Origins of High H_2S-bearing Natural Gas in China

Natural gas containing hydrogen sulphide （H2S） has been found in several petroliferous basins in China, such as the Sichuan Basin, Bohai Bay Basin, Ordos Basin, Tarim Basin, etc. Natural gas with higher HES contents （HES 〉5 % mol.） is mostly distributed in both the gas reservoirs of Dukouhe, Luojiazhai, Puguang and Tieshanpo, which belong to the Triassic Feixianguan Formation in the northeastern Sichuan Basin and those of the Kongdian-Shahejie formations in the northeastern Jinxian Sag of the Jizhong Depression, Bohai Bay Basin. In the Sichuan Basin, the HES contents of natural gas average over 9% and some can be 17 %, while those of the Bohai Bay Basin range from 40 % to 92 %, being then one of the gas reservoirs with the highest H2S contents in the world. Based on detailed observation and sample analysis results of a total 5000 m of core from over 70 wells in the above-mentioned two basins, especially sulfur isotopic analysis of gypsum, brimstone, pyrite and natural gas, also with integrated study of the geochemical characteristics of hydrocarbons, it is thought that the natural gas with high HES contents resulted from thermochemical sulfate reduction （TSR） reactions. Among them, the natural gas in the Feixianguan Formation resulted from TSR reactions participated by hydrocarbon gas, while that in the Zhaolanzhuang of the Jinxian Sag being the product of TSR participated by crude oil. During the consumption process of hydrocarbons due to TSR, the heavy hydrocarbons were apt to react with sulfate, which accordingly resulted in the dry coefficient of natural gas increasing and the carbon isotopes becoming heavier.     

Progress in Study of Potash Resources of Oil (Gas) Field Brine in China

With a population of 1.3 billion, China is a large agricultural country. However, China is short of potash resources as the external dependence is more than 50% for many years. With the limited possibility for increasing potash reserves from surface salt lakes, and the challenge of finding potash deposit from marine strata has not been yet overcome, the oil (gas) field brine resources has become the preferred source for the urgent needs of potash. In recent years, a lot of exploration and research work on the oil (gas) field brine has been done under the guide of “oil and potash co-exploration” policy and delightful achievements have been obtained. The research achievements at Qaidam Basin, Sichuan Basin, Jianghan Basin and Tarim Basin were summarized in the present paper. All of the above basins are the most important areas with great prospects of oil (gas) field brine. This paper mainly focused on three aspects, the brine characteristics, the brine geochemistry and resource assessment. After the summary, the characteristics of oil (gas) field brine and the progress in study of that were gotten in different basins. It was suggested that the research work of (gas) field brine at Qaidam Basin should be emphasized. It was concluded that the evaluation work of oil (gas) field brine resources is insufficient at the four basins, and it is urgent to establish oil (gas) field brine resources evaluation criteria and methods.     

四川盆地东北部三叠系飞仙关组硫酸盐还原作用对碳酸盐成岩作用的影响

四川盆地东北部三叠系飞仙关组存在广泛的硫酸盐还原作用,同时地层中也存在锶含量异常高的成岩流体。研究表明:热化学硫酸盐还原作用（TSR）和（或）细菌硫酸盐还原作用（BSR）造成的SO42-离子的消耗对成岩孔隙流体中SrSO4溶解度的改变是三叠系中高Sr成岩流体的形成机制之一,该机制使得孔隙流体从白云石化作用和碳酸盐矿物的新生变形作用中获得的Sr在流体中以高浓度的Sr2+形式存在,并使之在流体中极度富集,这也是四川盆地东北部三叠系中大型和超大型天青石矿床的形成机制之一。H2S和CO2是硫酸盐还原作用的重要产物,不同温度条件下溶于水中的H2S和CO2,与不溶于水的气体分子之间的平衡反应H2S（aq）H2S(g)和CO2(aq)CO2(g)的平衡常数和吉布斯自由能增量计算表明,当温度从25℃升高至220℃时,两个反应的平衡常数分别大致从10增至240和从20增至500,两个反应的平衡常数都始终大于1,说明H2S和CO2更趋向于以气体形式存在,同时温度越高,系统中以气体形式存在的H2S和CO2会越多,溶解于水中的H2S和CO2会越少,因而在深埋藏的高温条件下,H2S和CO2对碳酸盐矿物的溶解能力可能相对很小。相对低温的成岩环境、高温流体的向上和侧向运移、构造抬升、富氧流体与含有H2S流体的混合以及金属硫化物的沉淀是提高含H2S和（或）CO2流体对碳酸盐矿物溶解能力的五个途径。因此,与较早成岩阶段相对浅埋藏环境的碳酸盐溶解作用有关的H2S和CO2流体可能与细菌硫酸盐还原作用（BSR）关系更为密切;断层或其它流体运移通道是高温含有H2S和CO2流体向上运移的基础条件,具有原生孔隙度和渗透率的礁、滩相高能沉积物也是流体发生侧向运移的先决条件;大幅度的构造抬升造成的地层温度降低是提高含H2S和（或）CO2地层流体对碳酸盐矿物溶解能力的重要因素,地壳抬升至近地表造成的古喀斯特作用也可以为H2S的氧化提供良好的地质环境。在有关的勘探中应注意:在断层等流体运移通道造成高温含H2S和CO2流体向上运移的条件下,与之有关的构造低点应该是主要的勘探目标;在燕山运动导致的地层抬升并导致深部热流体降温的条件下,与之有关的构造高点应该是主要的勘探目标,应分别对待。     

四川盆地飞仙关组气藏硫化氢成因及其依据

四川盆地东北部下三叠统飞仙关组鲕滩气藏天然气烃类气体以甲烷为主,含量主要分布在75%～90%之间,C2＋含量为0～0.15%;非烃气体以H2S和CO2为主,含量分别为5%～20%和1%～10%。已有观点认为H2S为飞仙关组气藏附近的石膏经硫酸盐热化学还原作用（TSR）而成。随着川东北气区大中型高含硫化氢气田的发现,硫化氢成因机理的研究备受关注。应用金管、高压釜和石英管等实验方法模拟了硫化氢气体的生成,同时检测了模拟生成的硫化氢和石膏、硫磺等硫化物的硫同位素。实验结果表明:硫磺与正己烷在较低温度即可生成大量的硫化氢气体,而正己烷与硫酸钙的反应总体上比较困难,且生成的H2S量较少;富含黄铁矿的低成熟泥灰岩模拟生烃过程中可以生成与甲烷相当,甚至超过甲烷含量的硫化氢气体;含硫化合物与烃类反应生成的硫化氢的硫同位素值比原始物质的硫同位素值重。地层中的SO2－4是海相地层中H2S气体形成的最初来源。含硫烃源岩直接生成高硫化氢天然气和储层中单质硫与烃类的反应是川东北飞仙关组天然气中硫化氢形成的主要原因。     

Genesis of Marine Carbonate Natural Gas in the Northeastern Sichuan Basin, China

Sichuan Basin is one of the structurally stable and gas-rich basins, being regarded as one of China＇s important natural gas industry bases. Puguang and Jiannan gas fields, located in the eastern Sichuan Basin are two large fields with gas derived from Permian and Lower Triassic marine carbonate. The genesis of marine carbonate natural gas was examined using carbon isotope composition and hydrocarbon components of natural gas samples from the eastern and western Sichuan Basin, and compared with that of acidolysis gas derived from marine source rock in the eastern Sichuan Basin. It is concluded that the natural gas in the marine carbonate reservoir originated from pyrolysis of the earlier crude oil and light-oil, and then mixed with kerogen pyrolysis gas of the Permian and Lower Silurian source rock.     

海相沉积岩是中国石油工业未来的希望

回顾了中国陆相找油第一次创业的经验,认为中国的海相找油走过了一段“以南代北”和“以偏概全”的弯路。提出了该如何全面看待中国南方海相地层所遇到的破坏严重,地面暴露,保存条件差及油气层年代古老等问题。汇总了我国主要海相勘探区(塔里木盆地、鄂尔多斯盆地、四川盆地、渤海湾盆地)的油气勘探进展概况。建议中国的海相油气勘探因经验不足,可以借鉴俄罗斯海相古生界找油的经验。指出中国的海相沉积油气勘探可以包括十个领域:(1)稳定地台区的大型古隆起;(2)断陷盆地的海相沉积;(3)山间盆地海相沉积;(4)南方地区碳酸盐岩分布区;(5)南方复合盆地;(6)大陆架海域海相沉积;(7)西藏羌塘盆地侏罗系;(8)四川盆地的三叠系;(9)大型不整合;(10)逆掩断层带的海相沉积。     

中国西部古老海相沉积建造的典型结构样式及勘探指向

中国西部大型盆地（鄂尔多斯、四川、塔里木盆地）的古老海相地层受多期构造改造而变得复杂不一,造成难以准确识别和解析沉积建造并找准油气勘探目标。综合分析了三大盆地的海相碳酸盐岩的沉积大地构造背景和充填序列,建立了典型沉积建造的地质结构模型。结果表明:三大盆地海相碳酸盐岩主要沉积于前中生代中国陆块群的构造离散阶段,准稳定的鄂尔多斯盆地在古老碳酸盐岩建造沉积之前几乎没有碎屑岩垫底,次稳定的四川盆地和活动的塔里木盆地都具有碎屑岩垫底;基底和周缘发育古老的下伏裂谷是它们共有的特色,并形成了隐伏于盆地内部的牛头型建造;前印支期,都普遍发育若干不同规模的古隆起,围绕古隆起披覆沉积的似背斜建造是这些盆地又一显著特点;在构造相对稳定的间隙期,三大克拉通内部往往为广阔的浅水陆表海沉积,席状的台地潮坪白云岩建造是以往关注度最小的一类建造。上述古老克拉通盆地的牛头型建造、似背斜建造、席状白云岩建造埋藏深、隐伏性强,是重要的油气勘探指向。如何在被多旋回构造改造的叠合盆地中准确解析地层和岩相,并识别出这些建造的精细结构,是未来古老深层海相油气勘探极具挑战性和非常必要的研究方向。     

Post-Neogene Structural Evolution: An Important Geological Stage in the Formation of Gas Reservoirs in China

Tectonic movements since the Neogene have been the major developmental and evolutional stages of the latest global crustal deformation and orogenic movements. China is located in a triangular area bounded by the Indian landmass, the West Siberian landmass and the Pacific Plate, characterized by relatively active tectonic movements since the Neogene, and in this region, natural gas would have been very easy to dissipate, or difficult to preserve. Therefore, the characteristics of post-Neogene tectonic movements offer important geological factors in researching the formation and preservation of gas reservoirs in China. Summarizing the reservoiring history of gas fields in China, although there are some differences between various basins, they are all affected by the tectonic     

中国地热资源研究的进展

Based on recent year's advances of geothermal resources studies and explorations in China,this paper reviews the basic distributive characteristics of hot springs in the uplifted area and geothermal water in the Meso一Cenozonic sedimentary basins,suggests that two hydrothermal activity concentrated zones (S Tibet Autonomous Region-W Sichuan Province-W Yunnan Province and coastal area of SE China)，one large basin (North China Basin) and two smaller basins (Weihe Basin and Leiqiong Basin) are major areas of studies and explorations of geothermal resources in China continent, corysiders that geothermal resources in China have certain potential of exploitation and should be used，but thescale of exploitation seems to be limited, they cannot occupy an importan position in energy supply and can only be regarded as a supplementary energy source.     

中国中-西部4种新生代挤压盆地成藏地质条件及成藏期次

新生代挤压盆地是我国中-西部的重要油气勘探领域。根据挤压盆地的发育部位、盆地基底、充填层序、构造叠加和盆山耦合形式等条件,本文在我国中-西部识别出准(噶尔)西北缘型、四川盆地西缘型、柴(达木)北缘型和准(噶尔)南缘型等4种新生代挤压盆地,前两者发育海西晚期—印支期前陆盆地,后两者具有喜马拉雅造山期的再生前陆盆地特征。对准西北缘、四川盆地西缘、柴北缘和准南缘新生代挤压盆地的对比研究表明,它们在烃源岩、储盖组合等成藏条件上存在明显的差异,而晚期前陆发育对柴北缘型和准南缘型挤压盆地烃源岩演化具有明显的控制作用。在不同新生代挤压盆地典型油气藏解剖研究的基础上,认为燕山期及之前是准西北缘型和四川盆地西缘型挤压盆地主要的成藏期,喜马拉雅造山期则主要表现为准西北缘型挤压盆地的油气藏保存和四川盆地西缘型挤压盆地油气藏的调整和定型;喜马拉雅晚期是柴北缘型挤压盆地最主要的成藏期,而多期前陆盆地的准南缘型挤压盆地具有多期成藏的特征,但喜马拉雅晚期的油气成藏最为重要。     

四川含油气叠合盆地基本特征

随着近年来四川盆地油气勘探的不断突破,重新审视其基本地质特征和油气成藏特点变得迫切而必要.四川盆地是典型的叠合盆地,显生宙以来经历了震旦纪一中三叠世伸展体制下的差异升降和被动大陆边缘(海相碳酸盐岩台地)、晚三叠世-始新世挤压体制下的摺皱冲断和复合前陆盆地(陆相碎屑岩盆地)、渐新世以来的褶皱隆升改造(构造盆地)3大演化阶...     

中国海相克拉通盆地内部走滑断裂发育特征及控藏作用

走滑断控油气藏作为一种全新类型油气藏,其勘探潜力已初步显现。在对中国三大海相克拉通盆地内部走滑断裂发育特征与控藏作用开展对比分析的基础上,揭示了塔里木盆地、四川盆地、鄂尔多斯盆地内部走滑断裂空间结构与活动特征的相似性与差异性,并结合盆地动力学演化特征探讨了不同盆地内部走滑断裂成因机制,系统分析了三大盆地内部走滑断裂的控藏作用:(1)中国三大海相克拉通盆地内部均发育中小尺度滑移距走滑断裂,普遍具有“纵向分层,平面分段,垂向多期叠加”的空间结构特征。(2)三大克拉通盆地内部走滑断裂体系具有成因、分布和期次的差异性。塔里木盆地内部走滑断裂体系形成时间早,演化时间长,在盆地北部具有“南北对接,东西分区”特征;鄂尔多斯盆地西南缘受燕山期(侏罗纪—白垩纪)陆内挤压影响,形成了北西西向走滑断裂体系;四川盆地受控于二叠纪峨眉山大地幔柱影响,在盆地内部先存基底断裂基础上,形成了北西向、北西西向、近东西向张扭型走滑断裂。(3)中国三大海相克拉通盆地内部走滑断裂对油气成藏和富集具有重要的控制作用。在控储方面,受断裂-流体耦合改造控制,可形成断控缝洞型储集体、断-溶缝洞型或断控裂缝-孔隙型储集体;在控圈方面,在碳酸盐岩地层中可形成断控缝洞型、断溶缝洞型岩性圈闭;在控运方面,走滑断裂产状高陡,可直接沟通烃源岩和储层,构成重要的油气垂向输导体系。     

海拉尔盆地煤层气资源评价及潜力分析

利用钻井和地震资料,评价和预测了海拉尔盆地煤层的发育和分布,结合煤层含气量参数,预测了盆地内的煤层气资源前景。结果表明,海拉尔盆地的煤层气资源量约为10.79×10 11m3,其中呼和湖凹陷约为7.4 3×10 11m3,这远远超过了前人对整个东北区煤层气资源的评价。这表明,如果考虑煤层有一定埋深的含油气盆地,东北区的煤层气资源潜力还有相当大的增长空间。与美国已进行过成功煤层气勘探开发的含煤盆地对比表明,海拉尔盆地,尤其是呼和湖凹陷的煤层气潜力值得重视。      

中国东北地区油气地质特征与勘探潜力展望

中国东北地区发育50多个盆地,规模大小不一,较大的盆地包括松辽、二连、海拉尔盆地和5个跨境盆地。东北地区油气资源潜力巨大,油气储量增幅显著,同时面临油气上产、稳产难度仍然持续加大的现实。本文在深入分析东北地区构造与沉积古地理演化过程的基础上,总结了东北地区构造与沉积协同作用下的成藏组合差异发育特征。进一步结合勘探实践,针对油气勘探中存在的问题,围绕着新领域新层系的工作思路,提出了东北地区油气勘探的方向,包括:松辽盆地中央坳陷带中浅层油气精细勘探,松辽盆地南部深层火山岩油气勘探,松辽盆地西斜坡和北部倾末端油气勘探,东北地区古生界油气勘探,大三江盆地群油气勘探,东北地区页岩油和油页岩资源勘探。为未来东北地区油气资源的勘探部署提供了科学依据。     

Formation Mechanism and Controlling Factors of Natural Gas Reservoirs of the Jialingjiang Formation in the East Sichuan Basin

The Lower Triassic Jialingjiang Formation reservoirs are distributed widely in the East Sichuan Basin, which are composed mainly of fractured reservoirs. However, natural gas with high concentration of H2S, ranging from 4% to 7%, was discovered in the Wolonghe Gas pool consisting primarily of porous reservoirs, while the other over 20 fractured gas reservoirs have comparatively low, tiny and even no H2S within natural gases. Researches have proved the H2S of the above reservoirs are all from the TSR origin. Most of the Jialingjiang Formation natural gases are mainly generated from Lower Permian carbonate rocks, the Wolonghe gas pool＇s natural gases are from the Upper Permian Longtan Formation, and the natural gases of the Huangcaoxia and Fuchengzhai gas pools are all from Lower Silurian mudstone. The formation of H2S is controlled by the characteristics and temperature of reservoirs, and is not necessarily related with gas sources. The Jialingjiang Formation in East Sichuan is buried deeply and its reservoir temperature has ever attained the condition of the TSR reaction. Due to poor reservoir potential, most of the gas pools do not have enough room for hydrocarbon reaction except for the Wolonghe gas pool, and thus natural gases with high H2S concentration are difficult to be generated abundantly. The south part of East Sichuan did not generate natural gases with high H2S concentration because the reservoir was buried relatively shallow, and did not suffer high temperature. Hence, while predicting the distribution of H2S, the characteristics and temperature of reservoirs are the necessary factors to be considerd besides the existence of anhydrite.     

四川多旋回叠合盆地的形成与演化

四川盆地是典型的经历了多期构造演化过程的克拉通盆地,在其多套沉积层序中富含天然气,天然气的开发利用历史悠久.近年来连续发现了普光、龙岗、合川、新场、九龙山和元坝等多个大气田.揭示四川盆地的形成演化过程,不仅为探讨克拉通盆地的成因机制奠立重要基础,而且为探索强烈构造活动环境之下油气有效聚集与保存机制提供重要线索.本文利用...     

峨眉山大火成岩省对四川盆地油气储层的控制作用研究

四川盆地具有演化历史长、沉积盖层厚度大、油气资源丰富等特点,是我国大型含油气盆地之一。上扬子地区中、晚二叠世之间的峨眉山地幔柱活动改变了四川盆地古地理格局,造成地壳的快速抬升,盆地西南地区地壳抬升幅度最大,呈现古剥蚀高地,往北东方向的影响逐渐减弱,从而导致沉积环境自西南向北东由单一的海相依次转变为陆相、海陆过渡相至海相沉积。本文讨论了峨眉山大火成岩省的形成过程及对四川盆地油气储层的影响,认为峨眉山大火成岩省对四川盆地油气储层的影响主要体现在两个阶段、3种影响作用方式。两个阶段是指中二叠世末期和晚二叠世—早三叠世时期。3种方式是指峨眉山地幔柱导致的地壳抬升对下伏中二叠统灰岩储层的改造作用,表现为地幔柱核心区(大理—永仁)中二叠世地层发育风化壳岩溶型储层;峨眉山大火成岩省的火山喷发旋回对火山岩储层的空间发育的控制作用,发育了火山岩储层;峨眉山地幔柱活动控制的晚二叠世盆地构造格架对上覆沉积储层的控制作用,导致了峨眉山地幔柱外围伸展区(川东北—西北)发育海槽,控制了晚二叠世礁滩相沉积的发育等。峨眉山大火成岩省的形成过程不仅形成了优质的火山岩储层,同时也影响了沉积岩相的空间分布、改造了下伏碳酸盐岩的孔隙特征,进而控制了四川盆地的油气储层。     

天然气水合物在油气藏形成过程中的封盖作用——谈造山带中烃源岩对盆地区油气资源的贡献

在中国的造山带中普遍发育优质烃源岩,它们形成于海槽环境,而海槽环境也是形成天然气水合物的有利环境。水合物有良好的封盖作用,其下的油气受到封盖会向相邻的台地区运移,即油气从古海槽区(现今为造山带)向台地区(现今为盆地区)转移。因此造山带中的烃源岩对盆地区油气资源应有积极贡献。认为现今台西南海域的水合物与相邻油气藏具有同源性,这是水合物的封盖作用与油气藏形成之间具有密切联系的生动实例。四川盆地有限的烃源岩分布不能提供巨大的天然气储量,周边造山带可能也提供了相当的资源量。建议在四川盆地和秦岭造山带中系统采集气-液包裹体,以对比它们的亲缘关系,借以验证造山带中的烃源岩是否对盆地区的天然气成藏具有贡献。     

南海南沙海域沉积盆地与油气分布

在较详细分析南沙海域区域地质背景的基础上,研究该海域主要沉积盆地地质构造特征,分析不同区域沉积盆地的油气地质条件,研究和总结各盆地中的油气分布特征。研究表明,万安盆地、曾母盆地和文莱-沙巴盆地具有丰富的油气资源,北康盆地、北巴拉望盆地油气资源远景次之,礼乐盆地和南薇西盆地油气资源远景较差。     

中国中东部白垩纪沙漠的时空分布及其气候意义

本文介绍了中国中东部白垩纪沙漠沉积的时空分布，探讨了时空分布规律，认为：（１）中东部白垩纪沙漠分布严格受气候带控制，其实际分布限于北纬２０—４０°的干旱带（横跨当时的副热高压带），主要分布于鄂尔多斯盆地、四川盆地、江汉盆地和苏北盆地之中；（２）各盆地沙漠发生的时间不同，鄂尔多斯盆地为早白垩世，四川盆地为中白垩世晚期，江汉盆地为晚白垩世早期，苏北盆地为晚白垩世中期，（３）沙漠发生的穿时性反映了各盆地进入干旱带的顺序，由北到南，由西及东；（４）造成这种顺序的原因是由于亚洲在白垩纪时其总体为顺时针旋转，因而使西北部鄂尔多斯盆地率先进入干旱带，其次是西南部的四川盆地，然后是中部的江汉盆地。晚白垩世的降温事件迫使干旱带南移而使其滞后的最东部的苏北盆地进入干旱带，（５）中国白垩纪沙漠的存在说明处于“温室效应”的大气环流不仅不会“呆滞”而且还有所增强，季风的存在也说明当时的气候并不均一。本文提出了气候带漂变（ｃｌｉｍａｔｉｃｚｏｎｅｄｒｉｆｔ）的概念，认为气候变化的表现形式为气候带漂变。漂变既有长周期和短周期漂变之分，又有相对和绝对漂变之别。中国中东部白垩纪沙漠的时空变迁就是干旱气候带漂变的结果。