提升高温气井酸压有效缝长方法

为了提高川西地区深层高温气井酸压方案设计的有效性和准确性，建立了考虑酸压过程中井筒—裂缝综合热效应的酸压有效缝长数值计算模型。以区块内的一口预探井栖霞组储层的酸压改造为例，研究了酸压过程中不同的热效应对于酸压有效缝长的影响，并开展了施工参数对于酸压有效缝长的敏感性分析。结果表明：①井筒传热效应会提升缝口酸液温度，加剧近井地带裂缝壁面的酸岩反应，缩减酸压有效缝长；②相同注酸排量条件下，当注酸量达到一定量后，单纯提高酸量对酸压有效缝长的提升有限。相同注液量条件下，提高注酸排量有利于裂缝向深部扩展而降低缝口过度刻蚀，能有效提升酸压有效缝长。基于研究结论，为X1井设计了一套胶凝酸酸压方案，压后测试产量约为地质条件与改造规模相似邻井产量的1.4倍。

Simulation study of the approach to enhance acid penetration distance in high temperature gas well: Case study of Qixia Formatiom,western Sichuan Basin

For the purpose of improving the efficiency and accuracy of acid fracturing project design for the deep and high-temperature gas wells in western Sichuan Basin, an acid penetration distance of acid fracturing mathematical calculation model considering heat effects of well-bore and acid-rock reaction was established. An acid fracturing case of a field candidate well in Qixia Formation was taken as an example, the influence of different heat effects on acid penetration distance was researched and the sensitivity analysis of acid fracturing operation parameters was conducted. And the following research results were obtained. Firstly, heat transfer effect of wellbore elevated the acid temperature at the fracture inlet, which intensified the acid/rock reaction at fracture wall and decreased the acid penetration distance. Secondly, under the same injection condition, when the injected acid reached a certain volume, the increase of acid volume was limited to enhance the effective acid penetration distance. Finally, with the same injection volume condition, increasing injection rate could promote the propagation of fracture to the deep reservoir and reduced the excessive acid etching at the fracture inlet, which was beneficial to enhance acid effective penetration distance. Based on the results, a gelled acid treatment design was recommended for Well X1. The post-treatment production of Well X1 was 1.4 times that of the adjacent well, which have similar geological condition and treatment scale.