CEMENTING METHODS AND SYSTEMS FOR INITIATING FLUID FLOW WITH REDUCED PUMPING PRESSURE.

摘要

A method of initiating fluid circulation in a well bore (6) through a casing (3) inner diameter and an annulus (5) outside the casing, the method having the following steps: inducing an increase in the annulus fluid pressure; flowing cement composition into the annulus 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 cement composition has entered the annulus to drive fluid circulation by the added cement composition weight. A method of cementing a casing in a well bore, wherein an annulus is defined between the casing and the well bore, the method having the following steps: connecting a circulation fluid pump to the casing inner diameter; pumping circulation fluid out of the casing inner diameter, whereby fluid flow in a reverse-circulation direction through the casing inner diameter and annulus is initiated; maintaining fluid flow in a reverse-circulation direction through a well bore annulus and the casing inner diameter until enough cement composition has entered the annulus to drive fluid circulation by the added cement composition weight; disconnecting the low-pressure cement composition pump from the annulus; and flowing additional cement composition into the annulus to complete a cement composition operation.