水平井多级多缝加砂压裂技术研究与应用

川西低渗透气藏存在异常高压、储层品质差、气井控制半径小、产量递减快、气藏整体采收率低等问题,难动用储量占有较大的比例.直井开发效益差,无法实现效益开发.水平井分段压裂开发是低渗透气藏实现提高单井产能的重要手段.文章在水平井分段压裂适应性分析及人工裂缝参数优化的基础上,针对川西低渗透气藏工程地质特征,通过对工具改进和工艺的优化,创造性的将常规水平井分段压裂与限流压裂技术相结合,形成水平井多级多缝加砂压裂工艺.XS21-4H和XS21-11H井等14口井的现场试验对比结果分析表明,多级多缝压裂工艺在节约施工成本的同时,大大提高了加砂压裂改造效果,单井最高增产倍比达到6.7倍,经济效益显著,具有较好的现场推广价值.

STUDY AND APPLICATION OF HORIZONTAL WELL MULTI-FISSURE FRACTURING TECHNOLOGY

The low permeability gas reservoirs in Western Sichuan have the characteristics of abnormal high pressure, poor reservoir quality, small controlling radius, faster production degression, low gas reservoir recovery ratio, large difficult-to-produce reserve etc. The development benefit of vertical wells is poor, so, the horizontal well staged fracturing in low permeability gas reservoirs is the important means of improving per-well production. Based on adaptability analysis of horizontal well fracturing and artificial fracture parameters optimization, according to engineering geological characteristics of the low permeability gas reservoirs in Western Sichuan, the horizontal well multi-fissure fracturing technology was formed by tools improvement and optimization of process, and combined conventional staged fracturing and limited flow fracturing technology. Field application results showed that the multi-fissure fracturing technology could reduce the construction cost and improve postfracture response in well XS21-4 H and well XS21-11 H. So the economic benefit is remarkable, and it has a good promotion value.