Innovation and practice of drilling and completion technology in the Luojiazhai high-sulfur gas field,Sichuan Basin
The high-sulfide gas reservoirs in the Sichuan Basin are large in reserve scale,and their safe,green and efficient development is of great significance to the construction of a base with the natural gas productivity of one hundred billion cubic meters and the realization of the national"dual-carbon"goal.In high-sulfur gas fields,however,drilling and completion face engineering and technical challenges such as leakage,kick,collapse,sticking and toxicity.In order to accelerate the safe,green and efficient development of high-sulfur gas fields,this paper sorts out the technical difficulties of drilling and completion in high-sulfur gas fields,conductes researches and practices of optimal and fast drilling technology,completion technology and well control technology,and innovatively develops a series of drilling and completion technologies.The following results are obtained.First,the mature offshore Trulink non-stop pumping survey technology and logging while drilling(LWD)technology are applied to onshore high-sulfur well drilling in China for the first time,and fourth-spud drilling and completion in one trip and fifth-spud drilling and completion of production zone in one trip are realized respectively,presenting an excellent one-trip drilling footage,rate of penetration(ROP),directional cycle and other indicators,with the qualified rate of well trajectory of 100％.Second,the ultra-low density lead slurry system successfully deals with the challenge of severe circulation loss during well cementing,and the anti-gas channeling tough slurry system combined with the top packer ensures that the cementing job at the suspension position is of good quality,with both the qualified cementing rate and the high-quality cementing rate reaching the standard.Third,the two-step completion process reduces the well control risk during the completion process,and the downhole permanent pressure gauge can realize downhole real-time dynamic monitoring in the whole life cycle of the gas well.Fourth,the optimized BOP stack and well control equipment can ensure safe well control in the whole process of drilling and completion in high-sulfur gas fields.In conclusion,the technological innovation of drilling and completion process in Luojiazhai high-sulfur gas field in the Sichuan Basin has achieved remarkable achievements in high quality well construction,with a cumulative test gas yield of 590 × 104 m3/d,and absolute open flow of 3 204 × 104 m3/d.The optimized drilling and completion technology series developed in this paper can provide effective guidance for the large-scale safe and efficient development of similar high-sulfur gas fields.
Sichuan BasinLuojiazhaiHigh sulfur contentDrilling and completion technologyNon-stop pumping surveyLogging while drillingWell control safety
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