Accumulation process and model for the Ordovician buried hill reservoir in the western Lunnan area, the Tarim Basin

The Ordovician buried hill reservoir in the western Lunnan area, a type of dissolved fracture and cavernous reservoir, is mainly composed of heavy oil. The oil is the mixture sourcing from the Middle-Lower Cambrian and Middle-Lower Ordovician, with three stages of pool forming process： （1） the destruction and parallel migration/accumulation during the late Caledonian to early Hercynian; （2） the oil and gas accumulation during the late Hercynian characterized by adjustment upward along faults and parallel migration/accumulation; （3） the formation of heavy oil during the latest Hercynian. The Ordovician buried hill reservoir is affected by the diffusion of light oil and gas but had no hydrocarbon charging during the late Yanshan period to Himalayan period, but in this period, formed the association of heavy oil and dissolved gas cracked from crude oil with dry coefficient of 0.91-0.96. The study on accumulation process of the Ordovician buried hill reservoir has important implications for the exploration potential of early oil and gas accumulation in the cratonic area of the Tarim Basin.     

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.     

鲁克沁地区稀油油藏成藏过程分析

鲁克沁构造带工业稀油油流的获得,打破了鲁克沁地区只有稠油的历史,开辟了新的勘探领域。油源对比表明,鲁克沁构造带东段鲁8和鲁10井的稀油来自台南凹陷石炭系烃源岩;玉东9井稀油来自台南凹陷下侏罗统的煤系源岩。结合流体包裹体均一温度特征和埋藏史,综合分析了稀油成藏期次,认为鲁8和鲁10井的成藏期为在古近纪末-新近纪早期;推测玉东9井成藏期在新近纪早中期。其成藏过程为:古近纪末-新近纪早期,台南凹陷石炭系烃源岩生成的稀油,通过晚燕山-喜山期构造运动形成的断裂向浅层运移,进入三叠系和侏罗系储层,形成稀油油藏;新近纪中新世,台南凹陷下侏罗统煤系烃源岩成熟排烃,生成的煤系油沿三叠系顶部不整合面和断裂向上倾方向的鲁克沁构造带东段进行运移,并进入三叠系砂岩形成稀油油藏。     

川西南井研地区嘉陵江组气藏成藏条件及演化过程

利用岩石薄片鉴定、常规测井、烷烃气碳同位素、流体包裹体等分析测试资料,开展了川西南井研地区嘉陵江组气藏成藏地质条件研究,结合区域埋藏-热演化史和构造演化史恢复,恢复了嘉陵江组天然气成藏演化过程。研究结果表明：井研地区嘉陵江组天然气成藏条件良好,嘉四段云坪相孔隙型白云岩储层发育,以龙潭组为主的二叠系烃源岩为气藏的形成提供了充足油气来源,中-小型烃源断裂为天然气成藏充注提供了有利通道,低缓斜坡背景下的构造圈闭为天然气富集成藏提供了有利场所,区内嘉陵江组天然气成藏表现出一期持续性干气充注特征,其成藏演化经历3个重要阶段：印支晚期-燕山中期二叠系烃源岩成熟生烃;燕山晚期高成熟干气开始充注成藏;喜马拉雅期-现今持续充注与调整成藏。     

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.     

塔北轮南地区油气成因与成藏探讨

通过对塔里木轮南地区不同层位、不同部位原油烃类化学组成的剖析 ,认为该区原油至少可分为两种不同的成因类型 ,可能存在多成藏期次 .三叠系、侏罗系原油化学组成与分布均一 ,其与轮南中西部断垒、桑塔木断垒西部奥陶系原油性质极为接近 ,以低分子量正构烷烃占优势 ,重排补身烷与重排甾烷、三环萜烷及Ts不甚发育 ,C2 3 三环萜烷为主峰 ,相对低值C2 7/C2 9甾烷等为特征 (第I类 ) ,奥陶系原油还具有中性氮化合物含量高的特征 ;以两断垒带东部石炭系、奥陶系为代表的原油以高值饱芳比、正构烷烃主峰碳后移、高含量C15 重排倍半萜与重排甾烷、低含量中性氮化合物、C2 0 三环萜烷为主峰、相对高值C2 7/C2 9甾烷、甾烷 /藿烷、Ts/ (Ts+Tm)、三环萜 /五环萜值等为特征 (第Ⅱ类 ) .轮南地区原油类型不同由主系油源不同所致 .烃类与非烃类运移指标反映奥陶系、石炭系原油具有自西而东的运移趋势 ;三叠系原油具有不太明显的由北而南的运移趋势 .烃类指标反映三叠系、侏罗系与同类型奥陶系原油间的运移分馏效应不太明显 ,其可能来自相同的烃源岩但成烃与成藏期不同     

满加尔及周围地区主要储层中的油气运聚条件

运用流体势理论分析了塔里木盆地满加尔凹陷及周围地区主要储层中的油气运聚条件,指出封闭或半封闭的低势区因具多方汇油条件最有利于油气聚集;做出了奥陶系、石炭系及三叠系储集层在不同地质历史时期油势的低势区分布图。据此,结合油源、储层分布等特点,分析了油气运移和聚集条件,并指出了有利聚集区。     

塔里木盆地北部于奇地区东河砂岩油气成藏与勘探前景

东河砂岩是塔里木盆地勘探热点之一.以成盆、成烃和成藏理论为指导,应用储层预测、流体包裹体分析等技术和方法,综合研究了于奇地区东河砂岩油源条件、储集条件、保存与储盖组合、圈闭条件、油气成藏期次与成藏过程.结果表明,区内油源主要来自阿克库勒凸起南部寒武系—下奥陶统烃源岩,油源较充足,具有一定的资源潜力;储集层类型以孔隙型为主,为中等容积、中等渗透性能储层,有利的储层分布区位于于奇东部地区的东南一带;储盖组合为下储上盖式,盖层封盖能力好;圈闭类型主要为非构造圈闭,至少发生了一次油气注入成藏期即喜山早期.提出今后勘探应突破传统的构造圈闭的束缚,坚持以寻找多类型圈闭特别是地层圈闭为原则.     

塔中隆起奥陶系储层与油源断裂复合控藏模式

基于现有油、气、水勘探成果及储层、断裂资料,利用常规测井、地震、地化及数理统计等多种方法,对塔中隆起奥陶系油气分布及成藏特征开展研究。结果表明,奥陶系储层以礁滩沉积为基础,发育大量溶蚀孔洞及裂缝,控制了油气相对高孔渗富集。储层孔隙度和渗透率越大,与围岩之间的毛细管力差就越大,含油气概率越大、含油饱和度越高,存在油气富集的临界毛细管力（2.5 MPa）。奥陶系油源断裂交汇处为油气优先充注点,控制了油气的近源富集。距离充注点越远,油气充注强度越小,油气产能越低,油气地球化学性质规律性变化,存在油气富集的临界距离（距充注点20 km）。在储层和油源断裂联合控制下,塔中隆起奥陶系油气富集呈"近充注点-相对高孔"的地质模式,于充注点近端的高孔渗储层内优先成藏。     

鄂尔多斯盆地西缘古峰庄-红井子地区长9油藏特征及油气富集规律

鄂尔多斯盆地西缘古峰庄-红井子地区地跨西缘逆冲带和天环坳陷两大构造。通过地震资料解释、地层对比和构造对比等识别发现该区存在两种类型的断层,早期的逆断层位于研究区的西部,呈南北向和北西-南东向展布;晚期的正断层分布于区的中部,呈北西-南东向展布。天环坳陷的形成与长7烃源岩分布及生烃高峰期在时空上匹配,促进了油气侧向运移并成藏。古峰庄-红井子地区长9油藏发育3种类型油藏:早期鼻状隆起带成藏、西缘逆冲带逆断层成藏和晚期天环坳陷内正断层成藏。前两种类型同期形成于早白垩世末期,形成时间较早,为原始油藏;后者形成喜山期,时间较晚,属改造型油藏。晚期断层对油藏进行重新调整,造成断层下盘油藏被破坏。建立了古峰庄-红井子地区长9油藏的成藏模式,总结其成藏规律为断层是油气运移的通道、异常压力和底水浮力驱动是油气运移的动力、连通宽广的砂体是油气运移的载体、泥岩和断层阻挡以及构造高点是油气运移的最终落脚点。     

辽河东部凹陷茨榆坨低位潜山油气成藏研究

根据潜山区域构造、断层活动期、油气生成期、成藏期的配置关系及断层封闭性特点 ,对辽河东部凹陷茨榆坨低位潜山进行了研究。研究结果表明 ,茨榆坨潜山为一典型的低位潜山构造带 ,其构造形态是一平行型背向传递带 ;储集层为太古界花岗岩 ,储集空间主要为构造裂缝及溶蚀孔隙 ,其发育程度受断层控制。采用原油族组成、类异戊二烯烃和萜烷等地化参数 ,对牛居长滩洼陷和茨榆坨地区的油气进行了油源对比 ,并利用生物标志化合物w(甾烷C2 9ααα2 0S) /w(2 0S +2 0R)和w(C2 9ββ) /w(ββ +αα)、正构烷烃主峰碳数、原油物性等指标 ,对油气运移过程中的运移效应进行了分析 ,确定潜山的油气来自牛居长滩洼陷。对油气运移通道条件与运移过程分析认为 ,茨东、茨西断层控制了油气在潜山内的运移和聚集 ,断层和不整合面是油气运移的良好通道 ,油气向茨榆坨潜山的运聚具有氧化型成藏模式。     

羌塘盆地昂达尔错古油藏油气来源及成藏模式

昂达尔错油砂带是羌塘盆地内规模最大的古油藏,明确其油气来源和成藏模式对指导该地区的油气资源勘探具有重要意义。以饱和烃色谱-质谱、单体烃碳同位素和流体包裹体分析为基础,对羌塘盆地昂达尔错古油藏油气来源、成藏期次及成藏模式进行了探讨。研究表明：昂达尔错古油藏油苗与下侏罗统曲色组烃源岩具有相似的生物标志化合物组合特征,体现出两者具有较强的亲缘性;昂达尔错古油藏油气充注期次可划分为晚侏罗世(151.6～158.7 Ma)、早白垩世(142.3～143.9 Ma)与中新世(12.5～16.6 Ma)三期,其中早白垩世为该古油藏的主充注期;古油藏油源为下侏罗统曲色组页岩,储集层为中侏罗统布曲组砂屑灰岩和白云岩,盖层为布曲组泥晶灰岩,构成正常的“下生上储”式成藏组合。     

轮南地区奥陶系储层特征及其影响因素

奥陶系碳酸盐岩储层是轮南地区主要产层之一,油气藏类型为古潜山油藏.自早奥陶世(O1p)至晚奥陶世(O3S),奥陶系经历了半局限台地相→开阔海台地相→台地边缘相→台缘斜坡相→混积浅水陆棚相的沉积演化,沉积了多种岩石类型,储层岩石主要为亮晶颗粒灰岩.压实作用、胶结作用使得奥陶系储层基质孔隙度较低、孔喉结构差,为差或非储层.由于奥陶系后多次构造运动,使奥陶系裂缝、岩溶作用发育,形成有大量溶蚀孔、洞、缝的有效储层.岩溶、裂缝发育区,为储层的有利分布区.轮南地区西部、中部为风化壳岩溶发育区,东部为深部岩溶发育区.     

Relationship between the later strong gas-charging and the improvement of the reservoir capacity in deep Ordovician carbonate reservoir in Tazhong area, Tarim Basin

Some large-scale oil-gas fields have recently been discovered in marine carbonate in China, especially the significant discoveries in deep reservoir that reveals a favorable exploration prospect. Tazhong area is the first-order tectonic unit in Tarim Basin, where there are nearly trillion cubic meters of natural gas resources in the Ordovician limestone reef flat complex in Lianglitage Formation. The reservoir is shelf edge reef flat complex, characterized by ultra-low porosity, low permeability and strong heterogeneous, with a current burial depth of 4500―6500 m. Studies find that the formation and distribution of deep reservoir of the Lianglitage Formation were controlled not only by the early high-energy sedimentary facies and corrosion, but the fracture network formed by the strong gas-charging process since the Himalayan epoch, which played an important role in optimizing and improving reservoir properties. This paper discusses the relationship between the strong later gas-charging and the improvement of the reservoir capacity in deep Ordovician carbonate reservoir, and also builts the corresponding mechanisms and modes, which is favorable for the prediction and evaluation of the advantageous exploration targets.     

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.     

塔里木盆地轮古西地区奥陶系古岩溶储层特征

为了进一步挖掘轮古西区古溶岩探区潜力 ,利用常规薄片、扫描电镜、图像分析、同位素等测试手段 ,对该区古岩溶储层特征进行了研究 .结果表明 :轮古西地区下奥陶统碳酸盐岩基质具有低孔低渗特点 ,多属非有效储层 ;古岩溶储层的有效储集空间主要是溶蚀孔、洞和裂缝 .洞穴规模变化大 ,主要分布于距古风化壳面深度为 0～ 2 0 0m范围内 ,中、大型洞穴多分布于古岩溶剖面中下部 .各岩溶相带中 ,表层岩溶带的洞穴最发育 ,其次为水平潜流带和季节变动带 ,垂直渗流带洞穴较不发育 .裂缝类型以构造缝为主 ,以发育立缝和低角度缝为主 ,高角度缝和水平缝发育次之 .纵向上 ,季节变动带和水平潜流带的裂缝最为发育 ,表层岩溶带和垂直渗流带的裂缝发育程度较低 .储层类型主要包括孔洞型、裂缝型、裂缝—孔洞型及洞穴型 4种 .其中 ,洞穴型、裂缝—孔洞型储层的产能好 ,是该区的重要储层类型     

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.     

塔里木盆地塔中地区志留系油气成藏模式

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裂缝网络模型的建立及其在任丘潜山油藏中的应用

裂缝网络参数是潜山裂缝油藏开发和剩余油挖潜不可缺少的重要参数.针对潜山裂缝油藏依据油田区资料无法建立裂缝网络模型这一特点,提出了通过建立相似露头区裂缝网络模型来实现这一目的的思路和方法,并应用到任丘潜山油藏中.结果与开发动态资料吻合得非常好,说明利用相似露头是建立潜山裂缝油藏裂缝网络模型的有效手段.     

塔里木盆地乌什凹陷—温宿凸起油气运聚过程模拟实验研究

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