Characteristics of carbonate gas pool and multistage gas pool formation history of Hetianhe gas field, Tarim Basin, Northwest China

<正> Hetianhe is a big carbonate gas field which isfound and demonstrated in the period of "Chinese NationalNinth 5-Year Plan". The proved reserve of Hetianhe gas fieldis over 600 ×10⁸ m³. Its main producing layers are Carbon-iferous bioclastic limestone and Ordovician carbonate com-posed of buried hill. The former is stratified gas pool withwater around its side, and the latter is massive gas pool withwater in its bottom. The gases in the gas pools belong to drygases with normal temperature and pressure systems. Basedon the correlation of gas and source rock, the gases aremainly generated from Cambrian source rocks. According tothe researches on source rock and structure evolution, andthe observations on the thin section to reservoir bitumen andthe studies on homogenization temperature of fluid inclu-sions, the gas pool has been identified and divided into threeformation periods. The first is Late Caledonian when the oilgenerated from the Cambrian source rocks and migratedalong faults, as a form of liquid facies into Ordovician carbonate res-ervoir and accumulated there. After that, the crustuplifted, the oil reservoir had been destroyed. The second isLate Hercynian when condensate gases generated from theCambrian source rocks and migrated into Ordovician res-ervoir, as a form of liquid facies. Since the fractures hadreached P strata, so the trap might have a real poor preser-vation condition, and the large-scale gas pool formation hadnot happened. The third gas reservoir formation period oc-curred in Himalaya. The fractures on both sides of Hetianhegas field developed violently under the forces of compression,and thus the present fault horst formed. The dry gases gen-erated from Cambrian source rocks and migrated upwardsas the form of gas facies into Ordovician and Carboniferousreservoirs, and the large gas pool as discovered at presentwas formed finally.     

Petroleum enrichment characteristics in Ordovician carbonates in Lunnan area of Tarim Basin

Lunnan heave had experienced denudation during late Caledonian and Hercynian movements and reconstruction during Indosinian movement. Lunnan heave and its circumference areas are located on the direction of petroleum migration, and experienced three reservoir formation cycles that are divided by wave cycle: The first reservoir formation cycle is characterized by breakage, the second by alteration, and the third by enrichment. Three layers of dissolving-cave developed on the vertical in Lunnan area. Development degree of slit-cave system and their connectivity are important factors to control petroleum enrichment in the weathering crust reservoir. The area where dissolving-caves are communicated by silts and faults was a fine petroleum enrichment area, and water was often encountered in the area with isolation cave while drilling because of no oil and gas origin. The top part of the faulted-horst as a leaking area is bearing water area, and the higher part of slope nearing the top part of the faulted-horst as a high seepage area is a heavy oil area due to lack of fine caprock, and the lower part of slope and the platform are light and condensate oil area. The area with the middle-upper Ordovi-cian is the favorable area to explore original carbonate reservoir formed in the earlier stage. The best favorable petroleum enrichment area for carbonates is surrounding Lunnan heave along the slope down to the direction of sags. The precondition to discover petroleum in carbonates is accurately prognosticating the distribution area of silts and caves, and the key to improving the exploration success ratio is accurately recognizing silts and small faults.     

Reservoir petroleum inclusion GOR characteristics and geological significance from the Lunnan Low Uplift of the Tarim Basin

There were different opinions about the origin of petroleum property variations in the Lunnan Low Uplift of the Tarim Basin. In this paper, a software PVTsim was applied to investigate the compositions of the petroleum fluid inclusions in different sets of reservoir rocks from this area. The results show that there are three phases of petroleum inclusions in the Ordovician carbonate reservoirs and two types of petroleum inclusions in the Carboniferous and Tri-assic sandstone reservoirs. The three phases of the petroleum inclusions from the Ordovician reservoir rocks have similar compositions with the type 1 petroleum inclusion from the carboniferous and Triassic reservoir rocks, but the type 2 petroleum inclusion from the carboniferous and Triassic reservoirs is characterized by higher content of C1 and higher GOR values. With the combination of the geological background, it was inferred that the current petroleum pools in the Lunnan Low Uplift were formed mainly by two phases of petroleum charges, one is normal oils and another light oils, and both occurred during the late Tertiary. The light oils came from eastern-south direction, and migrated and charged into the reservoirs upward and toward northern west directions. On the basis of this, it was believed that the multiphases of the petroleum charges and some composition dissipation caused by the preserved condition changes would be the main reason of the petroleum property variations in the petroleum pools in this area.     

海拉尔盆地乌尔逊凹陷油气成藏期次分析

目的研究海拉尔盆地乌尔逊凹陷油气成藏期次。方法圈闭形成时期、烃源岩生排烃史、储层自生伊利石测年和包裹体均一温度法。结果海拉尔盆地乌尔逊凹陷油气成藏期主要分为两个大的阶段:第一阶段油气成藏时期大约在距今120~90 Ma,相当于伊敏组沉积时期,是海拉尔盆地乌尔逊凹陷最主要的成藏时期。油气大规模注入储层时期应该在105~90 Ma,相当于伊敏组二三段沉积时期,此时期为烃源岩大量生排烃时期,油气运移动力充足,有利于油气运移并聚集成藏;第二阶段为青元岗组沉积至今。青元岗组沉积以来,发生过近东西向的挤压反转,使已形成的油气藏重新调整,同时,二次生成的油气继续注入成藏。结论乌尔逊凹陷油气成藏时期研究取得新的认识,对于盆地下一步勘探具有重要的指导意义。     

对塔里木盆地库车坳陷东部侏罗纪湖盆边界的新认识

对库车坳陷东部地区侏罗纪的湖盆边界作了界定,着重对库车坳陷东部侏罗纪湖盆的北部边界进行了阐述,指出库如力—夏克阔坦东部是库车坳陷东部地区的沉积边界。     

塔里木盆地乌什凹陷-温宿凸起油气勘探前景

通过野外地质调查、岩性剖面与地震资料分析等方法，对塔里木盆地乌什凹陷-温宿凸起的油气前景进行了研究。野外调查结果证实，乌什凹陷发育二叠系、三叠系、侏罗系3套烃源岩及多套储盖组合。烃源岩热演化史及地面油苗显示证实本区有油气运移聚集的条件和历史。地震资料显示喜马拉雅晚期运动导致与逆冲断层伴生的挤压构造十分发育，以挤压背斜为主体的构造构成油气聚集的有利场所。温宿凸起在地质历史时期曾与塔北隆起连为一体，是长期继承性发育的占凸起，古近纪卡拉玉尔滚大型走滑断层将其与塔北隆起分开。温宿凸起被乌什和阿瓦提两个已证实被具有生烃能力的生烃凹陷所挟持，是油气运移的指向区。同时存在碳酸盐岩和砂岩两类多个勘探目的层。乌什凹陷-温宿凸起无疑是塔里木盆地油气勘探具有良好前景的战略接替区。     

塔中隆起北斜坡志留系储层特征及控制因素

在详尽的岩石学研究基础上,阐述了塔里木盆地塔中北斜坡志留系(主要是下砂岩段)储层的特征.志留系砂岩成分成熟度总体较低(岩屑砂岩为主),但在下砂岩段下亚段常夹数层高成熟度的石英砂岩;砂岩结构成熟度较高.储层成岩压实作用较强(粒间一般以线接触为主);以碳酸盐类及硅质和高岭石为主的胶结作用总体较强;溶蚀作用一般较弱,但局部层段以碳酸盐胶结物为主的溶蚀作用强烈,对储层性质影响较大.储层孔隙类型主要有残余原生粒间孔、颗粒(长石、岩屑)溶孔、碳酸盐(主要为方解石)胶结物溶孔和微孔隙.储层孔隙类型和组合在平面和纵向上存在一定变化,多数层段以粒间孔和微孔为主,局部层段碎屑颗粒间碳酸盐溶孔占较高的比例.进而总结了影响储层性质的主要因素为压实作用、成岩胶结作用和储层岩石学特征(碎屑组分和粒级等).较为优质的储层基本为中-细粒以上石英砂岩(或成分接近石英砂岩).     

塔里木盆地巴楚中奥陶统一间房组生物礁-滩发育模式和储集物性

依据精细的露头写实及室内分析,对塔里木盆地巴楚一间房露头区中奥陶统一间房组生物礁-滩沉积体系发育模式及储集性能进行研究。结果表明:一间房组自下而上共划分为5个三级层序,每个层序均由TST和HST构成,生物礁-滩沉积体系主要发育于层序1至层序3中,由生物礁、生物碎屑滩和台缘背景沉积3种成因相组合构成;层序1和层序2的HST内发育进积型生物礁-滩沉积体系,以沉积高能带向盆地方向迁移为特点;层序3的TST内发育退积型生物礁-滩沉积体系,以沉积高能带向台地方向迁移为特点,其中早期为海侵追补型,晚期为海侵并进型;在生物礁-滩沉积体系中,礁前内侧砂质滩和礁后内侧砂质滩具有相对较好的储集性能,是潜在的优质储层。     

塔里木盆地轮南奥陶系碳酸盐岩储层类型测井识别方法

通过对具有孔隙、裂缝、溶洞复杂孔隙空间结构的碳酸盐岩储层的测井响应特征的研究,建立了针对塔里木盆地轮南地区碳酸盐岩储层储集空间的测井识别方法.即利用常规测井资料判别储层类型方法并结合成像测井资料来判断储层的储集空间类型.应用此方法,可以准确地认识碳酸盐岩的储集空间类型.     

塔里木盆地周缘洋盆开合在盆地内部的构造沉积响应

依据塔里木盆地周缘蛇绿岩年龄及盆内钻井岩性、古生物、地球物理等资料,以古天山洋和古昆仑洋的开合演化为线索,将盆地构造沉积响应划分为五个期次。南华纪-震旦纪早世Rodinia泛大陆开始裂解,塔里木陆块北部发育南天山海槽、南部发育库地小洋盆,同期塔里木盆地只有中北部地区沉积碎屑物,塘古孜巴斯至古城墟地区为古隆起无沉积;震旦纪晚世-奥陶纪中世南天山洋和北昆仑洋(原库地小洋盆)进入成年期,塔里木陆块西部高地发育快速生长的碳酸盐岩台地,东部低地(满加尔)发育饥饿盆地,塔里木陆块形成了西台东盆的沉积格局;奥陶纪晚世-泥盆纪北昆仑洋和南天山洋分别向中昆仑和中天山微陆块俯冲(最终与塔里木陆块拼贴),塔里木陆块边缘逐渐出现不同规模的陆源剥蚀区,陆块内碳酸盐台地逐渐消亡;石炭纪-二叠纪中世北天山洋和南昆仑洋-阿尼玛卿洋关闭造山,塔里木陆块内部实际处于广义的弧后扩张状态,期间接受了海陆交互相碎屑岩沉积及海相碳酸盐岩沉积;二叠纪晚世至今金沙江洋、澜沧江洋、班公-怒江洋和雅鲁藏布江洋等先后关闭,受此影响天山、昆仑造山带强烈抬升,塔里木盆地发育库车和塔西南2个前陆盆地。     

Reservoir characteristics and genesis of high-porosity and high-permeability reservoirs in Tarim Basin

Based on detailed studies, this paper proposesthat in the Tarim Basin, hydrocarbon reservoirs widespreadeither in vertical sequences or in plane and high-porosity andhigh-permeability reservoirs are developed all over the basin.However, obvious difference and heterogeneity exist amongdifferent kinds of reservoirs. The lithologic characteristics,reservoir space types and reservoir properties in variousstrata have been probed. The result indicates that althoughthe Paleozoic carbonates have been deeply buried for a longperiod, high-quality reservoirs with the porosity of up to 5%—8% (12% as the maximum) and the permeability of10×10^-3—100×10^-3 μm² (1000×10^-3 μm² as the maximum)can be found in certain areas. These include the area withthe development of reefs and carbonate beaches, the weath-ered-crust buried-hill belts that have undergone thelong-term exposure, weathering and leaching, the area withthe development of dolomitization, and those areas that haveexperienced the resolution of carbonic acid and organic acidgenerated by the maturity of the organic matter. Finally, thegenesis of the high-porosity and high-permeability reservoirsin deep-buried conditions (with the depth more than 3500 m)have been investigated thoroughly.     

Main controlling factors for hydrocarbon reservoir formation and petroleum distribution in Cratonic Area of Tarim Basin

The Cratonic Area of the Tarim Basin is lo-cated in the central part of the basin, developing primarilywith Cambrian marine source rocks and secondly Middle toUpper Ordovician marine and Carboniferous-Permiantransitional facies source rocks. The source rocks werematured in the changeable period and space, formingmultiple hydrocarbon generating centers during the periods.The Cratonic Area experienced multiple tectonic orogenies,forming several palaeouplifts. The matching conditionbetween effective hydrocarbon generating centers and thepalaeouplifts in various periods is the main control factor forthe formation and distribution of hydrocarbon reservoirs.The palaeouplifts have experienced multiple hydrocar-bon-filling phases, several periods of modifications and evenbreakdown. The palaeouplifts and the adjacent slopesaround the effective hydrocarbon generating center composethe most favorable places for hydrocarbon accumulation.The hydrocarbon phase is related with the evolution of thehydrocarbon generating center. In the Tarim Basin'sCratonic Area, reservoirs were mostly formed during lateHercynian. The originally formed hydrocarbon reservoirswhich are adjacent to source kitchens and in the goodpreservation condition are the most favorable prospectingtargets. Hydrocarbon is richly accumulated under theregional caprock, surrounding the faulted trends, and overand below the unconformity surfaces. Reservoirs in theCarboniferous sandstone, Ordovician karstic weatheredcrust and carbonate rock inside the buried hill compose themain intervals for hydrocarbon accumulation. Carboni-ferous and Silurian sandstone pinchout reservoirs andcarbonate lithologic reservoirs with rich fractures and poresare the main targets for further prospecting.     

The distribution of the oil derived from Cambrian source rocks in Lunnan area,the Tarim Basin,China

There are great differences in biomarks between Cambrian oil and Middle-Upper Ordovician oil. In this stuty, the authors analyzed 40 oils found in Lunnan area by GC-MS and calculated the content of Cambrian oil in the 40 oils according to the steroid indexes of typical oil mixture and match experiment. The results show that it is a general phenomenon in Ordovician reservoir that the oil derived from Cambrian source rock mixed with the oil derived from Middle-Upper Ordovician source rock in Lunnan area, the mixture degree of the two oils is lower in Carboniferous reservoir than in Ordovician reservoir, and the oils kept in Triassic reservoir have single source, Middle-Upper Ordovician source rock. The mixture oils mainly composed of Cambrian oil (>50%) distributed in Sangtamu fault zone, and the oils found in Lunnan fault zone are Middle-Upper Ordovician oil. This distribution of oils in Lunnan area is owing to that Lunnan fault zone is located in anticline axis part, Lunnan fault zone underwent serious erosion, and the oils from Cambrian source rock accumulated in Lunnan fault zone were degraded completely during Caledonian-Hercynian movement. But the Cambrian oil accumulated in Sangtamu fault zone was not degraded completely and some of them were left for the location of Sangtamu fault zone is lower than Lunnan fault zone. Later, the oil derived from Middle-Upper Ordovician source rock mixed with the remained Cambrian oil, and the mixture oil formed in Sangtamu fault zone.     

The distribution of the oil derived from Cambrian source rocks in Lunnan area, the Tarim Basin, China

There are great differences in biomarks between Cambrian oil and Middle-Upper Ordovician oil. In this stuty, the authors analyzed 40 oils found in Lunnan area by GC-MS and calculated the content of Cambrian oil in the 40 oils according to the steroid indexes of typical oil mixture and match experiment. The results show that it is a general phenomenon in Ordovician reservoir that the oil derived from Cambrian source rock mixed with the oil derived from Middle-Upper Ordovician source rock in Lunnan area, the mixture degree of the two oils is lower in Carboniferous reservoir than in Ordovician reservoir, and the oils kept in Triassic reservoir have single source, Middle-Upper Ordoviclan source rock. The mixture oils mainly composed of Cambrian oil （〉50%） distributed in Sangtamu fault zone, and the oils found in Lunnan fault zone are Middle-Upper Ordovician oil. This distribution of oils in Lunnan area is owing to that Lunnan fault zone is located in anticline axis part, Lunnan fault zone underwent serious erosion, and the oils from Cambrian source rock accumulated in Lunnan fault zone were degraded completely during Caledonian-Hercynian movement. But the Cambrian oil accumulated in Sangtamu fault zone was not degraded completely and some of them were left for the location of Sangtamu fault zone is lower than Lunnan fault zone. Later, the oil derived from Middle-Upper Ordovician source rock mixed with the remained Cambrian oil, and the mixture oil formed in Sangtamu fault zone.     

鄂尔多斯塔巴庙地区上古气藏特征及成藏机理

根据塔巴庙地区上古生界砂体分布特征,区域性裂缝的纵向分布特征,烃源岩、储层、盖层组合特征,纵向上各层的地层压力分布、天然气成分特征等,对盒2～3段、山1～2段、太2段气藏特征及成藏机理进行了分析.认为在油气成藏中区域性裂缝起了关键的通道作用.下伏太原组、山西组烃源岩生成的天然气向上运移,造成了盒2～3段气藏的压力系数高和天然气轻烃(CH4)含量高的特征.在此基础上提出了天然气成藏概念模式.指出山1～2段、太2段气藏属于经过再次运移"破坏"后的"残余气藏",盒2～3段气藏属于裂缝形成后下伏天然气再次运移聚集形成的"次生气藏".     

MCI分析法在确定油气成藏期次中的应用

介绍了流体包裹体分子成分 (MCI)分析技术及其特点 ,以塔里木盆地英南 2气藏为例 ,利用 MCI技术及其研究方法进行油气成藏期次的研究。对塔里木盆地英南 2现今气藏储层中的烃类 (凝析油与储层沥青 )以及气藏志留系与侏罗系储层成岩矿物中的含油包裹体分子进行了地球化学成分分析 ,对比研究含油包裹体分子地球化学成分和现今气藏中的烃类的分子地球化学成分。研究表明油包裹体分子成分与原油和储层沥青分子成分相似 ,反映它们来源相同 ,是同一期烃类充注的产物 ,英南 2气藏油气成藏期次为一期     

塔里木盆地大中型油气田形成及分布规律

目的 探讨塔里木盆地油气藏形成及分布规律,为油气田勘探部署提供依据。方法 运用石油地质综合研究方法,探讨了区域构造背景,有效烃源岩分布及其成熟度、储盖组合、后期构造变动等对塔里木盆地大中型油气田形成及分布的控制作用。结果 塔里木盆地油气分布十分复杂,油气藏形成及分布受多重因素控制;早期形成、长期继承发育的大型稳定古隆起及其斜坡以及前陆逆冲带第2,3排构造分别是大中型油气田形成的最有利地区;古隆起控油、斜坡富集以及隆起高部位油气易发生调整、斜坡部位有利于保存,是克拉通区油气藏形成和分布的重要特点;已发现的油气藏具有多期成藏、晚期调整的特点,早期形成的原生油气藏后期特别是晚喜山期普遍受到了调整改造,以克拉通区海相油气藏最为突出;保存条件对塔里木盆地油气藏形成与分布具有重要控制作用,特别是优质区域盖层的存在,是大中型油气田形成和保存的关键。结论 继承性古隆起与隐伏前陆逆冲带是塔里木克拉通区与前陆区寻找大中型油气田的最有利地区。     

塔里木盆地白垩系层序地层学

通过地震剖面、测、钻井、野外地质露头以及岩心等资料的综合分析,白垩系可识别出8个三级层序边界,这些层序边界均为Ⅰ型层序边界。根据8个层序边界白垩系可划分出7个三级层序,分别为KSQ1~KSQ7层序。这些层序均可识别出低位体系域、湖侵体系域,由于基准面下降期间地层的剥蚀作用使高位体系域多发育不全。顺托果勒和阿瓦提地区大部分剖面缺失KSQ6和KSQ7层序。在研究区南部、东部和北部等盆地边缘区域白垩系下部地层呈现明显的下超和上超,导致缺失KSQ1或KSQ2层序。在盆地内部各层序均有分布。白垩系层序的发育特征明显受到构造运动、气候、沉积期古地貌和湖盆性质的影响。     

Silurian to Devonian foreland basin in the south edge of Tarim Basin

Based on the theory of plate tectonics, combin-ing with the isotopic dating of ophiolite, igneous and volcan-ics, geochemical test, rare earth element analyze and seismicinterpretation, this paper studies the pre-Carboniferous tec-tonics and sedimentary formation of the south edge of theTarim Basin and proves that there exists the Kunlun Oceanunder tensional tectonics during the Sinian and Cambrian inthe south edge of the Tarim Plate. After that, due to the colli-sion orogenesis, there formed the peripheral foreland basinin the south edge of Tarim. The Upper Silurian and Devo-nian molasses sedimentary system superposed on the Sinianand Middle Silurian passive margin flysch sedimentary sys-tem and formed the bivariate structure of the foreland basin.And at the same time, based on the field geology and seismicinterpretation, we have identified that the formation of theSilurian and Devonian have the character of half depositwhich shows thick in the south area and thin in the north,and the pre-Carboniferous thrust compression tectonics re-mained in the foreland thrust belt, which further demon-strates that there existed the Silurian and Devonian periph-eral foreland basin on the south edge of the Tarim Basin.