CEMENTING METHODS AND SYSTEMS FOR INITIATING FLUID FLOW WITHREDUCED 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 casin g 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 meth od having the following steps: connecting a circulation fluid pump to the casin g inner diameter; pumping circulation fluid out of the casing inner diameter, whereby fluid flow in a reverse-circulation direction through the casing inn er 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 additiona l cement composition into theannulus to complete a cement composition operatio n.