Explicit original gas in place determination of naturally fractured reservoirs in gas well rate decline analysis

Abstract

Naturally fractured gas reservoirs have contributed significantly to global gas reserves and production. The classical gas-well decline analysis relies largely on Arps’ empirical decline models, or modern production decline analysis associating with pseudo-variables. The explicit original gas in place determination methodology is extended from homogeneous reservoir to naturally fractured reservoir under constant or variable bottom-hole pressure conditions in gas-well rate decline analysis. Then, the relationship between gas flow rate and average reservoir pseudo-pressure in the boundary-dominated flow period is re-derived. This formula is in the same format with the equation for homogeneous reservoir by due to the introduction of a new productivity index parameter that captures the inter-porosity flow between fracture and matrix in the natural fractured reservoir. The proposed step-by-step procedures are applied here, which enable the estimation of decline exponent and the explicit and straightforward determination of the original gas in place without any iterative calculations. Four simulated cases prove that our methodology can be successfully used in heterogeneous naturally fractured reservoirs with irregular boundary under constant or variable bottom-hole pressure conditions.

Document Type: Original article

Cited as: Wang, Y., Wang, J., Zhao, W., Ji, P., Cheng, S., Yu, H. Explicit original gas in place determination of naturally fractured reservoirs in gas well rate decline analysis. Advances in Geo-Energy Research, 2023, 9(2): 117-124. https://doi.org/10.46690/ager.2023.08.05

References

Abou-Kassem, J. H., Mattar, L., Dranchuk, P. M. Computer calculations of compressibility of natural gas. Journal of Canadian Petroleum Technology, 1990, 29(5): 105-108.

Agarwal, R. G. “Real gas pseudo-time”-A new function for pressure buildup analysis of MHF gas wells. Paper SPE 8279 Presented at the Annual Technical Conference and Exhibition, Las Vegas, Nevada, 23-26 September, 1979.

Al-Hussainy, R., Ramey, H. J., Crawford, P. B. The flow of real gases through porous media. Journal of Petroleum Technology, 1966, 18(5): 624-636.

Andersen, P. O. Insights from Boltzmann transformation in solving 1D counter-current spontaneous imbibition at early and late time. Advances in Geo-Energy Research, 2023, 7(3): 164-175.

Arps, J. J. Analysis of decline curves. Transaction of the AIME, 1945, 160(1): 228-247.

Barenblatt, G. I., Zheltov, Y. P., Kochina, I. N. Basic concepts in the theory of seepage of homogeneous liquids in fissured rocks. Journal of Applied Mathematics and Mechanics, 1960, 24(5): 852-864.

Benson, A. L. L., Clarkson, C. R. Flowback rate-transient analysis with spontaneous imbibition effects. Journal of Natural Gas Science and Engineering, 2022, 108: 104830.

Blasingame, T. A., Lee, W. J. The variable-rate reservoir limits testing of gas wells. Paper SPE 17708 Presented at SPE Gas Technology Symposium, Dallas, Texas, 13-15 June, 1988.

Blasingame, T. A., McCray, T. L., Lee, W. J. Decline curve analysis for variable pressure drop/variable flowrate systems. Paper SPE 21513 Presented at SPE Gas Technology Symposium, Houston, Texas, 22-24 January, 1991.

Carter, R. D. Type curves for finite radial and linear gas-flow systems: Constant-terminal-pressure case. Society of Petroleum Engineers Journal, 1985, 25(5): 719-728.

Chen, M., Yan, M., Kang, Y., et al. Stress sensitivity of multiscale pore structure of shale gas reservoir under fracturing fluid imbibition. Capillarity, 2023, 8(1): 11-22.

Dranchuck, P. M., Abou-Kassem, J. H. Calculation of Z factors for natural gases using equations of state. Journal of Canadian Petroleum Technology, 1975, 14(3): 34-36.

Duong, A. N. Rate-decline analysis for fracture-dominated shale reservoirs. SPE Reservoir Evaluation & Engineering, 2011, 14(3): 377-387.

Fetkovich, M. J. Decline curve analysis using type curves. Journal of Petroleum Technology, 1980, 32(6): 1065-1077.

Fraim, M. L., Wattenbarger, R. A. Gas reservoir decline-curve analysis using type curves with real gas pseudopressure and normalized time. SPE Formation Evaluation, 1987, 2(4): 671-682.

Gerami, S., Pooladi-Darvish, M., Hong, H. Decline curve analysis for naturally fractured gas reservoirs: A study on the applicability of “pseudo-time” and “material balance pseudo-time”. Paper IPTC 11278 Presented at International Petroleum Technology Conference, Dubai, 4-6 December, 2007.

Jongkittinarukorn, K., Last, N., Escobar, F. H., et al. A straight-line DCA for a gas reservoir. Journal of Petroleum Science and Engineering, 2021, 201: 108452.

Jongkittinarukorn, K., Last, N. C., Kabir, C. S. Decline-curve analysis with decline rate for improving reserves estimation in gas reservoirs. Gas Science and Engineering, 2023, 116: 205044.

Kao, J., Wei, S., Wang, W., et al. Numerical analysis of the hydraulic fracture communication modes in fracture-cavity reservoirs. Petroleum Science, 2022, 19(5): 2227-2239.

Lee, A. L., Gonzalez, M. H., Eakin, B. E. The viscosity of natural gases. Journal of Petroleum Technology, 1966, 18(8): 997-1000.

Meng, M., Chen, Z., Liao, X., et al. A well-testing method for parameter evaluation of multiple fractured horizontal wells with non-uniform fractures in shale oil reservoirs. Advances in Geo-Energy Research, 2020, 4(2): 187-198.

Palacio, J. C., Blasingame, T. A. Decline-curve analysis with type curves-analysis of gas well production data. Paper SPE 25909 Presented at the Low-Permeability Reservoir Symposium, Denver, 26-28 April, 1993.

Pi, Z., Peng, H., Jia, Z., et al. Coupling mechanisms of displacement and imbibition in pore-fracture system of tight oil reservoir. Capillarity, 2023, 7(1): 13-24.

Pichit, V., Ayala, L. F., Zhang, M. Linear vs. Radial boundary-dominated flow: Implications for gas-well-decline analysis. SPE Journal, 2015, 20(5): 1053-1066.

Prat, G. D., Cinco-Ley, H., Ramey, H. Decline curve analysis using type curves for two-porosity systems. Society of Petroleum Engineers Journal, 1981, 21(3): 354-362.

Qin, J., Zhong, Q., Tang, Y., et al. Well interference evaluation considering complex fracture networks through pressure and rate transient analysis in unconventional reservoirs. Petroleum Science, 2023, 20(1): 337-349.

Stumpf, T. N., Ayala, L. F. Rigorous and explicit determination of reserves and hyperbolic exponents in gas-well decline analysis. SPE Journal, 2016, 21(5): 1843-1857.

Sutton, R. P. Compressibility factors for high-molecularweight reservoir gases. Paper SPE 14265 Presented at the SPE Annual Technical Conference and Exhibition, Las Vegas, Nevada, 22-26 September, 1985.

Wang, Y., Ayala, L. F. Explicit determination of reserves for variable bottom-hole pressure conditions in gas well decline analysis. SPE Journal, 2020, 25(1): 369-390.

Wang, Y., Cheng, S., Wei, C., et al. Gas rate decline analysis for boundary-dominated flow with fractal reservoir properties under constant/variable bottom-hole pressure conditions. Journal of Natural Gas Science and Engineering, 2021, 88: 103823.

Warren, J., Root, P. J. The behavior of naturally fractured reservoirs. Society of Petroleum Engineers Journal, 1963, 3(3): 245-255.

Wattenbarger, R. A., EI-Banbi, A. H., Vilegas, M. E., et al. Production analysis of linear flow into fractured tight gas wells. Paper SPE 39931 Presented at the SPE Rocky Mountain Regional/Low-Permeability Reservoirs Symposium, Denver, Colorado, 5-8 April, 1998.

Zaremoayedi, F., Ghaedi, M., Kazemi, N. A new approach to production data analysis of non-volumetric naturally fractured gas condensate reservoirs. Journal of Natural Gas Science and Engineering, 2022, 105: 104703.

Zhang, Z., Ayala, L. F. Analytical dual-porosity gas model for reserve evaluation of naturally fractured gas reservoirs using a density-based approach. Journal of Natural Gas Science and Engineering, 2018, 59: 224-236.