Production-Data Analysis of Gas Reservoirs With Apparent-Permeability and Sorbed-Phase Effects: A Density-Based Approach

Abstract

Summary Accounting for depletion-dependent permeability and sorbed-phase effects is an important step toward achieving reliable analysis of production performance in unconventional gas systems. This study demonstrates how to account for pressure-dependent apparent-permeability (e.g., gas-slippage) and desorption effects in gas-production analysis of boundary-dominated data with a density-based approach. In this work, apparent-permeability and desorption models are incorporated into the original density-based approach by modifying the definitions of depletion-driven variables that are the basis of the density-based type of analysis. The proposed modification of the original approach successfully enables associated analysis techniques to be applicable to natural-gas reservoirs with gas slippage and adsorbed gas. Results indicate that by modifying the definitions of the depletion-driven variables, the density approach can effectively and successfully capture the effects from gas slippage and desorption. Through a number of case studies, we show that gas-flow rate can be successfully predicted by rescaling liquid solution with the modified density-based variables. As an illustration, we show that resource calculations able to fully take into account these effects are possible when long-term production data are available. This work details the methodology required to do so, and illustrates its application to production-data prediction analysis for unconventional assets.

Integrated Analysis of Two-Phase Production Data in Hydraulic Fractured Deep Shale Reservoirs: Coupling Multiple Fluid Transport Mechanisms

“…The evaluation of reservoir and fracture parameters constitutes a critical part of the development of shale gas reservoirs. − Due to its rigorous theoretical foundation and operational simplicity, unconventional oil and gas reservoir rate transient analysis (RTA) technology is widely employed. , Scholars have proposed various analytical models, , semianalytical models, and dynamic drainage area models , to analyze flowback and production data from shale gas wells. Further research includes the utilization of multiphase flow RTA technology for fracture parameter assessment − and the application of numerical solution methods to model the complex fracture network postfracturing, thus enabling the inversion of fracture network parameters .…”

New Coupled Apparent Permeability Models for Gas Transport in Inorganic Nanopores of Shale Reservoirs Considering Multiple Effects

“…Physics of fluid flow in shale reservoirs which depends on the flow and porous medium conditions is quite different from conventional gas reservoirs. , The Knudsen number, which represents the relative degree of gas molecules’ collision with the gas molecules and pore walls, is usually used to divide the gas transfer mechanism into continuum flow, slip flow, transition flow, and free-molecular flow. − Furthermore, much research on apparent permeability has been carried out. Klingenberg first proposed the presence of gas slippage in porous media.…”