阿布扎比NEB油田超长水平井限流筛管完井与酸化优化设计

阿布扎比NEB油田低渗油藏普遍应用超长水平井开发生产，水平段布酸效果是制约超长水平井酸化后产能的关键因素。LEL限流筛管完井和酸化是实现超长水平井均匀酸化的有效手段，但目前常用的LEL限流筛管设计方法多与专业软件相结合，不利于参数敏感性分析和快速优化设计。 通过优选管流摩阻计算模型和孔眼流动摩阻计算模型，建立了LEL限流筛管孔眼分布的解析设计方法，可以对超长水平井LEL完井实施快速的孔眼数分布设计；同时结合酸蚀蚓孔长度计算模型和当量表皮系数计算模型进行了酸化效果的快速预测评价。以阿布扎比NEB油田某井实钻井眼情况为例，开展了LEL限流筛管孔眼分布设计和酸化效果预测，得出结论： LEL酸化井酸蚀蚓孔长度可达到1.32 ~ 1.63 m，酸化后当量表皮系数可达到 - 2. 85 ~- 3.06；酸液穿透岩心的PV数是LEL设计的一个关键参数，应当通过实验测取。同时认识到，均匀布酸并不能作为LEL酸化设计的唯一目标，应当综合考虑储层非均质性条件，以均衡蚓孔长度、均衡酸化后表皮系数、均衡酸化后产量剖面等为目标开展更加优化的孔眼分布设计

Optimization Design of Limited Entry Liner Completion and Acidizing for Ultra-long Lateral Horizontal Wells in NEB Oilfield,ABU Dhabi

Ultra-long horizontal wells are widely used in low-permeability reservoirs of NEB oilfield in ABU Dhabi, the acid distribution effect in lateral section is a key factor restricting the well performance of ultra-long horizontal wells after acidi-zing. LEL ( Limited Entry Liner) completion and acidification is an effective method to achieve uniform acidification of ultra-long horizontal wells. However, the commonly used LEL design methods mostly rely on special simulation tools, which are not convenient for parameter sensitivity analysis and fast design optimization. Based on the optimal selection of friction calculation models for pipe flow and orifice flow, analytical expressions for designing the hole number distribution of LEL are derived, which can be used to design the hole number distribution rapidly in ultra-long horizontal wells with LEL completion. Besides, the prediction and evaluation of acidizing effect were carried out based on the calculation models of wormhole length and equivalent skin coefficient. Taking the actual drilling condition of a well in NEB oilfield, ABU Dhabi as an example, the hole distribution design and acidification effect prediction of LEL were carried out. The results show that the wormhole length for LEL acidized wells can reach 1.32-1.63 m and the equivalent skin factor can reach - 2. 85 ~ - 3. 06. The PV to breakthrough is a key parameter for LEL design, which should be measured experimentally. Uniform acid coverage should not be the only goal of LEL design, reservoir heterogeneity should be taken into account, wormhole length, equivalent skin factor as well as uniform production profile are better to be taken as the goals of hole distribution design.