【作者】 杨希濮；

【导师】 孙卫；

【作者基本信息】 西北大学 ， 矿产普查与勘探， 2010， 硕士

【摘要】 研究区上古生界天然气勘探程度相对较低,对低渗透储层特征研究不够深入。本文通过先进的测试分析,从微观孔隙结构着手,深刻认识储层特征,在此基础上,对储层进行综合评价,划分出低孔、低渗背景上的优质储层,并从构造作用、沉积作用以及成岩作用综合分析的角度,对其主控因素进行探讨,取得了以下认识：1.研究区盒8段储层孔隙类型以岩屑溶孔和晶间孔为主,喉道类型主要为片状和管束状喉道,由于喉道较小,孔隙连通性较差,伊利石、高岭石等粘土矿物含量较高,造成该层段束缚水饱和度高,平均为48.9%,可动流体饱和度低,仅为14.5%。山2段储层孔隙类型以粒间孔、溶孔为主,喉道以片状、管束状和点状喉道为主,由于喉道较大,孔隙连通性较好,粘土矿物中伊利石含量较少,流体在其中渗流容易,所以该层段样品的束缚水饱和度较低,可动流体饱和度高,分别为29.4%和94.2%。在物性上表现为山2段整体好于盒8段。2.盒8、山2段目前处于中成岩B期,具有煤系地层的成岩特点,压实作用、压溶作用和硅质胶结作用发育,压实作用和胶结作用分别使储层损失了20%和17%的孔隙度。溶蚀作用使储层增加了3.2%的面孔率,有利的改善了储层物性,是优质储层发育的主要因素之一。3.优质储层受构造作用、沉积作用和成岩作用共同控制。由于水下分流主河道砂厚较大,水动力较强,石英含量高,压实作用和碳酸盐胶结作用相对较弱,溶蚀作用强烈,造成储层孔隙空间以连通性较好的溶孔—粒间孔孔隙组合为主,喉道较大,孔隙结构相对有利,物性较好,并且在差异压实作用下,一般处于鼻状隆起的相对高部位,含气饱和度较高。因此水下分流河道微相发育,溶蚀作用强烈,处于鼻状隆起高部位的储层一般为优质储层。相反,水下天然堤和水下分流河道边部砂体较薄,水动力弱,石英含量较低,杂基和塑性岩屑颗粒含量较高,在差异压实作用下,一般处于鼻状隆起的较低部位,成岩过程中压实作用强烈、碳酸盐岩胶结作用发育,溶蚀作用相对较弱,造成储层中连通性较差的晶间孔、粒内溶孔较发育,含气饱和度较低,该类储层一般物性较差。更多还原

【Abstract】 Because the Neopaleozoic gas degree of exploration is low in the region of interest, so the characteristics of low permeability reservoir are not deep enough. The thesis makes a thorough research, focusing on reservoir’s microscopic pore structure, based upon various analytical and measurement methods, including the techniques of casting section, SEM, XRD, cathodeluminescence, grading analysis, high pressure mercury penetration, relative permeability, rate-controlled mercury penetration and NMR. On these bases, we make a comprehensive evaluation of the reservoir; the favorable reservoir is divided from the low porosity and low permeability reservoir. And from the comprehensive angles of tectonism, deposition and diagenesis, we analyze the dominated factors of favorable reservoir. At last we get some conclusions as follows:1. The main pore types of the P2X8 reservoir in the region of interest are dissolved pores and intercrystal pores. The main throat types are lamellar throat and tube-shaped throat. Because the throat is small, the pore connectivity is poor, the contents of illite, kaolinite and other clay mineral are relatively high, causing the reservoir’s bound water saturation is high with an average of 48.9%, movable fluid saturation is low, only 14.5%.The main pore types of the P1S2 reservoir in the region of interest are primary pores and dissolved pores. The main throat types are lamellar throat tube-shaped throat and dotted throat. Since the large throat, better pore connectivity, less illite content of clay minerals, the reservoir’s bound water saturation is low, and movable fluid saturation is high, respectively 29.4% and 94.2%.2. P2X8&P1S2 are currently in mid B diagenetic stage. Target zone have coal strata of diagenetic features, such as strong compaction, pressolution and kiesel cementation. Compaction and cementation made the reservoir respectively lose 20% and 17% porosity. Dissolution made the reservoir increase 3.2% face porosity. So it’s one of the major factors, which can improve the reservoir’s physical property.3. Favorable reservoir is controlled mainly by tectonization, sedimentation and diagenesis. Favorable reservoir is general in the place, where develop underwater distributary channel microfacies, compaction and carbonate cementation are relatively weak, dissolution is strong, and it is in the relatively high position of nose. Because in this place the sand thickness is larger, hydrodynamic is strong and quartz content is high, dissolution is strong, resulting in larger throat and better pore connectivity, so the gas saturation and physical property are relatively high in the reservoir. On the contrary, the place where develop the microfacies of underwater natural levee or the edge of the underwater distributary channel, sand body is thin, water power is weak, quartz content is low, matrix and plastic debris particles are high, compaction and carbonate cementation are strong, and dissolution is relatively weak, resulting in smaller throat and worse pore connectivity, while it is usually in the lower parts of structural nose, as a result, the physical property of the reservoir is poor.更多还原