聚合物凝胶堵漏剂在大裂隙溶洞地层中的研究及应用

Polymer Gel Plugging Agent Used in Formation with Large Size Caverns and Fractures

摘要:

广东河源地区地质条件复杂，溶洞、裂隙十分发育。钻探生产中施工难度大，导致在钻孔施工中冲洗液漏失严重，施工周期长，成本高。针对该地区大裂隙溶洞地层研制的一种新型聚合物凝胶堵漏剂，从理论上探讨该新型凝胶堵漏剂的基本性能和作用机理，还通过室内试验与现场测试对凝胶堵漏剂进行研究，测试了凝胶堵漏剂的成胶时间、承压能力、破胶性能等。并针对凝胶堵漏材料的配方进行了对比试验，得出了现场的最佳应用配方，对漏失地层进行堵漏，取得了良好的效果，降低了钻井液的消耗，提高了钻井效率。广东河源地区的应用表明，所研制新型凝胶堵漏剂具有良好的流动性且成胶时间较短，符合生产需要，同时还具有很强的承压堵漏能力，破胶性能显著，不会卡住钻具。该新型堵漏剂对广东河源地区的堵漏施工效果较好，易于配制、调整，不需要特殊设备，对大裂隙溶洞地区的堵漏具有很好的推广应用前景。

关键词:大裂隙;溶洞地层;漏失;凝胶堵漏剂

Abstract:

The geological conditions in the Guangdong Heyuan area are complex with well developed karst caverns and fissures. Drilling difficulties usually lead to serious circulation loss, long construction period and high cost. A new type of polymer gel plugging agent was developed to cope with the local formation with large size caverns and fractures. Theoretical analysis is made of the basic performance and the mechanism of the new type gel plugging agent, with lab experiments and field tests conducted on the gel forming time, load bearing capacity, breaking performance, etc. Comparative tests were done on different gel formula, resulting in an optimum make-up which was applied to plugging with good performace, such as reducing consumption of the drilling fluid, increasing the drilling efficiency. Application in the Guangdong Heyuan area shows that the new type gel plugging agent provides liquidity with the short gelling time, meeting the field needs; meanwhile it can also bear high load, and offer significant gel breaking performance, eliminating pipe sticking. The new type plugging agent was very effective in the Guangdong Heyuan area, and featured of easy concoction and without adding any special equipment. It will find promising application in areas with large size caverns and fractures.

Key words:fractures; karst cavern; circulation loss; gel plugging agent