三高气田套管磨损研究及应用分析

Wear Research of Casings in High Hydrogen Sulphide,High Pressure and High Production Gas Field

依据套管磨损相关理论,给出了套管磨损深度预测模型,开展了模拟现场钻井条件下气田在用套管磨损室内试验。分析了三高气田套管磨损后带来的问题,用编制的套管磨损预测软件并结合试验测得的套管磨损参数和实钻井史资料,对龙岗气田部分井在用的244.5 mm技术套管的磨损情况和强度进行了计算。计算结果显示,技术套管普遍存在磨损情况,平均磨损率在10%左右,套管磨损后抗挤强度和抗内压强度都显著降低。探讨了影响套管磨损的主要因素,提出了考虑磨损后套管强度满足要求的三高气田套管柱设计安全系数。研究结果对提高三高气田钻完井安全性有一定的指导作用。

A casing wear depth prediction model is given and a laboratory test is conducted for gas field in- serve casing wear under simulated site drilling condition according to casing wear related theories. Problems arising from casing wear in the high hydrogen sulphide, high pressure and high production gas field are analyzed. Casing wear and strength are calculated for some wells of Longgang Gas Field by using casing wear prediction software based on casing wear parameters measured in the test and drilled well history data. Calculation results show interme- diate casings are generally subject to average wear of about 10% ; collapsing strength and internal pressure strength significantly decline in case of casing wearing. Main influencing factors of casing wear are discussed to propose de- sign safety factors for casing strings in the high hydrogen sulphide, high pressure and high production gas field in order to meet casing strength requirements in case of casing wear. The results have a certain guiding significance on improving safety of drilling and well completion in the high hydrogen sulphide, high pressure and high production gas field.