针对四川盆地元坝超深层大气田勘探开发难点,研究超深层生物礁优质储集层发育与成藏富集机理,创立超深层地震勘探、钻完井及测试等技术。通过对晚二叠世等斜缓坡—镶边台地动态沉积演化过程及区域沉积格架的恢复,建立四川盆地元坝地区二叠系长兴组“早滩晚礁、多期叠置、成排成带”的沉积模式,揭示“早期暴露溶蚀、浅埋白云石化形成基质孔隙、液态烃深埋裂解超压造缝”的储集层发育机理,提出“孔缝耦合”控制超深层优质储集层发育的认识。通过油源对比,提出深水陆棚相吴家坪组—大隆组是四川盆地北部地区二叠系主力烃源岩,建立超深层弱变形区“三微输导、近源富集、持续保存”的成藏模式。运用“孔缝双元结构模型”的孔隙结构参数进行地震反演,落实元坝气田高产富集带面积98.5 km²。创建特种井身结构、发展非常规井身结构,解决多压力系统复杂地层封隔难题,研发出整体式耐高压FF级采气井口及地面安全联动装置。图15表1参23

To solve the difficulties in exploration and development in Yuanba Great Ultra-deep Gas Feild in Sichuan Basin, SW China, the article studies the mechanism of development of quality reef reservoirs gas accumulation and innovates techniques for ultra-deep seismic exploration, drilling, completion and testing. Through the dynamic depositional evolution process of homoclinal ramp-fringed platform and reconstruction of regional depositional framework in the Permian, it is found that the reservoirs in the Changxing Formation of Yuanba area, Sichuan Basin are developed in a pattern of “early shoal and late reef, multiple stage stacking, in rows and belts”, dissolution in early exposure stage and dolomitization during shallow burial give rise to the pores in matrix, overpressure caused by cracking of liquid hydrocarbon during deep burial induces fractures, and coupling of pores and fractures controls the development of ultra-deep high quality reservoirs. From correlation of oil and source rock, it is concluded that the Wujiaping Formation and Dalong Formation of deep-water continental shelf are the major source rocks in the Permian of northern Sichuan Basin. The hydrocarbon accumulation mode in ultra-deep formations of low-deformation zones is characterized by “three-micro migration, near-source enrichment, and persistent preservation”. Through seismic inversion using the pore structure parameters of pore-fracture dual structure model, the high production gas enrichment area in Yuanba gas field is 98.5 km². Moreover, special well structure and unconventional well structure were used to deal with multiple pressure systems and sealing of complex formations. A kind of integral, high pressure resistant FF-level gas wellhead and ground safety linkage device was developed to accomplish safe and environmentally friendly gas production.

2011年以来，在四川盆地川中古隆起磨溪—高石梯地区发现震旦系、寒武系特大型气田，主力含气层系包括震旦系灯影组灯二段、灯四段及寒武系龙王庙组，地质储量规模超过万亿立方米。在简要回顾川中古隆起大气区战略发现历程的基础上，系统阐述川中古隆起龙王庙组特大型气田的形成条件及油气富集规律，指出大型古隆起背景、大型网状供烃系统、规模化的颗粒滩储集层以及区域性的储盖组合是特大型气田形成的重要条件；针对龙王庙组超深、高温、高压等复杂地层条件，分别在测井、地震、钻井、储集层改造等方面进行了技术攻关，并形成了相应的配套成果，应用效果良好，展示了四川盆地震旦系—寒武系巨大的油气勘探潜力。图13参13

Since 2011, a giant gas field has been discovered in the Sinian and Cambrian strata in Moxi–Gaoshiti region, central Sichuan paleo-uplift, with the geological reserves reaching more than one trillion cubic meters. The main gas-bearing layers include Deng 2 Member, Deng 4 Member of Sinian Dengying Formation and Cambrian Longwangmiao Formation. Based on brief review of the exploration history of large gas province in central Sichuan paleo-uplift, the paper systematically describes the formation conditions and petroleum accumulation patterns of the giant gas field, and points out the large ancient uplift background, huge net of hydrocarbon supply system, large-scale particle shoal reservoirs and regional reservoir-cap combinations are important material conditions for the formation of the giant gas field. In view of the huge depth, high temperature, high pressure and some other complex formation conditions, a lot of efforts have been put into the research on logging, seismic, drilling, reservoir stimulation etc, and a series of accomplishments have been achieved, which work well in the exploration and development of gas in Sichuan Basin. The Sinian and Cambrian strata in the Sichuan Basin have a great potential for petroleum exploration.

目前川中古隆起规模性勘探发现主要集中在深部震旦系—寒武系的高能滩相，中部二叠系处于台内斜坡相，以低能环境为主，勘探未受重视。为了进一步落实川中地区中二叠统气藏富集规律，通过岩心描述、薄片分析、U—Pb 测年与印模法古地貌恢复等手段，开展岩相古地理、储层成因及成储模式与气藏特征分析，对全盆地茅口组二段（茅二段）进行了重新认识。结果表明：（1）四川盆地茅二段发育南带、中带与北带3个北西向古地貌高带，川中地区处于南部古地貌高带中南部，发育规模滩体；（2）茅二段古地貌高带控制了沉积期滩体分布以及准同生期的岩溶、白云岩化作用，据此构建了川中地区茅二段白云岩储层发育模式，认为川中地区茅二段发育大面积优质白云岩储层；（3）创新建立茅二段薄层白云岩地震预测技术，古地貌高带控制了茅二段优质白云岩储层分布与气藏的高产富集。新认识带来勘探领域新突破，指导部署的潼深4井等5口井试气获超百万立方米高产，实现了四川盆地茅二段台内天然气勘探的重大突破，提交探明储量超千亿立方米。目前，川中地区茅二段气藏已成为“十四五”期间提交天然气探明储量的重要领域。

At present, large-scale discoveries in Central Sichuan paleo-uplift are mainly concentrated in the deep Sinian-Cambrian system of high-energy beach facies, while the exploration of the Permian is ignored by considering that it was generally developed in low-energy environment of intraplatform slope facies. In order to further identify the enrichment law of gas reservoirs in the Middle Permian in Central Sichuan Basin, the lithofacies paleogeography, reservoir genesis, reservoir development pattern and gas reservoir characteristics are analyzed by means of core description, thin section analysis, U-Pb dating and ancient landform restoration (impression method), and the second member of Maokou Formation (hereinafter referred to as Mao 2 member) is re understood at the basin level. The study results show that: (1) Three NW trending paleo high zones were developed in Sichuan Basin during the deposition period of Mao 2 member, namely, the southern zone, the middle zone and the northern zone. Central Sichuan Basin was located in the central-southern part of the southern paleo high zone and largescale beach body was developed; (2) The paleo high zones controlled the distribution of beach body, karstification in the penecontemporaneous period and dolomitization of Mao 2 member. On this basis, the reservoir development pattern is constructed, which indicates that high-quality dolomite reservoirs were widely developed in Mao 2 member in Central Sichuan Basin; (3) The seismic prediction technology of thin bedded dolomite of Mao 2 member is innovatively established, which shows that the distribution of high-quality reservoirs and the enrichment and high yield of gas reservoir in Mao 2 member were controlled by the paleo high zone. As a result, breakthroughs were obtained in the new exploration field guided by new geological understanding, achieving high gas flows of more than one million cubic meters during the test of five wells (including Well TS4), and marking a major breakthrough in gas exploration of Mao 2 member in Sichuan Basin, with the submitted proven gas reserves of exceeding 100 billion cubic meters. Now, the gas reservoir in Mao 2 member in Central Sichuan Basin is a major resource base for increasing proven reserves during the 14th Five-Year Plan period.

<p>Integrated with seismic profile interpretations, Petro-mineralogic observations and geochemical analyses, the present paper proposed that dolomites in the Middle Permian Qixia Formation-Maokou Formation of the central Sichuan Basin are of a structure-controlled hydrothermal origin. The characterization of the dolomites showed that:1) they are relatively thicker in a single layer, commonly in lenticular form, poor in lateral continuity, sometimes accompanied with developed strike-slip faults and having a &ldquo;concave-down&rdquo; reflection in seismic sections corresponding to dolomite intervals concerned; 2) matrix dolomites composed mainly of meso- or macro-crystalline grains have the saddle-shaped dolomite with undulatory extinction stuffed in their fractures and vugs, where a large amount of breccias with white dolomites filled between them develops, forming zebralike fabrics; and 3) homogenization temperatures of matrix and interstitial saddle-shaped dolomites are commonly 5℃ higher than those of strata during dolomitization, ranging between 105.8～159.6℃ and 113.2～138.6℃,respectively. In addition, they show lighter oxygen isotopes (-7.64&permil;～-7.95&permil;) and higher ⁸⁷Sr / ⁸⁶Sr ratios（0.708 369～0.709 684）. The development and distribution of structure-controlled hydrothermal dolomites are dominated by strike-slip faults. There would be a good lithologic reservoir if hydrothermal dolomites combine well with overlying tight limestones.</p>

川中地区茅口组白云岩主要位于茅口组二段中、上部和茅口组三段下部，根据岩石学特征可分为含灰质细-中晶白云岩、细-中晶白云岩、角砾白云岩，且以后两者为主。对比泥晶灰岩与不同类型白云岩样品地球化学特征后发现，白云岩相对于同层灰岩具有较低的Fe含量、较高的Mn含量和较低的Sr含量；泥晶灰岩与不同类型白云岩具有相似的稀土配分特征，均表现为LREE亏损、轻微正La异常和负Ce异常，且白云岩样品具有微弱的Eu正异常；细-中晶白云岩与角砾白云岩&delta;¹⁸O值均明显低于原始灰岩，而⁸⁷Sr/⁸⁶Sr比值则明显高于原始泥晶灰岩。不同类型白云岩与灰岩相似的稀土配分特征表明茅口组白云岩形成过程中保留了原始灰岩的部分地球化学特征，而白云岩微弱Eu正异常及其与灰岩同位素差异性可能是由于白云岩化过程中高温地质热流体的参与而引发的。茅口组白云岩化作用受多种因素控制：地层残余海水和岩浆活动伴生的热液流体为白云岩化作用中Mg的主要来源；峨眉山大火成岩省热效应为白云岩化提供异常高的古地温背景；断裂系统为异常地温对流和白云岩化流体提供了快速运移通道；颗粒滩相灰岩较好的孔、渗性使之比泥晶灰岩更易发生白云岩化。峨眉山大火成岩省伴生的异常地温和充足Mg供给是茅口组发生白云岩化的关键，不同类型白云岩形成于白云岩化过程的不同阶段。

<p>The dolomites in Maokou Formation, central Sichuan area are mainly developed in the mid-upper Member 2 and the lower Member 3 of Maokou Formation, which can be divided into fine-medium calcareous dolomite, fine-medium crystalline dolomite and brecciaous dolomite according to petrological characteristics, and the latter two are dominant. As viewed from the contrast in geochemical characteristics between micritic limestone and other types of dolomite samples, dolomites have lower Fe content, higher Mn content and lower Sr content than other limestone at the same layer. The micritic limestone and different types of dolomite present similar rare earth element (REE) distribution patterns with depletion of light REE, weak positive anomaly of La and negative anomaly of Ce, and dolomite sample also has weak positive anomaly of Eu. Fine-medium dolomite and brecciaous dolomite have lower &delta;¹⁸O values than primitive limestone, and obviously higher ⁸⁷Sr/⁸⁶Sr ratios than primitive micritic limestone. The similar REE distribution patterns between limestone and different types of dolomite indicate that some geochemical characters of primitive limestone are preserved during the dolomitization process in Maokou Formation, while the difference between the weak positive anomaly of Eu in dolomite and the limestone isotopes may be caused by the participation of high-temperature geo-hydrotherm during the dolomitization process. The dolomitization of Maokou Formation is dominated by multiple factors as follows: (1) the stratigraphic residual seawater and hydrotherm associated with magmatism are the major sources of Mg in dolomitization;(2) the thermal effect of Emeishan large igneous province provides abnormally high paleo-geothermal context for dolomitization;(3) the fault systems offer rapid migration channels for abnormal geothermal convection and dolomitization fluid;(4) the limestone with grain beach facies possesses favorable porosity and permeability, and thus have a higher possibility of dolomitization than micritic limestone. The abnormal geotherm associated with Emeishan Large igneous province in and abundant Mg content are the two key factors for dolomitization in Maokou Formation, and different types of dolomites were formed in different phases of dolomization process.</p>

Recently, continuous breakthrough have been made in the exploration of Qixia Formation and Maokou Formation in the western-central Sichuan Basin, which has attracted extensive attention to the dolomite reservoir. Based on the geological background of reservoir formation, taking outcrops and cores as the access point and combining with the experimental analysis, four significant conclusions on the genesis and distribution of reservoir are drawn: (1) Dolomite reservoirs in both Qixia Formation and Maokou Formation developed in the highstand systems tract. The platform margin facies and the syneclise margin facies are the main sedimentary environment of reservoir development.(2) Crystalline dolomite, including residual granular dolomite and medium to fine crystalline dolomite, is the main lithology of reservoir, and dissolution holes, residual intergranular pores, biological coelomic pores and fractures are the main reservoir space. Both the Qixia Formation with an average porosity of 3.87, and the Maokou Formation with an average porosity of 4.57, show good reservoir property. (3) Grain beach subfacies and penecontemporaneous dissolution are the two major controlling factors of reservoir formation. Grain beach is the material basis of reservoir development and the carrier of primary pore. Penecontemporaneous dissolution is the key to improve the reservoir space by enlarging primary pores into holes. (4) The marginal-platform shoals along Jian'ge-Ya'an and the marginal-syneclise shoals along Yanting-Guang'an are the favorable zones of dolomite reservoir development and the main target areas of gas exploration.

Based on data of outcrop, drilling core, logging, thin section and other macro and micro data, the characteristics of sedimentary facies, reservoir types, reservoir-controlling factors and reservoir distribution patterns of the Perimian Maokou Formation are systematically studied in Sichuan Basin. The author obtains the understanding as follows: (1) The sedimentary pattern of Maokou Formation is influenced by the NW-SE faults formed by Emei taphrogenesis, but not by Caledonian paleo-uplift. (2) Carbonate ramp, slope and basin are three main facies in Maokou Formation. The high-energy shoal of high-stand system tract developed in shallow ramp in the middle-late period of Maokou is the most favorable reservoir sedimentary facies. (3) Two types of reservoir such as hole-pore dolomite reservoir and karst fractured-vuggy limestone reservoir are developed in Maokou Formation. The high-energy bioclastic shoal is the material basis for reservoirs of Maokou Formation. Early dolomization is the key factor for the preserving of dolomite reservoir, tectonic movement and paleo-karstification are important conditions of reservoir development. (4) Dolomite reservoir is mainly distributed in the Ya'an-Leshan and the Yanting-Guang'an areas. Karst fractured-vuggy limestone reservoirs are distributed in the whole basin, but the Luzhou-Kaijiang uplift is the most developed area.

针对二叠系的构造&#x02014;沉积演化过程复杂、有利相带展布格局恢复困难及有利勘探区带不明朗等问题,利用近年新的二维和三维地震资料、盆缘野外及盆内钻井、录井资料,开展四川盆地二叠系构造沉积演化的系统研究,探索主要构造运动的响应特征及影响因素,建立各组、段之间的连续沉积演化关系,明确多套目的层系的有利沉积相带展布,为有利勘探区带的优选提供重要支撑。通过地质特征综合分析,认为：①二叠系沉积前古地貌、二叠纪拉张构造背景、地幔柱隆升及火山喷发等多种因素,造成了二叠系构造沉积分异;②四川盆地二叠纪表现为区域拉张构造动力背景,属克拉通裂陷盆地沉积体系,控制了多个层系边缘礁滩相带的展布,为发育规模岩性圈闭群奠定了基础;③三叠纪早期继承了二叠纪末期沉积格局,并受盆地边缘古陆、岛链、水下隆起影响,整体呈现填平补齐的特征,属克拉通坳陷盆地沉积体系,滩体受微地貌控制呈垂向加积、侧向进积的特点,平面上在清水台地区大面积席状展布;④基于构造&#x02014;沉积背景分析以及二维和三维地震资料的综合应用,明确了栖霞组&#x0201c;一缘两环带&#x0201d;,茅口组&#x0201c;一隆一缘&#x0201d;,长兴组&#x0201c;三隆三洼&#x0201d;,飞仙关组&#x0201c;三隆成滩、三洼补齐&#x0201d;等主要沉积面貌。综合含油气地质条件分析,指出川西地区栖霞组台缘带及川中&#x02014;蜀南地区台内高带,剑阁&#x02014;南充&#x02014;石柱地区茅口组台缘带,开江&#x02014;梁平地区海槽及蓬溪&#x02014;武胜&#x02014;石柱地区浅水陆棚长兴组边缘礁滩等,是四川盆地二叠、三叠系的主要勘探领域和方向。

The Permian system in Sichuan Basin is complex in tectono-sedimentary evolution, creating difficulties in restoring the distribution of favorable facies zones and uncertainties in favorable exploration belts. So, through the latest 2D and 3D seismic data as well as drilling and mud-logging data in and around the basin, this evolution was investigated systematically to identify response characteristics and influential factors of major tectonic movements. The relationship of continuous sedimentary evolution was established to every formation and member and the distribution of favorable facies zones with multiple targets was defined to provide an important support for optimizing the favorable exploration belts. After the comprehensive analysis on geological characteristics, it is revealed that (i) multiple factors, including ancient landform before the Permian deposition, and tensile tectonic setting, mantle plume uplift and volcanic eruption in the Permian, affect the tectonic-sedimentary differentiation of the Permian; (ii) representing a regional tensile tectonic setting, the Permian in Sichuan Basin was a sedimentary system of cratonic rifted basin, which controlled the distribution of bioreef-beach facies zones on the margin of multiple strata, laying a foundation for the development of massive lithologic traps; (iii) in the early Triassic, the basin inherited the sedimentary pattern in the late Permian, and exhibited one feature of filling and leveling up due to some effects, for example, ancient land, island chain and underwater uplift at the basin margin. It was a sedimentary system of cratonic depression basin, whose beaches in vertical and lateral accretion might be controlled by microgeomorphology and presented large-scale sheet-like distribution in Qingshuitai area in plane; and (iv) dependent on the analysis of tectono-sedimentary setting and the comprehensive application of 2D and 3D seismic data, the main sedimentary features were defined, such as &#x0201c;one margin and two ribbons&#x0201d; in Qixia Formation, &#x0201c;one uplift and one margin&#x0201d; in Maokou Formation, &#x0201c;three uplifts and three depressions&#x0201d; in Changxing Formation, and &#x0201c;three uplifting forming beaches and three depressions filling and leveling up&#x0201d; in Feixianguan Formation. In addition, the analysis of petroleum geology points that the main exploration domains and prospects of Permian and Triassic in Sichuan Basin will focus on the platform margin zone of Qixia Formation in western basin, the intraplatform highland zone in central-southern basin, the platform margin zone of Maokou Formation in Jian&#x02019;ge-Nanchong-Shizhu area, the trough in Kaijiang-Liangping area, and the bioreef-beach on the edge of Changxing Formation in shallow shelf of Pengxi-Wusheng-Shizhu area.

基于三维地震资料与钻井岩心资料，采用地震-地质解析方法和断层充填碳酸盐胶结物U-Pb定年的年代学方法，综合分析四川盆地中部地区深层走滑断层的形成时期、演化及其成因机制。研究表明：走滑断层在晚震旦世形成雏形，并在早寒武世基本发展为右行张扭断裂系统，在二叠系沉积前叠加至少一期压扭构造变形，在晚二叠世反转为左行弱张扭断裂系统，仅极少数在印支期及以后选择性复活;走滑断层受南华纪裂陷正断层和北西向基底深大断层等先存构造影响，震旦纪末—早寒武世属于斜向板内变换断层，调节德阳—安岳槽盆北强南弱的不均匀伸展，与德阳—安岳槽盆演化具有时间与强度上的匹配性，后期在不同构造背景下发生多次反转及选择性活化。

四川盆地中二叠统茅口组一段具有较大的天然气勘探潜力，但一直存在沉积相认识不清的问题。基于四川盆地中部2口最新钻井岩心厘米级精细描述以及多个野外露头观测，结合分析化验资料及测井曲线，开展了详细的沉积相标志分析，提出了新的茅一段沉积相划分方案。“眼球灰岩”与“眼皮灰岩”的主要区别在于泥质含量的多少，用自然伽马曲线能够有效区分这2种岩相；海相缺氧环境、大量风暴沉积构造以及硅质生物碎屑表明，茅一段沉积于缓坡型碳酸盐岩台地环境之下，受到风暴作用及与之伴生的风暴上升流的影响。基于沉积相标志，将茅一段划分为中缓坡外带和外缓坡上部2个亚相，中缓坡外带包括风暴碎屑流、风暴滩、风暴滩间洼地3个微相，外缓坡上部“眼皮灰岩”含量较高，微相组合为颗粒流、静水泥夹碎屑流，一般发育在茅一段上部或顶部。

The first Member of Maokou Formation has great potential for gas exploration，but the problem of unclear understanding of sedimentary facies always exists. Based on the fine centimeter-level description of two latest drilling cores in central Sichuan Basin and multiple field outcrop observations, combined with the analysis of laboratory data and logging curves，a detailed analysis of sedimentary facies markers is carried out, and a new sedimentary facies division plan of the first Member of Maokou Formation is proposed. The main difference between eyeball-shaped limestone and eyelid-shaped limestone lies in the amount of argillaceous content, and natural gamma curve can effectively distinguish these two lithofacies. The marine anoxic environment, a large number of storm sedimentary structures and siliceous bioclasts indicate that the first Member of Maokou Formation was deposited in a ramp carbonate platform environment and was affected by storm action and associated storm upwelling. Based on the facies markers，the first Member of Maokou Formation is divided into two subfacies：The outer belt of middle ramp and the upper part of outer ramp. The outer belt of middle ramp includes three microfacies: Storm debris flow, storm beach, storm inter beach depression. The upper part of outer ramp has relatively high content of eyelid-shaped limestone, the microfacies combination is particle flow and static mud intercalated debris flow, which generally develops in the upper part or the top of the first Member of Maokou Formation.

为解决溶液法难以实现的古老海相碳酸盐岩取样和超低U、Pb含量样品测年的难题,通过激光剥蚀进样系统与多接收电感耦合等离子体质谱仪的连用和对年龄为209.8 Ma实验室工作标样的开发和标定,建立了适用于古老海相碳酸盐岩的激光原位U-Pb同位素定年技术,并应用于四川盆地震旦系灯影组成岩-孔隙演化研究。通过充填孔洞、孔隙和裂缝中不同期次白云石胶结物的测年,指出灯影组白云岩储集层的埋藏成岩过程主要是原生孔隙和表生溶蚀孔洞逐渐被充填的过程。孔洞的充填作用发生在早加里东、晚海西&#x02014;印支、燕山&#x02014;喜马拉雅期3个阶段,孔隙的充填作用主要发生于早加里东期,未被胶结物充填的残留孔洞、孔隙和裂缝构成了主要储集空间,明确了四川盆地灯影组白云岩储集层的成岩-孔隙演化史。这些认识与该地区的构造-埋藏史、盆地热史具有很高的吻合度,说明测年数据的可靠性和激光原位U-Pb同位素定年技术的有效性,为古老海相碳酸盐岩成岩-孔隙演化研究和油气运移前有效孔隙评价提供了新的方法。图5表4参46

下寒武统肖尔布拉克组是塔里木盆地寒武系盐下领域主要勘探目的层之一，然而当前沉积相及储层成因认识不深制约了勘探的突破。以柯坪地区肖尔布拉克剖面为对象，在野外实测描述的基础上，优选样品开展了碳氧稳定同位素、锶同位素、白云石有序度、微量元素、稀土元素、U-Pb同位素定年和团簇同位素分析。结果表明：①肖尔布拉克组主要发育层纹石、凝块石、黏结颗粒、泡沫绵层石和叠层石5种微生物白云岩，自下而上的岩相组合特征可将其分为3个段5个亚段，整体构成一个三级层序；②柯坪地区早寒武世肖尔布拉克组沉积期整体处于温热—干热气候，相对正常—较高海水盐度、水体向上逐渐变浅和氧含量逐渐增加的海洋环境，发育碳酸盐缓坡背景下的外缓坡微生物层—中缓坡微生物丘—内缓坡微生物丘滩—潮坪沉积序列；③白云岩形成于准同生—浅埋藏期相对较低温度环境，白云石化流体为具有较高盐度的海水；④储层储集空间类型主要为原生微生物格架孔和受早表生期大气淡水溶蚀作用改造的溶蚀孔洞，沉积微相、高频层序界面和早期白云石化作用是控制储层发育的主要因素。研究成果可以为该领域岩相古地理编图和储层分布预测提供依据。

Lower Cambrian Xiaoerblak Formation is an important exploration target of Cambrian pre-salt in Tarim Basin, but the limited knowledge of sedimentary facies and reservoir genesis led to the restriction of exploration. This study took Xiaoerblak outcrop of Keping area as an example. Based on detailed description, 110 thin sections identification and multi-parameters geochemical (order degree, trace elements, rare earth elements, δ¹³C, δ¹⁸O, ⁸⁷Sr/⁸⁶Sr, U-Pb dating and cluster isotopes) data analysis, it was found that Xiaoerblak Formation can be divided into three members, and microbial dolomite is the main lithology. The characteristics of lithofacies assemblage form bottom to up indicate that it can be described as a complete three-order sequence. The sedimentary environment of Early Cambrian Xiaoerblak Period in Keping area characterized by warm-dry climate, normal-higher sea salinity, gradually increase oxygen content and upward shallower water. The sedimentary sequence was microbial layer-microbial mound/shoal-tidal flat in carbonated ramp background. Dolomitization took place in penecontemporaneous-early diagenetic stage and the main dolomitization fluid was high-saline seawater. Primary microbial framework pores and vugs which formed by the dissolution atmospheric water are the main reservoir spaces. Reservoir was mainly controlled by sedimentary microfacies, high frequency sequence interface and early dolomitization. These research results are of great significance for sedimentary facies mapping and reservoir prediction in Cambrian pre-salt field.