conventional reservoirs unconventional reservoirs spacing, reservoir model type (dual vs. single...
TRANSCRIPT
(Reservoir Engineering Aspects of Unconventionals) | PETE 631 - Petroleum Reservoir Description)
Petroleum Engineering 631 — Petroleum Reservoir DescriptionReservoir Engineering Aspects of Unconventional Reservoirs — A Brief Introduction
Slide 1
Conventional Reservoirs Unconventional Reservoirs (Shale)● Localized structural trap ● "Continuous-type" deposit● External HC sourcing ● Self-sourced HC● Hydrodynamic influence ● Minimal hydrodynamic influence● Porosity important ● Porosity may not be important● Permeability > 0.1 md ● Permeability << 0.1 md● Permeability ≠ f(p) ● Permeability = f(p)● Traditional phase behavior (PVT) ● Complex (HP/HT) PVT● Minimal extraction effort ● Significant extraction effort● Significant production history ● Limited production history● Often late development life-cycle ● Early development life-cycle● Few wells for commerciality ● Many wells for commerciality● Base reserves on volumetrics ● Base reserves on analogs ● Assess entire prospect before drilling ● Prospect driven by drilling ● Boundary-dominated flow (months) ● No boundary-dominated flow
● Traditional reserves methods ● Traditional reserves methods
Conventional Versus Unconventional:
?
Attributed to Brad Berg(Anadarko Petroleum Corporation)
(Reservoir Engineering Aspects of Unconventionals) | PETE 631 - Petroleum Reservoir Description)
Petroleum Engineering 631 — Petroleum Reservoir DescriptionReservoir Engineering Aspects of Unconventional Reservoirs — A Brief Introduction
Slide 2
b.Nelson, P.H.: "Pore-throat Sizes In Sandstones, Tight Sandstones, and Shales," AAPG Bulletin, v. 93, no. 3 (March 2009).
c.Loucks, R.G., Reed, R.M., Ruppel, S.C., and Jarvie, D.M., 2009, Morphology, Genesis, and Distribution of Nanometer-Scale Pores in Siliceous Mudstones of the Mississippian Barnett Shale: Journal of Sedimentary Research, v. 79, p. 848-861.
a.Archie, G.E.: "Introduction to Petrophysics of Reservoir Rock," Bull., AAPG (1950) 1-34.
d.Florence, F.A., Newsham, K., Rushing, J.A., and Blasingame, T.A.: "Improved Permeability Prediction Relations for Low Permeability Sands," paper SPE 107954 presented at the 2007 SPE Rocky Mountain Oil & Gas Technology Symposium held in Denver, CO, U.S.A., 16-18 April 2007.
(Reservoir Engineering Aspects of Unconventionals) | PETE 631 - Petroleum Reservoir Description)
Petroleum Engineering 631 — Petroleum Reservoir DescriptionReservoir Engineering Aspects of Unconventional Reservoirs — A Brief Introduction
Slide 3
TD Panel • So We Frac'd the Well, Now What? • Tom Blasingame (Texas A&M U.)
b.Schematic of "fracture stages" in a multi-fracture horizontal well.
c.Schematic of flow regimes which occur in a multi-fracture horizontal well (note linear and bilinear flow regimes).
a.Schematic of hyperbolic-exponential DCA approach.
d.Example of modern decline curve diagnostics (qDb-functions) used forproduction forecasting and estimation of EUR.
(Reservoir Engineering Aspects of Unconventionals) | PETE 631 - Petroleum Reservoir Description)
Petroleum Engineering 631 — Petroleum Reservoir DescriptionReservoir Engineering Aspects of Unconventional Reservoirs — A Brief Introduction
Slide 4
b.Phase diagrams of confined and unconfined heavy gas condensate mixture (Pedersen et al, 1989). (vertical( red) line is the reservoir temperature).
a.Critical point suppression due to pore size (various gases).
b.The percentage of liquid drop out (% by volume) of a heavy gas condensate mixture (Pedersen et al, 1989) at 400⁰F. (400⁰F is reservoir temperature — see plot at left).
PVT: (Issues/Challenges/Solutions?)● Undersaturated oil, pb suppression
(nano-pore volumes/distributions).● Volatile oil/critical fluid, nano-volume
effects less an issue (IFT/pc).● Gas condensates — composition issues/ variations in pCrit and TCrit.● Need molecular dynamics work to resolve/validate PVT in nano-pores.
From
:Sa
pman
ee, K
. (20
11).
"Effe
cts
of P
ore
Prox
imity
on
Beh
avio
r an
d Pr
oduc
tion
Pred
ictio
n of
Gas
/Con
dens
ate,
" M
.S. T
hesi
s, U
nive
rsity
of
Okl
ahom
a, 2
011.
From
:Sa
pman
ee, K
. (20
11).
"Effe
cts
of P
ore
Prox
imity
on
Beh
avio
r an
d Pr
oduc
tion
Pred
ictio
n of
Gas
/Con
dens
ate,
" M
.S. T
hesi
s, U
nive
rsity
of
Okl
ahom
a, 2
011.
(Reservoir Engineering Aspects of Unconventionals) | PETE 631 - Petroleum Reservoir Description)
Petroleum Engineering 631 — Petroleum Reservoir DescriptionReservoir Engineering Aspects of Unconventional Reservoirs — A Brief Introduction
Slide 5
b.Pressure gradient after 8 months (top) and 10 years (bottom) of production (Note times for different regimes, this is a relatively high permeability shale analog case).
a.Freeman, C.M., Ilk, D., Moridis, G.J., and Blasingame, T.A.: "A Numerical Study of Performance for Tight Gas and Shale Gas Reservoir Systems" paper SPE 124961 presented at the 2009 SPE Annual Technical Conference and Exhibition, New Orleans, LA, USA, 4–7 October 2009.
b.Typical transient response where PSS is seen in the SRV (Note times for different regimes, this is a relatively high permeability shale analog case).
Modeling: (Grand Challenges)● Fully integrated (not coupled) geo-
mechanical/flow simulation model.●Models may not be properly "parameter-
ized" — no data to validate.● Statistical versus deterministic models
(system is "too complex")?● Use models to establish/validate/bound
drainage volumes.● Use models to constrain assumptions
about geomechanics/fluid flow.
From
:K
APPA
Con
sort
ium
on
Unc
onve
ntio
nal R
esou
rces
(Dra
ft pr
ojec
t do
cum
ent)
7th
Febr
uary
201
1 (w
ww
.kap
paen
g.co
m).
From
:K
APPA
Con
sort
ium
on
Unc
onve
ntio
nal R
esou
rces
(Dra
ft pr
ojec
t do
cum
ent)
7th
Febr
uary
201
1 (w
ww
.kap
paen
g.co
m).
(Reservoir Engineering Aspects of Unconventionals) | PETE 631 - Petroleum Reservoir Description)
Petroleum Engineering 631 — Petroleum Reservoir DescriptionReservoir Engineering Aspects of Unconventional Reservoirs — A Brief Introduction
Slide 6
b.Time match of (calculated) bottomhole pressures .
c.Cumulative oil match of oil rate using 80- and 800-acre spacings.
a.Time match of oil (green) and gas (red) rate performance. Note thatthe match substantially degrades after the shut-in (reservoir effect?).
d.Plot of EUR versus well spacing (drainage area) for example case.
From
:Ilk
, D.,
Bro
ussa
rd, N
.J.,
and
Bla
sing
ame,
T.A
.,: "
Prod
uctio
n A
naly
sis
in th
e Ea
gle
Ford
Sha
le
—B
est P
ract
ices
for D
iagn
ostic
Inte
rpre
tatio
ns, A
naly
sis,
and
Mod
elin
g,"
pape
r SPE
160
076
pres
ente
d at
the
2012
SPE
Ann
ual T
echn
ical
Con
fere
nce
and
Exhi
bitio
n he
ld in
San
Ant
onio
, TX,
08-
10 O
ctob
er 2
012.
(Reservoir Engineering Aspects of Unconventionals) | PETE 631 - Petroleum Reservoir Description)
Petroleum Engineering 631 — Petroleum Reservoir DescriptionReservoir Engineering Aspects of Unconventional Reservoirs — A Brief Introduction
Comment: Left plot yields time required to estimate EUR (~12-32 months). The "hyperbolic" (or "constant b") flow regime is required to estimate EUR.
[all data obtained from publicly available sources — Dry Horizontal Shale Gas Wells ONLY]
From
:Hec
kman
, T.L
., et
al (
2013
): B
est P
ract
ices
for R
eser
ves
Estim
atio
n in
U
ncon
vent
iona
l Res
ervo
irs —
Pres
ent a
nd F
utur
e C
onsi
dera
tions
, Key
note
pr
esen
tatio
n pr
esen
ted
at th
e 20
13 S
PE U
ncon
vent
iona
l Res
ourc
es
Con
fere
nce,
The
Woo
dlan
ds, T
X (U
SA),
10-1
2 A
pril
2013
.
Slide 7
(Reservoir Engineering Aspects of Unconventionals) | PETE 631 - Petroleum Reservoir Description)
Petroleum Engineering 631 — Petroleum Reservoir DescriptionReservoir Engineering Aspects of Unconventional Reservoirs — A Brief Introduction
Comment: Results vary when segregated by geological area, completions, spacing, etc. Analyses represent an attempt to quantify the RANGE of values.
From
:Hec
kman
, T.L
., et
al (
2013
): B
est P
ract
ices
for R
eser
ves
Estim
atio
n in
U
ncon
vent
iona
l Res
ervo
irs —
Pres
ent a
nd F
utur
e C
onsi
dera
tions
, Key
note
pr
esen
tatio
n pr
esen
ted
at th
e 20
13 S
PE U
ncon
vent
iona
l Res
ourc
es
Con
fere
nce,
The
Woo
dlan
ds, T
X (U
SA),
10-1
2 A
pril
2013
.
[all data obtained from publicly available sources — Dry Horizontal Shale Gas Wells ONLY][P90/P50/P10 EUR Comparisons (Modified Hyperbolic Model with 30 year max life)]
Slide 8
(Reservoir Engineering Aspects of Unconventionals) | PETE 631 - Petroleum Reservoir Description)
Petroleum Engineering 631 — Petroleum Reservoir DescriptionReservoir Engineering Aspects of Unconventional Reservoirs — A Brief Introduction
What Keeps Us (Reservoir Engineers) Up at Night:●Stimulation/Fracture Geometry:
■Well spacing, reservoir model type (dual vs. single porosity), etc.?■ Does the SRV change with time (specifically, does it shrink)?
●Reservoir Model:■ Validity of dual /k models, enhanced k pods, fracture networks?■Model selection has a significant impact on POTENTIAL well spacing.■ Can we predict/incorporate influence of natural fractures?■ Is effort on geomechanics (really) going to lead to better understanding?.
●Data Collection:■ Taking data to validate model, or using model to guide development? ■ Downhole data — expensive — but are there any viable alternatives? ■ Poor data → poor engineering and poor modeling.■ Petrophysical data ( , k, pc) — scale, validity, integration?■ Role of "distributed" data? (temperature, pressure, rates, etc.)
●Process:■ No "cowboy-ing" the choke — develop a choke plan and stick to it!■ Incorporating artificial lift from inception! (including modeling)■ Use modeling to interpret performance and constrain parameters.■ Focus on what we can measure; use that as a basis for modeling.■ Start to consider statistics in addition to mechanistics.
Slide 9