川东北裂缝性碳酸盐岩气层钻井完井保护技术

为实现高酸性裂缝性碳酸盐岩气藏的安全钻井和气层的及时发现,以四川盆地川东北探区碳酸盐岩储层为研究对象,开展了钻井完井随钻暂堵堵漏及储层保护技术的研究.现场资料、X衍射及SEM分析表明,研究区H2S与CO2体积分数高,敏感矿物发育,井漏等钻井安全事故频发,储层损害十分严重,影响了探区天然气勘探开发的进程.针对储层及钻井安...

Protection technology of drilling and well completion of fractured carbonate gas reservoir in northeastern Sichuan Basin

Temporary plugging while drilling and formation damage control are studied in the process of drilling and well completion,taking the fractured carbonate reservoir in northeastern Sichuan Basin as an example,in order to realize the safe drilling and discovery of oil reservoir in time in the fractured carbonate gas reservoir with high-content sour gas.Field data and the analysis of X diffraction and SEM indicate that there is high-content CO2 and H2S in study area,that sensitive mineral developed,that drilling safe accidents of lost circulation and so on frequently occurred and the formation damage was serious,which delayed the exploration and development of natural gas.Aiming at the problems of reservoir and drilling safety,some techniques are discussed,including fracture width prediction,drilling-in fluid,temporary plugging additive optimization and temporary plugging of lost circulation.Based on related matching techniques,the temporary plugging drilling-in fluid system with low bentonite/amphoteric sulfonic/poly alcohol potassium formate is designed according to the requirement of reservoir geology and engineering.Laboratory experiment shows that the temporary plugging rate and permeability restoration rate of the system are all over 98%,and the bearing pressure of shielding ring reaches 25 MPa.Field experiments reveal that the research result is suit for the southern areas,which can reduce the leakage to occur,promotes the discovery of reservoir and improves the single well production.