| 鄂尔多斯盆地上古生界低压异常研究中应注意的几个问题 |
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| 引用本文： | 尤欢增,李仲东,李良,惠宽洋,过敏,王震.鄂尔多斯盆地上古生界低压异常研究中应注意的几个问题[J].矿物岩石,2007,27(2):64-69. |
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| 作者姓名： | 尤欢增 李仲东 李良 惠宽洋 过敏 王震 |
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| 作者单位： | 1. 中国石油化工股份有限公司华北分公司,河南郑州,450006
2. 成都理工大学"油气藏地质及开发工程"国家重点实验室,四川成都,610059 |
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| 摘 要： | 通过对鄂尔多斯盆地上古生界砂泥岩压实特征、压力成因的研究,结合上古生界不同岩性的组合关系分析,认为上古生界非烃源岩与烃源岩、砂岩和泥岩的地层压力成因有明显区别。非烃源岩系统泥岩的异常高压主要由“非均衡压实”作用产生;而生气作用是烃源岩增压的关键因素,同时也是上古生界天然气运移、成藏的主要动力源;砂岩与泥岩弹塑性有明显差别,构造抬升剥蚀成为砂岩降压的主要机理,而对泥岩影响有限,石千峰-上石盒子组非烃源岩目前仍具明显非均衡压实特征,多处于高压异常,而储层表现为低—正常压力,目前上古生界为一个高低压相间共存的复杂压力系统。上古生界压力的形成与演化历史表明,对于上古生界用流体势的高低来研究互不连通砂体之间的区域运移可能并不适宜。利用Berg临界烃类柱高度的公式计算,上古生界储层能引起天然气运移需要的最小连续气柱高度在22.07 m～67.36 m,远大于砂岩的单层厚度(5 m～15 m)。从天然气的生产能力、天然气聚集、成藏角度分析,山2段毛管中值压力平均值小于6.21MPa、砂岩厚度大于4 m以上的优质储层,才具有聚集、成藏和产出天然气能力,而排驱压力大、孔隙结构差、厚度小的砂岩,由于成藏动力小于成藏阻力,难于形成具规模的气层。
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| 关 键 词： | 鄂尔多斯盆地 上古生界 压力成因差别 泥岩压力状态 压力系统封闭性 |
| 文章编号： | 1001-6872（2007）02-0064-06 |
| 修稿时间： | 2007-02-18 |
SOME PROBLEMS IN THE RESEARCH OF LOW PRESSURE ANOMALY IN THE UPPER PALEOZOIC STRATUM IN THE ORDOS BASIN |
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| YOU Huan-zeng,LI Zhong-dong,LI Liang,XI Kuan-yang,GUO Min,WANG Zhen.SOME PROBLEMS IN THE RESEARCH OF LOW PRESSURE ANOMALY IN THE UPPER PALEOZOIC STRATUM IN THE ORDOS BASIN[J].Journal of Mineralogy and Petrology,2007,27(2):64-69. |
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| Authors: | YOU Huan-zeng LI Zhong-dong LI Liang XI Kuan-yang GUO Min WANG Zhen |
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| Institution: | 1. Exploration and Production Research Institute of Huabei Company,SINOPEC,Zheng zhou 450006,China 2. State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Chengdu University of Technology,Chengdu 610059,China |
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| Abstract: | Through the study of compaction character and pressure genesis of sandstone and mudstone in the Ordos basin,combined with the research of association relation of different lithology,it is considered that there exist obvious differences in the stratum pressure genesis between the hydrocarbon rock and non-hydrocarbon rock,sandstone and mudstone.The abnormal high pressure in the mudstone of non-hydrocarbon rock is resulted from the heterogeneous compaction and the gas formation is the key factor for the increment of pressure in the hydrocarbon rock as well as the dynamic source for the migration and accumulation of natural gas in the upper Paleozoic stratum.Tectonic uprising and erosion become the major mechanism for the pressure decrease in the sandstone,but has little effect on the mudstone because their elasticity nd plasticity are apparently different.At present,the non-hydrocarbon rocks of the Shiqianfeng Formation and Shihezi Formation possesses heterogeneous compaction and show high-pressure abnormality.The reservoir in the stratum shows low-normal pressure,indicting that low and high pressures coexist in the complicated pressure system in the upper Paleozoic stratum.The formation and evolution of pressure space in the upper Paleozoic reveals that it is not suitable to use the flow potential in the study of regional migration among unconnected sandbodies.According to the Berg formula,at least 22.07 m~67.36 m gas columns is needed to initiate the migration of gas,which is much thicker than the thickness of individual sandstone bed in the upper Paleozoic reservoir.On the basis of production capcity,gas accumulation and gas pool formation,only when the average pressure of Shan 2 Member is less than 6.22 MPa and the thickness of sandstone is over 4 m,can it possess the conditions of gas accumulation and gas pool formation.On the contrary,it is difficult for the sandstones with large driving pressure,poorly developed pore texture and small thickness to form large-scale gas reservoir. |
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| Keywords: | Ordos basin upper Paleozoic difference of pressure genesis pressure state of mudstone closure of pressure system |
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