The Effect of Pore Geometry on the Flow Unit and Its Impact to Permeability of the Reservoir Rock

[摘要] Rock type is defined as a rock interval with a unique pore geometry and it is related to the characteristics of the hydraulic flow unit. The quality of hydraulic unit of the rock is controlled by pore geometry which is a function of texture and mineralogy of the rock. In this research, it is conducted the study of the effect of pore geometry on the flow unit owned by the reservoir and its impact to the permeability value. This study used 191 of sandstone core samples from Upper Cibulakan Formation in the North West Java Basin. The hydraulic flow unit concept developed by Kozeny-Carman is used to determine the rock type in the reservoir. Afterward, microscopic geology features are identified based on rock texture in the form of grain size, grain sorting, and angularity as part of the pore geometry that controls the hydraulic quality of the rock. This identification was carried out to determine the pore geometry which generally composes each rock type. Based on the results of core data analysis, the reservoir under this study consists of eight flow units. Based on microscopic geology features identification, it is generally found that the better flow unit, the simpler texture it has, which is seen from the better of grain size and grain sorting. On the contrary, the lower quality of the flow unit, the texture tends to be more complex. From this study, it has also known that the better flow unit has a higher permeability value compared to the lower quality of flow unit, which causes the fluid flowing faster and the rock has the better reservoir quality index.

[发布机构] Petroleum Engineering Department, Faculty of Earth Technology and Energy, Universitas Trisakti, Jalan Kyai Tapa No.1 Grogol, Jakarta Barat; 11440, Indonesia^1

[关键词] Features identification;Fluid flowing;Hydraulic flow units;Hydraulic units;Reservoir quality index;Reservoir rock;Rock textures;Sandstone cores