热采井半预热固井技术

在热力采油井中,注入蒸汽加热油层套管,油层套管受热产生压应力,当压应力达到套管钢材的屈服极限后,套管开始变形。计算表明,如果用常规方法固井,在通常的注汽温度下,套管都因热应力而产生屈服变形。目前现场采用的防止热破坏方法在理论上没有得到论证。热采井半预热固井技术是在注水泥完毕后,通过井口向油层套管内下入加热器,加热油层套管到预定的温度,使水泥在加热条件下凝固,水泥终凝后取出加热器。该技术可使套管在整个开采过程中一直处于弹性状态,不发生塑性变形,从而解决了套管热破坏问题。

Half Pre-Heating Cementing Technology for Thermal Recovery Well

In thermal recovery wells, casing is heated by the injection steam and thermal stresses are produced in the casing. Casing deforms when the thermal stresses exceed the yield point of the steel. Studies show that casing deformation is likely to happen in the conventionally cemented wells in normal injection steam temperature. Conventional technologies used to protect casing from failure are inefficient theoretically. Half pre-heating cementing technology involves running in a heater down to the production casing section where it is subject to the heating by injection steam and heating the casing to a pre-determined temperature, WOC in the heating condition and pulling out the heater finally. This technology keeps the casing in an elastic state in the whole thermal recovery process without plastic deformation taking place, and thus resolves the problem of thermal casing failure.