【作者】 苏惠；

【导师】 金之钧； 张金川；

【作者基本信息】 中国地质大学（北京） ， 矿产普查与勘探， 2009， 博士

【摘要】 论文以东濮凹陷中生界砂岩裂缝研究为主线,通过中生界地层界定、油气源对比、砂岩裂缝储层成因机理、油气藏控制因素和分布规律等研究,明确了东濮中生界砂岩裂缝型油气藏分布规律,主要取得如下成果:(1)明确东濮凹陷中生界为中—下三叠统地层。东濮凹陷中生界地层时代归属长期不清,在卫77-3、卫77-4井中生界岩芯中发现了属于中下三叠统的宽肋粉、二肋粉等代表性化石,岩心同位素年龄分析在235Ma左右,确定了东濮凹陷中生界地层属中下三叠统。进一步建立了东濮凹陷与华北地区中生界地层的区域对比关系,明确了东濮中生界地层分布规律,从而使东濮凹陷30多年来一直悬而未决的中生界地层归属问题得到解决。(2)中生界有效储层为裂缝砂岩,受构造应力作用影响,裂缝的形成有两期特点。东濮凹陷北部中生界砂岩基质不具备储集性能,但砂岩裂缝发育,泥岩裂缝不发育,有效储层为砂岩裂缝和缝洞。中生界砂岩储层裂缝主要在燕山期和喜马拉雅期构造应力场作用下形成。早期在水平挤压应力场作用下主要形成了东西向裂缝,东营末期的构造反转期主要形成了北东向裂缝。构造应力是影响砂岩储层裂缝形成的外因,储层岩性、砂岩厚度、岩石力学性质等是影响砂岩储层裂缝形成的内因,测井解释和地震预测表明中生界上部和构造高部位裂缝发育程度较高。(3)中生界地层原油来自古近系,而天然气主要来自石炭-二叠系。根据油气源对比,文明寨明471、卫城地区卫77-3、卫77-4等井中生界原油来源于周边沙三、沙四段强还原环境条件下的低熟-成熟烃源岩,为新生中储油藏;户部寨地区卫79-9等井中生界气源来自下伏的石炭-二叠系煤系地层,为古生中储气藏。(4)中生界为砂岩裂缝构造层状潜山油气藏。中生界砂岩基质不含油,裂缝、缝洞含油,为砂岩纯裂缝型构造层状潜山油气藏,是渤海湾盆地发现的新油气藏类型。供烃条件决定油藏规模、砂岩控制裂缝发育、裂缝决定油气分布、构造影响油气富集。裂缝形成时期与生排烃时期的匹配关系决定了成藏的有效性。建立了东濮三叠系砂岩裂缝性油气藏3种成藏模式:即双断双向供烃、双断单向供烃和单断双向供烃成藏模式。预测油气资源潜力3800×10~4t,指出了3个有利的勘探区带。论文成果指导勘探部署,取得了东濮凹陷北部中生界潜山油气勘探的重大突破,研究成果也可为类似地区的油气地质研究提供借鉴。更多还原

【Abstract】 This thesis focuses on study of the fractures in the Mesozoic sandstone in Dongpu depression.Aimed to make clear of fractured reservoir distribution in the Mesozoic sandstone in Dongpu depression,a lot of work has been carried out on Mesozoic stratigraphic Chronology judgements,hydrocarbon-source correlation~-, fractured sandstone reservoirs forming,hydrocarbon accumulations controlling factors and distribution.The main conclusions drawn in this thesis are listed as follows.1.Confirming the Mesozoic stratum of Dongpu depression is middle-lower Triassic.Chronology of Mesozoic stratum of Dongpu depression has been unclear for a long time.In the Mesozoic of the Well Wei 77-3 and Wei 77-4,some middle-lower Triassic fossils were discovered in some cores,which is about 235Ma by isotopic age analysis.It provides evidence for cognizing Mesozoic stratum of Dongpu depression as middle-lower Triassic.Regional stratigraphic correlation in the Mesozoic between Dongpu depression and North China region is built up,which helps to realize the distribution of Mesozoic strata in Dongpu depression,which resolve the over 30-year disputations of stratum chronology in Dongpu depression.2.Mesozoic effective reservoir bed is fractured sandstone,which develop two-stage fractures controlled by tectonic stress.Mesozoic sandstone matrix in the north of Dongpu depression is not available for providing oil accumulating space. Sandstone fractures are well-developed,while mudstone fractures are not.Effective reservoir spaces are fractures and dissolved pore and cavities.Fractures in the Mesozoic sandstone reservoir were mainly formed by tectonic stress fields during Yanshan and Himalayas period.In the early stage,east-west trending fractures are formed mainly by horizontal extruding stress field,while North-east trending fractures are formed mainly by tectonic reverse which happened at the end of Dongying period. Tectonic stress is the extrinsic factor affecting sandstone fractures development. Lithology of the reservoir bed,thickness of sandstone and rock mechanics natures is the intrinsic factors for that.Fractures in the Upper Mesozoic strata and structural high are well developed through logging analysis and seismic interpretation.3.Petroleum in the Mesozoic derives from Neocene while natural gas from Carboniferous-Permian.According to hydrocarbon-source correlation,Mesozoic petroleum in the Well Ming 471 in Wenmingzai,Well Wei 77-3 and Wei 77-4 in Weicheng are from matured-low matured source rocks of interval ES3 and ES4. Mesozoic gas of Well Wei 79-9 in Hubuzhai is from underlying Carboniferous-Permian coal beds,supplying the Mesozoic reservoirs.4.Mesozoic reservoir is kind of laminated fractured burial hill reservoir. There is a new type of reservoir,called as laminated burial hill reservoir only with fractures as storage space,discovered in Bohai bay basin,characterized by oil only occurring in the fractures and dissolved pores and cavities,instead of occurring in the sandstone matrix.Hydrocarbon supplying condition determines the scale of the oil reservoir,lithology controls degree of fractures development,fractures controls hydrocarbon distribution and structure affects hydrocarbon accumulation.The time of Fracturing and its match with hydrocarbon generation and expulsion determines the effectiveness of hydrocarbon accumulation.3 types of hydrocarbon accumulations models are established for Tertiary fractured sandstone reservoir in Dongpu depression.The potential hydrocarbon resource is predicted as much as 3800×10~4t in this area and 3 favorable belts for exploration is proposed in this thesis.The research result of this thesis is used to assist in exploration decision-making,which brings great success in the oil and gas exploration in the Mesozoic burial hills in the north of Dongpu depression,which also can provide some clues for similar exploration work in other regions.更多还原