长庆油田小套管二次固井工艺技术研究与应用

Research and application of secondary cementing technology for slim casing in Changqing Oilfield

摘要:

针对长庆油田?139.7 mm生产套管中下?88.9 mm小套管二次固井环空间隙小、固井施工压力高，水泥环薄、密封完整性难以满足后期措施需求，固井前井筒界面环境差、二界面水泥胶结不佳等技术难点，通过技术创新及改进，研制出适用于小套管二次固井的低摩阻耐压防漏水泥浆体系、热固性树脂水泥浆体系，结合自主研发的界面增强型冲洗液和固井压塞液体系，形成一套长庆油田小套管固井工作液体系。优选性能可靠的固井配套工具，优化小套管固井管串结构，按照平衡压力固井原理，采用一次上返固井工艺，总结出了一套小套管二次固井工艺技术。现场应用10口井，固井质量优良率95%，增产效果显著，为长庆油田老井增潜挖效及套损井治理提供了有力的技术支撑。

Abstract:

In light of the difficulties in secondary cementing of ?88.9mm small casing set in ?139.7mm production casing in the Changqing Oilfield， such as small annulus， high pumping pressure， thin cement ring， uncertainty in sealing integrity for the follow-up treatment measures， poor wellbore boundary， poor cement bonding at the two boundaries， technological innovation and improvement was conducted to develop a low-friction， pressure-resistant and leak-proof cement slurry system， and a thermosetting resin cement slurry system. They were combined with the independently developed boundary enhancing acid flushing fluid and the cementing plugging fluid system to form the slim casing cementing fluid system in Changqing Oilfield. With optimization of the reliable cementing accessories and the structure of the small casing cementing string， and use of the single-stage cementing process according to the principle of balanced pressure cementing， the slim casing secondary cementing process has been developed. Field application in 10 wells showed the rate of excellent cementing quality up to 95% with significant stimulation effect， which can provide strong technical support for the potential enhancement of the old wells and the management of casing damaged wells in Changqing Oilfield.