高密度低摩阻水泥浆体系在高石梯区块的应用

Application of high-density and low-friction cement slurry system in the Gaoshiti Block

摘要:

高石梯区块在?177.8 mm尾管固井过程中面临油气显示活跃、施工泵压高、安全密度窗口窄、易漏失、井筒温差大等难题，对水泥浆体系的密度调控、流变性和稳定性提出了较高要求。为提升高密度水泥浆性能，通过优选微锰球形材料与铁矿粉复配作为加重剂，并结合低黏降失水剂与高分子悬浮稳定剂，开发出一种密度可调（2.1~2.4 g/cm3）的高密度低摩阻水泥浆体系。该体系具备优异的高温稳定性与泵送流动性，可有效降低摩阻并提升环空顶替效率。在区块内4口井的应用结果表明：施工泵压降低4~6 MPa，环空顶替效率提升至90%以上，固井质量合格率超过70%，水泥浆返至设计井深且全井段无漏失。理论摩阻压力计算值与实测数据高度吻合，验证了该体系的适应性与工程可行性，为其在高石梯区块的推广应用提供了有力支撑。

Abstract:

The Gaoshiti Block faces multiple challenges during the cementing of ?177.8 mm liners， including active oil and gas shows， high pumping pressure， a narrow window of safe density， susceptibility to lost circulation， and significant wellbore temperature variations. These conditions impose strict requirements on the density control， rheology， and stability of the cement slurry. To enhance the performance of high-density cement slurry， a high-density， low-friction system with an adjustable density （2.1~2.4g/cm3） was developed. This was achieved by optimizing a compound weighting agent consisting of micromanganese spherical particles and iron ore powder， in combination with a low-viscosity fluid-loss additive and a polymer suspension stabilizer. The system demonstrates excellent high-temperature stability and pumpability， effectively reducing friction and improving annular displacement efficiency. Field applications in four wells within the block showed a reduction in pumping pressure by 4~6MPa， an increase in annular displacement efficiency to over 90%， a cementing qualification rate exceeding 70%， full returns to the planned depth， and no fluid losses across the entire interval. The theoretical friction pressure closely matches field measurements， confirming the system’s adaptability and engineering feasibility， and providing strong support for its broader application in the Gaoshiti Block.