To address the limitations of Rate Transient Analysis (RTA), which lacks robust flow regime diagnostic capability and is restricted to boundary-dominated flow conditions, this study introduces a new analysis method for production data grounded in the principles of Pressure Transient Analysis (PTA), named as Variable-rate Pressure Transient Analysis (VPTA). Based on the convolution equation for variable-rate production, we derive a Rate-Normalized Pressure (RNP) equation (Tang-Luo equation) applicable to both the transient and boundary-dominated flow regimes with Analytical Deconvolution Method (ADM). This formulation explicitly depict the mathematical relationships among pressure drawdown, production rate, the pressure response function, and its derivative under variable-rate conditions. Subsequently, an explicit deconvolution algorithm for pressure response function and a characteristic flow regime analysis technique are developed. A standardized workflow is established, comprising data preprocessing, log-log diagnostic curve analysis, characteristic flow regime analysis, and parameter inversion, forming a production analysis approach centered on flow regime identification and straight-line fitting. Case study results demonstrate that the VPTA method enables a rigorous “diagnose-before-analyze” workflow, offering a more straightforward computational process than conventional RTA. It maintains interpretative reliability even under transient flow conditions, demonstrating its practical advantages and promising application potential.
VAN EVERDINGENA F, HURSTW. The application of the Laplace transformation to flow problems in reservoirs[J]. Journal of Petroleum Technology, 1949, 1(12): 305 - 324.
[2]
HORNERD R. Pressure build-up in wells[C]//Proceedings of the Third World Petroleum Congress, The Hague, Section II, 1951: 503 - 523.
[3]
MATTHEWSC S, RUSSELLD G. Pressure buildup and flow tests in wells[M]. New York: Henry L. Doherty Memorial Fund of AIME, 1967: 27.
FIRASA.A. Al - Kabbawi. The optimal semi-analytical modeling for the infinite-conductivity horizontal well performance under rectangular bounded reservoir based on a new instantaneous source function[J]. Petroleum, 2024, 10(1): 68 - 84.
AGARWALR G. A new method to account for producing time effects when drawdown type curves are used to analyze pressure buildup and other test data[C]//SPE Annual Technical Conference and Exhibition, 1980: SPE - 9289.
[8]
ROUMBOUTSOSA, STEWARTG. A direct deconvolution or convolution algorithm for well test analysis[C]//SPE Annual Technical Conference and Exhibition, 1988: SPE - 18157.
[9]
BOURDETD, AYOUBJ A, PIRARDY M. Use of pressure derivative in well-test interpretation[J]. SPE Formation Evaluation, 1989, 4(2): 293 - 302.
[10]
KUCHUKF J, CARTERR G, AYESTARANL. Deconvolution of wellbore pressure and flow rate[J]. SPE Formation Evaluation, 1990, 5(1): 53 - 59.
[11]
TIABD. Analysis of Pressure and Pressure Derivatives Without Type-Curve Matching: I—Skin and Wellbore Storage[C]//SPE Oklahoma City Oil and Gas Symposium/Production and Operations Symposium, 1993: SPE - 25426.
[12]
SCHROETERT V, HOLLAENDERF, GRINGARTENA C. Deconvolution of well-test data as a nonlinear total least-squares problem[J]. SPE Journal, 2004, 9(4): 375 - 390.
[13]
LEVITANM M. Practical application of pressure/rate deconvolution to analysis of real well tests[J]. SPE Reservoir Evaluation & Engineering, 2005, 8(2): 113 - 121.
[14]
GRINGARTENA C. From straight lines to deconvolution: The evolution of the state of the art in well test analysis[J]. SPE Reservoir Evaluation & Engineering, 2008, 11(1): 41 - 62.
SPIVEYJ P, LEEW J. Applied Well Test Interpretation[M]. Richardson, TX: Society of Petroleum Engineers, 2013: 187 - 229.
[17]
FETKOVICHM J. Decline curve analysis using type curves[C]//SPE Annual Technical Conference and Exhibition, 1973: SPE-4629.
[18]
FETKOVICHM J. Decline curve analysis using type curves[J]. Journal of Petroleum Technology, 1980, 32(6): 1065 - 1077.
[19]
FETKOVICHM J, VIENOTM E, BRADLEYM D, et al. Decline-curve analysis using type curves—case histories[J]. SPE Formation Evaluation, 1987, 2(4): 637 - 656.
[20]
ILK D, VALKOP P, BLASINGAMET A. Deconvolution of variable-rate reservoir-performance data using B-splines[J]. SPE Reservoir Evaluation & Engineering, 2006, 9(5): 582 - 595.
[21]
BLASINGAMET A, LEEW J. Variable-Rate Reservoir Limits Testing[C]//Permian Basin Oil and Gas Recovery Conference, 1986: SPE-15028-MS. DOI: 10.2118/15028-MS .
[22]
PALACIOJ C, BLASINGAMET A. Decline-curve analysis using type curves-analysis of gas well production data[C]//SPE Rocky Mountain Regional/Low Permeability Reservoirs Symposium, 1993: SPE-25909.
[23]
BLASINGAMET A, JOHNSTONJ L, LEEW J. Type-curve analysis using the pressure integral method[C]//SPE Western Regional Meeting, 1989: SPE-18799.
[24]
AGARWALR G, GARDNERD C, KLEINSTEIBERS W, et al. Analyzing well production data using combined type curve and decline curve analysis concepts[C]//SPE Annual Technical Conference and Exhibition, 1998: SPE-49222.
[25]
WATTENBARGERR A, EL-BANBIA H, VILLEGASM E, et al. Production analysis of linear flow into fractured tight gas wells[C]//SPE Rocky Mountain Petroleum Technology Conference/Low-Permeability Reservoirs Symposium, 1998: SPE-39931.
[26]
CLARKSONC R, PEDERSENP K. Tight oil production analysis: adaptation of existing rate-transient analysis techniques[C]//SPE Canada Unconventional Resources Conference, 2010: SPE-137352.
[27]
PRATIKNOH, RUSHINGJ A, BLASINGAMET A. Decline curve analysis using type curves—fractured wells[C]//SPE Annual Technical Conference and Exhibition, 2003: SPE-84287.
[28]
YINH, YUANH, FUC. Blasingame production decline analysis for a multi-fractured horizontal well in tight reservoirs[J]. Chinese Journal of Hydrodynamics, 2020, 35(2): 194 - 200.
[29]
BLASINGAMET A. Multiwell decline curve analysis using a type curve approach[C]//Unconventional Resources Technology Conference, 2022: 2261 - 2279.
[30]
JIANGR, HEJ, JIANGY, et al. Establishment and application of Blasingame production decline analysis method for fractured horizontal well in shale gas reservoirs[J]. Acta Petrolei Sinica, 2019, 40(12): 1503 - 1510.
[31]
BLASINGAMET A. Revisiting Time-Rate-Pressure Production Analysis—Where Are We Almost 40 Years Later?[C]//SPE Annual Technical Conference and Exhibition, 2023: D011S010R001.
ANDERSOND M, MATTARL. Material-balance-time during linear and radial flow[C]//PETSOC Canadian International Petroleum Conference, 2003: PETSOC-2003- 111.
[42]
AGNIAA K M. Data Bias in Rate Transient Analysis of Shale Gas Wells[D]. College Station: Texas A&M University, 2012.
[43]
HASANS S, MATTARL. Does Unit-Slope Beyond Maximum Producing Time Always Represent BDF in RTA?[C]//SPE Canada Unconventional Resources Conference, 2017: D011S003R002.
[44]
PANGW, DUJ, ZHANGT. Production data analysis of shale gas wells with abrupt gas rate or pressure changes[C]//SPE Middle East Oil and Gas Show and Conference, 2019: D041S046R001.
[45]
MOLINAO, SANTOSL, HERREROF, et al. Is decline curve analysis the right tool for production forecasting in unconventional reservoirs?[C]//SPE Annual Technical Conference and Exhibition, 2021: D031S060R001.
FRAIMM L, WATTENBARGERR A. Gas reservoir decline-curve analysis using type curves with real gas pseudopressure and normalized time[J]. SPE Formation Evaluation, 1987, 2(4): 671 - 682.