苏里格气田易漏井固井水泥浆体系的研究与应用

苏里格气田单级一次全井段固井技术可有效提高套管串的承压能力,但在部分低压易漏井施工过程中出现水泥浆漏失的问题。为确保水泥浆能够有效封固不同压力地层,避免固井漏失,通过对苏里格气田井漏特点分析,研发出以新型中空球状微末为减轻材料的低密度高强度防漏水泥浆体系。室内评价实验结果表明,该体系具有密度低、抗压强度高、气相渗透率低等特点,在一定条件下,120 h水泥石强度达到18 MPa,360 h水泥石强度超过20 MPa。现场试验5口井,固井施工顺利,水泥浆一次上返井口,未发生漏失,易漏层第一界面胶结良好率超过95%,第二界面胶结良好率超过85%,满足了苏里格气田低压易漏地层单级一次全井段封固的技术要求。

Research and application of cement slurry system in Sulige leakage wells

In the Sulige gas field in China, the single-stage primary full-hole cementing technique is applied, which effectively improve the load bearing capability of the casing string. However, leakage of cement slurry was observed in some low-pressure leakage wells during operations. To ensure that cement slurry effectively plug the formations under different pressure conditions to avoid loss, this paper analyzes the characteristic of circulation loss in the Sulige gas field, and proposes the low-density high-strength leak-preventive cement slurry system with innovative hollow ball micro-powder as the light-weight-additives. Evaluation test in lab shows that the system is characterized by low density, high compressive strength and low gas permeability. Under certain conditions, the strength of cement reaches 18 MPa in 120 hours and exceeds 20 MPa in 360 hours. The system has been tested in 5 wells, revealing successful cementing operation, no loss during one-trip return of slurry to the wellhead, and a cement quality of over 95% at the first interface and over 85% at the second interface in the leakage layer. The results meet the technical requirements of single-stage primary full-hole cementing in low-pressure leakage formations in the Sulige gas field.