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煤系地层赋存有非常丰富的非常规天然气,在煤系地层附近的页岩和致密砂岩中已经发现大量的分散有机质,这种有机质是从早期液态烃中析出的固体沥青,为一种运移态或残余态的固体沥青。加拿大西部盆地三叠系蒙特尼组岩性主要为粉砂岩,粉砂岩中广泛分布固体沥青及沥青纳米孔隙网络,这种固体沥青已经被证实起源为早期的液态烃裂解后形成的残余固体沥青,它广泛填充在该区海相粉砂岩间的孔隙网络,因其富含气泡孔而大幅提高了蒙特尼组砂岩的含气性(Chalmers et al., 2012; Bernard et al., 2013; Cardott et al., 2018; Wood et al., 2018a)。在蒙特尼组砂岩中,固体沥青及发育沥青质纳米孔隙网络是蒙特尼组砂岩储层质量的主要决定性因素。中国鄂尔多斯盆地是一个典型的陆内盆地,各种油气矿产资源丰富,勘探开发对象已经转向致密、深层、盆地周边及外围成藏条件复杂区域,勘探层系已面向品位更低、风险更大的深层资源(Fu Jinhua et al., 2019)。鄂尔多斯盆地古生界本溪组、太原组和山西组煤系地层中的煤层、暗色泥岩、致密砂岩互层分布,含气显示活跃。盆地东部山西组二段泥岩厚10~25m,总有机碳(TOC)含量1%~4%,埋深1600~3200m,山二段泥岩含气量为0.19~2.16m3/t,煤层含气量为20m3/t,致密粉细砂岩含气量为1.6m3/t,不同层系均具有良好的含气性。在鄂尔多斯盆地东部榆94井、桃50井等山西组煤系地层试气分别获6366m3/d和1226m3/d的工业气流,显示了良好的勘探潜力(Fu Jinhua et al., 2019)。由于鄂尔多斯盆地中生代构造热事件对油气煤等多种能源矿产的形成与分布具有重要的控制作用,许多学者已从多方面对鄂尔多斯盆地中生代晚期构造热事件进行了探讨(Zhang Shengli et al.,1996;Fu Ximing,2004;Ren Zhanli et al.,2006, 2007, 2017)。中生代异常热事件对煤系地层非常规天然气成藏的影响认识还远未到位,本文以鄂尔多斯东部榆林—绥德研究区为例,通过开展山西组煤系地层储层微观孔隙研究,提出了有机质纳米孔源自气泡变孔过程的设想,同时开展了液态烃气泡成孔过程的物理模拟,并进一步探讨了异常热事件背景下气泡变孔对非常规气储层的改造作用。
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1 区域油气地质特征
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鄂尔多斯盆地发育在华北克拉通古老基底上,作为华北板块的一部分经历了中新元古代拗拉谷演化阶段、古生代克拉通拗陷沉积阶段及中新生代内陆盆地演化阶段,形成了相对完整的中新元古界—下古生界海相沉积层序(Zhao Chongyuan et al., 1990;Du Jinhu et al.,2019)。盆地可划分为6个次级构造单元:西缘冲断带、天环坳陷、伊盟隆起、陕北斜坡、渭北隆起和晋西挠褶带(图1)(Yao Jingli et al., 2018)。本溪组至石千峰组发育多套储层,本溪组—太原组为滨岸环境的潮坪相沉积体系,山西组为海陆过渡相的曲流河三角洲沉积体系,下石盒子组为辫状河三角洲沉积体系,上石盒子组为浅水三角洲沉积体系,石千峰组为辫状河沉积体系,山西期由陆表海盆地演化为大型近海湖盆,三角洲平原上的低能环境为聚煤的重要场所。上古生界气源主要为本溪组—太原组发育的一套海陆交互相的煤系烃源岩,致密储层主要为三角洲前缘、三角洲平原分流河道砂体/潮坪砂体、决口扇(Chen Anqing et al.,2010; Ge Yan et al.,2018; Li lintao et al.,2019)。盆地自上而下发育4套含气组合,上部依次为石千峰组峰五段-上石盒子组成藏组合、下石盒子组成藏组合和山西组-太原组成藏组合,下部为马五段成藏组合。上古生界致密砂岩储层主要发育在本溪组、太原组、山西组、石盒子组及石千峰组,为河流-三角洲相沉积沉积体系,上、下石盒子组和山西组为主力储层,岩性主要为石英砂岩、岩屑石英砂岩及岩屑砂岩(Yao Jingli et al., 2018;Liu Honglin et al.,2020)。研究区位于盆地东部,范围北部从榆林—横山,南至延安—延长一带,西起陕参1井东部,东至绥德,区域构造上位于伊陕斜坡,构造平缓,断层稀少,区内分布米脂、绥德等多个气田。
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图1 研究区位置及主要成藏组合图(据姚泾利等,2018修改)
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Fig.1 Study area location and main reservoir assemblage (modified from Yao Jingli et al., 2018)
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2 盆地周缘异常热事件
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鄂尔多斯盆地及周缘异常热事件在燕山期具有普遍性和广布性,是鄂尔多斯盆地油气大面积成藏的重要特征。板块汇聚和陆内造山导致中国东部地区地壳岩石圈增厚,特别是华北板块地壳大幅度增厚,诱发了以华北为中心的岩石圈垮塌减薄和克拉通破坏事件,大规模的软流圈地幔上涌发生的底板垫托作用引发了巨量的岩浆侵入和火山喷发(Wang Xiyong et al., 2010;Kang Yu et al.,2018;Li Peng et al.,2021)。在燕山期,华北板块东部经历了强烈的构造和岩浆活动,板块西部的鄂尔多斯盆地内部西南部和北部发生了局部岩石圈减薄事件,导致以庆阳为中心的高成熟源岩存在,盆地整体较为稳定,但是其周缘区域构造运动十分强烈,多处出现岩浆侵入事件(图2),包括银川北部侵入岩、伊盟隆起保尔斯太沟玄武岩、龙门古隆起隐伏岩体、临县西北的紫金山碱性杂岩体、交城西北的狐偃山碱性侵入岩体。
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图2 鄂尔多斯盆地周缘侵入体及地壳减薄区分布(据任战利等,2006修改)
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Fig.2 Distribution of intrusions and crustal-thinning areas around Ordos basin (modified from Ren Zhanli et al., 2006)
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(a)—侵入岩体及推测减薄区;(b)—上地幔上涌减薄示意图;(c)—侵入体对油气藏改造作用
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(a)—Intrusive rock mass and inferred thinning area; (b)—schematic diagram of upper mantle upwelling and thinning; (c)—transformation effect of intrusive body on oil and gas reservoir
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鄂尔多斯盆地西缘广泛存在晚侏罗世—早白垩世的异常热事件,晚侏罗世—早白垩世是异常热事件的主要发生期(Yang Xingke et al., 2006; Zhang Yikai, 2007)。盆地西南缘中三叠世—早白垩世存在广泛的异常热事件,发育三大岩浆活动区,分别在铜城地区、安沟—二线子地区和龙门地区,龙门地区呈隐伏岩体侵入到不同层位地层中,龙门碱性隐伏岩体位于甘肃省灵台县龙门镇南,处于伊陕斜坡、天环坳陷、渭北隆起交汇部位龙门古隆起构造,面积大约380km2,岩性主要为正长斑岩和二长闪长岩,岩体年龄分别为237Ma和108Ma,隐伏岩体活动时代为中三叠世和早白垩世(Zou Heping et al., 2008)。盆地北缘异常热事件发生期早,持续时间较长。杭锦旗黑石头沟玄武岩Ar-Ar激光阶段加热定年126.2Ma,是燕山运动的直接证据,在伊盟隆起保尔斯太沟、伊12井一带的下白垩统泾川组见有玄武岩侵入,在喇嘛沟有辉绿岩侵入(Xiao Yuanyuan et al., 2007)。盆地东部发育多期中生代晚期的异常热事件,大多以岩浆侵入为特征,以临县西北的紫金山碱性杂岩体、交城西北的狐偃山碱性二长岩体和祁县隐伏石英二长岩体为代表,汾河富碱侵入岩带是华北克拉通中西部岩石圈破坏事件证据,时间138.7~125.0Ma,燕山期岩浆事件是鄂尔多斯盆地东部古生界煤系高热演化的原因,紫金山岩体起源于地幔(Xiao Yuanyuan et al., 2007;Wang Yaying et al., 2014)。总之,鄂尔多斯盆地地质历史上岩石圈减薄和岩浆侵入构成了鄂尔多斯盆地异常热时间的主要形式,控制了烃源岩的演化和油气成藏。
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3 山西组地层微观孔隙
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3.1 样品采集和实验方法
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研究区山西组泥页岩是陆源碎屑含煤建造下形成的泥质岩,在纵向上的发育情况有所不同。上段煤层不发育,泥岩多为灰色,有机质丰度相对较低,部分泥岩属于非有效烃源岩;下段是重要的煤系烃源岩发育层段,以深色泥岩、碳质泥岩和煤层为主。为详细研究储层特征,本文对位于鄂尔多斯盆地东部的部分取芯井如米37、神27等井获取的二叠系山西组样品进行微观孔隙分析,取样井位置见图1,样品岩性主要为泥质粉砂岩、粉砂质泥岩、泥岩、页岩等(图3),岩性矿物组成包括石英、黏土矿物、斜长石和黄铁矿等,石英含量25.15%~65.93%,黏土矿物含量8.51%~55.17%,斜长石含量4.29%~15.41%,黄铁矿含量3.23%~6.18%。样品的有机碳0.28%~1.11%,孔隙度2.19%~5.74%,渗透率0.00058×10-3~0.02514×10-3 μm2(表1)。为便于微观孔隙观察,沿着层理对样品切片,先用氩离子抛光仪Gatan Model697进行抛光和喷碳,然后使用FEI Helios 650F采用背散电子(BSD)模式进行微观孔隙观察,工作电压10kV,探针电流0.4nA。
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图3 鄂尔多斯东部钻井岩芯照片
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Fig.3 Photos of core from wells in eastern Ordos basin
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(a)—灰黑色含碳泥质粉砂岩;(b)—灰黑色页岩;(c)—灰黑色泥质粉砂岩;(d)—灰黑色页岩;(e)—灰黑色页岩;(f)—灰黑色粉砂质页岩
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(a)—Grayish black carbonaceous argillaceous siltstone; (b)—grayish black shale; (c)—grayish black argillaceous siltstone; (d)—grayish black shale; (e)—grayish black shale; (f)—grayish black silty shale
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3.2 山西组地层微观孔隙类型
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煤系地层中砂岩和页岩可以作为一种特殊类型的油气储集层,具有特低孔渗、储集空间类型多样等特征。参考于炳松(Yu Bingsong, 2013)分类方案,对山西组煤系地层主要孔隙类型划分为有机质孔隙、残余原生孔隙、不稳定矿物溶蚀孔、黏土矿物层间孔,其主要特征及发育情况见表2。残余原生孔隙由脆性矿物颗粒支撑,直径1nm~3 μm,不稳定的矿物溶蚀孔孔径变化大(30~720nm),连通性差,黏土矿物层间孔由于黏土矿物发生脱水转化而在层间形成微裂隙,缝宽50~300nm,连通性相对较好,有机质纳米孔为气泡固化形成的直径一般为5~750nm,按照国际理论和应用化学联合会(IUPAC) 分类方案,属于介孔和大孔,从分布密度和面孔率上看,总体较为发育。
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有机质孔主要来源于早期液态烃裂解后生成的气泡固化形成的孔隙,常见于砂岩中沥青条带或页岩中沥青条带中(图4a、b),黏土矿物层间孔主要为层状黏土矿物脱水、弯曲形变后形成的层间裂缝(图3c),不稳定矿物溶蚀孔,主要为方解石等矿物溶蚀形成的空洞(图4d),矿物经后期构造改造作用形成次生微裂缝(图4e),原生孔隙主要由矿物颗粒支撑形成(图4f),其成因、主要特征以及发育程度差别大(表2),其中黏土矿物层间孔和有机质孔隙是页岩储集空间的特色和重要组成部分,这是页岩储层与常规砂岩储层的显著区别。
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图4 鄂尔多斯盆地东部地区山西组微观孔隙类型
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Fig.4 Microscopic pore types of Shanxi Formation in eastern Ordos basin
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(a)—有机质孔隙,BSD照片,山西组页岩,米37井;(b)—有机质孔隙,BSD照片,山西组页岩,榆116井;(c)—黏土矿物层间孔,BSD照片,山西组泥质粉砂岩,榆93井;(d)—不稳定矿物溶蚀孔, BSD照片,山西组页岩,榆116井;(e)—方解石次生微裂缝, BSD照片,山西组页岩,榆93井;(f)—残余原生孔隙,BSD照片,山西组泥质粉砂岩,榆116井
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(a)—Organic matter pore, BSD photo, Shanxi Formation shale, well Mi37; (b)—organic matter pores, BSD photo, Shanxi Formation shale, well Yu 116; (c)—clay mineral interlayer hole, BSD photo, argillaceous siltstone of Shanxi Formation, well Yu 93; (d)—unstable mineral dissolution hole, BSD photo, Shanxi Formation shale, well Yu 116; (e)—calcite secondary microfracture, BSD photo, Shanxi Formation shale, well Yu 93; (f)—residual primary pores, BSD photo, argillaceous siltstone of Shanxi Formation, well Yu 116
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4 液态烃裂解产气实验
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4.1 样品采集和实验参数
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为研究山西组页岩和致密砂岩中有机质孔成因,采集了鄂尔多斯盆地延长组长6段原油样品用于气泡变孔实验模拟,采样深度1934.20m,原油密度0.86241g/mL,原油组成中烷烃36.1%,芳烃14.2%,非烃15.1%,沥青质34.6%。实验仪器采用DMP4500显微镜和LTS420型冷热台,利用显微镜载物片载样,载物片直接放置在抛光的加热元件上,载物台可以进行X、Y方向移动,由独立温度控制器进行温度控制,升温速率设定从0.1~50℃/min,最高温度可以升至450℃。
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图5 鄂尔多斯盆地延长组原油中的气泡变孔物理模拟
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Fig.5 Physical simulation of gas bubble converting to pore in oil from Yanchang from Ordos basin
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(a)—原油样品,灰色区域为原油,透射光,500×;(b)—加热到250℃,铝箔边缘的油产生小气泡,透射光,500×;(c)—加热到300℃,油中气泡增多,变大,透射光,500×;(d)—加热到500℃后冷却到室温,气泡保持稳定,透射光,500×
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(a)—Crude oil sample, gray area is crude oil, transmitted light, 500×; (b)—heated to 250℃, small bubbles generated at the edge of aluminum foil, transmitted light, 500×; (c)—heated to 300℃, increased and enlarged bubbles in the oil, transmitted light, 500×; (d)—heating to 500℃ and cooling to room temp., the bubbles remain stable, transmitted light×
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图6 鄂尔多斯盆地延长组原油中的天然气气泡分裂及聚并过程的物理模拟
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Fig.6 Physical beakup and combination simulation of natural gas bubbles in oil from Yanchang Formation, Ordos basin
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(a)—孤立气泡,透射光,500×;(b)—气泡1和4聚并,气泡2、3、5发生变形,透射光,500×;(c)—气泡1和4再分裂,气泡2、3、5继续发生变形,透射光,500×;(d)—气泡1变大,气泡4缩小,气泡2、3、5发生变形,透射光,500×
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(a)—Isolated bubble, transmitted light, 500×; (b)—combination of bubbles 1and 4, deformed bubbles 2, 3and 5,transmitted light, 500×; (c)—second breakup of bubbles 1and 4, continuously deforming of bubbles 2, 3and 5, transmitted light, 500×; (d)—enlarged bubble1, reduced bubble4, deformed bubbles 2, 3and 5, transmitted light, 500×
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4.2 实验步骤
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采集鄂尔多斯盆地延长组原油1~2滴,涂抹在特制的微型载玻片上,为便于观测和定位,加入一小段长度约50 μm、厚度约1 μm的铝箔,然后盖上盖玻片,压平,放置2h后备用。将做好的玻片放入冷热台,为便于对比观测,升温前对样品进行拍照留存(图5a),通电加热,升温速度设置为25℃/min,设定最高升温为500℃,同时在实验过程中可以根据需要随时终止升温程序。
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4.3 实验结果
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加热到250℃,铝箔边缘的油开始产生微小的气泡(图5b),直径小于0.1 μm,随着温度进一步升高到300℃,油中气泡开始明显增多,气泡也在变大(图5c),直径0.25~0.5 μm。进一步升温到500℃过程中,油中气泡开始明显增多,气泡也进一步变大(图5d),直径约0.5~1.1 μm,说明原油已经大量裂解产生了天然气泡。
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为模拟气泡产生后,气泡间的相互作用,本次实验采用降温的方式进行。在达到设定温度后,产生大量气泡,然后停止升温后,热台开始冷却,在冷却过程中进一步观察到俩气泡与气泡间发生分解和聚并的自然现象,如图6中的气泡1、气泡2、气泡3、气泡4、气泡5之间发生了分解和合并的过程,在分解和合并的过程中气泡的形态和大小不断发生变化,随着温度进一步降低,残余原油变得黏稠,气泡形态不在发生变化,位置也变得更为固定。
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5 煤系地层异常热事件对储层改造意义探讨
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山西组页岩和粉砂岩样品总有机碳含量0.21%~1.11%(表3),与蒙特尼组砂岩总机碳(0.5%~4.0%)相比略低(Wood et al., 2018b)。沥青纳米孔隙网络主要发育在残余固体沥青中,从镜下观测对比分析发现,山西组砂岩和页岩中也发育有沥青孔隙网络,发育程度弱于蒙特尼组砂岩,蒙特尼组砂岩沥青在电镜照片面积占比可达8%~12%(Wood et al., 2018b),而山西组页岩和粉砂岩仅有1%~4%,山西组发育数量较少,但是山西组沥青质气泡孔直径较大(1.02~1.24 μm),整体较为稀疏,蒙特尼组砂岩沥青中纳米孔直径0.5~1 μm,孔隙密度较大。
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图7 鄂尔多斯盆地东部地区山西组地层有机质纳米孔隙形成模式图
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Fig.7 Generation model of organic matter nanopores in Shanxi Formation
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(a)—煤系地层砂泥互层沉积;(b)—热解液态烃部分残留;(c)—液态烃裂解气泡变孔
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(a)—Sandstone and mudstone interbedding deposition of coal measure strata; (b)—partial residue of liquid hydrocarbon pyrolyzation; (c)—bubble converting to pore through liquid hydrocarbon cracking
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注:蒙特尼组资料据Wood et al., 2018b。
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山西组在晚三叠世生成了早期少量的液态烃,液态烃和天然气部分运移到邻近砂岩成藏,同时部分残余在页岩中;晚侏罗世—早白垩世,鄂尔多斯盆地广泛发生的异常热事件,地幔上涌和岩体浅层侵入对煤系地层产生强烈影响,砂岩和页岩中的液态烃受热后再次裂解产生天然气,部分逸散,部分以气孔的方式保留在残余沥青中(图7)。虽然山西组干酪根类型为过渡相环境,整体生成的液态烃数量要小于海相烃源岩,但是由于异常热事件发生时间短且集中,直接控制了生烃强度和范围,大幅度提高煤系地层非常规气的资源丰度,在异常热事件发生区域的周围形成较为有利的勘探区带,可以产生较大资源丰度的煤系地层资源富集,这一点在鄂尔多斯盆地东部煤系地层勘探中已经得到证实 (Zhang Hongjie et al., 2015; Jiang Tao et al., 2015;Gu Jiaoyang et al., 2016;Yao Haipeng et al., 2017; Shen Jian et al., 2018)。这一认识对于深入了解山西组煤系地层孔隙结构特征及非常规油气地质评价选区具有重要意义。
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6 结论
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(1)鄂尔多斯东部山西组地层孔隙类型种类较多,包括有机质孔隙、残余原生孔隙、不稳定矿物溶蚀孔、黏土矿物层间孔。黏土矿物层间孔和有机质孔隙是页岩储集空间的特色和重要组成部分,这是页岩储层与常规砂岩储层的显著区别。
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(2)鄂尔多斯东部山西组煤系地层广泛发育的有机质纳米孔形成于早期液态烃裂解和沥青化过程。经过模拟实验分析认为有机质孔形成于早期液态烃裂解气,随着生气结束,原油沥青化,气泡被固化在沥青条带中形成纳米孔隙,提升了储集空间。
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(3)鄂尔多斯盆地晚侏罗世至早白垩世末期集中发生的异常热事件对提高储层储集性能具有重要意义。地幔上涌和岩体浅层侵入对煤系地层产生强烈影响,异常热事件发生时间短且集中,直接控制了生烃强度和范围,大幅度提高煤系地层非常规储层孔隙和资源丰度。
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参考文献
-
Bernard S, Wirth R, Schreiber A, Bowen L, Aplin A C, Mathia E J, Schulz H M, Horsfield B, Aplin A, Mathia E. 2013. FIB-SEM and TEM investigations of an organic-rich shale maturation series from the lower Toarcian Posidonia Shale, Germany: nanoscale pore system and fluid-rock interactions. Electron microscopy of shale hydrocarbon reservoirs. AAPG Memoir, 102: 53~66.
-
Cardott B J, Curtis M E. 2018. Identification and nanoporosity of macerals in coal by scanning electron microscopy. International Journal of Coal Geology, 190: 205~217.
-
Chalmers G R L, Bustin R M. 2012. Geological evaluation of Halfway-Doig-Montney hybrid gas shale-tight gas reservoir, northeastern British Columbia. Marine and Petroleum Geology, 38(1): 53~72.
-
Chen Anqing, Chen Hongde, Lin Liangbin, Xu Shenglin, Zhu Zhijun, Li Jie. 2010. Difference of the upper Paleozoic lithostratigraphic gas reservoirs in Ordos basin, China. Journal of Chengdu University of Technology(Science & Technology Edition), 37(2): 120~126 (in Chinese with English abstract).
-
Du Jinhu, Li Xiangbo, Bao Hongping, Xu Wanglin, Wang Yating, Huanng Junping, Wang Hongbo, Wuanyan Rong, Wang Jing. 2019. Geological conditions of natural gas accumulation and new exploration areas in the Mesoproterozoic to Lower Paleozoic of Ordos basin, NW China. Petroleum Exploration and Development, 46(5): 820~835(in Chinese with English abstract).
-
Fu Jinhua, Fan Liyong, Liu Xinshe, Hu Xinyou, Li Jihong, Ji Haikun. 2019. New progresses, prospects and counter measures of natural gas exploration in the Ordos basin. China Petroleum Exploration, 24(4): 418~430(in Chinese with English abstract).
-
Fu Mingxi, Hu Shengbiao, Wang Jimin. 2004. Mesozoic thermal regime transition and its tectonic significance in eastern North China. Science in China (Series D: Earth Sciences), 34 (6): 514~520 (in Chinese with English abstract).
-
Ge Yan, Zhu Guanghui, Wan Huan, pan Xinzhi, Huang Zhilong. 2018. The influence of Zijinshan structural belt to the formation and distribution of tight sandstone gas reservoir in Upper Paleozoic in the Ordos basin. Natural Gas Geosciences, 29(4): 491~499 (in Chinese with English abstract).
-
Gu Jiaoyang, Zhang Bing, Guo Mingqiang. 2016. Deep coalbed methane enrichment rules and its exploration and development prospect in Linxing block. Journal of China Coal Society, 41(1): 72~79 (in Chinese with English abstract).
-
Jiang Tao, Liu Zhanyong, Wang Tong, Song Hongzhu. 2015. Discussion on gas accumulation mechanism of Upper Paleozoic coal measures in Northeast Ordos basin. Coal Geology of China, 27(7): 43~47 (in Chinese with English abstract).
-
Kang Yu, Chen Gang, Xia Xiaoyu, Ren Shuaifeng, Zhang Weigang, Shi Pingping. 2018. Detrial zircon U-Pb geochronology and its geological implication of the Nancaode and Zhuanghegou Formations in the southern margin Ordos basin. Acta Geologica Sinica, 92(9): 1829~1842 (in Chinese with English abstract).
-
Li Lintao, Wu Keqiang, Liang Jianshe, Chen Guihua, Zhang Lu, Guo Guangshan. 2019. The control of Zijinshan thermal event on tight gas accumulation in Block B in the eastern margin of Ordos basin. Natural Gas Geosciences, 30(10): 1430~1438 (in Chinese with English abstract).
-
Li Peng, Liu Quanyou, Bi He, Meng Qingqiang. 2021. Analysis of the difference in organic matter preservation in typical lacustrine shale under the influence of volcanism and transgression. Acta Geologica Sinica, 95(3): 632~642 (in Chinese with English abstract).
-
Liu Honglin, Wang Huaichang, Zhang Hui, Zhao Weibo, Liu Yan, Liu Dexun. 2020. Geological characteristics and exploration counter measures of shale gas in the Shanxi Formation of the Ordos basin. Acta Geologica Sinica, 94(3): 905~915 (in Chinese with English abstract).
-
Ren Zhanli, Zhang Sheng, Gao Shengli, Cui Junping, Liu Xinshe. 2006. Research on region of maturation anomaly and formation time in Ordos basin. Acta Geologica Sinica, 80 (5): 674~684 (in Chinese with English abstract).
-
Ren Zhanli, Zhang Sheng, Gao Shengli, Cui Junping, Liu Xinshe. 2007. Discussion on abnormal distribution area and formation period of geothermal evolution degree in Ordos basin. Science in China (Series D: Earth Sciences), 37(S1): 23~32 (in Chinese with English abstract).
-
Ren Zhanli, Yu Qiang, Cui Junping, Qi Kai, Chen Zhanjun, Cao Zhanpeng, Yang Peng. 2017. Geothermal evolution history of Ordos basin and its control on oil and gas. Geoscience Frontier, 24(3): 137~148 (in Chinese with English abstract).
-
Shen Jian, Qin Yong, Zhang Bing, Li Guozhang, Shen Yulin. 2018. Superimposing gas-bearing system in coal measures and its compatibility in Linxing block, east Ordos basin. Journal of China Coal Society, 43(6): 1614~1619 (in Chinese with English abstract).
-
Wang Xiyong, Zhang Qinglong, Wang Liangshu, Ge Rongfeng, Chen Juan. 2010. Structural features and tectonic stress fields of the Mesozoic and Cenozoic in the eastern margin of the Ordos basin, China. Geological Bulletin of China, 29(8): 1168~1176 (in Chinese with English abstract).
-
Wang Yaying, Cai Jianhui, Yan Guohan, Zhou Weiwei, Yan Zhijiao. 2014. SHRIMP zircon U-Pb age, geochemistry and Sr-Nd-Hf isotopic characteristics of the Zijinshan alkaline complex in Linxian County, Shanxi Province. Acta Petrologica et Mineralogica, 33(6): 1052~1072 (in Chinese with English abstract).
-
Wood J M, Sanei H, Haeri-Ardakani O, Curtis M E, Akai T. 2018a. Organic petrography and scanning electron microscopy imaging of a thermal maturity series from the Montney tight-gas and hydrocarbon liquids fairway. Bulletin of Canadian Petroleum Geology, 66(2): 499~515.
-
Wood J M, Sanei H, Haeri-Ardakani O, Curtis M E, Akai T, Currie C. 2018b. Solid bitumen in the Montney Formation: diagnostic petrographic characteristics and significance for hydrocarbon migration. International Journal of Coal Geology, 198: 48~62.
-
Xiao Yuanyuan, Ren Zhanli, Qin Jiangfeng, Zeng Zhen. 2007. Geochemistry and zircon LA-ICP MS U-Pb dating of the Zijinshan alkaline complex in the Linxian County, Shanxi Province: geological implication. Geological Review, 53(5): 656~663 (in Chinese with English abstract).
-
Yang Xingke, Yang Yongheng, Ji Lidan, Su Chunqian, Zheng Menglin, Zhao Liang. 2006. Stages and characteristics of thermal actions in eastern part of Ordos basin. Acta Geologica Sinica, 80(5): 705~711 (in Chinese with English abstract).
-
Yao Haipeng, Li Ling, Zhou Xiaogang. 2017. Deposition features of unconventional natural gas in Upper Paleozoic coal measures of Ordos basin. Coal Science and Technology, 45(4): 102~109+136 (in Chinese with English abstract).
-
Yao Jingli, Hu Xinyou, Fan Liyong, Liu Xinshe, Ji Haikun. 2018. The geological conditions, resource potential and exploration direction of natural gas in Ordos basin. Natural Gas Geosciences, 29(10): 1465~1474 (in Chinese with English abstract).
-
Yu Bingsong. 2013. Pore classification and characterization of shale gas reservoir. Earth Science Frontiers, 20(4): 211~220 (in Chinese with English abstract).
-
Zhang Hongjie, Chen Wangang, Yang Qi, Yu Xi. 2015. Reasons of low yield of tight gas in coal measure strata in eastern Ordos basin. Inner Mongolia Petrochemical Industry, 41(z1): 123~126 (in Chinese with English abstract).
-
Zhang Shengli, Li Baofang. 1996. Occurrence and affective geological factors of coalbed gas of the Carboniferous-Permian in the eastern margin of Ordos. Experimental Petroleum Geology, 18(2): 182~189 (in Chinese with English abstract).
-
Zhang Yikai. 2007. Mesozoic Cenozoic structural system transformation and hydrocarbon accumulation in the western margin of Ordos. PhD thesis of Northwestern University (in Chinese with English abstract).
-
Zhao Zhongyuan, Liu Chiyang. 1990. Formation and Evolution of North China Craton Sedimentary Basin and Its Hydrocarbon Occurrence. Xi'an: Northwest University Press (in Chinese with English abstract).
-
Zou Heping, Zhang Ke, Li Gang. 2008. Cretaceous tectono-thermal event in the Ordos block: an Ar-Ar chronological evidence from basalt at Hangjin Banner, Inner Mongolia, North China Craton. Geotectonica et Metallogenia, 32(3): 360~364 (in Chinese with English abstract).
-
陈安清, 陈洪德, 林良彪, 徐胜林, 朱志军, 李洁. 2010. 鄂尔多斯盆地上古生界东、西部岩性-地层气藏的差异性. 成都理工大学学报(自然科学版), 37(2): 120~126.
-
杜金虎, 李相博, 包洪平, 徐旺林, 王雅婷, 黄军平, 王宏波, 完颜容, 王菁. 2019. 鄂尔多斯盆地中新元古界—下古生界天然气成藏地质条件及勘探新领域. 石油勘探与开发, 46(5): 820~835.
-
付金华, 范立勇, 刘新社, 胡新友, 李继宏, 季海锟. 2019. 鄂尔多斯盆地天然气勘探新进展、前景展望和对策措施. 中国石油勘探, 24(4): 418~430.
-
付明希, 胡圣标, 汪集旸. 2004. 华北东部中生代热体制转换及其构造意义. 中国科学(D辑地球科学), 34(6): 514~520.
-
葛岩, 朱光辉, 万欢, 潘新志, 黄志龙. 2018. 鄂尔多斯盆地东缘紫金山侵入构造对上古生界致密砂岩气藏形成和分布的影响. 天然气地球科学, 29(4): 491~499.
-
顾娇杨, 张兵, 郭明强. 2016. 临兴区块深部煤层气富集规律与勘探开发前景. 煤炭学报, 41(1): 72~79.
-
江涛, 刘占勇, 王佟, 宋洪柱. 2015. 鄂尔多斯盆地东北部上古生界煤系气成藏机制探讨. 中国煤炭地质, 27(7): 43~47.
-
康昱, 陈刚, 夏晓雨, 任帅锋, 张卫刚, 师平平. 2018. 鄂尔多斯盆地南缘南曹德组与庄河沟组碎屑锆石年代学及其地质意义. 地质学报, 92(9): 1829~1842.
-
李林涛, 吴克强, 梁建设, 陈桂华, 张璐, 郭广山. 2019. 紫金山热事件对鄂尔多斯盆地东部B区块致密气成藏控制作用. 天然气地球科学, 30(10): 1430~1438.
-
李鹏, 刘全有, 毕赫, 孟庆强. 2021. 火山活动与海侵影响下的典型湖相页岩有机质保存差异分析. 地质学报, 95(3): 632~642.
-
刘洪林, 王怀厂, 张辉, 赵伟波, 刘燕, 刘德勋. 2020. 鄂尔多斯盆地东部山西组页岩气成藏特征及勘探对策. 地质学报, 94(3): 905~915.
-
任战利, 张盛, 高胜利, 崔军平, 刘新社. 2006. 鄂尔多斯盆地热演化程度异常分布区及形成时期探讨. 地质学报, 80(5): 674~684.
-
任战利, 张盛, 高胜利, 崔军平, 肖媛媛, 肖晖. 2007. 鄂尔多斯盆地构造热演化史及其成藏成矿意义. 中国科学(D辑: 地球科学), 37(S1): 23~32.
-
任战利, 于强, 崔军平, 祁凯, 陈占军, 曹展鹏, 杨鹏. 2017. 鄂尔多斯盆地热演化史及其对油气的控制作用. 地学前缘, 24(3): 137~148.
-
申建, 秦勇, 张兵, 李国璋, 沈玉林. 2018. 鄂尔多斯盆地东部临兴区块煤系叠置含气系统及其兼容性. 煤炭学报, 43(6): 1614~1619.
-
王锡勇, 张庆龙, 王良书, 葛荣峰, 陈娟. 2010. 鄂尔多斯盆地东部中—新生代构造特征及构造应力场分析. 地质通报, 29(8): 1168~1176.
-
王亚莹, 蔡剑辉, 阎国翰, 周伟伟, 闫志娇. 2014. 山西临县紫金山碱性杂岩体SHRIMP锆石U-Pb年龄、地球化学和Sr-Nd-Hf同位素研究. 岩石矿物学杂志, 33(6): 1052~1072.
-
肖媛媛, 任战利, 秦江锋, 曾震. 2007. 山西临县紫金山碱性杂岩LA-ICP MS锆石U-Pb年龄、地球化学特征及其地质意义. 地质论评, 53(5): 656~663.
-
杨兴科, 杨永恒, 季丽丹, 苏春乾, 郑孟林, 赵亮. 2006. 鄂尔多斯盆地东部热力作用的期次和特点. 地质学报, 80(5): 705~711.
-
姚海鹏, 李玲, 周晓刚. 2017. 鄂尔多斯盆地上古生界煤系非常规天然气赋存特征. 煤炭科学技术, 45(4): 102~109+136.
-
姚泾利, 胡新友, 范立勇, 刘新社, 季海锟. 2018. 鄂尔多斯盆地天然气地质条件、资源潜力及勘探方向. 天然气地球科学, 29(10): 1465~1474.
-
于炳松. 2013. 页岩气储层孔隙分类与表征. 地学前缘, 20(4): 211~220.
-
张红杰, 陈万钢, 杨琦, 余曦. 2015. 鄂尔多斯盆地东部煤系地层致密气低产原因分析. 内蒙古石油化工, 41(Z1): 123~126.
-
张胜利;李宝芳. 1996. 鄂尔多斯东部石炭二叠系煤层气分布规律及影响地质因素. 石油实验地质, 18(2): 182~189.
-
张义楷. 2007. 鄂尔多斯西缘中新生代构造体制转换与油气聚集. 西北大学博士学位论文.
-
赵重远, 刘池洋. 1990. 华北克拉通沉积盆地形成与演化及其油气赋存. 西安: 西北大学出版社.
-
邹和平, 张珂, 李刚. 2008. 鄂尔多斯地块早白垩世构造-热事件: 杭锦旗玄武岩的Ar-Ar年代学证据. 大地构造与成矿学, 32(3): 360~364.
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摘要
海陆过渡相煤系地层已经发现丰富的非常规天然气资源。本文以鄂尔多斯盆地东部山西组煤系地层为例,通过开展微观特征分析及物理模拟实验,查明山西组主要孔隙类型为有机质孔隙、残余原生孔隙、不稳定矿物溶蚀孔、黏土矿物层间孔,认为黏土矿物层间孔和有机质纳米孔隙是页岩储集空间与常规砂岩储层的显著区别;山西组煤系地层广泛发育的有机质纳米孔,经过模拟实验认为形成于早期液态烃裂解气,随着原油沥青化,气泡被固化在沥青条带中形成纳米孔隙;集中发生在晚侏罗世至早白垩世末的异常热事件控制了裂解气生成的强度和范围,在此过程中沥青化产生的有机质纳米孔大幅度提高煤系地层非常规气储集空间和资源丰度。这一认识对于深入了解山西组煤系地层孔隙结构特征及非常规油气地质评价选区具有重要意义。
Abstract
Abundant unconventional natural gas resources have been found in coal measures deposited transitional facies in the Carboniferous-Permian strata. In this paper, the author has undertaken microscopic investigations and physical simulation experiments on Shanxi Formation in Ordos basin. The results indicate that the main pore types of the Shanxi Formation include organic matter pore, residual primary pore, unstable mineral dissolution pore and clay mineral interlayer pore. Interlayer pores of clay minerals and nanopores of organic matter are significant differences between shale and conventional sandstone reservoirs. Nanopores of organic matter are widely developed in coal measure strata of the Shanxi Formation. Through simulation experiments, it is believed that the formation process of nanopores is closely related to the cracking gas of early formed liquid hydrocarbon in strata. With the asphaltation of crude oil, bubbles solidified in asphalt strips and converted nanopores. From Late Jurassic to the end of Early Cretaceous, abnormal thermal events which controlled the generation intensity and scope of pyrolysis gas occurred widely in Ordos basin. During the process of asphalting, lots of organic matter nanopores formed, which greatly improved the resource abundance of unconventional gas in coal measures. This knowledge from the experiments could improve the understanding of the pore structure characteristics in coal measures and be helpful for the selection of unconventional oil and gas prospecting area in the Shanxi Formation.
