顺北油气田超深碳酸盐岩储层深穿透酸压技术

顺北油气田碳酸盐岩储层具有超深、高温和高破裂压力等特点，酸压改造时存在酸蚀裂缝短、导流能力递减快等问题，为此，提出了应用深穿透酸压技术对超深碳酸盐岩储层进行改造的技术思路，并进行了技术攻关研究。合成了酸用稠化剂、高温缓蚀剂，研制了抗高温清洁酸，并进行了酸液非均匀刻蚀导流能力试验，分析了在闭合应力为20～90 MPa时仅注入清洁酸、仅注入胶凝酸和先注入清洁酸再注入胶凝酸3种注酸方式下裂缝的导流能力；同时，研究了酸液非均匀驱替流动机理，优化了非均匀刻蚀酸压工艺参数。研究发现，采用“清洁酸+胶凝酸”组合注入模式，不仅酸蚀裂缝导流能力有较大幅度提高，有效缝长也增加近1倍。超深碳酸盐岩储层深穿透酸压技术在顺北油气田进行了5井次现场试验，酸压施工成功率及有效率均达到100%，酸压后平均日产油107.7 m3，平均酸蚀缝长133.20 m，取得了明显的储层改造效果。研究认为，顺北油气田超深碳酸盐岩储层深穿透酸压技术可极大改善超深碳酸盐岩酸压效果，可为国内类似储层的酸压改造提供借鉴。 

Deep Penetration Acid-Fracturing Technology for Ultra-Deep Carbonate Oil & Gas Reservoirs in the Shunbei Oil and Gas Field

Carbonate reservoirs in the Shunbei Oil and Gas Field are characterized by ultra-deep, high temperature and high fracturing pressure gradient, which pose problems in short acid-etched fractures and rapid conductivity decline. In order to solve these problems, a team studied a deep penetration acid-fracturing technology for ultra-deep carbonate reservoirs, and they proposed a deep penetration acid-fracturingtechnique. Using a synthetic acid thickener and high temperature corrosion inhibitor, a high temperature resistant clean acid was developed. The acid fluid non-uniform etching conductivity test was carried out, and fracture conductivities with clean acid, gelled acid, and clean acid followed by gelled acid were analyzed at a closure stress of 20–90 MPa, respectively. The mechanism of the non-uniform displacement of acid fluid was studied, and the acid-fracturing process parameters of non-uniform etching were optimized. The study suggests that "clean acid + gelled acid" combined injection can greatly improve the conductivity of acid-etching fractures as well as nearly doubling effective fracture length. This new deep penetration acid-fracturing technology has been applied in 5 wells in the ultra-deep carbonate reservoir in Shunbei Oil and Gas Field. The success rate and effectiveness of the acid-fracturing operation reached 100% with post-frac production rate 107.7 m3/d, and average length 133.20 m. Consequently, this acid-fracturing technology can greatly improve the acid-fracturing effect in ultra-deep carbonate reservoirs, which provides a reference or best practices guidance in the acid-fracturing stimulation of similar reservoirs in China.