鄂尔多斯盆地中东部奥陶系盐下天然气富集规律与气藏主控因素
|
摘要
近年来,鄂尔多斯盆地中东部盐下储层,相继发现了一批高产工业气流井及一批低产、低效井,充分显示了盐下天然气分布的复杂性,给今后勘探部署决策增大了难度。本文在前人研究成果基础之上,通过野外露头地质调查、钻井岩芯观察与描述、镜下鉴定、实验室相关实验测试,同时引入构造应力场及流体势场数值模拟及构造曲率计算技术,系统研究盐下主力储层马五7亚段和马五9亚段天然气的富集规律。研究认为:沉积相带影响储层的储集性,天然裂缝影响气藏的分布,平面上天然气主要分布在工区中西部白云岩相对较厚的颗粒滩沉积微相中,其原因主要是该微相中天然裂缝系统发育,有效地改善了颗粒滩沉积微相储层的储集性能。在构造应力场作用下,天然气从高压低孔隙地带向低压高孔隙带运移与富集,微幅构造对气藏富集的控制作用明显,本区高产气井均位于鼻隆及其两侧的鼻翼位置。该研究为今后盐下气藏的勘探部署决策提供了地质依据。
In recent years,a number of high-yield industrial gas flow wells and a number of low-yield and low-efficiency wells have been discovered in the subsalt reservoirs in the central and eastern parts of the Ordos basin,which fully demonstrates the complexity of subsalt natural gas distribution and increases the difficulties for exploration and deployment in the future.On the basis of previous research results,this paper aims to systematically study the law of enrichment of natural gas in the main subsalt reservoirs Ma57 subsection and Ma59 subsection by means of field outcrop geological survey,observation and description of drilling cores,microscopic identification and laboratory related experimental tests,and introducing numerical simulation of tectonic stress field and fluid potential field and structural curvature calculation technology.The sedimentary facies belt affects the reservoir's property,and the natural crack affects the gas reservoir distribution.The natural gas on the plane is mainly distributed in the relatively thick granitic beach sedimentary microfacies of the central and western dolomite in the work area,mainly due to the development of the fracture system effectively improves the reservoir performance of the sedimentary microfacies reservoir.Under the action of tectonic stress field,natural gas migrates and enriches from high pressure and low porosity zone to low pressure and high porosity zone.The micro-structure has obvious controlling effect on gas reservoir enrichment.The high-production gas wells in this area are located on the nose and its sides position,which provides a geological basis for the exploration and deployment decision of the subsalt gas reservoirs in the future.
In recent years,a number of high-yield industrial gas flow wells and a number of low-yield and low-efficiency wells have been discovered in the subsalt reservoirs in the central and eastern parts of the Ordos basin,which fully demonstrates the complexity of subsalt natural gas distribution and increases the difficulties for exploration and deployment in the future.On the basis of previous research results,this paper aims to systematically study the law of enrichment of natural gas in the main subsalt reservoirs Ma57 subsection and Ma59 subsection by means of field outcrop geological survey,observation and description of drilling cores,microscopic identification and laboratory related experimental tests,and introducing numerical simulation of tectonic stress field and fluid potential field and structural curvature calculation technology.The sedimentary facies belt affects the reservoir's property,and the natural crack affects the gas reservoir distribution.The natural gas on the plane is mainly distributed in the relatively thick granitic beach sedimentary microfacies of the central and western dolomite in the work area,mainly due to the development of the fracture system effectively improves the reservoir performance of the sedimentary microfacies reservoir.Under the action of tectonic stress field,natural gas migrates and enriches from high pressure and low porosity zone to low pressure and high porosity zone.The micro-structure has obvious controlling effect on gas reservoir enrichment.The high-production gas wells in this area are located on the nose and its sides position,which provides a geological basis for the exploration and deployment decision of the subsalt gas reservoirs in the future.
引文
[1]徐黎明，周立发，张义楷，等．鄂尔多斯盆地构造应力场特征及其构造背景[J]．大地构造与成矿学，2006,30(4):455-462.XU Liming,ZHOU Lifa,ZHANG Yikai,et al.Characteristics and tectonic setting of tectono-stress field of Ordos basin[J].Geotectonica Et Metallogenia,2006,30(4):455-462．
[2]赵文韬，侯贵廷，张居增，等．层厚与岩性控制裂缝发育的力学机理研究---以鄂尔多斯盆地延长组为例[J]．北京大学学报：自然科学版，2015,51(6):1047-1058.ZHAO Wentao,HOU Guiting,ZHANG Juzeng,et al.Study on the development law of structural fractures of Yanchang formation in Longdong area,Ordos basin[J].Acta Scientiarum Naturalium Universitatis Pekinensis,2015,51(6):1047-1058．
[3]党犇，赵虹，付金华，等．鄂尔多斯盆地沉积盖层构造裂缝特征研究[J]．天然气工业，2005,25(7):14-16.DANG Ben,ZHAO Hong,FU Jinhua,et al.Characteristics of structural fractures in sedimentary strata of Ordos basin[J].Natural Gas Industry,2005,25(7):14-16．
[4]李剑．试论油田构造裂缝及其有效性[J]．中国石油和化工标准与质量，2013(11):120.LI Jian.Discussion on structural cracks in oilfield and their effectiveness[J].Petrochemical and Chemical Standard and Quality,2013(11):120．
[5]王建民，王佳媛．鄂尔多斯盆地伊陕斜坡上的低幅度构造与油气富集[J]．石油勘探与开发，2013,40(1):49-57.WANG Jianmin,WANG Jiayuan.Low-amplitude structures and oil-gas enrichment on the Yishaan slope,Ordos basin[J].Petroleum Exploration and Development,2013,40(1):49-57.
[2]赵文韬，侯贵廷，张居增，等．层厚与岩性控制裂缝发育的力学机理研究---以鄂尔多斯盆地延长组为例[J]．北京大学学报：自然科学版，2015,51(6):1047-1058.ZHAO Wentao,HOU Guiting,ZHANG Juzeng,et al.Study on the development law of structural fractures of Yanchang formation in Longdong area,Ordos basin[J].Acta Scientiarum Naturalium Universitatis Pekinensis,2015,51(6):1047-1058．
[3]党犇，赵虹，付金华，等．鄂尔多斯盆地沉积盖层构造裂缝特征研究[J]．天然气工业，2005,25(7):14-16.DANG Ben,ZHAO Hong,FU Jinhua,et al.Characteristics of structural fractures in sedimentary strata of Ordos basin[J].Natural Gas Industry,2005,25(7):14-16．
[4]李剑．试论油田构造裂缝及其有效性[J]．中国石油和化工标准与质量，2013(11):120.LI Jian.Discussion on structural cracks in oilfield and their effectiveness[J].Petrochemical and Chemical Standard and Quality,2013(11):120．
[5]王建民，王佳媛．鄂尔多斯盆地伊陕斜坡上的低幅度构造与油气富集[J]．石油勘探与开发，2013,40(1):49-57.WANG Jianmin,WANG Jiayuan.Low-amplitude structures and oil-gas enrichment on the Yishaan slope,Ordos basin[J].Petroleum Exploration and Development,2013,40(1):49-57.