基于微流控技术的裂缝性碳酸盐岩油藏脱气后水窜治理实验研究

Microfluidics experimental investigation of water channeling control strategy after degassing in fractured carbonate reservoirs

基于微流控技术,针对低压裂缝孔隙型碳酸盐岩油藏,设计了孔洞型和裂缝型两种微流控模型,在考虑前期衰竭式开发的条件下,开展了注气模拟脱气原油、注水、注药剂治理水窜等一系列微流控实验,基于水溶性化学剂组分追踪技术和微观剩余油量化分析技术,分析了衰竭式开发脱气后不同类型储层的注水开发效果及水窜后治理对策。实验结果表明,由于非连续相气体的存在导致原油流动阻力增加,使得孔洞型储层脱气后采出程度有明显降低;对于裂缝性储层而言,与井底相连的开放性裂缝内部由于压力更低,使得脱气程度更大,孔隙及裂缝中脱出的气体在裂缝中形成了连续气相,而非裂缝区域与孔洞型储层较为相似。不同类型储层水窜治理的微流控实验表明:对于孔洞型储层,可采用微球+润湿性调节剂组合调驱,对于裂缝型储层,可采用聚合物凝胶驱,针对不同储层类型所实施的水窜治理均能够有效改善储层的波及系数,提高其采出程度。将其应用于现场,效果良好,对应的水窜治理方法对裂缝性碳酸盐岩油藏开发具有指导和借鉴意义。

Based on microfluidic technology, two microfluidic models, pore type and fracture type, are designed for low pressure fractured porous carbonate reservoir. Considering early depletion development, a series of microfluidic experiments, such as gas injection simulation of degassed crude oil, water injection, and chemical injection treatment of water channeling, have been carried out. Based on the water-soluble chemical agent component tracking technology and microscopic residual oil quantitative analysis technology, this paper analyzes the water injection development effect of different types of reservoirs after depletion development and degassing and the treatment countermeasures after water channeling. The experimental results show that the flow resistance of crude oil increases due to the presence of non-continuous phase gas, which makes the recovery degree of porous reservoir significantly lower after degassing. For fractured reservoirs, the internal pressure of the open fractures connected to the bottom of the well is lower, which makes the degree of degassing greater. The gas released from the pores and the fractures form a continuous gas phase in the fractures, while the non-fracture areas are more similar to the porous reservoirs. The microfluidic experiment of water channeling control for different types of reservoirs shows that for porous reservoirs, the combination of microsphere and wettability modifier can be used for profile control and flooding, and for fractured reservoirs, polymer gel flooding can be used. Water channeling control for different types of reservoirs can effectively improve the sweep efficiency of reservoirs and enhance their recovery. Good results are obtained in field applications, and the corresponding water channeling control method has guiding and reference significance for the development of fractured carbonate reservoirs.