水泥浆失重对高压油气井固井质量的影响分析及工艺对策

高压油气井由于存在高压地层，在整个钻井工程中都引起了高度重视。有些高压油气井可能还存在低压易漏层。在固井候凝过程中，水泥浆会产生失重，进而降低了井筒内的液柱压力，如果液柱压力低于失重井段的地层压力，地层流体将会向环空侵入，造成窜槽，甚至会引发井控事故；如果液柱压力高于地层（破裂）压力将引起地层漏失，进而污染油气层，造成水泥浆低返。因此，处理好固井过程中井筒内动态压力和地层压力的关系以及制定相关的应急措施是高压油气井固井成败的关键。分析了水泥浆失重对高压油气井固井质量的影响因素，提出了高压油气井油气水侵的预防措施和固井中相关风险的应急措施和机制。

Analysis on the Impact of Weight Loss of Cement Slurry on Cementing Quality for High-pressure Oil and Gas Well and the Technical Countermeasures

The high-pressure formation has attracted high attention in the entire drilling engineering process of high-pressure oil and gas well, and there may be low-pressure thief zones in some of the high-pressure oil and gas wells. In the solidification period of cementing, cement slurry will have weight loss and fluid column pressure in the entire wellbore will be lowered. If the liquid column pressure is lower than the formation pressure in weightlessness well section, the formation fluid will invade the annulus to cause channeling, even lead to well control incidents; if the liquid column pressure is higher than strata (fracture) pressure, the formation leakage will occur, and further cause oil and gas reservoir pollution with less volume cement slurry returning. Therefore, proper handling the relationship between dynamic pressure and formation pressure and the formulation of relevant emergency measures are the key of success in high-pressure oil and gas well cementing.