| 准中4区块致密砂岩孔隙结构特征研究 |
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| 引用本文： | 刘惠民,王学军,杜振京,唐东,李静,王昊.准中4区块致密砂岩孔隙结构特征研究[J].地质力学学报,2020,26(1):96-105. |
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| 作者姓名： | 刘惠民 王学军 杜振京 唐东 李静 王昊 |
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| 作者单位： | 1.中国石化胜利油田分公司油气勘探管理中心, 山东 东营 257200 |
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| 基金项目： | 国家自然科学基金（41972138）；国家科技重大专项（2016ZX05002-002，ZD2019-183-007） |
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| 摘 要： | 致密砂岩孔隙结构是影响储层物性、储集性能和渗流特性的主要因素，准确表征岩石的孔隙结构特征是储层评价的重要内容之一。为此通过岩心观察、CT扫描成像及其图像处理等对准噶尔盆地中部4区块董11井致密砂岩储层孔隙结构特征进行了定性及定量综合研究。研究结果表明，采用USM锐化、阈值选取及中值滤波法对微CT扫描灰度图像进行图像处理，可以更好地区分岩石内部骨架和孔隙的边界，提高了图像的分割精度；当数字岩心立方体模型边长在450体素时，孔隙度趋近定值；研究区致密砂岩储层储集空间主要以粒间孔隙和微裂隙为主，伴有少量的解理裂隙，孤立孔隙较多，孔隙形状复杂，分布不均匀；研究区致密砂岩连续截面面孔率分布不均匀，离散性强，在连续截面上面孔率频繁出现极大值与极小值（跳跃性较大），容易在流体流动的过程中产生压降过大，造成部分孔隙喉道堵塞；研究区致密砂岩储层孔隙大小分布不均匀，孔隙直径在15~35 μm之间，占总孔隙数的60%左右，其面积占18%；直径在50~200 μm的孔隙数量占总孔隙数的20%，其面积占比达60%，为油气赋存提供了有利的储集空间。
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| 关 键 词： | 致密砂岩 CT扫描 孔隙结构 数字岩心 |
| 收稿时间： | 2019/2/1 0:00:00 |
| 修稿时间： | 2019/11/7 0:00:00 |
Study on pore structure characteristics of tight sandstone in Block 4 of the central Junggar Basin |
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| LIU Huimin,WANG Xuejun,DU Zhenjing,TANG Dong,LI Jing and WANG Hao.Study on pore structure characteristics of tight sandstone in Block 4 of the central Junggar Basin[J].Journal of Geomechanics,2020,26(1):96-105. |
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| Authors: | LIU Huimin WANG Xuejun DU Zhenjing TANG Dong LI Jing and WANG Hao |
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| Institution: | 1.Manage center of Oil and Gas Exploration of SINOPEC Shengli Oilfield Company, Dongying 257200, Shandong, China2.Research institute of exploration and development of Shengli Oilfield, Sinopec, Dongying 257015, Shandong, China3.Research Institute of Geological Mechanics and Engineering in China University of Petroleum, Qingdao 266580, Shandong, China |
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| Abstract: | The pore structure of tight sandstone is the major factor affecting physical property, performance and seepage characteristics of reservoir. The accurate characterization of rock pore structure is one of the important contents of reservoir evaluation. Therefore, the pore structure characteristics of tight sandstone reservoir in Well Dong-11, Block 4, central Junggar Basin were studied qualitatively and quantitatively through core observation, CT scanning imaging and image processing. The results show that:USM sharpening, threshold selection and median filtering were used for image processing of gray scale images in micro-CT scanning, which could better distinguish the boundary between skeleton and pore inside the rock and improve the image segmentation accuracy. Porosity tends to be constant when the side length of the digital core cube model is 450 voxel. The reservoir space of tight sandstone reservoirs in the study area is mainly composed of intergranular pores and micro-fractures, with a small number of cleavage fractures, and more isolated pores. Pores are characterized by complex shapes and uneven distribution. The porosity distribution of the continuous section of the tight sandstone in the study area is not uniform and highly discrete. The maximum and minimum values of porosity appear frequently on continuous sections (strong jumping), which is easy to cause excessive pressure drop in the process of fluid flow, resulting in partial pore throat blockage. The pore size distribution of tight sandstone reservoir in the study area is not uniform. The pore diameter is mainly from 15 microns to 35 microns, which accounts for about 60% of the total pore number, but its area only accounts for 18%. The pores take up 20% of the total number of pores from 50 microns to 200 microns in diameter, but the area takes up 60%, which provides favorable storage space for oil and gas. |
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| Keywords: | tight sandstone CT scanning pore structure digital core |
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