175. 地质力学与油藏模拟器耦合模拟复杂水力裂缝发育

Numerical Simulation of Complex Hydraulic Fracture Development by Coupling Geo-mechanical and Reservoir Simulator

水力压裂是油气工业为提高非常规油藏产量而采用的标准技术之一。储层性质和作业设计对水力压裂作业的有效性有重要影响。为优化水力压裂设计，对水力压裂机理进行了广泛研究。裂缝诊断技术的最新进展为复杂的裂缝几何形状带来了新的见解。数值模拟是研究裂缝几何形状生成及其对压后增产效果的经济方法。本工作提出了通过耦合地质力学模拟器Irazu和油藏模拟器CMG来研究裂缝复杂性的工作流程。地质力学模拟器用于模拟水力压裂过程，采用混合离散有限元方法，而油藏模拟器CMG用于油藏压裂后产量预测。

Abstract

Hydraulic fracturing is one of the standard techniques adopted by oil and gas industries to enhance production in unconventional reservoirs. Reservoir properties and treatment designs have a significant influence on the effectiveness of hydraulic fracturing treatments. Extensive studies on the mechanism of hydraulic fracturing have been conducted to optimize the hydraulic fracturing design. Recent advances in fracture diagnostic technology have brought new insights to the complex fracture geometry. Numerical simulation is an economical approach to investigate the generation of fracture geometry and its effect on post-treatment production enhancement. This work proposes a workflow to study the fracture complexity through coupling the geomechanical simulator Irazu and the reservoir simulator CMG. The geo-mechanical simulator is devised to simulate the hydraulic fracturing process employing the hybrid finite discrete element method while the reservoir simulator CMG is used for the reservoir posttreatment production forecast.

Prior to the actual fracturing treatment, numerical simulation of the treatment can provide a prediction on the reservoir response to different injection schemes, allowing for optimization on the treatment design. As is observed both in field cases and laboratory experiments, a few factors play crucial roles affecting the production enhancement, such as the complexity of the fracture network created by the injection. With the capability of the flow simulator CMG, the reservoir response to the different fracture network generated can be studied.

CMG IMEX is a reservoir simulator that can forecast flow behavior during reservoir activities such as production, water flooding, hydraulic fracturing, or other reservoir treatments. It employs an implicit finite difference time integration scheme to calculate reservoir pressure and temperature, allowing for larger time step size to save the computation cost.