Journal of Canadian Petroleum Technology, Vol.44, No.7, 16-19, 2005
Reverse circulation placement technique vs. conventional placement technique: A comparative study of cement job hydraulics design
Reverse circulation cement placement technique (RCCPT) has been suggested as an alternative for providing proper annular coverage for lost circulation zones. It is generally believed that RCCPT helps minimize the circulation pressure and hence, allows cement placement with no apparent losses. A basic hydraulic design study is conducted to determine the anticipated pressure losses during the cement jobs run by using both the RCCPT and the conventional cement circulation placement technique (CCCPT). Results have shown that, for each design case (i.e., wellbore geometry and the rheology of cement slurry), there is a critical depth above which the equivalent circulating pressure (ECD) with RCCPT can be higher than ECD with CCCPT. Examples of typical cement job design calculations are provided to illustrate the changing ECDs as a function of depth during both RCCPT and CCCPT.