光纤式油水界面仪井下损坏分析及防范措施

Analysis and preventive measures for the downhole damage of optical fiber based optical fiber oil-water interface instrument

刘亚静 乔宽 李天友 孟灵 王开红 邢艳辉

LIU Yajing QIAO Kuan LI Tianyou MENG Ling WANG Kaihong XING Yanhui

中国石油华北石油管理局有限公司江苏储气库分公司 中国石油华北油田分公司

Jiangsu Gas Storage Branch, Petro China Huabei Petroleum Administration Co. Ltd., Zhenjiang 212004, Jiangsu, China Petro China Huabei Oilfield Compamy, Cangzhou 062552, Hebei, China

在盐穴储气库溶腔建库的过程中，油水界面的位置是溶腔的关键，若溶腔过程中油水界面不精准，将会破坏腔体形状及稳定性，更严重可能导致腔体报废。光纤式油水界面仪是目前测量油水界面的主要手段。通过对光纤式油水界面仪在金坛盐穴储气库现场损坏现状进行分析，发现1/3以上井次油水界面仪存在不同程度的损坏，主要原因是由于不溶物含量高于80%，造腔过程中不溶物掉落，导致管柱摆动，砸损光纤。为了降低光纤式油水界面仪损坏发生的频率，遇到不溶物含量高于80%的夹层时，宜将造腔外管管鞋提到不溶物夹层之上，同时对光缆采取机械半保护措施。对金坛盐穴储气库2口井进行现场试验应用，经过半年的时间未再发现光纤损坏现象，说明该防范措施对光缆起到了有效保护。

The position of diesel-brine interface is a key factor in the solution mining process of salt-cavern underground gas storage. If the diesel-brine interface is not positioned accurately in the process of solution mining, the cavity shape and stability will be destroyed and even the cavity may be abandoned. Optical fiber based diesel-brine interface monitoring tool is currently the main means to measure diesel-brine interface. The on-site damage situations of optical fiber based diesel-brine interface monitoring tool in Jintan Salt-Cavern Underground Gas Storage were analyzed. It is shown that diesel-brine interface monitoring tools are damaged more than 1/3 well times in different degrees. The main reason for this phenomenon is that insoluble content is higher than 80% and the insoluble drops in the process of solution mining, which leads to string oscillation to damage the optical fiber. In order to reduce of damage frequency of optical fiber based diesel-brine interface monitoring tool, it is recommended to uplift the external pipe shoe for solution mining above the insoluble interbed and apply mechanical semi-protection measures to the optical fiber when there is an interbed with insoluble content higher than 80%. Half a year after these measures are tested and applied on site in 2 wells of Jintan Salt-Cavern Underground Gas Storage, no phenomenon of optical fiber damage is discovered. It shows that the preventive measures can effectively protect the optical cable.

10.13639/j.odpt.2020.04.026