冷冻暂堵作业井口压力变化规律研究

RESEARCH ON VARIATION OF WELL HEAD PRESSURE DURING FREEZING OPERATION

冷冻暂堵技术能快速安全更换井口泄露部件,它能够同时暂堵多层环空和油管内通道,为后续井口隐患治理作业创造安全的施工条件。目前对于冷冻暂堵技术的研究主要针对作业原理、技术特征及施工优势等方面,而对于作业过程中井口压力变化规律的分析则较少被提及。为此,以长庆油田冷冻暂堵作业10余井的井口压力变化数据为基础,开展了冷冻暂堵作业压力变化规律研究,依据压力变化趋势提出了油套环空和油管内冷冻桥塞形成的判别标准。此标准对于优化冷冻暂堵施工设计、缩短冷冻暂堵作业时间和提高施工效率具有重要意义,能够快速完成井口装置的抢险救援,减少有毒有害气体对大气的影响,有效保护环境。

The freezing temporary-plugging technology can quickly and safely replace wellhead leakage components. It can temporarily block multiple annuli and the tubing at the same time,creating safe operation conditions for following wellhead operations. At present, the research on freezing technology mainly focuses on operation principle,operation characteristics,and operation advantages. However,the analysis on the rules of wellhead pressure variation during operation is less mentioned.Therefore,based on the wellhead pressure change data gathered on more than 10 wells in Changqing Oilfield,the pressure variation rules of freezing temporary plugging operation were studied.According to the pressure variation trend,the criterion determining whether the freezing plugs formed in casing/tubing annulus and inside the tubing were proposed. They are of great significance in optimizing the freezing planning,shortening the freezing time,and improving the operation efficiency. It can quickly complete the wellhead wrecking operation,reduce the impact of toxic and harmful gases on the atmosphere,and effectively protect the environment.