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spectrumgeo.com MULTI CLIENT l SEISMIC IMAGING
IN THIS EDITION...
Mexico: An Old Frontier in a New World..............................................
Bay of Biscay: Vintage treasure...........................................................
Deepwater: Leading the fightback in the oil industry?....................
Africa: NW Coast and Somalia..........................................................
Cygnus 3D NW Shelf Australia...........................................................
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Oil ExplorationFuture
THE
Future OF
Oil Exploration
sixty six Q1 2016
The outbreak of hostilities between new unconventional oil supply and giant legacy oil production represents a violent threat to the sustainability of the conventional oil exploration industry.
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Mexico, Bay of Biscay
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It’s easy to forget that, back in the early days of modern oil exploration Mexico accounted for 25 percent of the world’s output of petroleum, making it the second most important producer after the United States in the early 1920’s. However, over the next decade Mexico’s oil output declined dramatically due to both political and technological changes. It would take the country over 50 years to reach the same level of output though it would never regain its market share.
During the last 75 years petroleum production in Mexico has been closed to outsiders, exclusively managed by state company Pemex. However, a plunge in output over the last decade lead Mexican politicians to pass an energy reform bill opening their country’s oil exploration to all in 2015.
With the re-opening of this crucial hydrocarbon region there has arisen a demand for high-quality exploration
tools, top of everyone’s list being modern seismic data acquisition. But with such a vast area to survey in a relatively short space of time Spectrum realised that a collaborative agreement between the world’s leading Multi-Client seismic data providers would provide its clients with the best solution.
During July 2015 Spectrum entered into a cooperative agreement with Petroleum Geo Services (PGS) and Schlumberger to acquire a modern, long-offset 2D data
program encompassing all the major hydrocarbon provinces offshore Mexico. This included those areas on offer for Mexico’s Round 1 in the Perdido Fold Belt, Mexican Ridges Province, Campeche Deep Sea Basin and will also provide seamless coverage across the Yucatan Platform tying to Spectrum’s extensive “Big Wave” seismic program in the eastern area of the US Gulf of Mexico.
At the time of the collaboration announcement Richie Miller, President Spectrum Inc,
Spectrum is confident this cooperation with Schlumberger and PGS will provide outstanding data to the industry...
Richie Miller, Executive Vice President, Spectrum Americas
‘’
commented: “Spectrum is confident this cooperation with Schlumberger and PGS will provide outstanding data to industry in a timely manner before Round 1 and future rounds to come.”
Acquisition of the survey offshore Mexico commenced in May 2015 with additional vessels joining in June and July 2015 to help in acquiring the large grid. The survey provides comprehensive broadband seismic coverage across the Gulf of Mexico, tying key wells in producing hydrocarbon basins and sampling emerging pre-salt plays. The strategically placed survey will help provide greater insight to clients preparing for current and subsequent licensing rounds.
Upon completion in Q4 2015, the Mexico survey comprised a total of 61,350 km with both PSTM and PSDM available for delivery to assist in the current deepwater license round.
As Mexico opens up it’s oil exploration to the world, a greater need for high quality modern seismic data is ensured
Squeezing Out the Details from Vintage Seismic
In 2015 Spectrum finalised the enhancement of legacy 2D data from the Bay of Biscay, bringing the total reprocessed dataset to 15,000 km. The reprocessing of these eight separate legacy datasets, all originally acquired with unique parameters, equipment and objectives into a consistent, high quality phase-matched dataset has allowed major advances in understanding play systems in this intriguing area.
Jake Berryman, Lead Explorationist for Spectrum in the Bay of Biscay, commented on the enhanced data, “We are now imaging critical play elements on both a regional and prospect level that are just not visible on the legacy dataset. Improvements within the resolving power of the seismic have squeezed out even the most subtle details, which would have previously been overlooked! The up-lift on the reprocessed data makes these lines the weapons of choice for
any explorers who are chasing oil plays and understanding here.”
The data covers the basins running off the northern Spanish coast, and those off the western French margin. Offshore Spain, oil discoveries have been made and several gas fields produced from compressional structures in clastic and carbonate reservoirs. In the Offshore west France Basins, the new data reveals the dominantly extensional structural regime rich in faulted structural and salt tectonic plays where oil is the main resource.
Included in this enhanced collection of seismic is Spectrum’s “Atlantic Deep” dataset. This seismic data lies over the shelf and slope of the Northern Bay of Biscay and is already revealing the thick Jurassic rift sequences, describing a rich, deepwater play-system with implications for regional and conjugate fairways.
The Bay of Biscay is a proven oil and gas province barely explored to date. New seismic is drawing the oil industry to revisit this area with a focus on newly imaged structures and plays. Major oil companies have shown interest in the area with potential to drill new, deeper targets.
Well Tie 12,500 kmYucatan ~31,150 kmWestern Ridges 17,700 km
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Block information
Round 1 Deepwater BlocksContractOpen
2015 reprocessing Atlantic Deep2014 Reprocessing Bay of Biscay2014 Reprocessing Bay of Biscay
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In association with
MexicoAn Old Frontierin the New World
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BACKGROUNDSince the invention of marine seismic in the 1950s, oil explorers have been on a journey through a wilderness of hope, laying bare the geology of the world’s continental shelves and discovering the oil that is fuelling our civilization. In the last 10-15 years, increasing competition for an ever smaller prize on the shelf has compelled a courageous few companies to creep down the continental slopes looking for new plays and resources. Outside of the Gulf of Mexico, success has been episodic because the targets have predominantly been stratigraphic channel plays which cannot be fully de-risked pre-drill. A high oil price has been milked by high rig-day-rates such that UDW has earned an expensive cache as a risky game for companies with deep pockets who don’t have to win every time. However, after the oil price fall of 2014, supply of UDW rigs has exceeded demand so that the cost of UDW drilling is significantly reduced. Indeed, the current low oil price environment may be the only time it makes sense for high risk UDW drilling. Intriguingly though, we suggest here that if we complete the journey into even deeper water, and reach the basin floor of the Atlantic, we will find large, low risk prospects, absolutely ripe for exploration in the current and near term climate.
The first question an explorer asks of a new province, of which UDW is no exception, concerns the probability ofthe presence and effectiveness of a source rock. Even cursory review of the National Oceanic and AtmosphericAdministration (NOAA) global maps of sediment thickness in the world’s oceans reveals that the world’s continents are frequently surrounded by thick sedimentary sequences, and these sediment filled basins can extend hundreds of km from the shelf. In fact there is an equal area above and below 3,000 m of water in the global oceans where more than 3 km of sediment have been deposited (Figure 1). On the passive southern Atlantic Margin this is important, as below this sediment lies nearly ubiquitous Early Cretaceous source rock. When Gondwana split apart in the Early Cretaceous, the rift was initially sub-areal. Syn-rift accommodation space was filled with fluvial and lacustrine clastics, including source rocks, within a myriad of axially developed small, restricted but interconnected basins. Rapidly, the Aptian Sea entered the rift leading to the deposition of marine sediments on the now drifting source rocks margin – or behind locally significant reflux barriers – salt basins (Hodgson and Intawong, 2014).
With restricted access to the global ocean both to the
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Future of Oil Exploration (at oil)north through the Brazil/Sahel transform, and the south through the South African/Falklands transform, the Aptian basin was predominantly a salt-water inland sea with restricted anoxia promoting the preservation of organic rich source rocks (Figure 2).
The ubiquity of Early Cretaceous oil prone source rock either in the syn-rift lacustrine package (e.g. Lung-Chuan, 1994; Dingle, 1999), for example the Melania and Kissenda of the Southern Gabon salt basin, or the marine Aptian source (Namibia, Northern Gabon, Sergipe Basin) is evidenced now by multiple wells in multiple basins on the southern Atlantic margins, and by seismic correlation of conjugate sequences (e.g. Van Der Spuy, 2003; Hodgson and Intawong, 2013). The impact of this ubiquitous source rock is profound as it lies at the base of the post-rift package, allowing us to use the NOAA sediment maps to predict, on a regional scale, where this source rock is likely to be buried deep enough to be mature for either oil or gas generation. The nature of the crust upon which the Early Cretaceous source rock sits varies along the margin, and heat-flow from the basement and geothermal gradient through the sediment pile is therefore also likely to vary. The uncertainty in geothermal
THE
The outbreak of hostilities between new unconventional oil supply and giant legacy oil production represents a violent threat to the sustainability of the conventional oil exploration industry. Coruscations from this battle starkly illuminate the explorer’s paradox; an imperative to focus on plays that have low risk and huge potential, whilst having to seek these within mature basins on well explored continental shelves. Where can we find sufficient prospects with dramatic enough scale to compete in the unconventional vs legacy giant wars?
Using 2D seismic acquired in the last two years on the Atlantic margins, we will examine the play systematics that manifest in Ultra-Deep Water (UDW) low risk prospects on a scale hitherto unimagined that will ultimately win conventional’s fight back to be the future energy supplier of choice
future of exploration
gradient however is relatively small, varying between 25 and 35 °C per km of for sediments over continental and attenuated continental crust, and 20-25 °C per km over old (Early Cretaceous) oceanic crust. It is a simple task then, for source rocks that will start to generate and expel oil between 90 to 100 °C, to calculate that 3 to 4.5 km of burial is all that is required to establish the basis for a working hydrocarbon system.
Crude as such a set of assumptions might be, it allows us to propose areas or basins that are likely to have a mature source, and ones that would require special pleading to establish a working model. For example, if a basin has thin sedimentary cover then it would require a complex history or high heat flow to make a basal source kitchen generative, all of which would need to be established or refuted on a local argument scale.
We have identified the areas of UDW along the south Atlantic margins that have a regional source rock, and identified where the kitchens for both oil and gas generation lie under a variety of boundary conditions. The surprising result of which is that in fact much of the South Atlantic margins below 3,000 m of water both on the
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Fig 1 (left and far left): Equal area above and below 3,000 m of water in the global oceans where more than 3 km of sediment have been deposited.
Fig 2 (above): Aptian basin was predominantly a salt-water inland sea with restricted anoxia promoting the preservation of organic rich source rocks.
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South American and West African margins, in the lower slope and abyssal plain setting, appear to have potential for a working hydrocarbon system.
RESERVOIR AND TRAPThe next question to be addressed for this UDW province is whether there is the possibility to encounter reservoirs and seals, and trapping structures within a basin. Actually, for the passive margins of the southern Atlantic this is where the seismic story gets really interesting. These passive margins were developed in the Early Cretaceous period, and subsequently have been inundated by clastic sediments being eroded from the continental hinterlands. On top of the Early Cretaceous syn-rift and marine source rocks 100 million years of Late Cretaceous and Tertiary clastics have been deposited, the sediments issuing from deltas along the continental margins. Famously these depocentres have moved with time, both as lobe switching within delta complexes and in physical location due to headwater capture and river migration. In areas of the shelf temporarily distant from clastic input, carbonate platforms developed, however these are rare beyond the shelf edge except in super starved parts of the margin. On the continental slopes of the South Atlantic, however, this heterogeneous Late Cretaceous to Tertiary fabric has one common characteristic – the slope is dominantly mud-prone, cut by channels or canyons that provide the conduit system for coarse clastics to be transported from the shelf to the abyssal plain. Of course, in the pro-delta setting, slope sediments can be more complex, including mass transport systems, gravity slides and other phenomena. However, the slope is largely the domain of fine clastics and muds, cut by constrained channel systems transporting coarse clastic down the slope.
In the Atlantic, most of the deep and ultra-deep drilling to date has focused on this slope domain. Although notable successes have been made in hybrid channel-structural and channel-bypass traps, many prospects drilled have been stratigraphic constrained channels that are simple up-dip pinch out in nature. Although modern seismic technology has proved to be very effective at delineating the channels, risk reduction of purely stratigraphic updip traps by identification of sedimentary by-pass zones has proved difficult as the identification of potential thief zones (and even more difficult – the absence of such) is mostly beyond seismic resolutions capability. Additionally, being steeply dipping constrained channels, significant hydrocarbon columns need to be intercepted to generate significant prospective resources. Consequently constrained channels with up-dip pinch-out plays are not only high risk, but often relatively low reward.
Yet the UDW prize does not lie on the slope in constrained channel systems, it lies on the basin floor in the associated basin floor fans. In the basin floor play discussed here,
coarse clastics have been transported to the abyssal plain and deposited as large unconstrained fans over huge areas. Basin floor fans have one particular characteristic that sounds so self-evident it is hardly worth mentioning – eventually, no matter how big the sediment source feeding the fan, if one goes far enough offshore – the turbidite will pinch out. As it turns out, this is far from unimportant. A classical model of a slope channel and basin floor fan suggests (Figure 3) that the basin floor fan will have a similar trapping issue to the constrained
channel i.e., that updip seal will be risky and will not be able to be de-risked with seismic data. This is evident on seismic lines that are displayed conventionally in two way time (Figure 4). However, when depth converted (using stacking velocities) or when processed by migrating pre-stack in the depth domain (Figure 5), the true geometries of the basin floor fan are revealed.
What becomes apparent is that the basin floor fans deposited at the base of the slope overlying directly the
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mature Aptian marine source rock, are in fact not dipping out to sea but dip back towards land. This occurs for two reasons, firstly because of the sediment loading on the margin of the basin floor causing differential subsidence to the basin further out-board, and secondly due to the continental margin being attenuated continental crust or oceanic crust that is older and cooler than the oceanic crust further outboard. The colder the material is the denser, and this differential density leads to the near land crust sinking further into the mantle to remain in buoyant equilibrium. Interestingly, these two controlling factors occur in exactly this way over most of the Southern Atlantic margins and therefore it is perhaps unsurprising that when these margins are viewed in true depth rather than two way time, the same geometry of fan trapping up-dip out to sea is observed.
Lateral fan trapping is either generated stratigraphically or by large wavelength undulations on the basement surface reflecting large changes in the loci of deposition discussed above, effecting the lateral loading pattern or variations in the style of crustal attenuation at the continent-ocean boundary and variations in growth at the spreading centre such as we observe on modern mid-Atlantic ridge. This geometrical relationship is formed on a plate tectonics scale, and again, unsurprisingly, it generates extremely large closures. Offshore Uruguay, we map potential 3-way dip closures, stratigraphically trapping up-dip out to sea over several thousand square kilometres. Although sand distribution will be heterogeneous within these closures, the resource potential, at relatively low risk due to the certain stratigraphic pinch-out seaward, and the location above mature Aptian source, is extraordinary. We have captured the schematic details in the model cartoon on Figure 6. Our first example is from the Pelotas Delta(s) of southern Brazil and Uruguay (Figure 5). However, the same geometric relationship can, however, be seen of PSDM profile from other basins on the margin – for instance the Sergipe Basin (Figure 7). Here, Petrobras has discovered more than 2 Bbbls recoverable oil in constrained channel systems. However, the down-dip basin floor fans with up-dip closure out board lie untested in open acreage. Proven Aptian source rock can be mapped extending far offshore below these fans. In the conjugate basins of West Africa, depth profile from Namibia and South Africa displays the same up-dip seaward geometry and pinch out relationships in the basin floor fans and the presence of underlying mature Aptian source rock was proven in the recent deep water wells drilled on the margin by HRT (Figure 8).
APPLICABILITY IN THE NORTH ATLANTICFollowing the recognition of a simple model for the prediction of mature early Cretaceous source rock in theSouth Atlantic, and a plate scale mechanism for generating very large low risk stratigraphic traps, we extended the
Fig 4: Apron Fans
Fig 5: Apron Fans base of slope
Fig 7: Sergipe example PSDM
Fig 8: South Africa Orange basinFig 6: Play model South Atlantic floor fans
Fig 3: Model of slope channel and basin floor fan
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study to other basins to look for analogues and understand the alternative models that need to be understood in varying situations. Offshore Mauritania depth profiles again reveal seaward up-dipping fan geometries similar to those seen offshore Senegal (Figure 9). Here, large quantities of coarse clastic materials have been transported (via constrained canyon systems being explored in the slope) into the deep basin loading the Jurassic oceanic crust generating up-dip trapping of basin floor fans. Two further aspects of this margin are worth mentioning. Firstly, steep, tight anticlines located in deep water offering a traditional fan or channel with 4-way close style of trap, and secondly in the seaward up-dipping fan play there is a new nuance to exploration regarding phase. Close to the shelf there is so much sediment that the Early Cretaceous or Jurassic source rocks are buried deep enough to enter the gas window. Further offshore and laterally from sediment source, with reduced burial, these source rocks are likely still to be in the oil window.
In Mauritania, two recent discoveries have been made on combined constrained channel and anticline plays similar to a feature seen offshore Senegal (Figure 10). The anticlines are curious, very thin and near vertical oriented shelf parallel. We currently interpret these as gravity driven ‘toe thrust’ features that key into remnant salt ridges above the basement. However, the abundant channels running down the slope offshore southern Mauritania that were targeted in the Tiof and Banda channel plays near shore, and are being successfully targeted in the current drilling campaign, are a testament to the volume of coarse clastics pouring into the basin in the Late Cretaceous and Tertiary.Down dip of these slope channels, we predict large basin
floor fans that have plate scale structural geometries showing up-dip trapping to the west. These are indeed visible on 2D seismic and are mappable as apron fans onthe basin floor over thousands of square km. Indeed on depth sections these display similar AVA responses to that seen over the reservoir intervals of the landward discoveries (Figure 10).
Offshore Mauritania, the loading and cooling of the Jurassic oceanic crust to the east is made more pronounced by the Miocene igneous province to the east, propping the eastern part of the basin up. This, and loading/cooling to the east develops the pinch out geometries for the basin floor fans and, coupled with the thick sediment cover ensures that the water depth even over the basin floor fans never exceeds 3,000 m. Curiously these basin floor fans lying in just over 3,000 m of water may be the most accessible giant prospects of this basin floor play scale in the Atlantic basins.
OUTSIDE THE ATLANTICThe model proposed for generating outboard dip closure for basin floor fans through plate cooling and sediment loading can be exported to other basins where significant sediment thicknesses over basement are observed. NOAA maps of sediment thicknesses in the global oceans indicate that there are some very extensive areas below 3,000 m with more than 5 km of sediment over basement in SE Asia, for example the Tertiary deltas of the Indus, and Bengal Basin. However, there is a significant difference in the play to that in the South Atlantic, in that SE Asian Tertiary deltas deposited on to oceanic crust predominantly in destructive margin settings need not have an underlying source rock. Instead, these tertiary deltas are considered
to be self-sourcing. That is, the source for hydrocarbons is organic material brought down to the basin floor along with the coarse clastic reservoirs. Such a mechanism is invoked in the Mahakam Delta of Eastern Kalimantan where self-sourced channels (in antiformal gravity driven structures) and basin floor fans are buried and mature producing a variety of fluids from biogenic gas to light oil. Down-dip of the vegetation rich Tertiary deltas of SE Asia, self-sourcing hydrocarbon systems will develop on the basin floor, charging turbiditic fans. The model we have discussed above for generating up-dip seaward fan trapping is based on the South Atlantic passive margin example where a combination of sediment loading and plate cooling near shore creates the near-shore synform, and outboard up-dip fan traps. Within the more complex plate geometries of SE Asia, including the accreted micro-continent terrains there are often complex relationships between the orientations of; boundaries (passive or destructive), plate ages (and thermal subsidence) and sediment loading. There are therefore margins and delta systems that are exceptions to the general principles discussed for passive margins either in their entirety or in part. For example, the Bengal Basin has a north to south depositional orientation from the Ganges and the Brahmaputra Deltas, over a north west to south east propagating younger oceanic crust. However, to the east, along the Rakhine margin, strike-slip accretion and overtrusting of the oceanic plate provides an additional loading mechanism to affect the plate scale geometry. Each case needs to be considered from the perspective of the plate orientation, sediment loading focus and local tectonics, however, the general model for generation of large prospect geometries beyond 3,000 m suggests that Ultra Deep Water of not
just the South Atlantic, but many of the world’s oceans has this same extraordinary potential that we have not yet begun to explore.
SUMMARYWhilst the battle between unconventional oil and production from giant legacy oil fields rages around us, conventional exploration in conventional places is unlikely to provide resources on a scale large enough to re-dominate energy supply. This is an inadequate strategy because neither increasing competition for well-worked exploration space on the explored shelf, nor continued exploration of constrained channels on the slope will generate enough commercial success at low cost to compete with new, unconventional sources of energy.
However, conventional oil and gas exploration need not diminish. A play style is proposed here that was developed on the passive South Atlantic margins where a ubiquitous source rock may be proposed, but is exportable with care to many of the world’s oceans. This play style manifests basin floor fan clastic prospects in seaward up-dipping structures generated by plate scale processes. These prospects are large and low-risk however, were it not for the fortuitous drop in oil price in 2014, and consequent oversupply of UDW drilling units, these may never have been drilled. Now, the market conditions are right to finish the journey into the deep, begin the fight-back of conventional oil, and provide the energy future of the future.
This article, written by Spectrum Geoscientists Karyna Rodriquez,
Neil Hodgson, Ashleigh Hewitt and Anongporn Intawong was
published in the February 2016 edition of First Break magazine.
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Fig 10: Similar AVA responses to that seen over the reservoir intervals of the landward discoveries
Fig 9: Offshore Mauritania depth profiles reveal seaward up-dipping fan geometries similar to those seen offshore Senegal
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It began with Senegal oil discoveries (FAN-1 and SNE-1) by Cairn Energy and Capricorn in 2014. These opened up the area to a new play concept and de-risked the deep water channels and basin floor fans along the deep water NW African Margin. They highlight clastic plays within this margin within prominently different play settings.
The SNE-1 well is located on the Mesozoic shelf edge at a water depth of 1,150 m. The well discovered 32° API in Albian deltaic sandstones with excellent reservoir in a 95 m gross oil bearing column (source: Cairn). These sandstones overlie the deeper target of the karstified and fractured Aptian carbonate platform which was the primary target; however, no hydrocarbons were encountered. The FAN-1 well was drilled further down the slope (1,437m water depth) and found oil ranging from 28° to 41° API in 29 m of net oil bearing reservoir of Santonian turbiditic basin floor fan play. This basin floor fan stratigraphically pinches out on the Senonian Unconformity.
The Senonian Unconformity is a regional unconformity and is clearly recognisable on Spectrum 2D seismic offshore The Gambia, further south of the Senegal discoveries. Analogues to the FAN-1 and SNE-1 discoveries can be applied here in the shelf break and slope settings. A stratigraphic pinch out play associated with structural closure shows bright amplitude reflectors which represent potential basin floor fans at Santonian and younger intervals. Multiple leads within these Late Cretaceous intervals have been identified. These show a noticeable continuation trend of Cairn’s
The African North-West Coast
prospects and leads further south. On the lower shelf of the Mesozoic platform setting, structural closures and bright amplitude reflectors within the Albian interval are also recognised and this is in a similar setting to the SNE-1 discovery.
Furthermore, similar plays to those associated with the Senegal discoveries have also been recognised on Spectrum seismic data offshore Guinea Bissau where, to date, the deep water plays have not been tested.
In 2015, Kosmos Energy made another play opening gas discovery at the Tortue-1 well offshore Mauritania. This Cenomanian interval discovery, drilled in 2,700 m of water depth, encountered 107 m of net hydrocarbon pay in the Lower Cenomanian sands (source: Kosmos website, 2015). This discovery has been recognised on Spectrum seismic with a bright amplitude seismic reflector.
Kosmos Energy’s second gas discovery, Marsouin-1, is located 60 km north of the Tortue-1 gas discovery, offshore Mauritania. The discovery was made in 2,400 m of water depth and targeted the Late Cretaceous channel reservoirs within a 4-way dip-closure charged by Early Cretaceous source rocks. The well encountered 70 m of net gas pay in the Cenomanian sand reservoirs interval (source: Kosmos).
These recent discoveries have significantly de-risked Cretaceous clastic plays along the NW African margin and open up the outboard petroleum system here. Spectrum 2D seismic data has shown that this area offers substantial continuation prospectivity in the deep water, including a diverse range of plays and fairways and number of deep water fans and shelf leads. The can be little doubt that there remains great potential for further gas and oil discovery across this margin.
east and West africa
Recent hydrocarbon discoveries in the deep water offshore Mauritania and Senegal (image below) have opened up new plays in the NW African Margin which have, in turn, begun to generate greater interest in hydrocarbon exploration here.
Unlocking Offshore SomaliaFollowing the installation of the Federal Government in Somalia, the country has begun to enjoy a more optimistic outlook and hydrocarbon explorers are starting to return to the region.
prospects. Streamer lengths of 10,050 m will be used in order to adequately record information at all offsets, further assisting imaging of the underlying syn–rift geometries. In addition, the new seismic complements 20,000 km of existing data that had been acquired in 2014, which is also available from Spectrum.
At the signing ceremony the Minister of Petroleum and Mineral Resources, His Excellency Mohamed Mukhtar Ibrahim, said “This historic seismic data agreement will be the resumption of the exploration program of the hydrocarbon reserves of our country, which will be a turning point for the economic development of our nation.”
His Excellency Omar Abdirashid A. Sharmarke, Prime Minister of the Federal Republic of Somalia who concluded the event stated “Seismic data can lead to good decision-making and a guided exploration strategy.”
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TiofC-4-6
Sinapa 2
Fan 1
Aigrette 1
Tevet 1Chinguetti
Labeidna 1
DomeFlore 1
SNE 1
Faucon 1Marsouin 1
Fregate 1
Banda
Cormoran 1
Tortue 1
Merou 1
Pelican 1
S i e r r aL e o n e
C o t ed ' I v o i r e
M a u r i t a n i a
M a l i
S e n e g a l
G a m b i a
L i b e r i a
G u i n e a - B i s s a u
G u i n e a
FIGURE 1: NW African discoveries in relation to Spectrum 2D seismic coverage
Legend
Mauritania repro 1,600 kmMauritania VER01MT 3,887 kmMauritania VERMAU 01 PL 444 kmSenegal VER01 MWT 1,727 kmGuinea Bissau 2012 reprocessing 3,043 kmGuinea Bissau PGB04 3,212 kmGuinea Bissau VERGB 81 repro 3,855 kmGuinea Bissau VERGB 88 repro 1,844 kmGuinea Bissau VERGB 99 160 kmGuinea BissauVERGB 82 repro 4,035 kmGuinea Bissau VFGB 00 3,515 kmGuinea VERGC 98 897 km
Somalia 2015-2016 up to 28,000 kmSomalia 2014 20,500 kmLicensed areas
Legend
Somalia has three main oil producing basins - the Permo-Triassic, Jurassic and Cretaceous basins. All of these carry significant exploration potential, but remain underexplored due to previous above ground risks; it is only now that the potential of these basins can begin to be unlocked.
As part of the first key steps toward stimulating exploration with this region, Spectrum entered into a Multi-Client master co-operation agreement with the federal government of Somalia in September last year. The agreement paved the way for Spectrum to acquire approximately 28,000 km of long offset 2D seismic data offshore south Somalia.
The carefully-designed acquisition program will be acquired at depths of between 30 m – 4,000 m, resulting in coverage over the shelf, slope and basin floor with dip, strike and recording time intervals suitable for defining a range of leads and
Together, the seismic surveys offshore Somalia will allow the in-depth study of hydrocarbon prospectivity offshore Somalia, which lies in close proximity to major discoveries on the East African margin. Notable successes to date have been the discoveries of multi-billion barrel exhumed oil fields within the Permo-Triassic basins of Madagascar and the huge undeveloped Permo–Triassic gas fields of the Ethiopian Ogaden basin.
Significant discoveries within the Jurassic have been made onshore Yemen and proof of this Jurassic petroleum system has been established in northern Somalia with the drilling of the Standard Vacuum 1959 Daga-Shabel discovery well. The Cretaceous petroleum system has also proven to be a strong producer in South Sudan and is only lightly explored in southern Somalia.
Modern processing algorithms will be applied to the raw data. This will allow optimal imaging of the steeply dipping extensional and compressional features in the survey area and illumination of subtle amplitude anomalies.
His Excellency Mohamed Mukhtar Minister of Petroleum and Mineral resources Somalia
‘This historic seismic data agreement will be the resumption of the exploration program of the hydrocarbon reserves of our country, which will be the turning point for the economic development of our nation.’
66issue66issue
Revealing African Oil PlaygroundsRevealing African Oil Playgrounds
Ahmeyim (previously Tortue)Gas Discovery8 TCf P50 Gross resource
Marsouin 1Gas Discovery 5 TCf P50 Gross resource
FAN - 1 Oil Discovery950 mmbbls P50 STOIIP
SNE - 1 Oil Discovery350 mmbbls P50 Contingent resource recoverable
Guembeul 1Gas Discovery
Spectrum NewsSpectrum News
NorwaySpectrum ASA+47 9018 [email protected]
United KingdomSpectrum Geo Ltd.+44 1483 730201 [email protected]
United StatesSpectrum Geo Inc.+1 281 647 0602 [email protected]
SingaporeSpectrum Geo Pte Ltd.+65 6827 [email protected]
AustraliaSpectrum Geo Pty Ltd.+61 8 9322 [email protected]
nW shelf australia
Spectrum’s extensive Multi-Client seismic library across the Australian NW shelf now includes the new 4,000 km2 3D Cygnus survey. This new project, over the Vulcan Sub-basin, focuses on key under-explored areas of hydrocarbon prospectivity providing excellent exploration opportunities.
The survey is being acquired by Polarcus in the structural dip direction using an XArrayTM configuration with a 12.5 m triple source shot interval and continuous recording, delivering 33% improved cross line sampling without any interpolation. Processing will be performed by DownUnder GeoSolutions through a broadband PSDM workflow and final processed data will be available from Q3 2016, with PSTM fast track data available from Q1 2016.
The main exploration targets in the Vulcan Sub-basin are sandstones in the Upper Triassic Challis and Nome Formations, fluvio-deltaic sandstones of the Middle Jurassic Plover Formation, Oxfordian shoreface/barrier bar sandstones of the Montara Formation, Tithonian submarine fans of the upper Vulcan Formation and submarine fans of the Upper Cretaceous Puffin Formation. Plays
New Cygnus 3D to build on NW Australian Opportunities
occur in stratigraphic traps, pinchouts, unconformity truncations, tilted fault blocks, horst blocks and anticlines.
Historically, sub-optimal acquisition and processing strategies have not been able to address the geological and geophysical challenges including the energy absorption and multiple issues caused by the thick Late Cretaceous-Tertiary carbonates. This new survey will address those challenges to provide the most detailed imaging of the area to date.
The Cygnus project is adjacent to Spectrum’s 2,810 km2 Cartier Main 3D survey, acquired in 2010 and recently reprocessed using a Broadband 5-iteration anisotropic PSDM workflow to further enhance imaging across this proven hydrocarbon region. With this latest survey, Spectrum’s 3D coverage in the Australian North West Shelf will total 40,000 sq. km of newly acquired 3D Multi-Client data (less than 5 years old).
Spectrum currently holds a total of 133,000 km2 of 3D seismic data and over 250,000 km of 2D data offshore Australia, predominantly on the NW shelf of the country.
Seen to BelieveWith government representatives from the industry’s frontier regions in attendance and a whole new library to explore, the annual seminars held in both Houston and London were certain to be the most stimulating and enlightening yet. Back by popular demand, our exclusive seminar events included a range of speakers and subjects from across the globe all with the aim of inspiring the oil industry’s finest to make the next big discoveries.
Held at the vintage theatre of Britain’s Magic Circle, the London seminar included a wide range of subject matter from East Africa to the Atlantic Conjugate Margin to the Black Sea and across the Atlantic to Mexico and the Caribbean. Along with Somalian government representatives, guest speakers from Mexico’s PEMEX and an academic scholar from the University of Leeds added their unique perspectives on the world’s most promising areas of future exploration.
In Houston our US clients were treated to a similar collection of technical talks. A large majority of the evening focused on the Western Hemisphere, beginning with the Gulf Coast of Mexico and its current licensing round to different frontier areas in the Caribbean. One country in particular being Barbados, whose presentation was given by the Barbadian Director of Natural Resources, discussing the opportunities of exploration in the region.
Following the talks at each seminar, an invaluable networking session was held to allow clients and guest speakers to exchange views after drinks and canapes.
Cartier Main 3DCygnus 3DReprocessed 3D3D acquisitions2015 acreage release blocksAcreage release blocksLicensed blocksLicense application blocksOil fieldsGas fields
Legend
66issue66issue
1212 Spectrum News l issue 66 spectrumgeo.com