钻井液快速封堵油层保护技术

华北油田在屏蔽暂堵技术基础上开发出了适用于砂岩油藏完井作业的快速封堵保护油层钻井液技术.该项技术的特点是封堵带薄且致密,渗透率趋于0,封堵深度小于1 cm,在一定负压差下不能反排解堵,易被射穿,在开采时通过射孔实现储层与井筒连通良好的目标.快速封堵保护油层钻井液技术可根据不同地区砂岩储层的特点和潜在损害因素,有针对性地研制油层保护剂,而且不用考虑油层保护材料的油溶性、酸溶性或水溶性,凡是能够起到快速封堵效果的材料,也包括钻井液中的处理剂均可考虑作为封堵材料.由于钻井液处理剂的引入,使快速封堵型油层保护剂既与现场钻井液有良好的配伍性,又同时发挥了钻井液处理剂的功效,走出了单一采用粒径匹配的固相颗粒进行封堵的思路,使封堵层更加致密,油层保护效果更佳.该项技术在二连油田231口开发井中进行了应用,完善井层百分率由37%提高到85%以上,储层严重损害百分率由36%降低到3.75%.

Drilling fluid instant sealing technology for formation damage control

Based on shielding temporary plugging theory, the instant sealing drilling technology for formation damage control available to the well completion in sand reservoir has been developed in Huabei petroleum. The plugged zone generated by this drilling fluid is thin and tight, the permeability approached zero and the sealed depth is no more than 1 cm. Sealing removal by reverse discharging can not occur at some negative differential pressure. The sealing zone can be penetrated by perforation to connect reservoir with borehole effectively. Instant sealing technology can make the temporary bridging agent developed selectively according to sandstone reservoir nature and potential damage factors in different fields without considering oil, acid or water solubility of these materials. Any material with instant sealing effect, including drilling fluid additives, can be an option. Moreover, the drilling additive as a bridging agent has a favorable compatibility with in-situ drilling fluid. And thus, has a tighter sealing zone and a better effect to formation damage control. practice of 231 development wells in Er-lian oil field indicates that reservoir improving has a rise from 37% to 85% above and formation severe damage has dropped from 36% to 3.75%.