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

Abstract:

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.

Key words:high-pressure oil and gas wells; weight loss of cement slurry; cementing quality