薄层底水碳酸盐岩油藏水平井含水上升模式及优化注水技术

Water-cut rising patterns and optimal water injection techniques of horizontal wells in thin carbonate reservoir with bottom water

水平井含水上升问题日益突出,对油田的产能建设影响较大。通过分析中东A油田KH油藏水平井含水上升的主控因素及模式,研究薄层底水碳酸盐岩油藏水平井含水上升规律,并有针对性地提出注水开发优化技术。基于岩心描述、铸体薄片、全直径岩心CT成像测井资料以及生产动态分析,厘清了影响薄层底水碳酸盐岩油藏水平井含水上升的主控因素,高渗条带、裂缝带、高黏油的分布以及底水能量的强弱为主要地质因素,开发技术对策如注采比、注采强度以及水平井与储层的关系为主要开发因素。研究表明,以上主控因素会造成水平井各段出水不均匀,表现为含水快速上升或暴性水淹;注入水或底水主要沿高渗条带流动,水平生产段部分呈条带状水淹的特征。为此,提出井网平衡注采、周期性注水及水平井侧钻等技术对策,并在油田现场实施,目前试验井组开发调整效果较好。优化注水技术可在同类油田推广应用。

The problem of water cut rising in horizontal wells is becoming more and more prominent,which has a great impact on oil field productivity construction. Water-cut rising performance of horizontal wells in a thin carbonate reservoir with bottom water in A oilfield in the Middle East was studied by analyzing main controlling factors and water flood models. Accordingly,optimal development techniques of water injection were also put forward. Through the analyses of core description,XRMI,thin section and CT scanning,the influencing factors including high-permeability zone,fracture belt,high viscosity oil,bottom water,injection-production ratio,injectionproduction intensity and the relationship between horizontal segments and reservoir were determined,which resulted in the uneven displacement and the rapid rise of water cut. The water-out rising rule was characterized by injected water or bottom water flowing along the high-permeability zone and“strip”flooding of horizontal well. Thus the optimum technical measures including the pattern balancing injection-production,the cyclic flood with variable water injection rate,and the horizontal well sidetracking were proposed,and the development effects of oil stabilization and water-out control have been achieved. These techniques can be applied to similar oil fields.