【作者】 盘昌林；

【导师】 刘树根； 马永生；

【作者基本信息】 成都理工大学 ， 矿产普查与勘探， 2011， 博士

【摘要】 川东北地区须家河组具备良好的勘探潜力，特别是元坝地区已经成为天然气增储上产的重点区块；但由于元坝地区中浅层研究程度相对较低，导致对该区须家河组天然气富集规律及成藏主控因素不甚明朗。基于此，本论文通过大量基础研究工作，从单井分析入手，采用沉积相、测井相、地震相综合研究手段，建立了研究区须家河组的沉积模式；利用大量分析化验资料，采用地质、地球物理相结合的研究手段，对川东北地区上三叠统须家河组致密砂岩气藏形成的静态要素和动态成藏过程开展了一系列的评价研究工作：（1）烃源岩分布、生烃演化过程及综合评价；（2）沉积特征、成岩作用与孔隙演化关系、储层发育分布规律及主控因素研究；（3）运聚、保存条件以及构造演化对其影响作用的研究；（4）储层综合预测及目标评价优选。取得了以下主要研究成果及创新性认识。四川盆地元坝地区须家河组烃源岩具有“多套、多层、全覆盖、单层薄、累计厚度大”，呈“三明治”或“千层饼”状特征；烃源岩总厚120－300米，向西南增厚；烃源岩以Ⅱ1、Ⅱ2型为主，Ro介于1.58%－2.38%之间，有机质演化处于高成熟阶段，以生气为主,具备良好的资源潜力；川东北元坝地区须家河组烃源、储集条件优越，源、储呈“三明治”式结构，运聚、保存条件良好，具有良好的勘探潜力，首次提出元坝西北部须二段有望形成规模超千亿方的大型致密砂岩气田，对工区勘探有重要指导意义。四川盆地元坝地区须家河组储层岩石类型主要为长石岩屑砂岩、岩屑砂岩、岩屑石英砂岩等；储集空间类型以粒间溶孔、粒内溶孔及粒间孔为主，属低孔、低渗致密储层；首次提出沉积微相是控制元坝地区须家河组储层发育的关键因素，优质储层主要发育在元坝西北部辫状河三角洲前缘水下分流河道、河口坝等高能相带，并建立了元坝地区须家河组沉积模式及储层发育模式；须家河组储层经历了深埋压实、压溶、胶结和溶解等复杂的成岩过程，其中压实作用和胶结作用是导致储层致密化的主要因素，溶解作用是形成优质储层的关键因素，利用地质综合研究成果结合地震反演，预测了主要储层平面分布特征。元坝地区西北部须二段砂岩储层埋藏深（4000-5000m）、物性好（孔隙度5%-12%之间，平均7%）、砂体厚度大（40-100m）、平面分布广(＞500Km2)，具备形成大型气田的基础地质条件；从而证实陆相碎屑岩储层在深埋藏、压实作用强烈背景下仍然存在物性相对较好的次生孔隙发育带。首次提出超深层大型相控型孔隙型致密砂岩气藏是川东北元坝地区乃至川西坳陷“中浅层”寻找大、中型气田的主要目标，对四川盆地陆相碎屑岩勘探有重要指导意义。川东北地区须家河组发育构造-岩性气藏、岩性气藏、构造气藏、岩性-构造气藏等多种类型气藏，马路背须二段、须四段及元坝须四段为岩性-构造气藏，元坝须二段气藏为大型岩性气藏，其中岩性气藏、岩性-构造气藏是本区的主要气藏类型，都属于非常规致密砂岩气藏；川东北地区须家河组致密砂岩气成藏主控因素包括：①良好的烃源岩是天然气聚集成藏的物质基础；②优质储层是天然气成藏的关键；③古今构造的叠合对油气藏聚集分布具有明显的控制作用；④后期成岩作用的改造特别是裂缝的发育控制了油气富集高产。根据烃源岩对比、天然气成藏示踪、输导体系及烃源岩与储层配置关系、运移动力等建立了元坝地区上三叠统须家河组致密砂岩气成藏模式。川东北须家河组致密砂岩气藏早期以近源成藏组合为主，以砂体及不整合面为主要输导，形成广覆式天然气聚集区；个别气藏发育断裂，天然气向上逸散，在上覆地层中形成次生气藏。建立了不同成藏组合的天然气充注模式：远源成藏组合运移动力主要为浮力，天然气充注动力早期魏源、储势能差,后期主要为浮力；近源成藏组合天然气运移动力主要为源、储势能差，天然气主要在储层致密化以前充注，储层致密化是气藏异常高压的主要因素，天然气充注方式主要为“连续生烃，持续充注”。明确了四川盆地元坝地区须家河组具备良好的资源背景，同时发育多套、多类型储层，多种类型圈闭共存，油气运移、聚集、保存条件优越，有利于油气的聚集成藏；从油气成藏条件的配置情况来看，川东北地区须家河组具备形成大-中型气田的基本条件。在此基础上恢复了川东北地区上三叠统须家河组致密砂岩气藏的形成过程，并通过典型气藏的解剖，总结了须家河组致密砂岩气藏成藏富集主控因素，初步明确了须家河组致密砂岩气藏的形成机理；进而利用“相控三步法”技术综合预测须家河组主要储层的分布范围，在此基础上优选出西北部大型非常规致密砂岩气藏为有利勘探目标，为川东北地区须家河组致密砂岩及其它陆相层系的勘探指明了方向。更多还原

【Abstract】 Based on the exploration and research of Sichuan basin, I know the reservoir of Xujiaheformation in Sichuan northeast possess favorable exploratory potentiality, particularly the Yuanbaarea have been the focal area of natural gas increased. But since the explored level is lowrelatively, the gas concentrated rule and the master controlling element with reservoirdevelopment of Xujiahe formation of this area are not clear. So this article utilizes considerablefundamental researches, which include individual well analysis, sedimentary facies, electrofacies,seismic facies etc. It establish the sedimentation model of Xujiahe formation of this area.Meanwhile the article have researched neogenic basic quiescent element of gas reservoir of tightsand and dynamic neogenic process of Xujiahe formation of Upper Triassic in Sichuan northeastby abundant testing data, reserching measure between geology and physics of the Earth:(1) thedistribution, generation, evolution and comprehensive evaluation of rock which generateshydrocarbon.(2) reservoir feature, sedimentary feature, diagenesis, honeycombed evolutionaryrelationship, developed distributive rule of reservoir and master controlled element researched.(3)researching the movement and accumulation, preservative condition and structural evolutionalaffection to reservoir.(4) comprehensive forecast to reservoir, objective evaluation and optimize.It has acquired following main research outcome and aware innovation.The hydrocarbon source rock of Xujiahe formation in Yuanba area Sichuan basin has thefeatures of multi-set, multi-layer, complete-coverage, thin-single layer, accumulative-totalthickness, which present the shape characters as sandwich or multilayer-cake; the totalthickness of source rock is120-300m, and gradually becoming thicker from the northeast to thesouthwest; the Source rocks is mainly consisted by Ⅱ1/Ⅱ2type-based and Ro ranged between1.58%-2.38%, organic matters are in the high maturity stage and gas-generating dominantly.Calculation natural gas resources in Xujiahe formation of Yuanba-Tongnanba area in NortheastSichuan total of7325billion party, and have good resource potential; The hydrocarbon source,reservoir condition of the Xujiahe formation in Yuanba area is superior and source-reservoir is"sandwich" type structure, and has condition good of transport and storage. one hundred billionparty form scale of large compacted sandstone gas field is expected to exceed at the secondsection of Xujiahe formation in Northwest Yuanba area is first put forward.The reservoir rock type of Xujiahe formation in Sichuan basin Yuanba area is mainlyfeldspar lithic sandstone, lithic sandstone, debris quartz sandstone,etc; Reservoir space type is mainly between grains solution pores, and in grains solution pores and grain of the hole, whichwas low porosity and permeability and tight; Sedimentary microfacies is the key factor to controlthe reservoir development of Xujiahe formation of Yuanba area is first put forward. The highquality reservoir was mainly developed in high energy zone such as underwater distributarychannel and mouth bar, and established the sedimentary model and development mode ofobjective reservoir of Xujiahe formation in Yuanba area; Reservoir of Xujiahe formation hadburied by complex diagenetic process of compaction, cementation, dissolved, pressure anddissolve, and compaction and cementation is a major factor lead to reservoir compaction whiledissolution is a key factor in the formation of high-quality reservoir. Predict the distribution of themain reservoir plane by using integration of comprehensive study of geology and seismicinversion results.Sandstone reservoir of the second section of Xujiahe formation in northwest Yuanba area hascharacteristics of deep buried (4000-5000m), good physical character(Porosity:5%-12%andaverage7%), great thickness(40-100m), wide distribution(＞500Km2), has formed the basisgeological conditions of large gas field; Therefore,it is confirmed that the continental clasticreservoirs in the deep burial, strong compaction background has still exist relatively goodsecondary porosity zone. The super-deep and large phased-type porous tight sandstone gasreservoirs is the main aim of explor large and medium-sized gas fields at northeast SichuanYuanba area, furthermore the middle-shallow strata in west Sichuan depression,which hasimportant guiding significance for exploration terrestrial clastic rock of Sichuan basinThe Xujiahe formation in Northeast Sichuan develop constructive-lithologic gas reservoir、lithologic gas reservoir、 constructive gas reservoir and lithologic-constructive gas reservoir etc.The gas reservoir of the second and forth section of Xujiahe formation in Malubei area islithologic-constructive. Also the reservoir of the forth section of Xujiahe formation in Yuanbaarea is. The reservoir of the second section of Xujiahe formation in Yuanba area is bull lithologicgas reservoir. Among these, lithologic gas reservoir and lithologic-constructive gas reservoir arethe main types of gas reservoir, which belong to unconventional tight gas resources of sandstone；the controlling factors of tight gas resources of Xujiahe formation in northeast Sichuan include:①Good source rocks are the material basis for natural gas gathering the accumulation;②Reservoirquality is the key to gas accumulation;③The superimpose of ancient and modern structuresonplays significant role in the control of accumulation and distribution of reservoir;④Thetransformation of late diagenesis, especially the development of cracks controls high productivityof oil and gas.According to the hydrocarbon source rock comparison, gas reservoir tracing, transformingsystem and relationship between hydrocarbon source rock and reservoir allocation, migratorydriving force etc. Gas migration and accumulation mode of Xujiahe formation of Upper Triassic inYuanba area was established. The Xujiahe formation in northeast Sichuan is mainly withnear-source play, with sand as the main carrier, forming a wide review of natural gas accumulationzone; Individual gas reservoir fractured, makes natural gas vertical dispersion, forming gaseffusion area, and secondary gas reservoir in overlying formation. Different gas filling in palymodes were established: migratory driving force in distal play is mainly buoyancy and the way ofgas filling is buoyancy force; The migratory driving force of gas in near-source paly is mainlyexcess pressure difference from source save. The gas filling is mainly in prior of tight reservoir.The reservoir fine and close is the major factor of gas reservoir normal high pressure. The gas filling manner basically is continued producing hydrocarbon, everlasting filling.Through the above research, we can further identify that the Xujiahe formation of Yuanbaarea in Sichuan Basin possesses a well background of resources, and simultaneously developedseveral sets, multiple types of reservoir. A lot of trap types are coexisting. The migration,aggregation, and preservation condition of the oil and gas are advantageous. All these contribute tothe accumulation of oil and gas reservoir. From allocate situation of gas developing to reservoirpointing of view, The Xujiahe formation in Northeast Sichuan possessed the basic conditions oflarge-medium gas field formation. On this basis, to restore the formation process of tight gasreservoir of sandstone of Xujiahe formation of Upper Triassic in Northeast Sichuan. And throughthe anatomy of a typical gas pool, sum up the controlling factors of gas concentrating of tight gasreservoir of sandstone of Xujiahe formation and initially identify the formation mechanism oftight gas reservoir of sandstone of Xujiahe formation. Furthermore with three stage method ofcontrolling facies technology, comprehensively predict the distribution range of chief reservoir ofXujiahe formation, based on which, pick bull unconventional tight gas reservoir of sandstone inNorthwest as advantageous exploration target, indicating the exploratory direction of tightsandstone of Xujiahe formation and other nonmarine layer system in Northeast Sichuan, andgreatly improving exploration efficiency.更多还原