摘要
塔里木盆地克深气田井距小，压裂易窜，造成裂缝相互干扰，严重影响压裂效果，然而邻井压窜机理尚不明确。基于扩展有限元数值方法，研究了储层原地应力场及有效最大、最小水平主应力（SH，Sh）大小、方向的变化范围，分析了子井人工裂缝在扰动应力场中的延伸机理及压窜机理，并据此提出了小井距防窜压裂工艺。结果表明：母井压裂过程中，储层SH，Sh的方向均发生变化，SH，Sh值均减小，且SH值减小幅度更大；母井生产过程中，储层SH，Sh方向的变化范围减小，SH，Sh值变化幅度小；半缝长与压裂液规模呈正相关关系，与压裂液黏度呈负相关关系；储层动用面积与半缝长呈正相关关系。基于该结果，进行了B井现场施工，改造后日产气53.64×104 m3，约是改造前的3.77倍，压裂施工增产效果显著。该研究对于致密砂岩气藏的压窜机理研究、防窜工艺参数优化设计具有一定意义。
Abstract
The Keshen gas field in Tarim Basin is characterized by small well spacing and easy fracturing pressure channeling, which results in the mutual interference of fractures and affects the fracturing effect seriously, but the mechanism of fracturing pressure channeling is not clear yet. Based on the extended finite element numerical simulation method, the variation range of magnitude and direction of the in-situ stress field and the effective maximum and minimum principal stress in the reservoir are studied, and the mechanism of extension and channeling of the artificial fracture in mother well is analyzed in the disturbing stress field. Based on this, the fracturing technology of anti-channeling in small well spacing is put forward. The results show that the size and direction of the effective maximum and minimum principal stress in the reservoir change during the fracturing process of the parent well, and the effective maximum principal stress decreases more greatly. The variation range of effective maximum and minimum principal stress in reservoir decreases during the production process of the mother well, and the variation range of effective stress in two directions is small. Half fracture length is positively correlated with liquid dosage, half fracture length is negatively correlated with fracturing fluid viscosity, and reservoir producing area is positively correlated with half fracture length. Based on the results, the field operation of well B was guided. After fracturing, the daily gas production rate was 536,400 m3 with 3.77 times of that before fracturing. The stimulation effect was significant. This research has potential significance for the study of anti-channeling mechanism and the optimization design of anti-channeling process parameters in tight sandstone gas reservoirs.
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