多场耦合作用下致密储层地应力场变化规律研究 ——以准噶尔盆地某区为例

地应力是储层改造方案设计、提高油气勘探开发效率的重要指标。致密储层所处环境复杂，需要综合考虑温度-应力-渗流多场耦合作用的影响。为此，以准噶尔盆地中部4区块某三维区致密储层为例，基于COMSOL Multiphyics软件，建立了温度-应力-渗流耦合控制方程，研究了多场耦合作用下研究区致密储层地应力场的变化规律。研究结果表明:研究区最大水平主应力范围在113~134 MPa之间，最小水平主应力范围在106~124 MPa之间，均表现为压应力；在油气开采过程中，最大水平主应力先增大后趋于稳定，随着油气开采的深入，应力变化范围逐渐由井口周围向附近断层延展，并且优先沿着断层的开裂方向发展；在断层的破碎过渡区应力值最小，断层核部应力值介于破碎过渡区与连续地层之间；随着油气开采的深入，致密储层会发生竖向变形，储层最大竖向变形出现在井口附近，位移量超过10 cm，随着距离变远，沉降量不断减小。 

STUDY ON THE VARIATION LAW OF CRUSTAL STRESS FIELD IN TIGHT RESERVOIR UNDER MULTI FIELD COUPLING

Crustal stress is an important index of reservoir reconstruction scheme design and improvement to oil and gas exploration and development efficiency. Due to the complex environment in which tight reservoirs are located, the multi field coupling of temperature, stress and seepage should be considered comprehensively. Therefore, the tight reservoir in Block 4 three-dimensional area of central Junggar Basin was taken as an example, the THM coupled control equation was established based on the COMSOL Multiphyics software, and the variation law of crustal stress field in tight reservoir under multi field coupling was studied. The result shows that:The maximum horizontal principal stress ranges from 113 to 134 MPa, and the minimum horizontal principal stress from 106 to 124 MPa, all showing as compressive stress. In the process of oil and gas exploitation, the maximum horizontal principal stress increases first and then tends to be stable. With the deepening of oil and gas exploitation, the range of stress change gradually extends from the wellhead to the nearby fault, and preferentially develops along the fracture direction of the fault. In the fault transition zone, the stress value is minimum, and the stress at the core of the fault is between the broken transition zone and the continuous stratum. With the deepening of oil and gas exploitation, the vertical deformation will occur in tight reservoirs. The maximum vertical deformation of the reservoir occurs near the wellhead, the displacement is more than 10cm, and the settlement decreases as the distance increasing.