CAJ | 학술논문

为认清页岩储层先压开裂缝应力干扰对后续压裂形成复杂裂缝的影响规律，指导页岩储层压裂优化设计，以均质、各向同性的二维平面人工裂缝模型为基础，利用位移不连续理论，推导建立非等裂缝半长、非等间距和任意裂缝倾角的水力裂缝诱导应力干扰数学模型，结合页岩储层复杂裂缝形成的地应力条件，判断不同射孔方式、裂缝参数和原始主应力条件下压裂形成复杂裂缝的可行性。结果表明，分段多簇射孔、多簇同时起裂方式比单段射孔、单段起裂方式应力干扰更强，更利于页岩储层形成复杂裂缝；压开裂缝的长度越长、净压力越大，裂缝诱导应力干扰越强，后续压裂形成复杂缝的可行性越大；距离先压裂缝，存在最利于后续裂缝形成复杂裂缝的位置；原始最大、最小水平主应力差太大的页岩储层利用裂缝应力干扰也达不到有效形成复杂裂缝的地应力条件，不宜将压裂形成复杂裂缝作为储层改造的主要目的。
위인청혈암저층선압개렬봉응력간우대후속압렬형성복잡렬봉적영향규률，지도혈암저층압렬우화설계，이균질、각향동성적이유평면인공렬봉모형위기출，이용위이불련속이론，추도건립비등렬봉반장、비등간거화임의렬봉경각적수력렬봉유도응력간우수학모형，결합혈암저층복잡렬봉형성적지응력조건，판단불동사공방식、렬봉삼수화원시주응력조건하압렬형성복잡렬봉적가행성。결과표명，분단다족사공、다족동시기렬방식비단단사공、단단기렬방식응력간우경강，경리우혈암저층형성복잡렬봉；압개렬봉적장도월장、정압력월대，렬봉유도응력간우월강，후속압렬형성복잡봉적가행성월대；거리선압렬봉，존재최리우후속렬봉형성복잡렬봉적위치；원시최대、최소수평주응력차태대적혈암저층이용렬봉응력간우야체불도유효형성복잡렬봉적지응력조건，불의장압렬형성복잡렬봉작위저층개조적주요목적。
In order to understand the impact of stress interference caused by the artificial open cracks on the formation of complex fractures of subsequent fracturing,and to guide the optimal design of shale fracturing,a model of stress interference of artificial fractures was established based on the homogeneous and isotropic two-dimensional artificial fracture model. The model considered the displacement discontinuity with the cracks of unequal half-lengths,unequal spacing and arbitrary angles of inclination between cracks and horizontal wellbore to study the feasibility of the formation of complex fractures with different perforations,crack parameters and original principal stress on the basis of geostress conditions. The calculated results indicate that the staged multi-cluster perforation and simultaneous multi-cluster fracture initiation have stronger stress interference for developing complicate fractures than the single-stage perforation and single stage fracture initiation do. The longer length the open cracks,the larger the net pressure and the stronger the interference of fracture induced stress,the greater the possibility of complex fractures formation by the subsequent hydraulic fracturing. The optimal crack spacing between the formal open cracks exists for the formation of complex fractures. Besides,if the difference between the original maximum and minimum horizontal principal stress is too large in shale reservoir,then it′s hard to achieve the geostress condition of complex fracture formation effectively even with the crack interference. So,forming complicate fractures by hydraulic fracturing should not be regarded as the main tool of reservoir stimulation.