胜利油田深探井固井技术难点与对策

Technical Difficulties and Countermeasures in Cementing of Deep Exploration Wells in Shengli Oilfield

针对胜利油田深探井固井面临地层压力层系多、井壁稳定性差、高温、高压等复杂地质条件,固井施工工艺复杂,压稳、防漏难度大,固井工具可靠性差,导致固井质量合格率偏低等问题,通过系统分析固井技术难点及其主要影响因素,研究了配套的深探井固井工艺技术。针对深探井高温、高压条件下进行固井施工时防窜、防漏等的需要,研制了高温水泥浆、晶格膨胀水泥浆、低密度高强度水泥浆、防窜抗渗水泥浆等4种水泥浆体系;通过压稳设计分析、钻井液性能调整、前置液优选、高压井防窜、固井工具优选等,研究了具有针对性的固井技术措施。2012年,该深探井固井工艺技术在胜利油田61口井进行了现场应用,结果表明,固井质量得到明显提高,其中第二界面固井质量合格率由之前的40%～50%提高到82%。实践证明,综合配套的深探井固井工艺技术能够满足该油田深探井固井施工需要。

Cementing technologies for deep exploration wells have been researched and developed by means of system analysis on the technical difficulties and major influencing factors of deep exploration wells in Shengli Oilfield, to deal with the complicated geological conditions like multiple strata pressure systems,poor borehole stability, high temperature and high pressure, and complex cementing process, as well as high difficulty in stable killing and leakage-proof and low cementing conformity rate caused by poor reliability of cementing tools. Furthermore, Rg〉D of four types of cement slurry systems, including high temperature cement slurry, lattice dilatation cement slurry, low density high strength cement slurry and an- ti-channeling/anti-leaking cement slurry,have also been presented in this article to deal with the channe- ling/leaking problems during cementing of HTHP deep exploration wells. On the basis of in-depth study on stable killing design, drilling fluid properties adjustment, pre-flush optimization, anti-channeling for high pressure wells and cementing tool optimization,etc. ,the specific cementing technical measures targeted to those problems noted above have been worked out, and widely applied in Shengli Oilfield and improved deep exploration well cementing quality significantly. The cementing conformity rate of the second interface has increased from 40%-50% to 82%. The practice suggests that the cementing technologies for deep ex- ploration wells can meet requirements of deep exploration well cementing in Shengli Oilfield.