新场气田分层压裂工艺技术应用评价

APPLICATION OF SEPARATE LAYER FRACTURING TECHNIQUES IN XINCHANG GAS FIELD

新场气田是川西多层系致密砂岩气藏的典型代表 ,从浅层的 35 0m至深层的 5 0 0 0m均有活跃的天然气显示 ,其中蓬莱镇组的含气层多达 2 5层 ,沙溪庙组的含气层也有 10层。一般单层砂体产能有限 ,为提高单井产量和气藏采气速度 ,同时也为减少作业次数和降低井下作业费用 ,需要进行分层压裂改造。文章通过对新场气田小层分布特征和地应力特征的分析 ,提出油管和油套管环空分注分压是适合该气田的分层压裂工艺类型 ,建立了分层压裂选井选层标准 ,开展了 12口井的现场试验。通过施工参数分析和增产效果评价表明 ,油管和油套管环空分注分压工艺不仅保证了分层压裂的施工成功率高、应用简便 ,而且增产效果显著 ,为新场气田多层系气藏整体压裂开发打下了坚实的技术基础。

Xinchang Gas Field is a typical representative of close sand gas reservoirs with multiple layers in the west Sichuan. There is active gas appearance from the shallow layer of 350 m. to the deep layer of 5000 m. The number of gas-bearing layers reaches up to 25 in Penglaizhen group,and at least 10 in Shaximiao group. Usually the productivity of a single sand layer is limited. To improve the production of a single well and the recovery rate of a gas reservoir,and to decrease the operation times and the down-hole service cost,it is necessary to conduct separate layer fracturing. With the characteristics analysis of the small layer distribution and the earth stress in Xinchang Gas Field,the article points out separate layer injecting and fracturing by the tubing and the annular between tubing and casing is the fracturing technique suitable to the gas field. The standards to select wells and layers are established. And the field tests have been conducted for 12 wells. With analysis of operating parameters and result evaluation of production increase,it is indicated that the technique of separate layer injecting and fracturing by the tubing and the annular between tubing and casing has not only high success rate and easy operation, but also obvious production increase. The technique provides strong technical support for thoroughly fracturing of gas reservoirs with multiple layers in Xinchang Gas Field.