A New Analytical Method for Analyzing Linear Flow in Tight/Shale Gas Reservoirs: Constant-Flowing-Pressure Boundary Condition
- Morteza Nobakht (Encana Corporation) | Christopher R. Clarkson (University of Calgary)
- Document ID
- Society of Petroleum Engineers
- SPE Reservoir Evaluation & Engineering
- Publication Date
- June 2012
- Document Type
- Journal Paper
- 370 - 384
- 2012. Society of Petroleum Engineers
- 5.8.2 Shale Gas
- 12 in the last 30 days
- 1,705 since 2007
- Show more detail
- View rights & permissions
|SPE Member Price:||USD 10.00|
|SPE Non-Member Price:||USD 30.00|
Many tight/shale gas wells exhibit linear flow, which can last for several years. Linear flow can be analyzed using a square-root-of-time plot, a plot of rate-normalized pressure vs. the square root of time. Linear flow appears as a straight line on this plot, and the slope of this line can be used to calculate the product of fracture half-length and the square root of permeability.
In this paper, linear flow from a fractured well in a tight/shale gas reservoir under a constant-flowing-pressure constraint is studied. It is shown that the slope of the square-root-of-time plot results in an overestimation of fracture half-length, if permeability is known. The degree of this overestimation is influenced by initial pressure, flowing pressure, and formation compressibility. An analytical method is presented to correct the slope of the square-root-of-time plot to eliminate the overestimation of fracture half-length. The method is validated using a number of numerically simulated cases. As expected, the square-root-of-time plots for these simulated cases appear as a straight line during linear flow for constant flowing pressure. It is found that the newly developed analytical method results in a more reliable estimate of fracture half-length, if permeability is known. Our approach, which is fully analytical, results in an improvement in linear-flow analysis over previously presented methods. Finally, the application of this method to multifractured horizontal wells is discussed and the method is applied to three field examples.
|File Size||1 MB||Number of Pages||15|
Agarwal, R.G., Gardner, D.C., Kleinsteiber, S.W., and Fussell, D.D. 1999.Analyzing Well Production Data Using Combined-Type-Curve and Decline-CurveAnalysis Concepts. SPE Res Eval & Eng 2 (5): 478-486.SPE-57916-PA. http://dx.doi.org/10.2118/57916-PA.
Anderson, D.M. and Mattar, L. 2005. An Improved Pseudo-Time for GasReservoirs with Significant Transient Flow. Paper CIPC 2005-114 presented atthe Canadian International Petroleum Conference, Calgary, 7-9 June. http://dx.doi.org/10.2118/2005-114.
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. http://dx.doi.org/10.2118/131787-MS.
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. http://dx.doi.org/10.2118/114591-MS.
Bello, R.O. and Wattenbarger, R.A. 2010. Modelling and Analysis of Shale GasProduction With a Skin Effect. J Can Pet Technol 49 (12):37-48. SPE-143229-PA. http://dx.doi.org/10.2118/143229-PA.
Carlson, E.S. and Mercer, J.C. 1989. Devonian Shale Gas Production:Mechanisms and Simple Models. J Pet Technol 43 (4):476-482. SPE-19311-PA. http://dx.doi.org/10.2118/19311-PA.
El-Banbi, A.H. and Wattenbarger, R.A. 1998. Analysis of Linear Flow in GasFlow Production. Paper SPE 39972 presented at the SPE Gas Technology Symposium,Calgary, 15-18 March. http://dx.doi.org/10.2118/39972-MS.
Fraim, M.L. and Wattenbarger, R.A. 1987. Gas Reservoir Decline CurveAnalysis Using Type Curves with Real Gas Pseudopressure and Normalized Time.SPE Form Eval 2 (4): 671-682. SPE-14238-PA. http://dx.doi.org/10.2118/14238-PA.
Ibrahim, M. and Wattenbarger, R.A. 2005. Rate Dependence of Transient LinearFlow in Tight Gas Wells. Paper CIPC 2005-057 presented at the CanadianInternational Petroleum Conference, Calgary, 7-9 June. http://dx.doi.org/10.2118/2005-057.
Ibrahim, M. and Wattenbarger, R.A. 2006. Analysis of Rate Dependence inTransient Linear Flow in Tight Gas Wells. Paper SPE 100836 presented at the AbuDhabi International Petroleum Exhibition and Conference, Abu Dhabi, UAE, 5-8November. http://dx.doi.org/10.2118/100836-MS.
Mayerhofer, M.J., Lolon, E.P., Youngblood, J.E., and Heinze, J.R.2006. Integration of Microseismic Fracture Mapping Results with NumericalFracture Network Production Modeling in the Barnett Shale. Paper SPE 102103presented at the SPE Annual Technical Conference and Exhibition, San Antonio,Texas, USA, 24-27 September. http://dx.doi.org/10.2118/102103-MS.
Moghadam, S., Jeje, O., and Mattar, L. 2011. Advanced Gas Material Balancein Simplified Format. J Can Pet Technol 50 (1): 90-98.SPE-139428-PA. http://dx.doi.org/10.2118/139428-PA.
Nobakht, M. and Clarkson, C.R. 2011. A New Analytical Method for AnalyzingProduction Data from Shale Gas Reservoirs Exhibiting Linear Flow: Constant RateProduction. Paper SPE 143990 presented at the North American Unconventional GasConference and Exhibition, The Woodlands, Texas, USA, 14-16 June. http://dx.doi.org/10.2118/143990-MS.
Nobakht, M. and Mattar, L. 2010. Analyzing Production Data fromUnconventional Gas Reservoirs with Linear Flow and Apparent Skin. Paper SPE137454 presented at the Canadian Unconventional Resources and InternationalPetroleum Conference, Calgary, 19-21 October. http://dx.doi.org/10.2118/137454-MS.
Nobakht, M., Mattar, L., Moghadam, S., and Anderson, D.M. 2010. SimplifiedYet Rigorous Forecasting of Tight/Shale Gas Production in Linear Flow. PaperSPE 133615 presented at the SPE Western Regional Meeting, Anaheim, California,USA, 27-29 May. http://dx.doi.org/10.2118/133615-MS.
Wattenbarger, R.A., El-Banbi, A.H., Villegas, M.E., and Maggard, J.B. 1998.Production Analysis of Linear Flow Into Fractured Tight Gas Wells. Paper SPE39931 presented at the SPE Rocky Mountain Regional/Low-Permeability ReservoirsSymposium, Denver, 5-8 April. http://dx.doi.org/10.2118/39931-MS.