【作者】 徐波；

【导师】 孙卫；

【作者基本信息】 西北大学 ， 油气田地质与开发， 2009， 博士

【摘要】 在前人研究成果基础上,综合运用岩石学、沉积学、构造地质学、石油地质学、油气田开发地质学及地质统计学等相关学科理论,以岩心观察、岩石薄片及铸体薄片分析、测井及其解释、物性分析及高压压汞、电镜扫描和阴极发光分析、试气评价等为手段,以孔隙形成与演化为线索,以陕200井区为解剖点,对靖边气田东部下奥陶统马五段储层特征和天然气富集规律进行了综合研究,得到了相关认识,为靖边气田东扩提供一定理论指导和开发建议。（1）研究区构造环境较为稳定,马五段顶部各小层的隆起和凹陷区具有一定的继承性和相似性。研究区发育东西向展布的2排鼻状隆起,对天然气的富集有一定的控制作用。研究区发育的3条沟槽,对马五段天然气的富集程度起着重要的控制作用。（2）研究区沉积环境以广泛发育的云坪为主体微相,以含膏（膏）云坪为次主体微相。不同沉积微相和成岩作用类型造就了研究区储集空间以晶间溶孔及晶间孔为主,次为溶孔和膏模孔。广泛发育的微裂缝很好地沟通了各类孔隙,并且是天然气经由沟槽垂向运移转为侧向进入储层并在储层内部运移的主要通道。对于马五段储层各小层而言,沟槽与微裂缝的配置关系越好,即垂向通道和侧向通道配置越好,天然气富集程度越高。（3）在沉积、成岩作用所形成的非均质性基础上,裂缝的发育程度又对非均质性起着控制作用。裂缝发育区,裂缝能够提高晶间溶孔及晶间孔、溶蚀孔洞、膏模孔等的连通程度,尤其当裂缝密集发育区与大量溶蚀孔洞叠合时,通常形成高产气藏。但另一方面,这种情况又会加重裂缝发育区和非发育区间的非均质差异,导致气藏分布面积与天然气富集程度在研究区存在明显的非均质性。（4）研究区储集空间分为4种孔隙组合类型,并以裂缝—溶孔—孔隙组合类型为主。综合研究认为,气田东部主力层仍为马五₁³、马五₁⁴和马五₂²小层。马五₄¹小层在气田东部变差,不能作为主力层。根据建立的储层分类标准,研究区以厚度相对稳定、连片发育的较好储层（Ⅱ类）和中等储层（Ⅲ类）为主。这两类储层孔隙和微裂缝匹配良好,储渗能力强,含气面积大,但其非均质性应在勘探开发中予以重视。更多还原

【Abstract】 This dissertation studies synthetically the reservoir characteristics and natural gas’ enrichment at the top of fifth member of The Ordovician Majiagou carbonate formation of Jingbian Gas-field, Ordos Basin. Drawing on the findings of previous research on this topic, comprehensively applying the theories of relevant disciplines such as petrology, sedimentology, structural geology, petroleum geology, oil and gas field development geology, and geostatistics, and analyzing the data collected from core observation, rock casting thin sections, log, physical properties, high-pressure mercury, scanning electron microscopy and cathodoluminescence analysis, and gas well test of Shaan 200 well area, this study arrives at the following conclusions in the hope of providing theoretical guidelines and development suggestions for the eastward expansion of the Jingbian Gas-field.（1） The study area is relatively stable in tectonic environment, with some inherited similarities in the uplift and depression of the upper layers of the fifth member of Majiagou formation. The two nose-shaped upheavals, which have developed from west to east in the study area may somewhat exert some control over the enrichment of natural gas. The three ancient valley, which have developed in the study area, play an important role in controlling the degree of natural gas enrichment of the fifth member of Majiagou formation.（2） The depositional environment of the study area is characterized primarily by the extensively developed dolomite fiat microfacies, and secondarily by gypsum-bearing dolomite flat microfacies and gypsum-dolomite flat microfacies. Different types of sedimentary microfacies and diagenesis of the study area have created the reservoir space made up of primarily intercrystalline dissolution pores and intercrystalline pores, and secondarily solution vugs and anhydrite-moldic pores. The extensively developed micro-fissures link up various types of pores, serving as the main channels for natural gas to migrate vertically in the trenches and then laterally in the reservoir. For the upper layers of the fifth member of Majiagou formation, the better configuration of trenches and micro-fissures, namely, the better configuration of vertical and lateral channels, the higher degree of natural gas enrichment.（3） On the basis of heterogeneity formed by deposition and diagenesis. the degree of micro-fissure development plays an important role in controlling heterogeneity. In the micro-fracture development zone, micro-fissures can improve the connectivity among intercrystalline dissolution pores, intercrystalline pores, dissolution pores （vugs） and anhydrite- moldic pores, etc. In particular, the microfissure-intensive development area filled with a large number of dissolution pores （vugs） is usually the formation of high-yield gas reservoir. On the other hand, this situation will increase the non-homogeneous difference between the microfissure -developing and non- microfissure -developing zones, leading to the significant heterogeneity in distribution area of gas reservoirs and enrichment of natural gas in the study area.（4） The reservoir space of the study area is divided into four types of pore combination, with the type of microfissure - dissolution pore （vug） - pore combination as the leading one. A comprehensive analysis shows that the main reservoirs in the eastern part of the gas field are still Ma₅（1-3）, Ma₅（1-4） and Ma₅（2-2）. The performance of Ma₅（4-1）is poor and it cannot be a main reservoirs in the eastern part of the gas field. By the criteria for reservoir classification, the main reservoirs in the study area are Category II and Category III, which are of relatively stable thickness and continuous development. These two categories of reservoirs has such strong points as good configuration of pores and microfissure, good performance of reservoir and seepage, and a sizable gas-bearing area. However, their heterogeneity should be taken seriously in the process of exploration and development.更多还原