Rate-Decline Analysis for Fracture-Dominated Shale Reservoirs
- Anh N. Duong (ConocoPhillips)
- Document ID
- Society of Petroleum Engineers
- SPE Reservoir Evaluation & Engineering
- Publication Date
- June 2011
- Document Type
- Journal Paper
- 377 - 387
- 2011. Society of Petroleum Engineers
- 5.1.1 Exploration, Development, Structural Geology, 5.6.9 Production Forecasting, 1.2.3 Rock properties, 5.8.2 Shale Gas
- Production Analysis, Shale Gas, EUR, Rate Decline, Fracture
- 17 in the last 30 days
- 4,554 since 2007
- Show more detail
- View rights & permissions
|SPE Member Price:||USD 10.00|
|SPE Non-Member Price:||USD 30.00|
Traditional decline methods such as Arps' rate/time relations and their variations do not work for wells producing from supertight or shale reservoirs in which fracture flow is dominant. Most of the production data from these wells exhibit fracture-dominated flow regimes and rarely reach late-time flow regimes, even over several years of production. Without the presence of pseudoradial and boundary-dominated flows (BDFs), neither matrix permeability nor drainage area can be established. This indicates that matrix contribution is negligible compared with fracture contribution, and the expected ultimate recovery (EUR) cannot be based on a traditional concept of drainage area.
An alternative approach is proposed to estimate EUR from wells in which fracture flow is dominant and matrix contribution is negligible. To support these fracture flows, the connected fracture density of the fractured area must increase over time. This increase is possible because of local stress changes under fracture depletion. Pressure depletion within fracture networks would reactivate the existing faults or fractures, which may breach the hydraulic integrity of the shale that seals these features. If these faults or fractures are reactivated, their permeabilities will increase, facilitating enhanced fluid migration. For fracture flows at a constant flowing bottomhole pressure, a log-log plot of rate over cumulative production vs. time will yield a straight line with a unity slope regardless of fracture types. In practice, a slope of greater than unity is normally observed because of actual field operations, data approximation, and flow-regime changes. A rate/time or cumulative production/time relationship can be established on the basis of the intercept and slope values of this log-log plot and initial gas rate.
Field examples from several supertight and shale gas plays for both dry and high-liquid gas production, and for oil production were used to test the new model. All display the predicted straight-line trend, with its slope and intercept related to reservoir types. In other words, a certain fractured flow regime or a combination of flow types that dominate a given area or play because of its reservoir-rock characteristics and/or fracture-stimulation practices all produce a narrow range of intercepts and slopes. An individual-well performance or EUR can be derived that is based on this range if the best 3-month average or the initial production rate of the well is already known or estimated. The results show that this alternative approach is easier to use, gives a reliable EUR, and can be used to replace the traditional decline methods for unconventional reservoirs. The new approach is also able to provide statistical methods to analyze production forecasts of resource plays and to establish a range of results of these forecasts, including probability distributions of reserves in terms of P90 (lower side) to P10 (higher side).
|File Size||1 MB||Number of Pages||13|
Agarwal, R.G., Carter, R.D., and Pollock, C.B. 1979. Evaluation andPerformance Prediction of Low-Permeability Gas Wells Stimulated by MassiveHydraulic Fracturing. J Pet Technol 31 (3): 362-372;Trans., AIME, 267. SPE-6838-PA. doi: 10.2118-6838-PA.
Anderson, D.M., Nobakht, M., Moghadam, S., and Mattar, L. 2010. Analysis ofProduction Data from Fractured Shale Gas Wells. Paper SPE 131787 presented atthe SPE Unconventional Gas Conference, Pittsburgh, Pennsylvania, USA, 23-25February. doi:10.2118/131787-MS.
Arévalo-Villagrán, J.A., Wattenbarger, R.A., and Samaniego-Verduzco, F.2006. Some History Cases of Long-Term Linear Flow in Tight Gas Wells. J CanPet Technol 45 (3): 31-37. JCPT Paper No. 06-03-01. doi: 10.2118/06-03-01.
Arévalo-Villagrán, J.A., Wattenbarger, R.A., Samaniego-Verduzco, F., andPham, T.T. 2001. Production Analysis of Long-Term Linear Flow in Tight GasReservoirs: Case Histories. Paper SPE 71516 presented at the SPE AnnualTechnical Conference and Exhibition, New Orleans, 30 September -3 October. doi: 10.2118/71516-MS.
Arps, J.J. 1945. Analysis of Decline Curves. SPE-945228-G. Trans.,AIME, 160: 228-247.
Bagnall, W.D. and Ryan, W.M. 1976. The geology, reserves, and productioncharacteristics of the Devonian Shale in southwestern West Virginia. InDevonian Shale Production and Potential: Proceedings of the SeventhAppalachian Petroleum Geology Symposium held at Morganstown, West Virginia,March 1-4, ed. R.C. Shumaker and W.K. Overbey Jr., MERC/SP-76/2, 41-53.Alexandria, Virginia, USA: National Technical Information Service.
Bello, R.O. and Wattenbarger, R.A. 2008. Rate Transient Analysis inNaturally Fractured Shale Gas Reservoirs. Paper SPE 114591 presented at theCIPC/SPE Gas Technology Symposium, Calgary, 16-19 June. doi: 10.2118/114591-MS.
Bello, R.O. and Wattenbarger, R.A. 2010. Multi-stage Hydraulically FracturedHorizontal Shale Gas Well Rate Transient Analysis. Paper SPE 126754 presentedat the North Africa Technical Conference and Exhibition, Cairo, 14-17 February.doi: 10.2118/126754-MS.
Cinco-Ley, H. and Samaniego-V., F. 1981a. Transient Pressure Analysis forFractured Wells. J Pet Technol 33 (9): 1749-1766.SPE-7490-PA. doi:10.2118/7490-PA.
Cinco-Ley, H. and Samaniego-V., F. 1981b. Transient Pressure Analysis:Finite Conductivity Fracture Versus Damaged Fracture Case. Paper SPE 10179presented at the SPE Annual Technical Conference and Exhibition, San Antonio,Texas, USA, 4-7 October. doi:10.2118/10179-MS.
Cinco-Ley, H., Samaniego-V., F., and Dominguez A.N. 1978. Transient PressureBehavior for a Well With a Finite-Conductivity Vertical Fracture. SPE J. 18 (4): 253-264. SPE-6014-PA. doi: 10.2118/6014-PA.
Clarkson, C.R. and Beierle, J.J. 2010. Integration of Microseismic and OtherPost-Fracture Surveillance with Production Analysis: A Tight Gas Study. PaperSPE 131786 presented at the SPE Unconventional Gas Conference, Pittsburgh,Pennsylvania, USA, 23-25 February. doi: 10.2118/131786-MS.
Fetkovich, M.J. 1980. Decline Curve Analysis Using Type Curves. J PetTechnol 32 (6): 1065-1077. SPE 4629-PA. doi: 10.2118/4629-PA.
Frantz, J.H. Jr., Williamson, J.R., Sawyer, W.K., Johnston, D., Waters, G.,Moore, L.P., Macdonald, R.J., Pearcy, M., Ganpule, S.V., and March, K.S. 2005.Evaluating Barnett Shale Production Performance Using an Integrated Approach.Paper SPE 96917 presented at the SPE Annual Technical Conference andExhibition, Dallas, 9-12 October. doi: 10.2118/96917-MS.
Gringarten, A.C., Ramey, H.J. Jr., and Raghavan, R. 1975. Applied PressureAnalysis for Fractured Wells. J Pet Technol 27 (7):887-892. SPE-5496-PA. doi:10.2118/5496-PA.
Ilk, D., Rushing, J.A., and Blasingame, T.A. 2009. Decline Curve Analysisfor HP/HT Gas Wells: Theory and Applications. Paper SPE 125031 presented at theSPE Annual Technical Conference and Exhibition, New Orleans, 4-7 October. doi: 10.2118/125031-MS.
Ilk, D., Rushing, J.A., Perego, A.D., and Blasingame, T.A. 2008. Exponentialvs. Hyperbolic Decline in Tight Gas Sands--Understanding the Origin andImplications for Reserve Estimates Using Arps' Decline Curves. Paper SPE 116731presented at the SPE Annual Technical Conference and Exhibition, Denver, 21-24September. doi:10.2118/116731-MS.
Lee, W.J. and Sidle, R.E. 2010. Gas Reserves Estimation in Resource Plays.Paper SPE 130102 presented at the SPE Unconventional Gas Conference,Pittsburgh, Pennsylvania, USA, 23-25 February. doi: 10.2118/130102-MS.
Mattar, L., Gault, B., Morad, K., Clarkson, C.R., Freeman, C.M., Ilk, D.,and Blasingame, T.M. 2008. Production Analysis and Forecasting of Shale GasReservoirs: Case History-Based Approach. Paper SPE 119897 presented at the SPEShale Gas Production Conference, Fort Worth, Texas, USA, 16-18 November. doi: 10.2118/119897-MS.
Newsham, K.E. and Rushing, J.A. 2002. Laboratory and Field Observations ofan Apparent Sub-Capillary-Equilibrium Water Saturation Distribution in a TightGas Sand Reservoir. Presented at the SPE Gas Technology Symposium, Calgary, 30April-2 May. Search and Discovery Article #40400.
Soltanzadeh, H. and Hawkes, D.C. 2008. Semi-analytical models for stresschange and fault reactivation induced by reservoir production and injection.J. Pet. Sci. Eng. 60 (2): 71-85. doi:10.1016/j.petrol.2007.05.006.
Spencer, C.W. 1987. Hydrocarbon Generation as a Mechanism for Overpressuringin Rocky Mountain Region. AAPG Bulletin 71 (4):368-388.
Valkó, P.P. 2009. Assigning Value to Stimulation in the Barnett Shale: ASimultaneous Analysis of 7000 Plus Production Histories and Well CompletionRecords. Paper SPE 119639 presented at the SPE Hydraulic Fracturing TechnologyConference, The Woodlands, Texas, USA, 19-21 January. doi: 10.2118/119639-MS.
Warpinski, N.R. and Branagan, P.T. 1989. Altered-Stress Fracturing. J PetTechnol 41 (9): 990-997. SPE-17533-PA. doi: 10.2118/17533-PA.
Weng, X. and Siebrits, E. 2007. Effect of Production-Induced Stress Field onRefracture Propagation and Pressure Response. Paper SPE 106043 presented at theSPE Hydraulic Fracturing Technology Conference, College Station, Texas, USA,29-31 January. doi:10.2118/106043-MS.