Lithofacies and pore features of marine-continental transitional shale and gas enrichment conditions of favorable lithofacies:A case study of Permian Longtan Formation in the Lintanchang area,southeast of Sichuan Basin,SW China

In this work,the Permian Longtan marine-continental transitional shale in the southeast of Sichuan Basin was taken as study object.Through petrology and geochemical analysis,lithofacies types of the marine-continental transitional shale were classified,key controlling factors of physical properties and gas content of the different shale lithofacies were analyzed.The research results show that the Longtan Formation marine-continental transitional shale in the study area has four types of lithofacies,namely,organic-lean calcareous shale,organic-lean mixed shale,organic-lean argillaceous shale,and organic-rich argillaceous shale,among which the organic-rich argillaceous shale is the most favorable lithofacies of the study area.The pore types of different lithofacies vary significantly and the clay mineral-related pore is the dominant type of the pore system in the study area.The main controlling factor of the physical properties is clay mineral content,and the most important factor affecting gas content is TOC content.Compared with marine shale,the marine-continental transitional shale has low average values,wide distribution range,and strong heterogeneity in TOC content,porosity,and pore structure parameters,but still contains some favorable layers with high physical properties and gas contents.The organic-rich clay shale deposited in tidal flat-lagoon system is most likely to form shale gas sweet spots,so it should be paid more attention in shale gas exploration.

A study on the genetic relations between Permian Longtan Formation coal series strata and Carlin-type gold deposits,southwestern Guizhou Province,China

A large number of the Carlin-type gold deposits occur in the Longtan Formation in southwestern Guizhou Province.The Long-tan Formation contains abundant basalt,tuff and siliceous rocks.All rocks of the Longtan Formation are enriched in gold,which were deposited in a limited platform environment in the transition zone from marine to continental.The process of sedimentation was accompanied by the eruption of Emeishan basalt and hydrothermal deposition controlled by co-sedimentary submarine deep faults in the west,which led to the formation of a peculiar gold-bearing formation with coal series strata.This formation controlled the occurrence of the Carlin-type gold deposits in southwestern Guizhou Province.In response to the remobilization of the Emei mantle plume during the Yanshanian period,As,Au and other ore-forming materials were continuously extracted by deeply circulating waters from the Emeishan basalt and coal seams,thereafter forming ore-forming hydrothermal solutions.When these elements were transported in the coal seams,large amounts of As,Au and other elements were enriched in pyrite within the coal seams,thus forming high-As coal and Carlin-type gold deposits in the Longtan Formation coal series strata.

Sedimentary Facies and Coal Accumulation of the Northern Type Longtan Formation in Central Hunan,Southern China

The northern type Longtan Formation of the Late Permian in central Hunan is dominated by an assemblage of greyish black mudstone,siltstone, sandy mudstone,fine sandstone and coals,and contains a variety of sedimentary structures such as thin sandstone-mudstone interbedded bedding,flaser beddings,lenticular beddings,horizontal

Natural gas characteristics and gas-source comparisons of the Lower Triassic Feixianguan Formation,Eastern Sichuan Basin,China

There is great controversy regarding the origin and source of natural gas in the Lower Triassic Feix-ianguan Formation in the Eastern Sichuan Basin.This seriously restricts the study of natural gas dy-namics in the Feixianguan Formation and thus hampers natural gas exploration in the region,so further study is urgently required.Using experimental tests of natural gas composition,stable isotopes,and noble gas isotopes with gas chromatography(GC)and mass spectrometry(MS)studies of source rock and reservoir asphalt saturated hydrocarbons,the natural gas geochemical characteristics,the genetic identification and a gas-source comparison of the Feixianguan Formation were studied.Then,con-strained by the thermal history,the histories of gas generation and expulsion were restored by basin simulation technology.Finally,a gas accumulation model was established for the Feixianguan Formation.The results showed that(1)the H_(2)S-rich and H2S-poor gas reservoirs of the Feixianguan Formation are distributed on the east and west sides of the Kaijiang-Liangping trough in the Eastern Sichuan Basin,respectively.The carbon and hydrogen isotope compositions of the natural gas in the gas reservoirs are generally heavy and have typical characteristics of high-maturity dry gas reservoirs.(2)The natural gas of the Feixianguan Formation is organic thermogenic gas,which is mainly oil-type gas generated by the secondary cracking of crude oil.The gas-generating parent material is mainly type II kerogen.(3)The natural gas of the Feixianguan Formation in the Eastern Sichuan Basin was mainly generated by argil-laceous source rocks of the Upper Permian Longtan Formation.(4)Natural gas accumulation occurred as follows:the paleo-structure heights were filled with crude oil in the Early Jurassic,and paleo-oil res-ervoirs were formed in the Feixianguan Formation;during the Middle-Late Jurassic,the paleo-oil res-ervoirs were cracked when the reservoir temperatures rose above 160 C,and paleo-gas reservoirs were formed.Since the end of the Late Jurassic,the paleo-gas reservoirs have been adjusted and reformed to form the present-day natural gas reservoirs.These results provide a basis for studying natural gas accumulation dynamics of the Feixianguan Formation in the Eastern Sichuan Basin.

Geological characteristics and co-exploration and co-production methods of Upper Permian Longtan coal measure gas in Yangmeishu Syncline, Western Guizhou Province, China

Coal measure gas(also known as coal-bearing unconventional gas)is the key field and development direction of unconventional natural gas in recent years.The exploration and evaluation of coal measure gas(coalbed methane,coal shale gas and coal measure tight sandstone gas)from single coalbed methane has greatly expanded the field and space of resource evaluation,which is of positive significance for realizing the comprehensive utilization of coal resources,maximizing the benefits and promoting the innovation of oil and gas geological theory and technological advances in exploration and development.For the first time,in Yangmeishu Syncline of Western Guizhou Province,the public welfare coalbed methane geological survey project of China Geological Survey has been carried out a systematic geological survey of coal measure gas for the Upper Permian Longtan Formation,identified the geological conditions of coal measure gas and found high quality resources.The total geological resource quantity of coalbed methane and coal shale gas is 51.423×109 m3 and the geological resource abundance is up to 566×106 m3/km2.In this area,the coal measures are characterized by many layers of minable coal seams,large total thickness,thin to the medium thickness of the single layer,good gas-bearing property of coal seams and coal measure mudstone and sandstone,good reservoir physical property and high-pressure coefficient.According to the principle of combination of high quality and similarity of key parameters of the coal reservoir,the most favorable intervals are No.5-2,No.7 and No.13-2 coal seam in Well YMC1.And the pilot tests are carried out on coal seams and roof silty mudstone,such as staged perforation,increasing hydraulic fracturing scale and"three gas"production.The high and stable industrial gas flow with a daily gas output of more than 4000 m3 has been obtained,which has realized the breakthrough in the geological survey of coal measure gas in Southwest China.Based on the above investigation results,the geological characteristics of coal measure gas in the multi-thin-coal-seam-developed area and the coexploration and co-production methods,such as the optimization method of favorable intervals,the highefficiency fracturing and reservoir reconstruction method of coal measures,and the"three gas"drainage and production system,are systematically summarized in this paper.It will provide a reference for efficient exploration and development of coal measure gas in similar geological conditions in China.

川东地区龙潭组页岩岩性序列及勘探意义

川东地区龙潭组具有较大的页岩气勘探前景,该地层沉积于海陆过渡环境,沉积相变化快,岩性复杂,存在难以通过常规的矿物成分方法划分岩相以及当前岩相划分尚不精确的问题,制约了该地区龙潭组页岩有利岩相带识别及勘探。本文基于岩心观察、野外剖面实测和薄片鉴定,结合钻井的泥地比、单层岩性厚度,建立了川东地区龙潭组7种特征岩性组合模式(泥页岩型、富泥含砂型、富泥含灰型、灰泥互层型、富灰含泥型、致密灰岩型和火成岩型);综合TOC、孔隙度、含气性、脆性指数等页岩储层特征参数,明确了不同岩性组合在龙潭组各段的平面分布规律。研究表明,纵向上优势岩性组合主要为龙潭一段富泥含灰型和泥页岩型,龙潭二段主要为泥页岩型、灰泥互层型和富泥含灰型。平面上龙潭一段优势岩性组合富泥含灰型主要分布在开州—云阳一带,泥页岩型主要分布在重庆—綦江一带;龙潭二段优势岩性组合泥页岩型分布在巴南—綦江一带,灰泥互层型分布在达州一带,富泥含灰型分布在万州—梁平—石柱一带。该项研究成果为川东地区龙潭组页岩气勘探提供了重要依据。

川东二叠系龙潭组不同沉积环境下的页岩弹性波速度特征

笔者选取川东地区FT1井龙潭组页岩进行实验测试,在岩相划分的背景下,通过主微量元素研究川东龙潭组不同岩相的沉积环境,结合沉积环境对石英成因、TOC的影响,探讨不同沉积环境下的弹性波速度变化特征。研究结果表明:①混合质页岩和黏土质页岩处于低古生产力、富氧、陆源碎屑输入较高的沉积环境,其石英以陆源碎屑石英为主,TOC含量偏低;硅质页岩处于高古生产力、缺氧、陆源碎屑输入较低的沉积环境,其石英以生物成因石英为主,TOC含量较高。②混合质页岩和黏土质页岩以黏土颗粒作为岩石骨架,弹性波速度较低,且弹性波速度随石英含量呈上升趋势;硅质页岩以石英颗粒作为岩石骨架,弹性波速度较高,且弹性波速度随石英含量呈下降趋势。研究结果可为龙潭组页岩优势岩相勘探提供依据。

织纳地区龙潭组煤系页岩气储层特征与勘探潜力评价

为查明织纳地区龙潭组页岩气勘探前景,通过分析Z2井龙潭组泥页岩样品的矿物组成、有机地化特征、微观孔隙特征、钻孔泥页岩厚度、分布情况及其含气性特征,研究龙潭组页岩气储层特征并对页岩气勘探潜力进行评价。结果表明:泥页岩有机质类型为Ⅱ_(2)-Ⅲ型,且以Ⅱ_(2)为主,总有机碳含量为1.34%~8.25%,平均值为3.68%,有机质成熟度为0.92%~3.24%,平均值为2.45%,属于高-过高成熟演化阶段,具有较好的生气潜力。扫描电镜结果显示泥页岩样品主要发育四类微观孔隙,包括粒内孔、粒间孔、有机质孔和微裂隙,内部孔隙发育,为页岩气提供良好的储集空间。Z2井泥页岩脆性矿物含量为24.40%~63.08%,平均值为41.22%,泥页岩总厚度为170.74 m,占比42%,发育5个有效连续厚度大于15 m的泥页岩层,与邻井可形成2个泥页岩层段,适宜进行压裂改造。织纳地区龙潭组泥页岩具备良好的生气条件、储集条件和可压裂性,具有较大勘探潜力。

重庆地区二叠系龙潭组煤系地层非常规气地质特征分析

为探索重庆地区二叠系龙潭组煤系地层非常规气地质特征,基于区内煤田勘查、煤层(系)气勘查取得的地质资料及测试数据,对二叠系龙潭组煤系地层煤储层、暗色泥页岩储层、致密砂岩储层基本特征进行分析总结。研究表明,区内煤储层具有煤体结构以碎裂—块状为主、埋深中等、孔隙不发育、低孔低渗、含气量高的特点;暗色泥页岩储层具有低脆性、单层厚度薄、孔隙不发育、低孔低渗、含气量一般的特点;致密砂岩储层具有单层厚度薄、孔隙不发育、低孔低渗、含气性一般的特点。若考虑组合开发,具备一定的开发前景。

渝南地区二叠系龙潭组C_(25)煤层煤层气基础地质条件分析

渝南地区二叠系龙潭组煤层气勘探开发处于起步阶段,为揭示该区主力煤层C_(25)的煤层气基础地质条件,基于区内煤田钻孔、煤层气钻井获取的地质资料和实验测试数据,对煤岩煤质、煤层孔渗、含气性等特征进行了分析。结果表明:研究区二叠系龙潭组C_(25)煤层具有“发育稳定、厚度相对大、孔渗低、变质程度高、含气量高”的特征。C_(25)煤层全区发育稳定,呈“北厚南薄”的趋势,北部一般大于1.5 m;煤岩煤质属于半亮型煤;有机组分中镜质组含量介于51.7%~72.2%;镜质组最大反射率整体介于1.8%~2.2%,变质程度处于高成熟—过成熟阶段;煤岩孔渗较差,孔隙度介于3.46%~8.46%,渗透率大多低于0.01×10^(-3)µm^(2);含气性好,一般大于10.0 m^(3)/t;同时,煤层顶底板均为良好封隔层。结合綦煤1井、Y2井产气效果,认为渝南地区二叠系龙潭组C_(25)煤层具备较好的煤层气勘探开发基础地质条件。

川东南南川区块龙潭组深部煤层气成藏特征及勘探前景

四川盆地东南缘南川区块Y2井直井自喷日产气1.3×104m^(3),获四川盆地东南缘深部煤层气勘探战略突破。为了系统揭示南川区块深部煤层气富集高产规律,通过区域地质、测试、化验及生产资料,从煤岩煤质、孔裂隙发育特征、含气性、可压性入手,开展深部煤层气成藏特征及勘探潜力评价。结果表明:研究区深部煤储层全区稳定分布,厚度在1.5~4.2 m,镜质体随机反射率Rran在1.6%~2.2%,为高镜质组含量、低灰分煤层,为煤层气成藏提供了物质基础;煤储层为“微孔-微裂隙”型储层,微孔占比达78.4%,其比表面积贡献达95%,利于煤层气吸附与保存,微裂隙发育,利于压裂改造及气体渗流;煤层具有“高含气量、富含游离气”的特征,总含气量12~37m^(3)/t,深部煤层气游离气占比一般在24%~36%,吸附临界转换深度在1500m左右;深部煤层水平应力差异系数小,煤体结构好,顶板为良好的应力隔档,天然裂缝与最大主应力夹角小,具有良好的可压性;丁山、林滩场等盆缘宽缓背斜及盆内高陡背斜是川东南深部煤层气勘探的有利区带。研究成果对川东南深部煤层气勘探具有重要的指导作用,也可为全国类似盆地深部煤层气勘探提供借鉴。

川南兴文地区上二叠统龙潭组黏土岩锂的富集特征及赋存状态

四川南部位于二叠纪峨眉山大火山岩省中—外带,广泛分布与火成岩风化-沉积有关的上二叠统龙潭组黏土岩,具有形成锂等关键金属矿产资源的地质背景和成矿条件。本文对川南兴文地区上二叠统龙潭组下部黏土岩进行了较为系统的地质调查,对研究区以及钻孔岩芯样品进行了化学分析,以确定黏土岩中锂等元素的分布特征及富集规律。在此基础上,利用粉晶X-射线衍射(XRD)分析了富锂黏土岩的矿物组成,采用聚焦离子束飞行时间二次离子质谱仪(FIB-TOF-SIMS)分析了富锂黏土岩微米尺度上的元素分布特征。结果表明,龙潭组下部黏土岩中富集Li以及Ga、Nb等元素,是一个多种关键金属的富集层,具有良好的成矿潜力和找矿前景。本区黏土岩来源于峨眉山大火山岩省火山岩的风化产物,富锂的矿层主要为含黄铁矿高岭石黏土岩,其沉积成岩环境为海陆过渡地区的潟湖还原咸水环境,Li含量与化学风化强度(CIA指数)密切相关,具有风化-沉积型矿床的特征。富锂黏土岩中锂除少量赋存于锂云母之中外,主要是被吸附于黏土岩的蒙脱石相中,部分进入蒙脱石矿物结构,还有一部分赋存于伊利石中。Li除了来自火山岩的风化释放以外,部分还可能来自滨海浅层地下卤水的直接补给,从而形成含锂云母的高品位的富锂黏土岩。

六盘水煤田陈家沟煤矿煤中硫的分布特征及成因探讨

六盘水煤田主要含煤地层为二叠世阳新统龙潭组,为一套海陆交互相多旋廻沉积地层,该地层在六盘水煤田沉积厚度大,分布范围广,含煤层数较多。煤岩成分和煤岩类型,尤其是显微煤岩类型和显微煤岩成分的含量与分布最能反映成煤的环境,各种煤岩成分信息蕴含了泥炭沼泽形成时的诸多环境信息。通过对陈家沟煤矿大量的勘探工作,对矿区内各煤层共采取800余份样品进行化验测试分析结果揭示,矿区内煤层硫分变化较大,原煤干燥基全硫为0.12%~9.75%,平均1.85%,区内煤中硫分呈上下高,中间低,且底部高于上部的特点,煤中硫的形成及变化受海进海退的变化影响,过渡相中形成的煤硫分质量分数偏高的特点,而浮煤中的硫化铁硫和硫酸盐硫有较大程度的降低,说明煤中的无机硫易洗选,对后期的煤的洗选利用起到指导作用。

安徽省宣城地区龙潭组页岩孔隙发育特征及其影响因素

安徽省宣城地区上二叠统龙潭组页岩气资源潜力大,已有钻井揭示其页岩含气性差异大,页岩气赋存富集机理复杂。通过总有机碳含量分析、岩石热解实验、X衍射、低温液氮吸附、二氧化碳吸附和场发射扫描电镜观测等手段,研究宣城地区龙潭组页岩中孔隙的大小、结构及类型,探讨影响其孔隙发育的主要因素。研究表明:(1)宣城地区龙潭组页岩中孔隙主要为半开放型,并且存在一定量的细颈瓶孔。其中,矿物孔较发育,主要为微米孔,孔隙数量多;有机孔发育数量较少,孔径为纳米级—微米级。(2)龙潭组页岩BET比表面积为4.2601~10.3068 m^(2)/g,平均为7.4290 m^(2)/g。介孔+宏孔体积为0.0049~0.0179 cm^(3)/g,平均为0.0089 cm^(3)/g;微孔体积为0.0019~0.0038 cm^(3)/g,平均为0.0026 cm^(3)/g。孔径大于10 nm的孔隙是页岩孔隙体积的主要贡献者。(3)高演化、矿物含量差异大等使得宣城地区龙潭组页岩孔隙发育规律性变得复杂,TOC含量和矿物含量明显影响着宣城地区龙潭组页岩孔隙体积,但与孔隙比表面积没有明显线性相关性。在宣城地区龙潭组页岩气后续勘探开发中,应注重较高TOC含量、较高碳酸盐矿物含量和较低黏土矿物含量的页岩。

贵州金沙煤矿东部晚二叠世龙潭组底部铝土质泥岩中镓富集规律及找矿前景

研究区位于金沙县东部,龙潭组底部铝土质泥岩中镓含量为24.7269.38 ug/g,平均43.87 ug/g。通过相关关系法,分析了Ga与SiO_(2)、Al_(2)O_(3)、Fe_(2)O_(3)、TiO_(2)的相关关系,其中Ga与SiO_(2)呈中负相关,与Al_(2)O_(3)+Fe_(2)O_(3)+TiO_(2)呈强正相关,表明镓在风化、搬运和沉积过程中更容易追随Al与Ti,主要以离子吸附态或以氢氧化物胶体方式赋存。根据含镓岩系岩性、沉积构造及化石特征,富铝粘土岩系沉积时期由下至上古水深为深-浅-深,氧化还原环境为还原-弱氧化-还原环境,风化作用相对弱-强-相对弱的变化规律。结合大地构造背景,镓的富集有利区为滨海平原及低洼地带,主要经历源岩风化-搬运-再风化淋滤过程。研究区北东部田湾煤矿-沙土-中心一带含矿品位高,为找矿前景区。

川南地区二叠系黏土型锂矿地质特征及找矿潜力

近年来,世界各国为了力争实现《巴黎协定》所设立的环境保护目标,就加强绿色经济可持续发展达成了共识,在此背景下世界各主要经济体先后推出相关政策和行动以推动本国能源结构转型发展,从而推动了锂等新能源产业快速发展(邢凯等,2022)。锂享有“白色石油”和“21世纪最有应用潜力的金属”等美誉.

川渝地区煤岩气水平井安全钻井技术探索——以JT1H井为例

为了安全有效开发四川盆地二叠系龙潭组煤岩气藏,保障川渝地区天然气能源供应的有效接替,需对龙潭组煤岩气井的开发难点进行研究,解决易发生的故障复杂等问题。为此以中国石油西南油气田公司重点探井JT1H井为研究对象,分析了该井面临的煤岩段裂缝发育、岩性复杂可钻性差、井眼轨迹变化大、钻井液性能控制困难等工程地质难点,从井眼轨迹、钻井液体系、钻井参数、精细操作防卡等方面开展复杂处理技术研究。研究结果表明:①采用五段式井眼轨迹设计,有效降低了狗腿度,满足了长度1000 m以上水平段安全钻井需要;②充分发挥地质工程一体化优势,做好煤层厚度、井下岩性、地层倾角等预测,为工程措施优化提供支撑,减少复杂;③建立煤岩气水平段钻压、转速、排量等关键钻井参数控制方法,减少煤层冲刷,降低地层垮塌程度;④应用地层岩性元素分析技术,及时发现高密度、高硬度的煤矸石,精细操作防卡。结论认为:①优选高效PDC钻头+旋转导向工具+螺杆复合钻井提速,保障了储层钻遇率,JT1H井水平段安全穿越二叠系龙潭组6套煤层,累计厚度为209 m,水平段长达1160 m;②优化钻井参数异常变化处理技术,充分使用好振动筛、一体机、离心机,探索形成煤灰机械消泡技术,减少了阻卡;③推广应用川渝地区煤岩水平段安全钻井技术,对于后续深入开展煤岩气开发技术研究具有指导意义。

渝西大安地区上二叠统龙潭组煤岩气地质特征及勘探前景

上二叠统龙潭组煤系地层是四川盆地重要的烃源岩层系,在钻探过程中普遍见到良好的油气显示,但前期的研究工作仅停留在烃源岩评价层面,未对煤岩气的地质条件开展评价。基于此,通过对渝西大安地区龙潭组煤岩的取心实测数据和相关钻井资料的综合分析,对龙潭组煤岩的分布特征、烃源特征、储层特征、含气性特征和保存条件等方面进行了研究,明确了渝西大安地区龙潭组煤岩气地质条件及勘探前景。研究认为:大安地区位于龙潭组煤岩沉积有利相带,煤岩广泛分布,单层厚度薄,发育较为集中;煤岩结构以原生结构为主,具有中低灰分特征,割理和孔隙发育;煤岩含气性好,游离气含量高,具有高孔隙度、高地层压力和高含气量的特征;煤岩顶底板发育泥岩,保存条件好。综合评价表明,大安地区龙潭组煤岩孔渗性好、含气量高且埋深适中,具有良好的勘探前景。

四川盆地上二叠统龙潭组深层煤岩气成藏地质特征及资源潜力

近年来,深层煤岩气已经在中国部分盆地获得高产工业气流,显示出了巨大的勘探开发潜力。2023年中国石油西南油气田公司在四川盆地部署实施的风险探井--NT1H井,在二叠系龙潭组煤岩层测试获高产工业气流,有望成为盆地非常规油气接替新领域。但四川盆地二叠系龙潭组薄-中厚层煤层群的区域勘探程度低,地质研究薄弱,因此也制约了该盆地煤岩气的勘探开发进程。为此,基于四川盆地中部地区(以下简称川中地区)最新部署的煤岩气风险探井资料,结合区域内老井数据,开展了扫描电镜、物性测试、含气性、吸附性检测等实验,分析了区域内煤岩的展布特征、矿物组成、储集性能、含气性特征,讨论了煤岩气成藏和保存条件以及勘探潜力。研究结果表明:①川中-川南地区龙潭组煤岩分布广、层数多、厚度大;②煤岩主要发育微孔,平均有效孔隙度为6.53%;③煤质演化程度高,镜质体反射率普遍大于2.0%,3000~4000 m埋深的煤岩含气量为20~25 m^(3)/t,含气饱和度超过120%,含气性优越;④煤岩顶、底板的泥岩分布广,厚度大,区域内深大断层不发育,煤层压力高,利于煤岩气的规模成藏和持续保存。结论认为,川中-川南龙潭组煤岩气具有优越的成藏基础和有利的成藏特征,勘探潜力巨大。经过地质评价,初步落实煤岩气勘探有利区面积约10400 km2,资源量约1.10×10^(12)m^(3)。

海陆过渡相与海相页岩气储层特征差异性分析——以南川地区龙潭组与龙马溪组为例

南川地区发育海陆过渡相、海相2种沉积类型的页岩层系,以龙马溪组为代表的海相页岩气实现了商业开发,而对以龙潭组为代表的海陆过渡相页岩气的认识程度较低。利用野外露头、钻井岩芯、薄片及氩离子抛光扫描电镜等实验数据和地层微电阻率扫描成像(FMI)测井等资料,从沉积相、岩性组合、储集条件、矿物组分、可压性及含气性等方面,开展这2套页岩储层特征的差异性分析。结果表明,2套储层在以上方面都存在较大差异:①龙潭组岩性复杂,发育粉砂质页岩、炭质页岩、灰质页岩、灰岩及煤层,而龙马溪组主要以硅质页岩为主;②受岩性、有机质类型及热演化程度影响,龙潭组储集空间主要以微裂缝(粒缘缝和收缩缝)和无机孔为主,而龙马溪组主要以有机质孔和微裂缝为主;③龙潭组页岩黏土矿物含量高(47.6%),脆性矿物含量低(35.8%),杨氏模量低(32.3 GPa),泊松比高(0.3),塑性较强,可压性差于龙马溪组页岩;④龙潭组页岩含气量平均为2.2 m^(3)/t,吸附气占比54.5%,而龙马溪组页岩含气量平均为5.2 m^(3)/t,吸附气占比43.3%。通过2套页岩层系储层差异性分析,明确了龙潭组页岩储层具有岩性复杂、黏土矿物含量高、可压性差、吸附气占比高的特征。龙潭组谭一段页岩连续厚度大、含气量高、储集物性好,从整体性评价来看,是龙潭组的“甜点”段;但其黏土矿物含量也高,且地质“甜点”与工程“甜点”的耦合性较龙马溪组页岩差,建议优化压裂工艺,提高缝网改造体积和单井产量,实现勘探突破。