【摘要】：為了深入了解湘西北下寒武統(tǒng)牛蹄塘組的頁巖氣資源潛力,需對該地區(qū)牛蹄塘組中下部硅質頁巖和碳質頁巖層段進行可壓裂性評價。通過室內實驗等手段分析了影響頁巖可壓裂性的4類關鍵物理和力學因素。結果顯示:牛蹄塘組中下部硅質頁巖的脆性礦物平均含量(51.58%)高于碳質頁巖(40.55%),而其黏土礦物平均含量(14.13%)低于碳質頁巖(24.49%);硅質頁巖的脆性系數(基于泊松比和彈性模量)比碳質頁巖高34%;硅質頁巖的內摩擦角較大,碳質頁巖的黏聚力較小;碳質頁巖的孔隙度(平均3.67%)較大,但硅質頁巖充填性天然裂縫發(fā)育程度較高。結合影響因素分析和前人經驗,構建了涉及6項指標的頁巖可壓裂性評價體系。分別求得硅質頁巖、碳質頁巖和北美Barnett頁巖的可壓裂系數為0.59、0.29、0.62~0.64。從可壓裂系數可以看出,湘西北牛蹄塘組中下部硅質頁巖層段的壓裂預期效果與北美Barnett頁巖相當,且高出碳質頁巖1倍,具有較高的開發(fā)潛力。
[Abstract]:In order to understand the shale gas resource potential of the Lower Cambrian Niutangtang formation in the northwest of Hunan Province, it is necessary to evaluate the fracturing ability of the middle and lower siliceous shale and carbonaceous shale strata of the Niujiutang formation in this area. Four kinds of key physical and mechanical factors affecting fracturing property of shale are analyzed by laboratory experiments. The results show that the average content of brittleness minerals in the middle and lower siliceous shale of Niujiutang formation (51.58%) is higher than that of carbonaceous shale (40.55%), while the average content of clay minerals (14.13%) is lower than that of carbonaceous shale (24.49%). The brittleness coefficient (based on Poisson's ratio and elastic modulus) of siliceous shale is 34% higher than that of carbonaceous shale, the internal friction angle of siliceous shale is larger, and the cohesive force of carbonaceous shale is smaller. The porosity (average 3.67%) of carbonaceous shale is higher than that of siliceous shale (3.67%), but the filling nature fracture of siliceous shale is higher than that of siliceous shale. Combined with the analysis of influencing factors and the experience of predecessors, a shale fracturing evaluation system involving six indexes was constructed. The fracturing coefficients of siliceous shale, carbonaceous shale and North American Barnett shale are 0.59, 0.29, 0.62 and 0.64, respectively. It can be seen from the fracturing coefficient that the expected fracturing effect of the middle and lower siliceous shale segments of the Niujiutang formation in northwest Hunan is equal to that of the North American Barnett shale, and is twice as high as that of the carbonaceous shale, so it has a high development potential.
【作者單位】： 中南大學有色金屬成礦預測與地質環(huán)境監(jiān)測教育部重點實驗室;中南大學地球科學與信息物理學院;西南石油大學油氣藏地質及開發(fā)工程國家重點實驗室;
【基金】：國家自然科學基金項目(41302124) 油氣藏地質及開發(fā)工程國家重點實驗室(西南石油大學)資助項目(PLN201609) 中南大學中央高�；究蒲袠I(yè)務費專項資金資助項目(2016zzts433)
【分類號】：TE31
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本文編號：2435430