普光“三高”气田安全钻井技术

Safe Drilling Techniques Applied in Puguang HPHT Sour Gas Field

普光气田是我国迄今为止发现的最大的酸性整装气田,具有井深超深和高含硫、高压、高产特性,且地质环境异常复杂。为了安全、高效开发该气田,进行了持续的技术攻关。在综合考虑地质、井控、固井质量、开发寿命及钻井成本等诸多因素的基础上,优化了井身结构设计;通过研究形成了高抗挤、耐腐蚀、适用于高压气井的管材优选技术;针对超深、多套压力系统和复杂层位共存于同一裸眼段内,钻井液安全密度窗口窄,易发生喷漏同存,以及"三高"气田井控风险大的情况,高标准地配备了井控装备和防喷工具,制定和采取了一系列有针对性的井控特别管理措施;针对裸眼段长、温差大、安全密度窗口窄、间隙小、压稳与防漏矛盾突出、防气窜难度大、顶替效果差等固井难题,采用了分段压稳设计,优选了水泥浆体系,优化了浆柱结构,形成了一套适合超深"三高"气田的综合固井工艺技术。普光气田通过综合应用"三高"气田安全钻井技术,实现了安全钻井,提高了钻井速度,保证了固井质量,确保了气井长期安全生产。

Puguang gas field is the largest sour gas field ever found in China. It is an ultra-deep formation with complex geological structure, high sulfur content, high pressure and high production rate. For safe and efficient development of the field, a lot of technical researches were conducted. Through the comprehensive study on geology,well control, cementing, effective production period, and costs etc. , the well casing program is optimized with consideration of weltbore stability, corrosion resistance and high pressure. Due to the narrow margin between breakdown and fracture breakout pressure gradient,complicated strata system, and high risk of gas well control, high-standard well control equipment and BOP were used and a series of well con- trol measures were adopted. For the problem of long open hole, large temperature difference, narrow safe mud win- dow, small annular clearance, low displacement efficiency, etc., cementing techniques for ultra-deep gas well were used,including stage cementing and optimization of slurry. A comprehensive cementing technique in HPHT sour gasfield was developed. The application of this technique in Puguang gas field ensured the safe drilling, improved drilling speed,ensured the cementing quality and the long-term gas production.