A Semianalytical Forecasting Method for Unconventional Gas and Light Oil Wells: A Hybrid Approach for Addressing the Limitations of Existing Empirical and Analytical Methods
- Christopher R. Clarkson (University of Calgary) | Farhad Qanbari (University of Calgary)
- Document ID
- Society of Petroleum Engineers
- SPE Reservoir Evaluation & Engineering
- Publication Date
- February 2015
- Document Type
- Journal Paper
- 94 - 110
- 2015.Society of Petroleum Engineers
- unconventional gas, forecasting, semianalytical, unconventional light oil
- 19 in the last 30 days
- 698 since 2007
- Show more detail
- View rights & permissions
|SPE Member Price:||USD 12.00|
|SPE Non-Member Price:||USD 35.00|
The rapid pace of exploitation of unconventional gas and light oil plays in North America has necessitated the development of new production-forecasting methodologies to aid in reserves assessment, capital planning, and field optimization. The generation of defendable forecasts is challenged not only by reservoir complexities but also by the use of multifractured horizontal wells (MFHWs) for development. In this work, a semianalytical method (SAM) is developed to provide a solid theoretical basis for forecasting. The technique is analytical in that it uses the methods of Agarwal (2010) to calculate contacted oil in place and contacted gas in place (COIP/ CGIP) from production rates, flowing pressures, and fluid properties. The rate-normalized pressure (RNP) derivative (RNP) is a key component of the calculation; pseudopressure is used for gas cases. The technique is also empirical in that an empirical function is fitted to the resulting COIP/CGIP curve vs. time. Although the method is flexible enough that any equation can be used to represent the COIP/CGIP curve, and hence, the sequence of flow regimes exhibited by MFHWs, the equation must be capable of being integrated to allow the extraction of RNP. The stabilized COIP/CGIP during boundary-dominated flow (BDF) must be specified for forecasting -- thereafter, the method uses a materialbalance simulator to model BDF. Hence, if the well is still in transient flow, a range in forecasts may be generated, depending on the assumed stabilized COIP/CGIP. The new SAM addresses some of the current limitations of empirical and fully analytical (modeling) approaches. Empirical methods, which have been adapted to account for long transient and transitional flow periods associated with ultralow-permeability reservoirs, lack a theoretical basis, and therefore input parameters may be difficult to constrain. However, empirical methods are simple to apply and require a minimum amount of data for forecasting. Analytical models, while representing the physics better, nonetheless require additional reservoir and hydraulic-fracture data that may not be available on every well in the field. The SAM proposed herein is intended to bridge the gap between empirical and modeling-based approaches -- it is more rigorous than purely empirical methods, while requiring a lesser amount of data than fully analytical techniques. The new method is tested against simulated and field cases (tight oil and shale gas). Although a simple power-law function is used in the current work to represent the COIP/OGIP curve, which appears adequate for the cases studied, one should note that wells exhibiting long transitional flow periods (e.g., elliptical/ radial) will likely require a different functional form.
|File Size||2 MB||Number of Pages||17|
Adegbesan, K.O., Costello, J.P., Elsborg, C.C. et al. 1996. Key Performance Drivers for Horizontal Wells Under Waterflood Operations in the Layered Pembina Cardium Reservoir. J Can Pet Technol 35 (8): 25–35. SPE-96-08-02-PA. http://dx.doi.org/10.2118/96-08-02-PA.
Agarwal, R.G. 2010. Direct Method of Estimating Average Reservoir Pressure for Flowing Oil and Gas Wells. Presented at the SPE Annual Technical Conference and Exhibition, Florence, Italy, 19–22 September. SPE-135804-MS. http://dx.doi.org/10.2118/135804-MS.
Agarwal, R.G., Gardner, D.C., Kleinsteiber, S.W. et al. 1999. Analyzing Well Production Data Using Combined Type Curve and Decline Curve Concepts. SPE Res Eval & Eng 2 (5): 478–486. SPE-57916-PA. http://dx.doi.org/10.2118/57916-PA.
Arps, J.J. 1945. Analysis of Decline Curves. Trans., AIME 160: 228–247.
Ayala, L. and Ye, P. 2012. Unified Decline Type-Curve Analysis for Natural Gas Wells in Boundary-Dominated Flow. SPE J. 18 (1): 97–113. SPE-161095-PA. http://dx.doi.org/10.2118/161095-PA.
Behmanesh, H., Hamdi, H., and Clarkson, C.R. 2013. Production Data Analysis of Liquid Rich Shale Gas Condensate Reservoirs. Presented at the Canadian Unconventional Resources Conference–Canada, Calgary, Alberta, Canada, 5–7 November. SPE-167150-MS. http://dx.doi.org/10.2118/167150-MS.
Brown, M., Ozkan, E., Raghavan, R. et al. 2011. Practical Solutions for Pressure-Transient Responses of Fractured Horizontal Wells in Unconventional Shale Reservoirs. SPE Res Eval & Eng 14 (6): 663–676. SPE-125043-PA. http://dx.doi.org/10.2118/125043-PA.
Clarkson, C.R. 2013a. Production Data Analysis of Unconventional Gas Wells: Review of Theory and Best Practices. International J. Coal Geology 109–110: 101–146.
Clarkson, C.R. 2013b. Production Data Analysis of Unconventional Gas Wells: Workflow. International J. Coal Geology 109–110: 147–157. http://dx.doi.org/10.1016/j.coal.2012.11.016.
Clarkson, C.R. and Beierle, J.J. 2011. Integration of Microseismic and Other Post-Fracture Surveillance With Production Analysis: A Tight Gas Study. J. Natural Gas Sci. & Eng. 3: 382–401. http://10.1016/j.jngse.2011.03.003.
Clarkson, C.R., Bustin, R.M., and Seidle, J.P. 2007. Production-Data Analysis of Single-Phase (Gas) Coalbed-Methane Wells. SPE Res Eval & Eng 10 (3): 312–331. SPE-100313-PA. http://dx.doi.org/10.2118/100313-PA.
Clarkson, C.R. and Pedersen, P.K. 2010. Tight Oil Production Analysis: Adaptation of Existing Rate-Transient Analysis Techniques. Presented at the Canadian Unconventional Resources & International Petroleum Conference, Calgary, Alberta, Canada, 18–21 October. SPE-137352-MS. http://dx.doi.org/10.2118/137352-MS.
Clarkson, C.R. and Pedersen, P.K. 2011. Production Analysis of Western Canadian Unconventional Light Oil Plays. Presented at the Canadian Unconventional Resources Conference, Calgary, Alberta, Canada, 15–17 November. CSUG/SPE-149005-MS. http://dx.doi.org/10.2118/149005-MS.
Clarkson, C.R., Williams-Kovaks, J.D., Qanbari, F. et al. 2014. History-Matching and Forecasting Tight/Shale Gas Condensate Wells Using Combined Analytical, SemiAnalytical, and Empirical Methods. Presented at the SPE/CSUR Unconventional Resources Conference, Calgary, Alberta, Canada, 30 September–2 October. SPE-171593-MS. http://dx.doi.org/10.2118/171593-MS.
Currie, S.M., Ilk, D., and Blasingame, T.A. 2010. Continuous Estimation of Ultimate Recovery. Presented at the SPE Unconventional Gas Conference, Pittsburgh, Pennsylvania, 23–25 February. SPE-132352-MS. http://dx.doi.org/10.2118/132352-MS.
Duong, A.N. 2011. Rate-Decline Analysis for Fracture-Dominated Shale Reservoirs. SPE Res Eval & Eng 14 (3): 377–387. SPE-137748-PA. http://dx.doi.org/10.2118/137748-PA.
Fetkovich, M.J., Fetkovich, E.J., and Fetkovich, M.D. 1996. Useful Concepts for Decline Curve Forecasting, Reserve Estimation, and Analysis. SPE Res Eng 11 (1): 13–22. SPE-28628-PA. http://dx.doi.org/10.2118/28628-PA.
Ilk, D. and Blasingame, T.A. 2013. Decline Curve Analysis for Unconventional Systems—Variable Pressure Drop Case. Presented at the SPE Unconventional Resources Conference-Canada, Calgary, Alberta, Canada, 5–7 November. SPE-140556-MS. http://dx.doi.org/10.2118/140556-MS.
Ilk, D., Perego, A.D., Rushing, J.A. et al. 2008a. Integrating Multiple Production Analysis Techniques to Assess Tight Gas Sand Reserves: Defining a New Paradigm for Industry Best Practices. Presented at the CIPC/SPE Gas Technology Symposium Joint Conference, Calgary, Alberta, Canada, 16–19 June. SPE-114947-MS. http://dx.doi.org/10.2118/114947-MS.
Ilk, D., Rushing, J.A., and Blasingame, T.A. 2011. Integration of Production Analysis and Rate-Time Analysis via Parameteric Correlations —Theoretical Considerations and Practical Applications. Presented at the SPE Hydraulic Fracturing Conference, The Woodlands, Texas, 24–26 January. SPE-140556-MS. http://dx.doi.org/10.2118/140556-MS.
Ilk, D., Rushing, J.A., Perego, A.D. et al. 2008b. Exponential vs. Hyperbolic Decline in Tight Gas Sands: Understanding the Origin and Implications for Reserve Estimates using Arps’ Decline Curves. Presented at the Annual Technical Conference and Exhibition, Denver, Colorado, 21–24 September. SPE-116731-MS. http://dx.doi.org/10.2118/116731-MS.
Mattar, L. and Anderson, D.M. 2003. A Systematic and Comprehensive Methodology for Advanced Analysis of Production Data. Presented at the SPE Annual Technical Conference and Exhibition, Denver, Colorado, 5–8 October. SPE-84472-MS. http://dx.doi.org/10.2118/84472-MS.
Mattar, L. and Anderson, D.M. 2005. Dynamic Material Balance (Oil or Gas-in-Place Without Shut-Ins). Presented at the Canadian International Petroleum Conference, Calgary, Alberta, Canada, 7–9 June. SPE-2005-113-MS. http://dx.doi.org/10.2118/2005-113-MS.
Nobakht, M., Clarkson, C.R., and Kaviani, D. 2013. New Type-Curves for Analyzing Horizontal Well With Multiple Fractures in Shale Gas Reservoirs. J. Natural Gas Sci. & Eng. 10: 99–112.
Nobakht, M. and Mattar, L. 2012. Analyzing Production Data From Unconventional Gas Reservoirs With Linear Flow and Apparent Skin. J Can Pet Technol 51 (1): 52–59.
Ozkan, E., Brown, M., Raghavan, R. et al. 2011. Comparison of Fractured-Horizontal-Well Performance in Tight Sand and Shale Reservoirs. SPE Res Eval & Eng 14 (2): 248–259. SPE-121290-PA. http://dx.doi.org/10.2118/121290-PA.
Palacio, J.C. and Blasingame, T.A. 1993. Decline-Curve Analysis Using Type Curves—Analysis of Gas Well Production Data. Presented at the SPE Joint Rocky Mountain Regional and Low Permeability Reservoirs Symposium, Denver, Colorado. SPE-25909-MS. http://dx.doi.org/10.2118/25909-MS.
Robertson, S. 1988. Generalized Hyperbolic Relation. Paper SPE 18731, unsolicited manuscript.
Valko, P.P. and Lee, W.J. 2010. A Better Way To Forecast Production From Unconventional Gas Wells. Presented at the SPE Annual Technical Conference and Exhibition, Florence, Italy, 19–22 September. SPE-134231-MS. http://dx.doi.org/10.2118/134231-MS.
Wattenbarger, R.A., El-Banbi, A.H., Villegas, M.E. et al. 1998. Production Analysis of Linear Flow Into Fractured Tight Gas Wells. Presented at the SPE Rocky Mountain Regional/Low-Permeability Reservoirs Symposium, Denver, Colorado, 5–8 April. SPE-39931-MS. http://dx.doi.org/10.2118/39931-MS.
Williams-Kovacs, J.D., Clarkson, C.R., and Nobakht, M. 2012. Impact of Material Balance Equation Selection on Rate-Transient Analysis of Shale Gas. Presented at SPE Annual Technical Conference and Exhibition, San Antonio, Texas, 8–10 October. SPE-158041-MS. http://dx.doi.org/10.2118/158041-MS.