考虑应力场变化的水平井压后产能计算方法 ——水平井井筒沿最小主应力方向

低渗、特低渗油气藏水平井的分段压裂产能模拟计算，一般不考虑储层应力变化对裂缝形态的影响，计算误差较大。将二维诱导应力场计算模型与预估的每段分压时间间隔相结合，计算已存在的人工裂缝对应力场变化的影响，预测后续压裂人工裂缝形态，并根据预测结果建立地质模型，采用三维三相黑油模型计算水平井压后产能，从而建立了考虑人工裂缝存在时应力场变化后的水平井分段压裂产能计算方法。结果表明，在考虑应力场变化时，人工裂缝形态会发生明显变化，由预期的横切裂缝，变成类似于“T”形的人工裂缝，且横切缝部分会远离预定的射孔位置。JM 油藏实例分析得出，考虑8 条横切裂缝存在时水平井产能与不考虑应力场变化时所计算的产能相比， 5 年末的累计产量相差5.6%，验证了进行水平井分段压裂产能计算时考虑实施过程中应力场变化的必要性。

Post-fracturing productivity computation method of horizontal well with consideration to stress field variation: along the minimum principal stress in horizontal wellbore

The effect of reservoir stress variation on the fracture morphology is usually not considered in the simulation calculation on staged fracturing productivity of horizontal wells in low permeability and ultra-low permeability oil and gas reservoirs, leading to large calculation errors. In this paper, the 2D induced stress field computation model was combined with the estimated staged fracturing time interval in each stage to calculate the effect of the existing artificial fractures on the stress field variation and predict the artificial fracture morphology in subsequent fracturing. Then, based on the prediction results, a geologic model was established, and the 3D threephase black-oil model was used to calculate the post-fracturing productivity of horizontal wells. Finally, a staged fracturing productivity computation method of horizontal wells with consideration to the stress field variation in case of existence of artificial fractures was defined. According to the study results, when the stress field variation is considered, the artificial fracture morphology would change obviously, from the expected transverse fractures to T-like artificial fractures, and some transverse fractures would be far away from the planned perforation location. The field application in the JM reservoir shows that the five-year cumulative production of horizontal wells obtained with consideration to the existence of 8 transverse fractures is 5.6% different from that without consideration to the stress field variation. This verifies the necessity that the stress field variation should be considered in calculating the staged fracturing productivity of horizontal wells.