中东地区孔隙型碳酸盐岩油藏水平井水淹模式

水平井注水开发是中东地区孔隙型碳酸盐岩油藏的主体开发技术之一,而水平井水淹是制约注水开发效果的关键因素,为了尽快建立这类油藏的高效注水开发方式,需要对水平井水淹规律及其模式进行深入研究。与中国缝洞型碳酸盐岩油藏不同,中东孔隙型碳酸盐油藏具有发育生物碎屑灰岩、孔隙结构呈多模态、物性夹层及高渗条带普遍分布等特征,注水开发效果存在很大不确定性。岩心分析和测井解释表明高渗条带、断裂带和高黏流体是薄层孔隙型碳酸盐岩油藏水平井水淹的主控因素,导致水平段各部分见水不均衡,表现为点状见水局部水淹、多点见水局部水淹和线状见水整体水淹三种类型。基于主控地质因素和动态响应特征建立四类水平井水淹模式,并分析了不同模式下水平井见水规律、剩余油分布特征及开发调整对策。研究成果可以为中东地区孔隙型碳酸盐岩油藏水平井水淹治理和注水开发调整提供理论和技术指导。

Waterflooding Model of Horizontal Wells for Porous Carbonate Reservoirs in the Middle East

The water injection development with horizontal wells is one of the main development mode for porous carbonate reservoirs in the Middle East, while waterflooding performance in horizontal wells significantly influences the efficiency of water drive development. In order to establish the efficient water injection mode, it is necessary to conduct in-depth research on the water-out performance and pattern for horizontal wells. Compared with fracture-cavity carbonate reservoirs in northwestern China, porous carbonate reservoirs in the Middle East are characterized by bio-clastic limestone, multimodal pore structure, physical interlayer and high permeability zone, which result in uncertainty of water injection development. The core analysis and the logging interpretation indicate that the major controlling factors of non-uniform waterflooding in the horizontal wells are high-permeability layers, fault zones and high viscosity oil, which cause uneven water-out and displacement. The typical water-out types include single spot breakthrough-partial waterflooding, multi-spots breakthrough-local waterflooding and linear breakthrough-global waterflooding. Based on the analyses of geological and dynamic response characteristics, four types of waterflooding pattern were established. Then water-out performance, distribution characteristics of remaining oil and adjustment strategies were proposed. This study provides theoretical and technical guidance for waterflooding management and efficient water injection adjustment in the Middle East.