金华—秋林致密气藏直井层内分簇压裂裂缝扩展规律及应用

Fracture Propagation of Intra-Zone Cluster Fracturing and Its Application in Jinhua-Qiulin Tight Gas Reservoirs

造长缝是金华—秋林地区沙二段致密气藏直井压裂改造的主要目标,如何进一步提高裂缝长度对该储层的勘探开发有重要意义。针对该问题,文章基于工区储层地质特征,建立了直井压裂裂缝扩展数值模型,分析了射孔簇数、射孔位置等因素对裂缝形态的影响。研究结果表明,储层全部打开时,裂缝高度最大,长度最小,分2~4簇射孔时,裂缝高度相对较低,长度相对较长。射孔长度越长,射孔位置离储层中部越远,裂缝长度越低。相比储层全部射开,层内分簇压裂工艺有利于控制裂缝高度,提高裂缝长度。实践证明,该工艺取得了较好的压裂改造效果,对同类型的致密砂岩压裂改造具有重要借鉴意义。

Creating long fractures is the main target of vertical well fracturing in the tight gas reservoirs of Shaximiao formation in Jinhua-Qiulin area.How to further increase the fracture length is of great significance to the exploration and development of this reservoir.To solve this problem,based on the reservoir geological characteristics,a numerical model for fracture propagation in vertical wells is established,and the influence of perforation cluster number,perforation position and other factors on fracture morphology are analyzed.The results show that the reservoir thickness is a key parameter affecting fracture morphology.For thicker reservoirs,it is necessary to take measures to control the propagation of fracture height.When the reservoir is fully perforated,the fracture height is the maximum and the length is the minimum.When the perforation is divided into 2-4 clusters,the fracture height is relatively small and the length is relatively long.The longer the perforation length is,the further away the perforation location is from the middle of the reservoir,and the lower the fracture length is.It is concluded that compared with fully perforated,intra-layer cluster fracturing technology can reduce the fracture height and increase the fracture length.It has been proven that this technology has achieved good fracturing response,and has important guidance for the same type of tight sandstone fracturing.