Methods of Cementing in Subterranean Formations Involving Reduced Pumping Pressure

摘要

A method of initiating fluid circulation in a well bore with a casing inner diameter and an annulus is provided. The method includes increasing the casing inner diameter fluid pressure at the top of the well bore; flowing a cement composition into the casing inner diameter at the top of the well bore; maintaining a difference in pressure between the fluid pressure of the casing inner diameter and the fluid pressure of the annulus until enough of the cement composition has entered the casing inner diameter to drive fluid circulation by the added cement composition weight; reducing the casing inner diameter fluid pressure at the top of the well bore while flowing a further portion of cement composition into the casing inner diameter; and pumping at a relatively higher fluid pressure the cement composition from the casing inner diameter into the annulus through a lower end of the casing.