热采井套管损坏机理及防治技术——以单家寺油田为例

Casing damage mechanism and prevention -cure technique in thermal recovery wells-taking Shan- jiasi oilfield as an example

热采井经多轮次蒸汽吞吐后套管易疲劳损坏是稠油油藏开发过程中普遍存在的问题。通过对单家寺油田现 场调查分析,找出了热采井套管损坏的基本规律,重点对油层出砂及注汽时对套管的损害机理进行研究,并采用有 限元数值模拟方法分析了高真空隔热管注汽时对井筒热应力场的影响规律。开发了热采井防砂、环空充氮、采用 新型热敏封隔器等防治技术,现场应用取得了较好的效果。通过综合防治,单家寺油田油井套损率已由2000年的 0.33％下降到2003年的0.16％。

The common problem existed in heavy oil reservoir development is that casing tends to be damaged after multiple-cycle steam stimulation in thermal recovery wells. Through on-site investigation and analysis in Shanjasi oilfield, the basic rule of casing damage in thermal recovery wells was discovered. The casing damage mechanism caused by sand production in oil-bearing formations and steam injection was studied on focus. By u-sing finite element numerical simulation method, the influencing rules on thermal stress field of well bore were analyzed when steam injected through high vacuum insulated tubing. Several prevention -cure techniques have been developed such as sand control, an-nulus nitrogen injection and new type of thermal sensitive packers, and have achieved good result in field applications. By comprehensive prevention -cure for several years, the damage rate of oil well casing in Shanjasi oilfield has decreased from 0.33% in 2000 to 0.16% in 2003.