An Approximate Semianalytical Multiphase Forecasting Method for Multifractured Tight Light-Oil Wells With Complex Fracture Geometry
- Christopher R. Clarkson (University of Calgary) | Farhad Qanbari (University of Calgary)
- Document ID
- Society of Petroleum Engineers
- Journal of Canadian Petroleum Technology
- Publication Date
- December 2015
- Document Type
- Journal Paper
- 489 - 508
- 2015.Society of Petroleum Engineers
- multi-phase flow, complex fracture geometry, analytical forecasting , light tight oil wells
- 5 in the last 30 days
- 506 since 2007
- Show more detail
- View rights & permissions
|SPE Member Price:||USD 10.00|
|SPE Non-Member Price:||USD 30.00|
There is now an array of analytical, semianalytical, and empirical forecasting methods that can be used to history match and forecast multifractured horizontal wells (MFHWs) completed in low-permeability (tight) reservoirs. Recent developments in analytical modelling have extended model application to cases in which the fracture geometry associated with MFHWs is complex. However, analytical modelling is still primarily limited to single-phase-flow problems, which is very restrictive, and potentially inaccurate, for tight oil and liquid-rich gas reservoirs flowing at less than saturation pressure.
In this work, a semianalytical method is presented for history matching and forecasting MFHWs with simple and complex fracture geometry completed in tight, black-oil reservoirs and flowing at less than the bubblepoint pressure. The linear-to-boundary (LTB) model, commonly used to model flow in the inner (stimulated) region of an MFHW, is altered to account for two-phase flow of oil and gas. The enhanced-fracture-region (EFR) case, in which both stimulated and nonstimulated regions contribute to flow, is approximated (empirically) by superposition of two modified LTB models (one representing the inner fractured region and the other the outer, nonstimulated region), and similarly altered to account for two-phase flow. An important observation is that, for MFHWs flowing at less than bubblepoint at constant flowing bottomhole pressure during transient linear flow, the slope of the square-root-of-time plot for both oil and gas phases is constant [i.e., gas/oil ratio (GOR) is constant]. The slope and intercept of the square-root-of-time plot for the primary phase (e.g., oil in the cases studied) can therefore be used to generate a forecast during the transient linear-flow period for oil and for gas (by assuming constant GOR). For boundary-dominated flow, a robust method for forecasting gas and oil was developed using material balance for both phases combined with a modified productivity-index equation that accounts for multiphase flow. A fully implicit approach has been used to solve the flow equations for oil and gas.
The new modified LTB and EFR models simplify forecasting considerably for low-permeability black-oil reservoirs exhibiting multiphase flow behaviour, relative to numerical simulation, although they are not as rigorous. The new models can, however, be tied directly to the results of rate-transient analysis and are flexible enough to be applied to common conceptual models used in the literature for forecasting MFHWs under certain conditions.
The new modified LTB model has been compared with both simulated and field examples. The initial results demonstrate that transient- and boundary-dominated-flow periods for oil and gas are reasonably matched with the new approach, although slight mismatches may occur, particularly during early boundary-dominated flow. The limits of the new forecasting method will continue to be explored in future work.
|File Size||2 MB||Number of Pages||20|
Arps, J. J. 1945. Analysis of Decline Curves. Trans, AIME. 160: 228–247.
Behmanesh, H., Hamdi, H., Sureshjani, M. H. et al. 2014. Production Data Analysis of Overpressured Liquid-Rich Shale Reservoirs: Effect of Degree of Undersaturation. Presented at the SPE Unconventional Resources Conference, The Woodlands, Texas, USA, 1–3 April. SPE-168980-MS. http://dx.doi.org/10.2118/168980-MS.
Behmanesh, H., Hamdi, H., and Clarkson, C. R. 2015a. Production Data Analysis of Tight Gas Condensate Reservoirs. Journal of Natural Gas Science and Engineering 22: 22–34. http://dx.doi.org/10.1016/j.jngse.2014.11.005.
Behmanesh, H., Hamdi, H., and Clarkson, C. R. 2015b. Analysis of Transient Linear Flow Associated with Hydraulically-Fractured Tight Oil Wells Exhibiting Multi-Phase Flow. Presented at the SPE Middle East Unconventional Resources Conference and Exhibition, Muscat, Oman, 26–28 January. SPE-172928-MS. http://dx.doi.org/10.2118/172928-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. and Pedersen, P. K. 2010. Tight Oil Production Analysis: Adaptation of Existing Rate-Transient Analysis Techniques. Presented at the Canadian Unconventional Resources and International Petroleum Conference, Calgary, 19–21 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, 15–17 November. SPE-149005-MS. http://dx.doi.org/10.2118/149005-MS.
Clarkson, C. R. and Qanbari, F. 2015. A Seminanalytical Forecasting Method for Unconventional Gas and Light Oil Wells: A Hybrid
Approach for Addressing the Limitations of Existing Empirical and Analytical Methods. SPE Res Eval & Eng 18 (1): 94–110. SPE-
Clarkson, C. R., Williams-Kovacs, J. D., Qanbari, F. et al. 2014. History-Matching and Forecasting Tight/Shale Gas Condensate Wells Using Combined Analytical, Semi-Analytical, and Empirical Methods. Presented at the SPE/CSUR Unconventional Resources Conference, Calgary, 30 September–2 October. SPE-171593-MS. http://dx.doi.org/10.2118/171593-MS.
Nobakht, M., Mattar, L., Moghadam, S. et al. 2012. Simplified Forecasting of Tight/Shale-Gas Production in Linear Flow. J Can Pet Technol 51 (6): 476–486. SPE-133615-PA. http://dx.doi.org/10.2118/133615-PA.
Nobakht, M., and Clarkson, C. R. 2012a. A New Analytical Method for Analyzing Linear Flow in Tight/Shale Gas Reservoirs: Constant-Rate Boundary Condition. SPE Res Eval & Eng 15 (1): 51–59. SPE-143990-PA. http://dx.doi.org/10.2118/143990-PA.
Nobakht, M., and Clarkson, C. R. 2012b. A New Analytical Method for Analyzing Linear Flow in Tight/Shale Gas Reservoirs: Constant-Flowing-Pressure Boundary Condition. SPE Res Eval & Eng 15 (3): 370–384. SPE-143989-PA. http://dx.doi.org/10.2118/143989-PA.
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.
Qanbari, F. and Clarkson, C. R. 2013. Analysis of Transient Linear Flow in Tight Oil and Gas Reservoirs with Stress-Sensitive Permeability and Multi-Phase Flow. Presented at the SPE Unconventional Resources Conference—Canada, Calgary, 5–7 November. SPE-167176-MS. http://dx.doi.org/10.2118/167176-MS.
Qanbari, F. and Clarkson, C. R. 2014. Analysis of Transient Linear Flow in Stress-Sensitive Formation. SPE Res Eval & Eng 17 (1): 98–104. SPE-162741-PA. http://dx.doi.org/10.2118/162741-PA.
Stalgorova, E. and Mattar, L. 2012. Practical Analytical Model to Simulate Production of Horizontal Wells with Branch Fractures. Presented at the SPE Canadian Unconventional Resources Conference, Calgary, 30 October–1 November. SPE-162515-MS. http://dx.doi.org/10.2118/162515-MS.
Stalgorova, E. and Mattar, L. 2013. Analytical Model for Unconventional Multifractured Composite Systems. SPE Res Eval & Eng 16 (3): 246–256. SPE-162516-PA. http://dx.doi.org/10.2118/162516-PA.
Sureshjani, M. H. and Clarkson, C. R. 2015. An Analytical Model for Analyzing and Forecasting Production From Multifractured Horizontal Wells With Complex Branched-Fracture Geometry. SPE Res Eval & Eng 18 (3): 356–374. SPE-176025-PA. http://dx.doi.org/10.2118/176025-PA.
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, 5–8 April. SPE-39931-MS. http://dx.doi.org/10.2118/39931-MS.
Whitson, C. H. and Sunjerga, S. 2012. PVT in Liquid-Rich Shale Reservoirs. Presented at the SPE Annual Technical Conference and Exhibition, San Antonio, Texas, USA, 8–10 October. SPE-155499-MS. http://dx.doi.org/10.2118/155499-MS.