A Numerical Model for Simulating Pressure Response of Well Interference and Well Performance in Tight Oil Reservoirs With Complex–Fracture Geometries Using the Fast Embedded–Discrete–Fracture–Model Method

Abstract

Summary The effect of well interference through fracture hits in shale reservoirs needs to be investigated because hydraulic fracturing is abundantly used in the development of unconventional oil and gas resources. Although numerous pressure tests have proved the existence of well interference, relatively few physical models exist to quantitatively simulate the pressure response of well interference. The objective of the present study is to develop a numerical compositional model in combination with a fast embedded-discrete-fracture-model (EDFM) method to simulate well interference. Through nonneighboring connections (NNCs), the fast EDFM method can easily and properly handle complex-fracture geometries, such as nonplanar hydraulic fractures and a large amount of natural fractures. Using public data for Eagle Ford tight oil, we build a reservoir model including up to three horizontal wells and five fluid pseudocomponents. The simulation results show that the connecting hydraulic fractures play a more-important role than natural fractures in declining bottomhole pressure (BHP) of the shut-in well. Matrix permeability has a relatively minor effect on pressure drawdown, and well productivity remains only slightly affected by the overall low permeability used. The BHP pressure-decline profiles change from convex to concave when the conductivity of the connecting fractures increases. At early times, the BHP of the shut-in well decreases when the number of natural fractures increases. At later times, the natural-fracture density has a lesser effect on the pressure response and no clear trend. The opening order of neighboring wells affects the well-interference intensity between the target shut-in well and the surrounding wells. After a systematic investigation of pressure drawdown in the reservoir, we formulate practical conclusions for improved production performance.