Assessment of Rate Transient Analysis Techniques for Multiphase Flow in Unconventional Reservoirs: Application to Eagle Ford Formation

2017 ◽  
Author(s):  
Ilkay Uzun ◽  
Erdinc Eker ◽  
Younki Cho ◽  
Hossein Kazemi ◽  
J. M. Rutledge
Keyword(s):  
Multiphase Flow ◽  
Transient Analysis ◽  
Unconventional Reservoirs ◽  
Eagle Ford ◽  
Analysis Techniques ◽  
Rate Transient Analysis

Rate-Transient Analysis of a Constant-Bottomhole-Pressure Multihorizontal Well Pad with a Semianalytical Single-Phase Method

SPE Journal ◽  
2020 ◽  
Vol 25 (06) ◽  
pp. 3280-3299
Author(s):  
Hongyang Chu ◽  
Xinwei Liao ◽  
Zhiming Chen ◽  
W. John John Lee
Keyword(s):  
Transient Analysis ◽  
Single Phase ◽  
Unconventional Reservoirs ◽  
Phase Method ◽  
Production Data ◽  
Transition Flow ◽  
Well Spacing ◽  
Rate Transient Analysis ◽  
Negative Effect ◽  
Bottomhole Pressure

Summary Because of readily available production data, rate-transient analysis (RTA) is an important method to predict productivity and reserves, and for reservoir and completion characterization in unconventional reservoirs. In addition, multihorizontal well pads are a common development method for unconventional reservoirs. Close well spacing between multifractured horizontal wells (MFHWs) in the multiwell pads makes interference from adjacent MFHWs especially significant. For RTA of production data from multihorizontal well pads, the influence of adjacent MFHWs cannot be ignored. In this work, we propose a semianalytic RTA model for the multihorizontal well pad with arbitrary multiple MFHW properties and starting-production times. Combining Laplace transformation and finite-difference analysis, we obtained a general solution of a multiwell mathematical model to use in RTA. Our model is applicable to cases of multiple MFHWs with different bottomhole pressures (BHPs), varying hydraulic-fracture properties, and different starting-production times. In the solutions, we observe bilinear flow, linear flow, transition flow, and multi-MFHW flow. Rate-normalized pressure (RNP) and its derivative are also affected by multi-MFHW flow. Two case studies revealed that the negative effect of interwell interference on the parent-well productivity is closely related to the pressure distribution caused by the production of child wells.

Treatment of Rate-Transient Analysis During Boundary-Dominated Flow

SPE Journal ◽  
2018 ◽  
Vol 23 (04) ◽  
pp. 1145-1165 ◽  
Author(s):  
H.. Behmanesh ◽  
L.. Mattar ◽  
J. M. Thompson ◽  
D. M. Anderson ◽  
D. W. Nakaska ◽  
...  
Keyword(s):  
Multiphase Flow ◽  
Transient Analysis ◽  
Single Phase ◽  
Material Balance ◽  
Operating Conditions ◽  
New Method ◽  
Productivity Index ◽  
Production Data ◽  
Rate Transient Analysis ◽  
Wide Range

Summary Significant advances have been made in the development of analytical models for performing rate-transient analysis (RTA) for single-phase oil and gas reservoirs. The primary complication associated with the adaptation of these solutions to wells exhibiting multiphase flow is the single-phase assumption in the development of the material-balance time function. Despite some efforts in modifying existing dry-gas formulations for use with gas/condensate reservoirs, that approach is not practical for analyzing multiphase flow from oil wells with multiphase-flow characteristics. In this work, we present a simple yet semianalytical model that provides a solution for analyzing production data from wells exhibiting multiphase flow during boundary-dominated flow periods. The solution is obtained by combining the material-balance equation and the productivity index (PI) for all flowing phases. Appropriately defined total pseudopressure and total pseudotime are introduced to handle the associated multiphase nonlinearities in the governing flow equations of oil, gas, and water phases simultaneously. A generalized flowing-material-balance (FMB) equation is derived from the total pseudovariables to estimate original fluid in place and drainage area (given volumetric input). The presented model provides a theoretical framework for analyzing production data considering a wide variety of reservoir-fluid systems. The new method is validated against numerical simulation, covering a wide range of fluid properties and operating conditions. In all simulated cases, the new method matches simulation input acceptably. Two field examples are also analyzed to demonstrate the practical applicability of this approach. This work serves as a practical and simple engineering tool for production-data analysis on wells exhibiting single and multiphase flow during boundary-dominated flow.

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