Reverse Cement Placement Technique:A Case Study from Deepwater Gulf of Mexico

摘要

Reverse cement placement is an existing technology that is being used infrequently,mainly during land cement operations.During reverse cement placement,the cement travels down the casing–open hole annulus and up the casing.Although reverse cement placement is not very common in deepwater cementing,it has many potential benefits compared to the conventional placement. Simulation of reverse placement is not possible with existing commercial software.Therefore,jobs were designed using specialized prototype software that enabled the design engineer to accurately reconstruct field conditions.Reverse cement placement will result in lower bottom hole circulating pressures as the direction of the flow follows gravity for the majority of the job.The reverse flow path also has an effect on the temperature the cement will see during placement,which needs to be accurately identified for proper laboratory testing.Proper mud removal is very important to achieve the cement job objectives.Careful attention needs to be given to fluid design as the fluid density and rheological hierarchy are reversed during the placement compared to conventional placement. A deepwater well in the Gulf of Mexico was identified for permanent plug and abandonment.Based on certain design limitations in the well,the operator requested that several cement plugs be set using the reverse placement technique.In total,seven cement plugs in four wells were set successfully using the reverse placement technique.