大牛地气田大98井区水平井开发技术政策研究

Research on horizontal well development technology policy of Da98 well area in Daniudi gas field

大牛地气田剩余未动用储量大部分为Ⅱ—Ⅲ类低品位储量,水平井开发将是气田产能建设的主要方式.因此,优化研究多级压裂水平井开发技术政策很重要.基于多级压裂水平井数值模拟概念模型,对单井设计、压裂缝、井网和井距进行研究,结果表明：单井水平段延伸方向应垂直于最大主应力方向,水平段位于气层中部最好,压裂缝尽量穿过含气砂体并以锯齿型分布最优,平均压裂半缝长为158m,平均压裂缝间距为112m,采用排状交错井网最优.结合数值模拟法、动态分析法及经济评价法,确定大98井区合理井距为1 000 ～1 200 m,根端距为700m.

The majority of remaining non-producing reserves in Daniudi gas field are Ⅱ-Ⅲ low-grade reserves, and horizontal well development will be the primary way for gas field productivity construction. Therefore, the optimization study on the multi-stage fracturing development technology policy of horizontal well is extremely significant. Based on numerical simulation model of multi-stage fractured horizontal wells, the paper investigated single well design, pressure cracks, well pattern and well spacing. The study eventually demonstrates that the extending direction of single well horizontal section should be perpendicular to the maximum principal stress direction. Horizontal section is better to be located in the middle of gas reservoir. Crushed fractures crossing gas-bearing sand body with a crenellated distribution are optimal. When average half- length of the fracture is 158 meters and average fracture spacing is 112 meters, row-interleaving well patter is optimum. Combined with numerical simulation method, dynamic analysis method and economic evaluation method, it is suggested that the reasonable well spacing in Da98 well area ranges from 1 000 meters to 1 200 meters, and well array spacing is 700 meters.