Sedimentary system characteristics and depositional filling model of Upper Permian——Lower Triassic in South Yellow Sea Basin

In the South Yellow Sea Basin,Mesozoic–Paleozoic marine strata are generally well developed with large thickness,and no substantial breakthroughs have been made in hydrocarbon exploration.Through research,it is believed that the Upper Permian–Lower Triassic can be regarded as a long-term base-level cycle.Based on drilling data,characteristics of the lithology–electric property combination cyclicity,and the special lithology,the long-term base-level cycle was divided into five medium-term base-level cycles(MC1–MC5).On this basis,the Permian–Triassic sedimentary systems and their filling model were analyzed in accordance with the change of base-level cycle and transition of sedimentary environment,as well as characteristics of the drilling sedimentary facies and seismic facies.The results show that there were six sedimentary systems(fluvial,delta,tidal flat,open platform,restricted platform,and continental shelf)developed in the Upper Permian–Lower Triassic,the sedimentary systems were distributed such that the water was deep in the northwest and shallow in the southeast,and there were two base-level cycle filling models(a relatively stable tidal flat facies and a rapidly transgressive continental shelf facies to stable platform facies)developed in the Upper Permian–Lower Triassic.These models can provide a basis for evaluation of the Mesozoic–Paleozoic hydrocarbon geology in the South Yellow Sea Basin.

Genesis of the low-permeability reservoir bed of upper Triassic Xujiahe Formation in Xinchang gas field,western Sichuan Depression

The genesis of a reservoir is a result of the combined action of deposition, diagenesis, tectonic reworking, and interaction of rock and fluid and the evolutionary environment. We discuss the genetic and evolution mechanism of a low-permeability reservoir bed of the Xujiahe Formation in the western Sichuan Depression on the basis of the study of diagenesis, diagenetic reservoir facies and the diagenetic evolution sequence. The research indicated that this reservoir bed can be divided into five types of diagenetic reservoir facies, namely strong dissolution, chlorite-lined intergranular pores, compaction and pressure solution, carbonate cementation and secondary quartz increase. There are, however, just two diagenetic reservoir facies which provide low-permeability reservoir beds, namely strong dissolution and chlorite-lined intergranular pores. We also analyzed their diagenetic evolution sequences and the origin of the low-permeability reservoir bed. Besides, it was also indicated that the composition and structure of sandstones, types of sedimentary microfacies, diagenesis history as well as the tectonic reworking in later periods are the main factors controlling the formation of the low-permeability reservoir bed. The above- mentioned factors establish the foundation for the forecasting the distribution of high quality reservoir beds.

Characteristics of Triassic Petroleum Systems in the Longmenshan Foreland Basin,Sichuan Province,China

The Triassic in the Longmengshan foreland basin is rich in oil and gas resources. Its reservoirs feature low-porosity, low-permeability, small pore throat, high water saturation, and strong heterogeneity. The existence of abnormally high pressure and various reservoir-cap combinations developed at different times provide favorable conditions for trapping oil and gas. Taking the theory of petroleum systems as a guide, and beginning with research on tectonics, sedimentary history, distribution and evolution of source rocks, reservoir evolution, hydraulic force distribution, and hydrocarbon migration, analysis and study of static factors like source rocks, reservoirs and cap rocks, and dynamic factors such as hydrocarbon generation, migration, and accumulation revealed the characteristics of the Upper Triassic petroleum system in western Sichuan province. The deepbasin gas in the central hydrocarbon kitchen of the Upper Triassic, structural-lithological combination traps on the surrounding slopes, and the structural traps of the Indo-Chinese-Yangshan paleohighs, are potential plays. The relatively well- developed fault zones in the southern segment of the Longmengshan foothill belt are favorable Jurassic gas plays. Pengshan-Xinjin, Qiongxi, and Dayi are recent exploration targets for Jurassic oil/gas reservoirs.

Petrophysical and capillary pressure properties of the upper Triassic Xujiahe Formation tight gas sandstones in western Sichuan,China

The tight sandstones of the Upper Triassic Xujiahe Formation（T_3x） constitute important gas reservoirs in western Sichuan.The Xujiahe sandstones are characterized by low to very low porosity （av.5.22%and 3.62%） for the T_3x^4 and T_3x^2 sandstones,respectively）,extremely low permeability（av. 0.060 mD and 0.058 mD for the T_3x^4 and T_3x^2 sandstones,respectively）,strong heterogeneity,micronano pore throat,and poor pore throat sorting.As a result of complex pore structure and the occurrence of fractures,weak correlations exist between petrophysical properties and pore throat size,demonstrating that porosity or pore throat size alone does not serve as a good permeability predictor.Much improved correlations can be obtained between permeability and porosity when pore throat radii are incorporated. Correlations between porosity,permeability,and pore throat radii corresponding to different saturations of mercury were established,showing that the pore throat radius at 20%mercury saturation（R_（20）） is the best permeability predictor.Multivariate regression analysis and artificial neural network（ANN） methods were used to establish permeability prediction models and the unique characteristics of neural networks enable them to be more successful in predicting permeability than the multivariate regression model.In addition, four petrophysical rock types can be identified based on the distributions of R_（20）,each exhibiting distinct petrophysical properties and corresponding to different flow units.

Petrography and Geochemistry of the Upper Triassic Sandstones from the Western Ordos Basin, NW China: Provenance and Tectonic Implications

Petrographic and geochemical characteristics of the Upper Triassic sandstones in the western Ordos Basin were studied to provide insight into weathering characteristics,provenance,and tectonic implications.Petrographic features show that the sandstones are characterized by low-medium compositional maturity and textural maturity.The CIA and CIW values reveal weak and moderate weathering history in the source area.The geochemical characteristics together with palaeocurrent data show that the northwestern sediments were mainly derived from the Alxa Block with a typical recycled nature,while the provenance of the western and southwestern sediments were mainly from the Qinling-Qilian Orogenic Belt.The tectonic setting discrimination diagrams signify that the parent rocks of sandstones in the western and southern Ordos Basin were mainly developed from continental island arc,which is closely related to the evolution of the QinlingQilian Orogenic Belt.However,the sandstones in the northwestern Ordos Basin show complex features,which may be resulted from a typical recycling process.Overall evidence from petrography,geochemistry and sedimentology,together with previous researches suggest the Kongtongshan and Helanshan areas were the southwestern and northwestern boundary of the Ordos Basin,respectively,and there was no clear boundary between the Hexi Corridor Belt and Ordos Basin,where a large,uniform sediment dispersal system developed during the Late Triassic.

Hydrocarbon Generation and Expulsion of the Upper Triassic T3x5Source Rocks in the Western Sichuan Depression: Assessment for Unconventional Natural Gas

Tight-sand gas in the Jurassic and shale gas within the fifth member of Xujiahe Formation （T3xs） in the Western Sichuan Basin （WSD） are currently regarded as the most prolific emerging unconventional gas plays in China. This study conducted a conventional evaluation of T3x5 source rocks in the WSD, and investigated their hydrocarbon generation and expulsion characteristics, including intensity, efficiency and amount. The results show that, the T3x5 source rocks are thick （generally 〉200 m）, and have a high total organic content （TOC）, ranging from 2.5 to 4.5 wt%. It is thus indivative of a great hydrocarbon generation potential when they underwent high thermal evolution （Ro〉1.2%） in the area. In addition, an improved method of hydrocarbon generation potential is applied, indicating that the source rocks reached a hydrocarbon expulsion threshold with vitrinite reflectance （Ro） reaching 1.06%. and that the comprehensive hydrocarbon expulsion efficiency is about 60%. The amount of hydrocarbon generation and expulsion from Tax5 source rocks is 3.14x10^10 t and 1.86x10^10 t, respectively, with a residual amount of 1.28x10^10t within them. Continuous-type tight-sand gas is predicted to have developed in the Jurassic in the Chengdu Sag of the WSD because of the good source-reservoir configuration; the Jurassic sandstone reservoirs are tight, and the gas expelled from the T3xs source rocks migrates for very short distances vertically and horizontally. The amount of gas accumulation in the Jurassic reservoirs derived from T3x5 source rocks is up to 9.3x10s t. Geological resources of shale gas are up to 1.05x10TM t. Small differences between the amounts calculated by the volumetric method and those obtained by hydrocarbon generation potential method may be due to other gas accumulations present within interbedded sands associated with gas shales.

Quantitative identification of relatively highlevel radioactive sandstone in the Upper Triassic Yanchang Formation of the Ordos Basin, China

Most relatively high-level radioactive sandstone(HRSS)reservoir has considerable oil(or gas)resource potential.HRSS is often wrongly identified due to its similar logging response characteristics as mudstone,which leads to the omission of effective reservoirs.In this paper,a quantitative identification method for HRSS is proposed after the analyzing of the response characteristics and relationship between spontaneous potential log and natural gamma-ray log in conventional sandstone and mudstone strata.Take the Upper Triassic Yanchang Formation in Ordos Basin as an example:the responses of spontaneous potential log and the responses of natural gamma-ray log are synchronized and positively correlated in conventional sandstone and mudstone strata,but they are not synchronized in HRSS.Quantitative identification of HRSS was realized based on this synchronization feature,and a"virtual compensation"of natural gamma-ray log was performed.At the same time,logging evaluation method about HRSS has been discussed.The final results shows that this identification method work effectively,and can reduce the misjudgment and omission of effective reservoirs.

Characteristics and discovery significance of the Upper Triassic–Lower Jurassic marine shale oil in Qiangtang Basin,China

Mesozoic marine shale oil was found in the Qiangtang Basin by a large number of hydrocarbon geological surveys and shallow drilling sampling.Based on systematic observation and experimental analysis of outcrop and core samples,the deposition and development conditions and characteristics of marine shale are revealed,the geochemical and reservoir characteristics of marine shale are evaluated,and the layers of marine shale oil in the Mesozoic are determined.The following geological understandings are obtained.First,there are two sets of marine organic-rich shales,the Lower Jurassic Quse Formation and the Upper Triassic Bagong Formation,in the Qiangtang Basin.They are mainly composed of laminated shale with massive mudstone.The laminated organic-rich shale of the Quse Formation is located in the lower part of the stratum,with a thickness of 50–75 m,and mainly distributed in southern Qiangtang Basin and the central-west of northern Qiangtang Basin.The laminated organic-rich shale of the Bagong Formation is located in the middle of the stratum,with a thickness of 250–350 m,and distributed in both northern and southern Qiangtang Basin.Second,the two sets of laminated organic-rich shales develop foliation,and various types of micropores and microfractures.The average content of brittle minerals is 70%,implying a high fracturability.The average porosity is 5.89%,indicating good reservoir physical properties to the level of moderate–good shale oil reservoirs.Third,the organic-rich shale of the Quse Formation contains organic matters of types II1 and II2,with the average TOC of 8.34%,the average content of chloroform bitumen'A'of 0.66%,the average residual hydrocarbon generation potential(S1+S2)of 29.93 mg/g,and the Ro value of 0.9%–1.3%,meeting the standard of high-quality source rock.The organic-rich shale of the Bagong Formation contains mixed organic matters,with the TOC of 0.65%–3.10%and the Ro value of 1.17%–1.59%,meeting the standard of moderate source rock.Fourth,four shallow wells(depth of 50–250 m)with oil shows have been found in the organic shales at 50–90 m in the lower part of the Bagong Formation and 30–75 m in the middle part of the Quse Formation.The crude oil contains a high content of saturated hydrocarbon.Analysis and testing of outcrop and shallow well samples confirm the presence of marine shale oil in the Bagong Formation and the Quse Formation.Good shale oil intervals in the Bagong Formation are observed in layers 18–20 in the lower part of the section,where the shales with(S0+S1)higher than 1 mg/g are 206.7 m thick,with the maximum and average(S0+S1)of 1.92 mg/g and 1.81 mg/g,respectively.Good shale oil intervals in the Quse Formation are found in layers 4–8 in the lower part of the section,where the shales with(S0+S1)higher than 1 mg/g are 58.8 m thick,with the maximum and average(S0+S1)of 6.46 mg/g and 2.23 mg/g,respectively.

Geological characteristics and models of fault-foldfracture body in deep tight sandstone of the second member of Upper Triassic Xujiahe Formation in Xinchang structural belt of Sichuan Basin,SW China

In the second member of the Upper Triassic Xujiahe Formation(T_(3)x_(2))in the Xinchang area,western Sichuan Basin,only a low percent of reserves has been recovered,and the geological model of gas reservoir sweet spot remains unclear.Based on a large number of core,field outcrop,test and logging-seismic data,the T_(3)x_(2) gas reservoir in the Xinchang area is examined.The concept of fault-fold-fracture body(FFFB)is proposed,and its types are recognized.The main factors controlling fracture development are identified,and the geological models of FFFB are established.FFFB refers to faults,folds and associated fractures reservoirs.According to the characteristics and genesis,FFFBs can be divided into three types:fault-fracture body,fold-fracture body,and fault-fold body.In the hanging wall of the fault,the closer to the fault,the more developed the effective fractures;the greater the fold amplitude and the closer to the fold hinge plane,the more developed the effective fractures.Two types of geological models of FFFB are established:fault-fold fracture,and matrix storage and permeability.The former can be divided into two subtypes:network fracture,and single structural fracture,and the later can be divided into three subtypes:bedding fracture,low permeability pore,and extremely low permeability pore.The process for evaluating favorable FFFB zones was formed to define favorable development targets and support the well deployment for purpose of high production.The study results provide a reference for the exploration and development of deep tight sandstone oil and gas reservoirs in China.

Coal petrology,sedimentology and depositional environment of the Parvadeh coais in the Upper Triassic,Tabas Block of Central-East Iran

Peat forming environment strongly influences the economic value of any coal seam and coal-bearing strata.Hence,pal-aeoenvironmental studies provide important information for coal resource exploration.In this context,detailed studies on selected coals from the Parvadeh Area,Iran,were conducted using sedimentology,coal petrology,X-ray diffraction(XRD),scanning electron microscopy-energy dispersive X-ray analyzer(SEM-EDX),and proximate analysis.The sedi-mentary facies above and below the coal seams are mainly marine or marine-influenced facies,supporting that the coal-forming mires in the Parvadeh Area developed in a paralic environment,where the base level must be closely related to sea level.Sulfur contents are moderate to high and mark the influence of brackish/marine water,especially during transgres-sion after peat growth in a lower delta plain environment.The peat-forming mires extended on coastal/delta plain lobes.The lower delta plain/coastal plain coals are characterized by lateral continuity and substantial thickness,whereas few coals possibly representing the upper delta plain are thin and more discontinuous.The detrital nature and composition of the numerous partings and the overall high ash yield in the coal seams indicate an active tectonic area with high rates of creation of accommodation space over peat growth.Coal petrology and coal facies analysis exhibits a permanently high water table within a forest swamp and mostly rheotrophic conditions,sometimes with connection to the seawater.Accord-ing to paleoenvironmental reconstructions,it seems that coal layers may be thicker,with less sulfur(pyrite),but more clastic minerals and partings toward the western part of the area.Although these coal seams presently have low economic potential for the mining operation,partly due to great depth,this humic,high-volatile to medium-volatile bituminous coal may be suitable for exploration of coal bed methane resources.

Biostratigraphy of Triassic Marine Reptiles in Southwest Guizhou and Its Adjacent Area

This paper briefly reviews the Triassic marine reptile fossils in Guizhou Province, especially the fossils that have been recently found in the Guanling area. Based on three sections at Guanling and Xingyi, Guizhou Province and Luoping, Yunnan Province, four horizons with vertebrate fossils are recognized in the Middle and Upper Triassic of this area; They are from bottom to top: Member I and Member II of the Guanling Formation, and the Zhuganpo Member and the Wayao Member of the Falang Formation.

Alkaline diagenesis and its genetic mechanism in the Triassic coal measure strata in the Western Sichuan Foreland Basin,China

The reservoir of the upper Triassic Xujiahe Formation (T3x) in the Western Sichuan Foreland Basin is a set of terrigenous clastic rocks in an environment of coal measure sediments. Diagenesis greatly controls the physical properties of the reservoir through different responses of minerals to acidic and alkaline diagenetic environment. The dissolution of unstable components such as feldspar, rock fragments, carbonate cement, and clay minerals is the major source of secondary pores under acidic diagenesis, while the dissolution of quartz increases the reservoir space in the fault-fold zone of Longmen Mountain and Leikoupo paleo-hills. The dissolution of quartz is a result of cross-formation flow of fluid in the Himalaya epoch and the invasion of alkaline formation water from the Triassic Leikoupo and Jialingjiang formations through fault and fracture systems. In the vertical succession, acidic dissolution occurs at a shallow depth of less than 2,180 m, and alkaline dissolution occurs at a greater depth of more than 2,280 m. The reservoir space is formed by the influence of both acidic and alkaline dissolution in the depth interval of 2,180–2,280 m.

致密砂岩微观特征及沉积古环境——以梓潼—秋林地区须三、二段为例

四川盆地西北部上三叠统须家河组纵向上发育多套致密砂砾岩气藏,具备多层系立体勘探的广阔前景。目前针对该区域须家河组沉积古环境及物源体系的认识还不够深入,导致勘探上有点无面,严重制约了下一步攻关方向,需要加强该区域沉积古环境的研究。通过显微薄片鉴定、全岩矿物X衍射、稀土微量元素分析,结合井、震资料,对主要层段须三段—须二段含气砂体岩石类型、矿物含量、物源条件、古气候、古盐度及古氧化还原条件进行系统分析和对比研究。研究结果表明:(1)须二上亚段以长石岩屑砂岩为主,石英及长石矿物发育,石英含量超过50%;(2)受龙门山碳酸盐物源供给影响,须三下亚段普遍含钙质,岩屑成分以碳酸盐岩为主,方解石与白云石矿物发育,石英含量低于50%;(3)须三下亚段砂体稀土元素特征较须二上亚段更为复杂,指示多物源特征,两者沉积时该区整体处于潮湿性干热古气候,沉积环境偏淡水氧化环境,但须三下沉积期比须二上沉积期气候更为潮湿、古盐度略高、氧化性也更强。研究成果对川西北部须家河组重点砂岩层段微观特征、沉积古环境及地层划分新方案具有一定参考意义。

四川盆地上三叠统—侏罗系含油气系统特征及油气富集规律

根据烃源岩发育特征和油气藏类型,将四川盆地上三叠统—侏罗系含油气系统进一步划分为上三叠统含气系统和侏罗系含油系统两个子系统。以含油气系统的基本要素研究为基础,分别探讨了上三叠统含气系统和侏罗系含油系统的成藏条件、主控要素和油气富集规律。上三叠统含气系统成藏主控因素为强充注的气源、燕山期古隆起和断裂裂缝,晚侏罗—早白垩世是气藏的主要形成期。侏罗系含油系统在不同区带具有不同的成藏规律及主控因素,川中地区油气藏形成主要受油源区、古隆起、断裂或裂缝、有效储集体展布四个因素控制,主要形成裂缝—岩性油藏;巴中—平昌地区主要受生烃中心和裂缝的控制,形成岩性—裂缝油藏为主;在大巴山前缘成藏主控因素为断裂、有效储集砂体和保存条件,形成裂缝—岩性油气藏。

准噶尔盆地上三叠统源岩TOC含量预测方法

根据对准噶尔盆地三叠系暗色泥岩在不同层段发育特征的分析,发现暗色泥岩主要发育于上三叠统,中、下三叠统分布有限。针对准噶尔盆地上三叠统暗色泥岩实测有机碳含量数据偏少、测井曲线系列较完整的实际情况,利用声波测井与电阻率测井重叠法,建立了准噶尔盆地上三叠统暗色泥岩有机碳含量的预测模型,并估算了主要探井上三叠统暗色泥岩的有机碳含量。综合预测和实测有机碳含量平面分布特征发现,上三叠统有机碳含量显示有4个相对高值区,分别位于乌伦古坳陷的索索泉凹陷、中央坳陷带的阜康凹陷、盆1井西凹陷和玛湖凹陷,以索素泉凹陷有机碳含量最高,阜康凹陷和盆1井西凹陷其次,玛湖凹陷总体较低。有机碳含量表明上三叠统为一套中等-较好的烃源岩。

姬塬油田砂岩储层成岩作用与孔隙演化

目的研究姬塬油田延长组砂岩的成岩作用及其对储层物性的控制作用。方法采用了染色、铸体薄片鉴定、电镜扫描、阴极发光、X射线衍射、镜质体反射率测定及流体包裹体测温等多种分析测试手段。结果成岩作用主要有压实作用、胶结作用、溶解作用和交代作用,胶结物有硅质、碳酸盐和黏土矿物,成岩阶段已达中成岩A期;成岩作用对本区砂岩储层孔隙演化起着重要的控制作用,早期的机械压实和胶结作用使原生孔隙大量丧失,长石的溶蚀对储层物性起重要的改善作用,以铁方解石为主的胶结物又使砂岩孔隙再度降低。结论原生孔隙的大量丧失和胶结物中次生孔隙的不发育是造成砂岩低孔、低渗的主要原因。

鄂尔多斯盆地上三叠统延长组沉积体系特征及演化

在野外剖面观察、岩心描述及测井、测试资料分析的基础上,综合前人研究成果,对鄂尔多斯盆地上三叠统延长组沉积体系的类型、特征进行了详细分析,并深入讨论了鄂尔多斯盆地延长组沉积体系垂向上的演化规律。结果表明:鄂尔多斯盆地延长组主要发育冲积扇、扇三角洲、河流、河流三角洲、湖泊和湖泊浊积扇六大类沉积体系。长8期湖盆开始形成,主要发育神木-乌审旗、安塞和正宁-合水等三角洲沉积体系;长7期湖盆进一步扩展,三角洲规模萎缩;长6期湖水大面积退缩,三角洲前缘连片,面积最大,东北三角洲前缘已推进至吴旗-甘泉一线,西南缘推进至华池-庆阳一带;长4+5期以浅湖亚相为主;长3、长2期以三角洲平原沉积为主;长1期湖盆继续萎缩至消亡,局部出现沼泽环境。盆地沉积体系的演化,在纵向上构成了五套储盖组合。

四川类前陆盆地须家河组层序充填样式与油气分布规律

通过对四川类前陆盆地上三叠统须家河组地表剖面、钻井岩芯和测井资料的沉积相和层序分析,结合区域地质背景和油气地质特征,对须家河组沉积层序、充填样式和油气分布规律进行分析,将须家河组划分为两个超长期旋回层序(SLSC1和SLSC2),分别对应于"须下盆"和"须上盆"2个盆-山耦合次系统的成盆构造活动期,5个长期旋回层序(LSC1—LSC5),分别对应于5个区域性湖进—湖退沉积旋回。在此基础上,选择长期基准面上升和下降半旋回为等时地层单元编制全盆地地层等厚图和岩相古地理图,结果表明:须家河组二段和三段沉降-沉积中心位于川西坳陷,须四段开始向川东北方向迁移,须五段—须六段迁移至川东北坳陷;不同的沉积演化阶段和前缘坳陷具有不同的层序充填样式和油气分布规律;伴随"须下盆"和"须上盆"2个盆-山耦合次系统的沉降-沉积中心和优越的生、储、盖组合条件自川西坳陷向川东北坳陷迁移,油气藏分布也具有自南向北再折向北东方向迁移和围绕前陆隆起带发育的特点。

四川盆地东缘上三叠统中侏罗统层序地层特征

根据层序地层理论,在四川盆地东缘晚三叠世中侏罗世陆相盆地充填系列中划分出3个构造层序和5个层序。3个构造层序代表3个充填演化阶段。早期稳定沉降补偿充填阶段,气候潮湿炎热,有利于储层及烃源岩发育;中期中等强烈沉降欠补偿补偿充填阶段,气候潮湿半潮湿,有利于烃源岩及盖层发育;晚期强烈沉降补偿充填阶段,气候半干旱,对储层及盖层发育有利。

四川盆地上三叠统沉积储层研究进展与热点分析

四川盆地上三叠统天然气资源丰富,常规气藏和非常规气藏共存,等时地层格架下的沉积储层控制了天然气资源时空分布和富集。随着天然气勘探不断深入,沉积储层研究不仅体现了重要的科学意义和战略价值,而且取得了显著进展。在建立四川盆地上三叠统层序地层格架基础上,确定了前陆盆地对称型和不完全对称型结构层序地层样式及演化模式。四川盆地马鞍塘组—须家河组三段(须三段)为海相沉积,须家河组四段(须四段)—须家河组六段(须六段)为陆相沉积,但仍受到海侵作用的影响。马鞍塘组主要发育礁滩相、潟湖相、潮坪相和三角洲相,小塘子组主要发育障壁砂坝-潟湖沉积,盆地周缘发育小型三角洲。川西须家河组须二段、须四段和须六段主要发育冲积扇、扇三角洲和辫状河三角洲沉积,须三段主要发育滨海-三角洲沉积,须五段主要发育湖泊-三角洲沉积。晚三叠世四川盆地存在秦岭古陆、大巴山古陆、松潘-甘孜褶皱带(古龙门山)、康滇古陆和江南(雪峰)古陆等5大物源区,不同物源区的物源性质、影响范围和程度均存在巨大差异。整体上,须二段-须三段沉积时期,物源主要来自于盆地北部,其他方向物源影响范围相对较小。须家河组发育致密砂岩储层,压实作用造成本地区砂岩原生孔隙度大幅度减小,Ⅱ期和Ⅲ期石英加大进一步减小原生孔隙,封闭的地下流体环境是储层保持致密化的又一原因。须家河组甜点储层的形成受沉积微相、溶蚀作用,绿泥石衬边和裂缝控制,三角洲前缘水下分支河道砂体为有利沉积微相。近年来,浅水三角洲研究和页岩气勘探开发取得重大进展,四川盆地上三叠统浅水三角洲、细粒沉积学及沉积机理、沉积过程模拟、细粒沉积储层特征及其成因机制是目前研究的热点领域及未来发展方向。