高含硫气井安全高效钻完井配套技术——以川东北罗家寨气田为例

四川盆地东北部罗家寨气田具有高含H_2S、高压、高产等特点,钻井过程中面临喷、漏、塌、卡、斜、硬、毒等难题。为此,以高含硫气井安全高效钻完井为目标,将目前先进的钻完井工艺技术进行了技术集成应用;按照国际一流水准的HSE管理体系要求,充分利用JSA、BBS卡、PTW、SWA、上锁挂签等安全工具.对各个专业化施工单位进行安全、环境及质量的全过程受控管理,真正做到界面清晰、衔接有序、高效运作。现场应用效果表明:①合成基钻井液完全满足本区域高含硫气井钻井要求;②PDC+旋转导向+随钻测井测斜+循环堵漏短节配套井下工具能满足高钻速、井眼轨迹优质、精控钻井液密度、及时应对堵漏等要求,且能钻达固井井深即可下套管;③采用封隔式尾管悬挂器为主体的防气窜配套工艺技术,配合使用弹性水泥浆体系,成功解决了喇叭口窜气问题,完全满足了后续作业对井筒完整性的要求;④LJ20井钻井周期较该气田平均钻井周期缩短了20%,平均机械钻速提高了41%.创造了该地区钻井的新纪录。所形成的钻完井配套技术可以有效地指导类似地区高含硫气田的安全高效开发。

Safe and efficient drilling and completion technologies for high-sulfur gas wells: A case history of the Luojiazhai Gasfield in the Northeastern Sichuan Basin

The Luojiazhai Gasfield in the northeastern Sichuan Basin is characterized by such high H₂S, high pressure, and high productivity that many technical challenges involving blowout, lost circulation, borehole collapse, sticking, deviation, hardness and toxicity have been often encountered during drilling. In view of this, state-of-art drilling and completion technologies were integrated and applied to ensure safe and efficient drilling and completion of high-sulfur wells. As is required in the internationally adopted HSE management system, JSA, BBS card, PTW, SWA, tag-out & log-out, together with other safety tools were used to achieve full-process control and management over safety, environment and quality in all relevant contractors. Meanwhile, clear interfaces, orderly coordination and high-efficiency operations were all achieved. Field applications show that the synthetic drilling fluid can fully meet the demands of drilling of high-sulfur wells within the concerned area. A combination of PDC with rotary steering, MWD, circulating leakage-free sub, and other supplementary tools can satisfy the requirements of high-speed drilling, borehole trajectory optimization, delicate control over densities of drilling fluids and timely elimination of lost circulation. In addition, casings can be installed as soon as the cementation depth is reached. Application of matching technologies with an independent liner hanger as the key component for the prevention of gas channel, together with elastic cement slurry system, can effectively remove gas channeling around the bellmouth, meeting the requirements of subsequent operations for borehole integrity. In addition, the drilling period of Well LJ20 was made 20% shorter than the average time used for drilling in the gasfield with the average ROP enhanced by 41%, setting the best record in drilling operations in the concerned area. Relevant matching technologies for drilling and completion may be used effectively for safe and high-efficient development of high-sulfur gasfields in similar areas.