Abstract
Abstract Fluid flow is strongly affected by fractures in unconventional reservoirs. It is essential to deeply understand the flow characteristics with fractures for improving the production and efficiency of unconventional reservoir exploitation. The purpose of this work is to develop an accurate numerical model to evaluate the transient-pressure response for well intersecting fractures. The meshes generated from Fullbore Formation Micro-Imager (FMI) images ensure an efficient numerical description of the geometries for fractures and interlayers. The numerical simulation is implemented by an inhouse finite element method-based code and benchmarked with drill stem test (DST) data. The results show that three flow regimes appear in the reservoir with fractures within the test period: wellbore afterflow, pseudolinear flow, and radial flow. In contrast, only the wellbore afterflow and radial flow appear for the wells without fractures. The results also reveal that fractures dominate the flow near the wellbore. Verification and application of the model show the practicability of the integrated approach for investigating the transient-pressure behaviors in the unconventional reservoir.
Highlights
Many fractures have formed in coal after the long-term geological process, which significantly influences coal seam gas (CSG) development [1, 2]
Microscale fracture analysis is mainly based on focused ion beam scanning electron microscopy (FIB-SEM) [7], scanning electron microscopy (SEM) [8], nuclear magnetic resonance (NMR) [9], X-ray micro-computed tomography (Micro-CT) [10]
The meshes of 104,760 nodes and 98,600 hexahedral elements generated from Formation Micro-Imager (FMI) images are successfully applied to describe the highly complex CSG reservoir with eight open inclined fractures and three intercalations
Summary
Many fractures have formed in coal after the long-term geological process, which significantly influences coal seam gas (CSG) development [1, 2]. Multiple scale fractures have been investigated, ranging from nanoscale to field scale with hundreds of meters [3,4,5,6]. Field-scale fractures can be detected by geophysical methods [11]. The characterization of meter-scale fractures in coal seams directly is still a challenge. The analytical model of wells with inclined fractures has appeared gradually.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
