Rate-Transient Analysis Based on Power-Law Behavior for Permian Wells
- W. Chu (Pioneer Natural Resources) | N. Pandya (Pioneer Natural Resources) | R. W. Flumerfelt (Pioneer Natural Resources) | C. Chen (Kappa Engineering)
- Document ID
- Society of Petroleum Engineers
- SPE Annual Technical Conference and Exhibition, 9-11 October, San Antonio, Texas, USA
- Publication Date
- Document Type
- Conference Paper
- 2017. Society of Petroleum Engineers
- 5.6.3 Pressure Transient Analysis
- unconventional reservoirs, Rate Transient Analysis, power law, Chow group
- 22 in the last 30 days
- 460 since 2007
- Show more detail
- View rights & permissions
|SPE Member Price:||USD 8.50|
|SPE Non-Member Price:||USD 25.00|
In unconventional reservoirs, the application of many rate-transient analysis (RTA) techniques rely heavily on the identification and analysis of the linear flow regime, which is characterized by a ½ slope on a log-log plot of Δp vs. t. Through our analysis of more than 400 wells with downhole pressure gauges in the Wolfcamp shale of the Permian basin, we observed power law behavior, but with slopes much different than ½ over long periods of time. In many cases, the duration of the straight line with a slope different from ½ lasts for years, without ever converging to ½. In some cases, the slope changes over time but rarely is the characteristic ½ slope observed over long periods. Rate forecasts would be in error if were to assume that the slope would converge to ½ slope at a later time.
In this work, we present examples of Permian Wolfcamp horizontal wells with measured bottomhole pressure (BHP) to demonstrate the characteristic power-law behavior with slopes different from ½. Power-law behaviors are typical in heterogeneous systems and are identified using the Chow pressure group (CPG).
Based on the concept of the power-law behavior, we have developed a workflow to analyze multiphase rate-transient data with high quality measured BHP. Ultimately, the new workflow for rate-transient analysis uses power-law characteristics to evaluate well performance and is a complementary tool to traditional methods such as Arps decline-curve analysis. This paper outlines a power-law analysis workflow scheme and demonstrates that the Chow group is a convenient means to identify the exponents of straight lines. In addition, we present case studies to demonstrate the application of this technique to predict the long-term well performance from choked-back wells, to evaluate long-term performance changes associated with offset frac hits, and to estimate the hyperbolic decline-curve b-factor.
|File Size||1 MB||Number of Pages||14|
Arps, J. J. 1945. Analysis of Decline Curves. Trans. AIME, 160(1). SPE-945228-G. http://dx.doi.org/10.2118/945228-G.
Bello, O.R. & Wattenbarger, A.R. 2010. Multi-stage Hydraulically Fractured Horizontal Shale Gas Well Rate Transient Analysis. Paper SPE 126754 presented at the 2010 SPE North Africa Technical Conference and Exhibition, Cairo, Egypt, 14-17 February. doi:10.2118/126754-MS.
Chen, C. & Raghavan, R. 2013. On Some Characteristic Features of Fractured-Horizontal Wells and Conclusions Drawn Thereof. SPE Reservoir Evaluation & Engineering, (1), 19–28. doi:10.2118/163104-PA.
Clarkson, C. R., & Beierle, J. 2010. Integration of Microseismic and Other Post-Fracture Surveillance with Production Analysis: A Tight Gas Study, Paper SPE-131786-MS presented at the SPE Unconventional Gas Conference, 23-25 February, Pittsburgh, Pennsylvania, USA. doi:10.2118/131786-MS.
Clarkson, C.R. & Qanbari, F. 2015. A Semianalytical Forecasting Method for Unconventional Gas and Light Oil Wells: A Hybrid Approach for Addressing the Limitations of Existing Empirical and Analytical Methods. SPE Reservoir Evaluation & Engineering, (1), 94–108. doi:10.2118/170767-PA.
Deen, T., Shchelokov, V., Wydrinski, R., Reed, T., & Friedrich, M. 2013. Horizontal Well Performance Prediction Early in the Life of the Wolfcamp Oil Resources Play in the Midland Basin, Paper URTEC-1582281-MS. Presented at the Unconventional Resources Technology Conference, Denver, 12-14 August.
Duong, A.N. 2011. Rate-Decline Analysis for Fracture-Dominated Shale Reservoirs. SPE Reservoir Evaluation & Engineering, (3), 377–387. doi:10.2118/137748-PA
Palacio, J. C. & Blasingame, T.A. 1993. Decline-Curve Analysis With Type Curves – Analysis of Gas Well Production Data, paper SPE 25909 presented at the SPE Rocky Mountain Regional/Low Permeability Reservoirs Symposium, Denver, Colorado, 12-14 April. doi:10.2118/25909-MS.
Raghavan, R., Chen, C. & Agarwal, B. 1997. An analysis of horizontal wells intercepted by multiple fractures, SPE Journal, (3) 235–245, doi: 10.2118/27652-PA.
Seshadri, J. & Mattar, L. 2010. Comparison of Power Law and Modified Hyperbolic Decline Methods. Paper SPE 137320 presented at the Canadian Unconventional Resources & International Petroleum Conference, Calgary, Alberta, Canada, 19-21 October. doi:10.2118/137320-MS.
Scott, K. D., Chu, W.-C., & Flumerfelt, R.W. 2015. Application of Real-Time Bottom-Hole Pressure to Improve Field Development Strategies in the Midland Basin Wolfcamp Shale, Paper URTEC-2154675-MS presented at the Unconventional Resources Technology Conference. doi:10.15530/URTEC-2015-2154675.
Thomas, O.O., Raghavan, R., & Dixon, T.N. (2005), Effect of Scaleup and Aggregation on the Use of Well Tests to Identify Geological Properties" SPE Reservoir Evaluation and Engineering, (3), 248–254 doi: 10.2118/77452-PA.
Uzun, I., Kurtoglu, B., & Kazemi, H. 2016. Multiphase Rate-Transient Analysis in Unconventional Reservoirs: Theory and Application, SPE Reservoir Evaluation & Engineering, (4), 553–566. doi:10.2118/171657-PA.
Wattenbarger, R.A., El-Banbi, A.H., Villegas, M.E. & Maggard, J.B. 1998. Production Analysis of Linear Flow into Fractured Tight Gas Wells. Paper SPE 39931 presented at SPE Rocky Mountain Regional/Low Permeability Reservoirs Symposium and Exhibition, Denver, Colorado, 5-8 April. doi:10.2118/39931-MS.
Winestock, A. G., & Colpitts, G.P. 1965. Advances in Estimating Gas Well Deliverability, Journal of Canadian Petroleum Technology, (3): 111–119. doi:10.2118/65-03-01.