Transient Pressure Analysis for Multifractured Horizontal Well with the Use of Multilinear Flow Model in Shale Gas Reservoir

Abstract

Shale gas reservoirs (SGR) have been a central supply of carbon hydrogen energy consumption and hence widely produced with the assistance of advanced hydraulic fracturing technologies. On the one hand, due to the inherent ultralow permeability and porosity, there is stress sensitivity in the reservoirs generally. On the other hand, hydraulic fractures and the stimulated reservoir volume (SRV) generated by the massive hydraulic fracturing operation have contrast properties with the original reservoirs. These two phenomena pose huge challenges in SGR transient pressure analysis. Limited works have been done to take the stress sensitivity and spatially varying permeability of the SRV zone into consideration simultaneously. This paper first idealizes the SGR to be four linear composite regions. What is more, the SRV zone is further divided into subsections on the basis of nonuniform distribution of proppant within the SRV zone which easily yields spatially varying permeability away from the main hydraulic fracture. By means of perturbation transformation and Laplace transformation, an analytical multilinear flow model (MLFM) is obtained and validated as a comparison with the previous models. The flow regimes are identified, and the sensitivity analysis of critical parameters is conducted to further understand the transient pressure behaviors. The research results provided by this work are of significance for an effective recovery of SGR resources.

Well-Testing Model for Dual-Porosity Reservoir considering Stress-Sensitivity and Elastic Outer Boundary Condition

“…Wu et al [48], Ji et al [49], Huang et al [50], and Wu et al [51] established the well-testing models for the multifractured horizontal well in the stresssensitivity tight reservoirs. Wang et al [52], Liu et al [53], and Du et al [54] presented the well-testing models for the multifractured horizontal wells in the stress-sensitivity shale gas, and Chen et al [55] and Wang et al [56] presented the mathematical model of the transient pressure features in the stress-sensitivity coalbed methane reservoirs. Liu [57] discussed the well-testing model for multifractured horizontal wells, considering the effect of stress sensitivity and the threshold pressure gradient in a low-permeable reservoir.…”

“…Although such strong heterogeneity gives for detailed characterization of different aspects of the reservoir, it may be tedious and time-consuming in real application. In order to simply describe the stress-sensitivity reservoir, many researchers have introduced a conception of the permeability modulus to ensure the robustness of the analytical solution [20,36,40,47,48,52,58,59].…”

Green’s function-based type curves for multi-fractured horizontal gas wells in unconventional reservoirs

“…GFM is recognized by its systematic protocol, and the availability of a vast number of tabulated GF solutions for a variety of differential operators and domain geometries favors its implementation for a variety of physical processes [38]. While GFM has been explored in different reservoir engineering problems in the past, its application has been limited to slightlycompressible fluid-based formulation [39,40,41,42,43,44,45,46].…”

A Comprehensive Model for Estimating Stimulated Reservoir Volume Based on Flowback Data in Shale Gas Reservoirs

“…The development of shale gas has gained increasing attention with the decline of the production from conventional reservoirs [1,2]. Due to the ultralow permeability of shales (from 10 −23 to 10 −17 m 2 ) [3], a combination of horizontal drilling and multistage hydraulic fracturing has been widely used to SRV, which increases effective contact significantly to improve gas production from an individual well.…”