川西北部地区栖霞组超深高温气井酸压技术

川西北部地区栖霞组埋藏深、温度高、不同程度发育小洞和中洞，酸压改造面临摩阻高、酸岩反应速率快和酸蚀裂缝导流能力保持困难等难题。为提高栖霞组储层酸压设计的针对性，建立了酸岩反应热模型，开展了多场耦合酸压裂缝形态模拟。模拟结果表明:酸岩反应热会提高酸岩反应速率，降低酸蚀缝长，200 m3酸量对酸蚀缝长的影响最高达9 m；施工排量恒定时，酸蚀缝长随着酸量的增加而增加，但增加幅度逐渐减小。开展了4井次现场试验，井均测试产气量67.03×104 m3/d。现场试验表明，酸岩反应热对超深高温气井酸蚀裂缝形态的影响不可忽略，多场耦合酸压设计方法在川西北部地区栖霞组具有较好的适应性。

An acid fracturing technology suitable for high-temperature ultradeep gas wells in the Qixia Formation in the north of Western Sichuan

The Qixia Formation in the north of Western Sichuan is characterized by great burial depth, high temperature and small and medium pores with different development degrees, and its acid fracturing is faced with a series of difficulties, e.g. high friction resistance, fast acid-rock reaction and difficult maintenance of flow conductivity of etched fractures. In order to improve the pertinence of acid fracturing design to the reservoir of Qixia Formation, the acid-rock reaction heat model was established and the morphologies of the fractures induced by multi-field coupling acid fracturing were simulated. It is indicated that the acid-rock reaction heat can increase the acid-rock reaction rate and reduce the length of etched fracture. When there is 200 m3 acid, the maximum effect on the length of etched fracture is 9 m. When the construction displacement is constant, the length of etched fracture increases with the increase of acid volume, but its increasing amplitude declines gradually. Field tests were carried out 4 well times and the average gas production per well was 67.03×104 m3/d. It is revealed that the effect of acid-rock reaction heat on the morphologies of etched fractures in high-temperature ultradeep gas wells shall not be neglected and multi-field coupling acid fracturing design method is better adaptable to the Qixia Formation in the north of western Sichuan Basin.