大牛地气田下套管作业中环空波动压力分析

Analysis of annular fluctuation pressue pattern during casing running operation in Daniudi Gas Field

大牛地气田刘家沟组为低破裂压力带,套管下入过程中产生波动压力,易引起漏失。针对此问题,以稳态波动压力理论为依据,考虑扶正器的局部阻力效应,建立下套管波动压力计算模型,根据建立模型分析钻井液性能、套管下入速度、环空间隙等因素对波动压力的影响,结果表明,随着钻井液密度、稠度系数、静切力、套管下入速度、扶正器的增加,环空间隙的减小,波动压力增加。针对波动压力影响因素,提出现场安全下套管技术对策,对下套管过程中避免因波动压力引起刘家沟组漏失具有重要的参考意义。

Liujiagou Formation of Daniudi Gas Field is low fracture pressure belt, so lfuctuating pressure caused by casing running may easily lead to lfuid leakage. In order to solve this problem, a model for calculating lfuctuating pressure when running casing was built based on the steady lfuctuating pressure theory, considering the local resistance effect of cenrralizer. Then the effect of drilling lfuid properties, casing running speed and annular clearance, etc. on lfuctuating pressure were analyzed based on the model. Result shows that, with increase of drilling lfuid density and consistency coefifcients, gel strength, casing running speed and centralizers, the lfuctuating pressure increases with the decrease of annular clearance. In view of the inlfuencing factors of lfuctuating pressure, this paper presents the technical countermeasures for safe casing running, which is of great reference signiifcance to avoid leakage of Liujiagou Formation caused by pressure lfuctuation during casing running.