准噶尔盆地西北缘二叠系碎屑岩次生孔隙发育控制因素

发布时间：2019-02-26 15:17

【摘要】：二叠系碎屑岩储集层是准噶尔盆地西北缘地区重要的勘探层位,埋藏深度大,研究其次生孔隙分布及其控制因素是研究区储集层研究的一项难点。利用岩芯、铸体薄片、荧光薄片、扫描电镜、黏土矿物等资料,结合沉积相、构造演化及有机质演化特征,对二叠系碎屑岩次生孔隙发育控制因素进行了研究。研究结果表明:二叠系碎屑岩除发育原生粒间孔外,还发育颗粒溶孔、胶结物溶孔及裂缝等次生孔隙。颗粒溶孔、碳酸盐及沸石胶结物溶孔主要受烃源岩热演化产生的有机酸及大气淡水无机酸作用的范围、规模控制。无机酸成因的溶孔主要发育于不整合面和断裂发育的盆地边缘区域,有机酸成因的次生孔主要发育于紧临烃源岩的盆地中部区域;裂缝主要是在构造挤压应力作用下产生,受构造应力大小、岩性粒级及杂基含量控制,主要分布于西北缘逆冲断裂带内低杂基含量的砂砾岩中。平面分布上,西北缘二叠系碎屑岩储集空间类型在盆地边缘以原生粒间孔为主、其次为无机酸成因的溶蚀孔及裂缝;向盆地中部过渡为有机成因的溶孔为主,原生粒间孔次之的储集空间组合。结合研究区沉积相展布、胶结物分布、构造特征及有机质演化特征,指出盆地中部的扇三角洲前缘区带,浊沸石胶结物发育,靠近烃源岩,处于三期有机酸运移的上倾方向,是有利的浊沸石溶蚀孔隙发育区带。
[Abstract]:Permian clastic rock reservoir is an important exploration horizon in the northwest margin of Junggar Basin with large burial depth. It is difficult to study the secondary pore distribution and its controlling factors in the study area. The controlling factors of secondary pore development in Permian clastic rocks were studied by using core, casting, fluorescence, scanning electron microscopy, clay minerals and so on, combined with sedimentary facies, structural evolution and evolution characteristics of organic matter in Permian clastic rocks. The results show that in addition to primary intergranular pores, secondary pores such as granular solution pores, cementation solution pores and fractures are also developed in Permian clastic rocks. Particle pore, carbonate and zeolite cementitious pore are mainly controlled by the range and scale of organic acids produced by thermal evolution of hydrocarbon source rocks and inorganic acids of atmospheric fresh water. The dissolved pores of inorganic acid origin are mainly developed in the unconformable surface and fault-developed basin margin area, while the secondary pores of organic acid origin mainly develop in the central region of the basin adjacent to the source rocks. Fractures are mainly caused by tectonic compressive stress, controlled by the size of tectonic stress, lithologic particle size and heterosis content, and mainly distributed in the sand conglomerate with low hetero-base content in the thrust fault zone of the northwest margin. In plane distribution, the reservoir space type of Permian clastic rocks in the northwest margin is dominated by primary intergranular pores, followed by inorganic acid-based dissolution pores and fractures. The transition to the middle part of the basin is dominated by organic dissolved pores, followed by the reservoir space assemblages of primary intergranular pores. Based on the sedimentary facies distribution, cementitious distribution, structural characteristics and organic matter evolution characteristics of the study area, it is pointed out that the turbidite cements develop in the fan delta front zone in the middle of the basin and are close to the source rocks, and they are in the updip direction of organic acid migration in the third stage. It is a favorable zone of turbidite dissolution pore development.
【作者单位】：中国石油杭州地质研究院;
【基金】：国家重点基础研究发展计划(973计划)项目(2014CB239002)~~
【分类号】：P618.13

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