厚层强非均质砂岩储层酸液立体放置优化设计

Optimal design on the stereoscopic layout of acid system in strong-heterogeneity thick sandstone reservoirs

郭建春 任冀川 苟波 王世彬

Guo Jianchun REN Jichuan GOU Bo WANG Shibin

西南石油大学油气藏地质及开发工程国家重点实验室

State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu 610500, Sichuan, China

TZ气田吉迪克组储层具有巨厚、中孔、中低渗、天然裂缝发育不均等特征。钻井液侵入对储层的伤害主要为储层强非均质性引起的“非线性”伤害、天然裂缝引起的“非径向”伤害，解堵难度较大。基于实验研究优选了酸液体系，基于天然裂缝开启判别模型明确了张开天然裂缝的临界排量，通过实验评价了裂缝性储层网络裂缝酸化的解堵效果。研究成果联合均匀布酸及网络裂缝酸化工艺的理念，形成了酸液立体放置优化方法，最终优选了13.5%HCl+1%HF+4%转向剂的土酸自转向酸进行均匀布酸以及13.5%HCl+1%HF的土酸进行深度酸化，并优化了实现网络裂缝酸化的最低排量为3 m³/min。提出的优化方法在TZ-C-X2井进行了现场应用，酸化后总表皮因数由15.43降低至0.09，酸化效果明显，为厚层非均质砂岩的高效酸化设计提供了技术支撑。

The reservoir of Jidike Formation in the TZ Gas Field is characterized by great thickness, moderate porosity, moderate-low permeability and non-uniformly developed natural fracture. The reservoir damages caused by the invasion of drilling mud mainly include the “non-linear” damage induced by strong reservoir heterogeneity and the “non-radial” damage induced by natural fractures, and led to greater difficulty in blockage removing. The acid system was selected based on experimental studies, the critical displacement to open natural fractures was determined by means of the natural fracture opening discrimination model, and the blockage removing effects of network-fracture acidizing in fractured reservoirs were experimentally evaluated. Based on the research results, combined with the concepts of combined uniform acid distribution and network-fracture acidizing process, the optimal stereoscopic acid layout method was developed, the self-diverting mud acid of 13.5%HCl+1%HF+4% diverting agent was selected for uniform acid distribution, the mud acid of 13.5%HCl+1%HF was selected for in-depth acidizing, and the minimum displacement of network-fracture acidizing was optimized to be 3 m/min. The proposed optimization method was applied on site in Well TZ-C-X2. The acidizing effect is remarkable with the total skin factor dropping from 15.43 to 0.09 after the acidizing. The research results provide the technical support for the design of efficient acidizing in thick heterogeneous sandstones.

10.13639/j.odpt.2019.05.016