伊拉克S油田碳酸盐岩油藏裂缝封堵

伊拉克S油田主力开发层系为中高孔、中低渗的孔隙-裂缝型碳酸盐岩油藏,酸化压裂是该碳酸盐岩储层改造的主要技术手段之一。由于储层裂缝溶洞发育,非均质强,酸液滤失量大,作用距离有限,需要结合裂缝暂堵技术,实现对非均质储层的均匀改造。根据该油田储层地质油藏资料,对裂缝尺寸进行分析,并将储层裂缝划分为微缝和常规缝。实验通过巴西劈裂,对储层标准岩心进行劈裂造缝,模拟了真实粗糙微缝(0.03 mm、0.05 mm、0.08 mm),然后采用3D打印岩板模拟了常规粗糙裂缝(1 mm、2 mm、3 mm),最后将粉末、纤维、颗粒合理配比作为暂堵剂对裂缝进行封堵,优选了裂缝封堵配方。实验结果表明：针对微缝,纤维和粉末均能有效封堵裂缝,纤维相比粉末更易封堵微缝,封堵后承压均超过30 MPa；针对常规缝,采用纤维或纤维与颗粒组合可有效堵裂缝,封堵后承压均超过30 MPa。通过裂缝封堵实验,探索了碳酸盐岩缝内封堵规律,优选了暂堵剂配方,可为现场裂缝封堵施工提供理论依据。

Study on Pore-fractured Carbonate Reservoir Cracks Plugging

The main development zone is high porosity and low permeability pore-fractured carbonate reservoir in S Oilfield in Iraq, and acid fracturing is a main technique of stimulation for carbonate reservoir. Due to the development of reservoir fracture and cave, strong heterogeneity, large amount of acid filtration, limited reacted radius, we need combined with the crack temporary plugging technology to realize the homogeneous stimulation for heterogeneous reservoir. According to the oilfield reservoir geological reservoir data, we analyze the crack size and grade the reservoir fracture level (micro seam and conventional seam). By the Brazilian splitting, the standard of reservoir cores was split to simulate the real rough micro seam (0.03 mm, 0.05 mm and 0.08 mm). 3D printing plates are adopted to simulate the conventional rough fracture (1 mm, 2 mm, 3 mm); Using powder, fibers, particles as temporary plugging agent to seal cracks and optimize fracture plugging formula. The experimental results show that: in view of the micro seam, fiber and powder can effectively block cracks. Compared with fiber, micro powder is easier to block seam, besides, the sealing pressure is more than 30 MPa. In view of the conventional seam, using fiber or fiber and particle combination can effectively plug fracture, and the sealing pressure is more than 30 MPa. Through the crack sealing experiment, we explore the rule of within carbonate fissure sealing and optimize the temporary plugging agent formula. All these can provide theoretical basis for on-site crack sealing construction.