Many operators of tight gas reservoir fields are interested in determining the infill well potential in these fields. Over drilling may prove to be uneconomical; whereas, under drilling would leave unexplored reserves under the ground. In predicting EUR (expected ultimate recovery) of a potential infill well, operators are interested in knowing what percentage of the production will be come from incremental reserves (newly accessed) and what percentage is from acceleration reserves (which can be produced from existing wells). So, higher the percentage of incremental reserves better is the potential of an infill well. In this paper, we present a novel method for determining the incremental versus acceleration potential for infill well in a tight gas reservoir. We evaluate the existing wells by plotting the data in a form so that the data can be linearly extrapolated. Then, we can predict the EUR for individual wells before and after new wells in the vicinity are drilled. By knowing how much gas is “diverted” from the older wells, we determine the acceleration component of an infill well. By repeating the process as the field is being developed, we can determine the fraction of acceleration and incremental components of the EUR at each stage of infill drilling. We will also know how the EUR is changing as the well spacing is slowly reduced. To ensure our results are reasonable, we also compare our EUR values with EUR’s reported by the operator as proved reserves. Armed with this information, we can extrapolate infill well potential for a smaller spacing, including the contribution due to acceleration versus incremental production. We applied this procedure for Wamsutter field in Wyoming. Using the procedure, we recommended infill well locations to the operator. Operator has drilled seven wells based on our recommendations. Using this new method, we can predict the EUR for infill well as well as acceleration and incremental contribution of the infill well. Thus, potential of infill wells at different locations can be evaluated and compared.

References

References
1.
Perry
,
K.
,
2009
, “
Microhole Coiled Tubing Drilling: A Low Cost Reservoir Access Technology
,”
ASME J. Energy Resour. Technol.
,
131
, p.
013104
.10.1115/1.3000100
2.
Bennion
,
D.
, and
Thomas
,
F.
,
2005
, “
Formation Damage Issues Impacting the Productivity of Low Permeability, Low Initial Water Saturation Gas Producing Formations
,”
ASME J. Energy Resour. Technol.
,
127
, pp.
240
247
.10.1115/1.1937420
3.
Cipolla
,
C. L.
, and
Wood
,
M. C.
,
1996
, “
A Statistical Approach to Infill-Drilling Studies: Case History of the Ozona Canyon Sands
,” Presented at the 1996 Gas Technology Symposium, Calgary, Alberta, Canada, Apr. 28–May 1, SPE Paper No. 35628.
4.
Guan
,
L.
,
McVay
,
D. A.
,
Jensen
,
J. L.
, and
Voneiff
,
G. W.
,
2002
, “
Evaluation of a Statistical Infill Candidate Selection Technique
,”
SPE
Gas Technology Symposium, Calgary, Alberta, Canada, Apr. 30–May 2, SPE Paper No. 75718-MS. 10.2118/75718-MS
5.
Guan
,
L.
,
McVay
,
D. A.
,
Jensen
,
J. L.
, and
Voneiff
,
G. W.
,
2004
, “
Evaluation of a Statistical Method for Assessing Infill Production Potential in Mature, Low-Permeability Gas Reservoirs
,”
ASME J. Energy Resour. Technol.
,
126
, pp.
241
245
.10.1115/1.1781672
6.
Gao
,
H.
, and
McVay
,
D. A.
,
2004
, “
Gas Infill Well Selection Using Rapid Inversion Methods
,”
SPE
Annual Technical Conference and Exhibition, Houston, TX, Sept. 26–29, SPE Paper No. 90545-MS. 10.2118/90545-MS
7.
Cheng
,
Y.
,
Lee
,
W.
, and
McVay
,
D.
,
2008
, “
Quantification of Uncertainty in Reserve Estimation From Decline Curve Analysis of Production Data for Unconventional Reservoirs
,”
ASME J. Energy Resour. Technol.
,
130
, p. 043201.10.1115/1.3000096
8.
Singh
,
K.
,
Holditch
,
S.
, and
Ayers
,
W.
,
2008
, “
Basin Analog Investigations Answer Characterization Challenges of Unconventional Gas Potential in Frontier Basins
,”
ASME J. Energy Resour. Technol.
,
130
, p.
043202
.10.1115/1.3000104
9.
Guppy
,
K. H.
,
Cinco
,
H.
, and
Ramey
,
H. J.
, Jr.
,
1981
, “
Transient Flow Behavior of a Vertically Fractured Well Producing at Constant Pressure
,” SPE Paper No. 9963-MS.
10.
Kelkar
,
M.
,
2008
,
Natural Gas Production Engineering
,
Penn Well Corporation
,
Tulsa, OK
, pp.
216
228
.
11.
Arps
,
J. J.
,
1945
, “
Analysis of Decline Curves
,”
Trans. AIME
,
160
, pp.
228
247
.
12.
Hough
,
E.
, and
McClurg
,
T.
,
2011
, “
Impact of Geological Variation and Completion Type in the U.S. Bakken Oil Shale Play Using Decline Curve Analysis and Transient Flow Character
,”
Presentation at AAPG International Conference and Exhibition
, Milan, Italy, Oct. 23–26.
13.
Southwest Energy
,
2009
, “
2009 Investor Presentation
,” http://www.swn.com
14.
Chesapeake Energy
,
2009
, “
2009 Investor Presentation
,” http://www.chk.com
15.
BP America Production Company
,
2007
, “
Application for Increased Density
,” Wyoming O&GCC Hearing Docket No. 239-2007, June 12.
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