Research On The Gas-channeling Prevention Performance Evaluation Method Of Cement Slurry

Since the cement injection job having been brought into operation,the gas channeling has been one of the questions puzzled the cement job.Once the gas channeling takes place,even cost a great deal of manpower and material resources can hardly repair original isolation state of individual zones.By estimate, about 25 percent of all wells have gas channeling problem during well completion. How to evaluate the gas-channeling prevention performance of cement slurry objectively and accurately,it is still a question can not resolved perfectly for the cement industry at home and abroad.This thesis tries to set out from the most important factor for the gas channeling--Slurry Weight Loss(SWL) to carry on the research of Gas-channeling Prevention Performance evaluation method.This thesis set out from the angle of system engineering.In view of influence factors (slurry properties,well condition...etc.)to SWL carry on experiment method research. Study shows that: The slurry initial setting time,free water and volumetric shrinkage exist good line behavior with the average weight loss of slurry;Different hole condition also influence the average weight loss of slurry with different degree. Using the Mathematical Statistics method this thesis obtain cement weight-loss model, And according to the basic principle of control and estimate the gas channeling is maintenance pressure balance,using the pressure balance relation deduces its differential expression,then put forward to the new Gas-channeling Prevention Performance evaluation method,and prove it with experiment.It provides a new reference method for the cement design.