四川盆地震旦系气藏大斜度井水平井酸压技术

Study on the Acid Fracturing Technology for High-inclination Wells and Horizontal Wells of the Sinian System Gas Reservoir in the Sichuan Basin

李松 马辉运 张华 叶颉枭 韩慧芬

LISong MAHuiyun ZHANGHua YEJiexiao HANHuifen

中国石油西南油气田分公司工程技术研究院, 四川 成都 610017 国家能源高含硫气藏开采研发中心, 四川 广汉 618300 中国石油西南油气田分公司蜀南气矿, 四川 泸州 646000

Engineering Research Institute of Southwest Oil and Gas Field Company, CNPC, Chengdu, Sichuan 610017, China National Energy High-sour Gas Reservoir Exploitation and R & D Center, Guanghan, Sichuan 618300, China Shunan Gas Field of Southwest Oil and Gas Field Company, CNPC, Luzhou, Sichuan 646000, China

四川盆地震旦系灯四段碳酸盐岩储层溶蚀孔、缝、洞发育，储集空间类型复杂，具有埋藏深、高温、高压、强非均质性、高含HS、CO等酸性气体的特点，对现有储层改造工艺技术提出了挑战。大斜度井/水平井储层改造的关键是长改造井段酸液布置和酸蚀裂缝深穿透沟通储层天然缝洞系统。根据储层地质及地应力分布特征，优化并形成了大斜度井/水平井机械分层分段改造工艺，纵横向上层间或段间物性差异大的裸眼完成井，采用封隔器实现分段改造；层内或段内物性差异大的射孔完成井，采用可降解暂堵材料实现分层改造。天然缝洞发育的裂缝孔洞型储层采用缓速酸酸压技术疏通天然缝洞系统，对于裂缝孔隙型及孔隙型储层，采用前置液酸压技术形成深穿透酸蚀裂缝沟通孤立的天然缝洞系统，形成的两种大斜度井水平井酸压技术现场试验取得了一定程度的储层改造效果；探索了滑溜水+自生酸+胶凝酸的复杂缝网酸压工艺，一定程度上提升了储层改造效果。

The carbonate rock reservoir of the Dengying subgroup of the Sinian System in the Sichuan Basin is characterized by complex types of reservoir spaces as a result of its well-developed dissolution pores, fractures, and holes, and it is characterized by high buried depth, high temperature, high pressure, high heterogeneity, and high contents of such acid gases as HS and CO. These features and characteristics present challenges to the current reservoir reform processes. The key to reservoir reform for high-inclination and horizontal wells is the deployment of acid liquid and in-depth permeation of acid dissolution fractures in long well sections to link the natural fractures and pores in the reservoir into a connected system. The current reservoir reform processes with mechanical stratification and segmentation for high-inclination/horizontal wells were improved in light of the geological characteristics and geostress distribution patterns as follows. open-hole sections with a big difference between vertical layers or horizontal segments in physical properties were reformed with packers in a segment-by-segment manner, while perforation segments with a big intralayer or intrasegmental difference in physical properties were reformed with degradable filling materials in a layer-by-layer manner. Fracture-hole-type reservoirs with well-developed natural fractures and holes were reformed with retarded-acid based acid fracturing technology to link the fractures and holes into a connected system, while fracture-pore-type and pore-type reservoirs were reformed with pad-fluid-based acid fracturing technology to form deep acid dissolution fractures to link isolated fractures and pores into a connected system. As demonstrated by on-site tests, the two types of acid fracturing technology developed for high-inclination and horizontal wells can improve reservoir reform efficiency. An exploratory study was also conducted on self-generating acid and slick water-based acid fracturing technology for complex networks of fractures, with some degree of success in improving reservoir reform efficiency.

10.11885/j.issn.1674-5086.2017.07.03.01