北部湾涠西钻井液技术

涠西地区地质构造复杂，尤其是涠洲组涠二段和流沙港组流二段泥页岩地层断层多、地层破碎，微裂缝发育、水敏性强，在钻井过程中极易发生井壁坍塌、漏失，甚至发生卡钻事故。通过分析研究涠西南地区易垮地层岩性、硬脆性泥页岩的垮塌机理，研发了KCl-聚合醇强抑制封堵钻井液体系，并利用这一体系已成功完成了海2井、涠4井、涠5井的施工。现场应用表明，该钻井液有良好的抑制性和封堵性能，保证了井壁的稳定及井下安全。应用该钻井液已成功施工3口井，井径较规则，无井下复杂情况，成功解决了涠西地区的井壁稳定问题，并在涠4井试油过程中发现高产油气流，日产油气超过千吨。

Study of Drilling Fluid Technology for Weixi Block on Beibu Gulf

Geological structure is complex in Weixi block. Especially the mudstone intervals in the 2nd segment of Weizhou Formation and 2nd segment of Liushagang Formation are characterized by well-developed faults, micro fractures and strong sensitivity. During the drilling operation, collapse, drilling mud leakage and even sticking accidents is easily happened. Based on the analysis and study on the collapse mechanism in the hard and brittle mudstone in Weixi, KCl-Polyglycol drilling fluid system, a strong inhibition and plugging drilling fluid, was developed and used in the drilling operations of Well H2, Well W4 and Well W5 successively. Field application shown the drilling fluid system has good inhibition and seal performance, which guaranteed wellbore stability and downhole safety. The application of KCl-Polyglycol drilling fluid system ensures the wellbore stability and also contributes to the success of Well W4 from high production of more than one thousand tons of oil and gas per day was tested.