINVIE\Iun:1
LYTLE~~ MORRISON
\JoG)-
(Q
-"c.v
Figure 15. East-west electric-log section from Eldorado Springs outcrop (modified from MacKenzie,1971) to east side of Wattenberg Field (see Figure 3 for section location). Lithologic symbols for surfacesection are shown on Figure 7. after Weimer and Sonnenberg, 1989
DUDLEY D. RICE
\\j'oo.
olr
o
50 kilometersJ1
30 miles
after Rice, 1984
FIgurE! 1. Index map of Denv&!' basin showing present-<!ay depth of burlal to top 01 Niobrara Foonat!oo (modified Irom Shurr, 1980~ Coritourvalues are In meters. Locstlon 01 wells Irom which gas samples were analyz&d are labeled by numbers and Irom core sampleswere analyzed are labeled by letters ..
POG fig. 14
WYO
Plainview ProspectGradients
AREA OF MATURESOURCE ROCKS (TAINTER, 1984)
f).'
KANS
F/100 It
, Figure 24. Geothermal gradients in n-cirthernportion of Denver Basin, in FO per 100 ft.C.M.B. is Colorado Mineral Belt, a Precambrianstructural trend with a zone of Tertiary intrusions, exposed in the Front Range Uplift.after Weimer & Sonnenberg, 1989.
POG fig. 15