大庆油田化学驱上下返机械封堵技术现状及发展方向

上下返封堵技术是实现化学驱返层开发的主要手段，以机械封堵技术为主，现场应用的多种机械封堵技术的适用范围、技术特点各不相同，封堵效果也不同，为此对大庆油田目前应用的上下返机械封堵技术进行分析，介绍了上返可钻式、卡瓦悬挂、注堵一体和膨胀管等机械封堵技术，以及下返注入井、采出井机械封堵技术，分析了不同技术的优缺点。由分析结果可知，可钻桥塞封堵性能可靠，可满足当前上返封堵需求；注堵一体封堵技术尚不成熟；卡瓦悬挂和膨胀管可作为上返封堵技术的有限补充；桥式双管跨层封堵技术在可靠性方面优势明显，应作为注入井下返封堵的主要技术；现有采出井下返封堵技术配合验封技术可满足采出井下返封堵需要。建议下一步开展套变井下返机械封堵技术和精准验窜技术的研究，保证封堵效果，降低封堵成本；同时建立统一规范的封堵工艺技术体系，形成封堵技术选择图版，指导封堵工艺选择。

Current situation and development direction of upward and downward return mechanical plugging technology for chemical flooding in Daqing Oilfield

The upward and downward return plugging technology is the main means to facilitate chemical flooding into the stimulation layers, and among which, the mechanical plugging technology is the most commonly used technique. The application scope and technical characteristics of various mechanical plugging technologies applied in the field varies, and the plugging performance is also quite different. Therefore, this paper analyzes the upward and downward return mechanical plugging technologies used in Daqing Oilfield, introduces the mechanical plugging technologies such as upward return plugging drillable bridge plugs, slip-hanging packers, injection-plugging integration and expandable pipes, as well as the mechanical plugging technologies of downward return for injection wells and production wells, and analyzes the advantages and disadvantages of different technologies. The following conclusions are drawn: the plugging performance of drillable bridge plugs is reliable and can meet the current requirements of upward return plugging; the integrated injection-plugging technology is not yet mature; the slip-hanging packers and expandable pipes can be used as a limited supplement to the upward return plugging technology; the bridge-type double-pipe cross-layer plugging technology has obvious advantages in reliability, and should be used as the main technology for the downward return plugging of the injection wells. The existing downward return plugging technology of production wells, combined with the sealing verification technology, can meet the needs of downward return plugging of production wells. It is recommended to carry out the research on the mechanical plugging technology and accurate channeling detection technology used in wells with casing deformation in the next step to ensure the plugging performance and reduce the plugging cost. Besides, a unified and standardized plugging technology system should be established to form a plugging technology selection chart to guide the plugging technology selection.