Reverse Circulation PlacementTechnique vs.Conventional PlacementTechnique -A Comparative Study ofCement Job Hydraulics Design

摘要

Reverse circulation cement placement technique (RCPT)has been suggested as an alternative for providing properannular coverage for lost circulation zones. It is generallybelieved that RCPT helps minimizing the circulation pressureand hence, allows cement placement with no apparent losses. A basic hydraulic design study is conducted to determinethe anticipated pressure losses during the cement jobs run byusing both the RCPT and the conventional cement placementtechnique (CCPT). Results have shown that for each design case (I.e. wellboregeometry and the rheology of cement slurry)there is a criticaldepth above which ECD with RCPT can be higher than ECDwith CCPT. This is in contradiction with the generalassumption that RCPT always leads to lower circulatingpressure losses than CCPT. Examples of typical cement job design calculations areprovided to illustrate the changing ECD's as a function of depthduring both RCPT and CCPT.