0 引言
1 鄂尔多斯盆地区域地质概况及海陆过渡相页岩气勘探进展
2 鄂尔多斯盆地东缘海陆过渡相页岩基础条件
2.1 海陆过渡相页岩层系沉积环境及岩相特征
2.1.1 沉积环境
2.1.2 岩性组合特征
2.2 海陆过渡相页岩烃源岩特征
表2 鄂尔多斯盆地东缘海陆过渡相页岩累积厚度分布及有机地球化学特征Table 2 Cumulative thickness distribution and organic geochemical characteristics of transitional shale in the eastern margin of Ordos Basin |
区域 | 层位 | 累积厚度/m | 有机质类型 | TOC/% | R O/% | 含气性/(m3/t) |
---|---|---|---|---|---|---|
大宁—吉县[4,48,61] | 山2段 | (21.4~92.3)/41.2 | II2 | (1.14~10.91)/6.88 | (2.63~2.68)/2.66 | (1.11~3.08)/2.0 |
延川[58,60,62-64] | 山1段 | (15~45)/38.92 | III | (0.51~3.54)/0.85 | (1.76~3.38)/2.39 | (0.59~4.05)/1.30 |
山2段 | (18~50)/36.87 | III | (0.58~5.15)/0.97 | (2.0~3.34)/2.51 | ||
临兴[44-45,65] | 山西组 | (12.5~54.65)/34.51 | III | (0.04~37.3)/2.26 | (0.92~1.11)/1.03 | (0.6~2.49)/1.04 |
太原组 | (29.0~76.02)/49.03 | II2 | (0.26~34.7)/3.8 | (1.01~1.3)/1.06 | (0.48~2.46)/1.30 |
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2.3 海陆过渡相页岩孔隙结构特征及储集物性条件
表3 鄂尔多斯盆地东缘海陆过渡相页岩储层表征参数Table 3 Reservoir parameters of transitional shale in the eastern margin of Ordos Basin |
区域 | 层位 | 孔隙形态 | 孔径/nm | 比表面积/(cm3/g) | 孔隙度/% | 渗透率/(10-3 µm2) |
---|---|---|---|---|---|---|
大宁—吉县[41,66-68] | 山2段 | 狭缝状、墨水瓶状 | (1.9~126.8)/13.6 | (0.68~8.49)/4.09 | (1.25~4.85)/3.80 | (0.01~0.10)/0.04 |
延川[69-70] | 山1段 | 狭缝状、墨水瓶状 | (9.1~23.9)/19.0 | (0.59~3.95)/2.68 | (0.4~1.5)/0.77 | (0.006 6~0.241 6)/0.04 |
临兴[40, 44,71] | 山西组 | 狭缝状、墨水瓶状 | (6.35~24.48)/12.69 | (4~6.83)/5.73 | (0.97~1.59)/1.252 | (0.001~0.055)/0.012 2 |
太原组 | 狭缝状、墨水瓶状 | (9.37~16.94)/13.87 | (0.71~7.45)/3.93 | (1.11~1.52)/1.315 | (0.001~0.142)/0.048 3 |
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图6 鄂尔多斯盆地东南缘山西组页岩TOC、黏土矿物含量与比表面积(氮气吸附)关系Fig.6 Relationship between TOC, clay mineral contents and specific surface area (nitrogen adsorption) of shanxi Formation shale in the southeastern Ordos Basin |