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针对非均质严重油藏,采用室内实验对注水前后实际岩心样品进行对比分析,研究了注水开发过程中的流体动力地质作用。结果表明,酸性介质条件的化学动力作用加速了碎屑组分中的长石类矿物尤其是斜长石的溶蚀,同时生成了新的高岭石晶体并分布于细小孔喉,但对碳酸盐类矿物的影响较小。注水冲刷等物理动力地质作用造成了储集层泥质矿物总量的降低和粉砂—极细砂级石英颗粒的缺失,且主要发生在物性较好且优势渗流通道较发育的层段。在储集层孔喉变化方面,注水开发既使相对较大孔喉增加,改善了储集层的渗滤条件,也使孔喉分选程度降低,加剧了储集层微观非均质性。从储集层孔隙度、渗透率等宏观参数变化看,注水开发致使储集层总体平均有效孔隙度降低4.63%,而总体平均有效渗透率上升8.93%,原始物性不同的储集层注水后物性变化呈现出明显的“马太效应”。
In the case of severe heterogeneous reservoirs, the laboratory experiments were used to compare the actual core samples before and after water injection, and the fluid dynamic geology in the process of water injection development was studied. The results show that the chemical kinetics of acidic media accelerates the dissolution of feldspathic minerals, especially plagioclase, and produces new kaolinite crystals distributed in the pore throats, but the carbonate Less affected by minerals. The physical and dynamical geological processes such as water scouring cause the decrease of the total amount of argillaceous minerals and the absence of silt-ultrafine-grained quartz grains in the reservoir, which mainly occur in the layers with better physical properties and more favorable seepage channels. In the aspect of pore-throat changes of reservoirs, even though relatively large pore-throat increases, the percolation conditions of reservoirs are improved and the degree of pore-throat sorting is also reduced, which aggravates the micro-heterogeneity of reservoirs. In view of the change of macroscopic parameters such as porosity and permeability of reservoir, the average effective porosity of reservoir decreases 4.63% while the average effective permeability increases by 8.93% due to the development of water injection. The physical property of waterflooding reservoirs with different original properties Changes show a clear “Matthew effect ”.