The coupling of dynamics and permeability in the hydrocarbon accumulation period controls the oil-bearing potential of low permeability reservoirs:a case study of the low permeability turbidite reservoirs in the middle part of the third member of Shahejie

The relationships between permeability and dynamics in hydrocarbon accumulation determine oil- bearing potential （the potential oil charge） of low perme- ability reservoirs. The evolution of porosity and permeability of low permeability turbidite reservoirs of the middle part of the third member of the Shahejie Formation in the Dongying Sag has been investigated by detailed core descriptions, thin section analyses, fluid inclusion analyses, carbon and oxygen isotope analyses, mercury injection, porosity and permeability testing, and basin modeling. The cutoff values for the permeability of the reservoirs in the accumulation period were calculated after detailing the accumulation dynamics and reservoir pore structures, then the distribution pattern of the oil-bearing potential of reservoirs controlled by the matching relationship between dynamics and permeability during the accumulation period were summarized. On the basis of the observed diagenetic features and with regard to the paragenetic sequences, the reservoirs can be subdivided into four types of diagenetic facies. The reservoirs experienced two periods of hydro- carbon accumulation. In the early accumulation period, the reservoirs except for diagenetic facies A had middle to high permeability ranging from 10 × 10-3 gm2 to 4207 × 10-3 lain2. In the later accumulation period, the reservoirs except for diagenetic facies C had low permeability ranging from 0.015 × 10-3 gm2 to 62× 10-3 -3m2. In the early accumulation period, the fluid pressure increased by the hydrocarbon generation was 1.4-11.3 MPa with an average value of 5.1 MPa, and a surplus pressure of 1.8-12.6 MPa with an average value of 6.3 MPa. In the later accumulation period, the fluid pressure increased by the hydrocarbon generation process was 0.7-12.7 MPa with an average value of 5.36 MPa and a surplus pressure of 1.3-16.2 MPa with an average value of 6.5 MPa. Even though different types of reservoirs exist, all can form hydrocarbon accumulations in the early accumulation per- iod. Such types of reservoirs can form hydrocarbon accumulation with high accumulation dynamics; however, reservoirs with diagenetic facies A and diagenetic facies B do not develop accumulation conditions with low accumu- lation dynamics in the late accumulation period for very low permeability. At more than 3000 m burial depth, a larger proportion of turbidite reservoirs are oil charged due to the proximity to the source rock, Also at these depths, lenticular sand bodies can accumulate hydrocarbons. At shallower depths, only the reservoirs with oil-source fault development can accumulate hydrocarbons. For flat surfaces, hydrocarbons have always been accumulated in the reservoirs around the oil-source faults and areas near the center of subsags with high accumulation dynamics.

Characteristics of Fluid Inclusions and Determination of Hydrocarbon Accumulation Period of Caofeidian 18-1/2Buried Hill Reservoirs in Bozhong Depression,Bohai Bay Basin

The study area Caofeidian 18-1/2 structure is located in the Shadongnan structural belt at the southeast subduction end of the Shaleitian salient in the western Bohai Sea. The characteristics of reservoirs and fluid inclusions from 13 core samples near the buried hills in the study area are studied,and regional geology and conditions for reservoir formation are analyzed to reveal the characteristics and the processes of reservoir formation. Phase I oil and gas inclusions are mainly developed,and the abundance of oil and gas inclusions in this period is high( GOI is about 15%). The homogenization temperature of the hydrocarbon-containing brine inclusions accompanying them is mainly 90-120 ℃ . The simulation results of burial history and thermal history show that the main charging period of oil and gas is the present Himalayan tectonic movement period since 8 Ma,and mainly through unconformities,faults,and drainage systems,they are migrated and accumulated into fault anticline traps of Dongying Formation mudstone( E_d).

Key oil accumulation periods of ultra-deep fault-controlled oil reservoir in northern Tarim Basin, NW China

A giant fault-controlled oilfield has been found in the ultra-deep(greater than 6000 m) Ordovician carbonate strata in the northern Tarim Basin. It is of great significance for hydrocarbon accumulation study and oil exploitation to determine the key oil accumulation periods. Based on detailed petrographic analysis, fluid inclusion association(FIA) in calcite samples filling in fractures from 12 wells were analyzed, and key accumulation periods of the strike-slip fault-controlled oilfield was studied by combining oil generation periods of the source rocks, formation periods of the fault and traps, and the fluid inclusion data.(1) There are multiple types of FIA, among them, two types of oil inclusions, the type with yellow fluorescence from the depression area and the type with yellow-green fluorescence from the uplift area with different maturities indicate two oil charging stages.(2) The homogenization temperature of the brine inclusions in FIA is mostly affected by temperature rises, and the minimum temperature of brine inclusions symbiotic with oil inclusions is closer to the reservoir temperature during its forming period.(3) FIA with yellow fluorescence all have homogenization temperatures below 50 ℃, while the FIA with yellow-green fluorescence have homogenization temperatures of 70–90 ℃ tested, suggesting two oil accumulation stages in Middle-Late Caledonian and Late Hercynian.(4) The Middle-Late Ordovician is the key formation period of the strike-slip fault, fracture-cave reservoir and trap there.(5) The oil generation peak of the main source rock of the Lower Cambrian is in the Late Ordovician, and the oil accumulation stage is mainly the Late Ordovician in the depression area, but is mainly the Early Permian in the uplift area. The key oil accumulation period of the strike-slip fault-controlled reservoirs is the Late Caledonian, the depression area has preserved the primary oil reservoirs formed in the Caledonian, while the uplift area has secondary oil reservoirs adjusted from the depression area during the Late Hercynian. Oil reservoir preservation conditions are the key factor for oil enrichment in the strike-slip fault zone of northern Tarim, and the Aman transition zone in the depression is richer in oil and gas and has greater potential for exploration and development.

Enrichment Mechanism and Prospects of Deep Oil and Gas

With the deepening of oil and gas exploration,the importance of depth is increasingly highlighted.The risk of preservation of storage space in deep reservoirs is greater than that in shallow and medium layers.Deep layers mean older strata,more complex structural evolution and more complex hydrocarbon accumulation processes,and even adjustment and transformation of oil and gas reservoirs.This paper systematically investigates the current status and research progress of deep oil and gas exploration around the world and looks forward to the future research focus of deep oil and gas.In the deep,especially the ultra-deep layers,carbonate reservoirs play a more important role than clastic rocks.Karst,fault-karst and dolomite reservoirs are the main types of deep and ultra-deep reservoirs.The common feature of most deep large and medium-sized oil and gas reservoirs is that they formed in the early with shallow depth.Fault activity and evolution of trap highs are the main ways to cause physical adjustment of oil and gas reservoirs.Crude oil cracking and thermochemical sulfate reduction(TSR)are the main chemical modification effects in the reservoir.Large-scale high-quality dolomite reservoirs is the main direction of deep oil and gas exploration.Accurate identification of oil and gas charging,adjustment and reformation processes is the key to understanding deep oil and gas distribution.High-precision detection technology and high-precision dating technology are an important guarantee for deep oil and gas research.

GPS time-series and its response to M_S=8.1 Kunlunshan earthquake

In this paper, observation data in 25 GPS reference stations of China have been analyzed by calculating GPS position coordinate time-series with GIPSY. Result shows there is an obvious trend variation in such time-series. The trend variations of time series along the longitude and latitude coordinate reflect the motion of each position in the global-plate, in which the trend variation in the vertical direction reveals some large-scale construction information or reflects the local movement around the positions. The analysis also shows that such time-series have a variation cycle of nearly 1.02 a, but the reason still remains to be further studied. At the end of this paper, response of the time-series to MS=8.1 Kunlunshan earthquake was analyzed, and the seismogenic process of MS=8.1 Kunlunshan earthquake, according to the time proceeding and the feature of anomaly, was divided into 3 phases-changes in blocks with forces, strain accumulation, quick accumulation and slow release of energy. At the initial stage of seismogenic process of MS=8.1 earthquake and at the imminent earthquake, coseismic process as well as during the post earthquake recovery, anomaly in vertical direction is always in a majority. The anomalous movement in vertical direction at the initial stage resulted in a blocking between faults, while at the middle stage of seismogenic process, the differential movement between blocks are in a majority, which is the major reason causing energy accumulating at the blocking stage of faults.

Assessing reservoir connectivity with pressure/rate surveillance data

Estimating reservoir connectivity is critical for assessing infill-drilling prospects and initiating fluid injection in enhanced oil recovery operations. Several methods have appeared in the literature over decades to meet these business needs, given that all tools, including seismic imaging, have limitations. Besides imaging, geochemical fingerprinting constitutes a powerful tool to gauge the compartmentalization question. However, real-time pressure/rate surveillance data allows assessing interwell connectivity vis-à-vis the overall drainage volume.This study presents a simplified approach to using the reciprocal-productivity index (RPI) vs. the total-material-balance time (tTMB) plot. This tool exhibits the same slope for those wells in the same compartment beyond the start of the boundary-dominated flow (BDF) period. The wells showing different slopes imply that they are in separate drainage volumes. The early-time transient period remains muted to minimize confusion on this Cartesian plot. We validated the proposed tool's efficacy with 2D and 3D models with increased degrees of reservoir complexity, followed by the verification phase with four field examples. The use of other analytical tools complemented our findings.

杭锦旗地区二叠系储层油气成藏期次及流体势特征

杭锦旗地区是鄂尔多斯盆地北部重要的含油气区,油气成藏期次及流体势研究有利于探究油气充注的世代以及流体势的分布特征,并进一步判定成藏期油气的运移方向。本文以什股壕区块和十里加汗区块5口井的二叠系下石盒子组盒一段储层砂岩为研究对象,基于流体包裹体分析厘定油气成藏期次,并结合流体势理论计算研究区关键成藏期的流体势并揭示油气的运移方向。研究结果显示:什股壕区块盒一段储层油气的成藏时间为132~102 Ma;十里加汗区块盒一段储层油气的成藏时间为132~101 Ma。杭锦旗北部的什股壕盒一段储层油气的流体势为18 128~22 872 J/kg;杭锦旗南部的十里加汗区块盒一段储层油气的流体势为22 975~27 153 J/kg。本文认为研究区二叠系盒一段储层油气成藏时间在早白垩世,十里加汗区块整体的流体势要高于什股壕区块,油气具备由南部向北部运移的趋势。

Fluid inclusion evidence for petroleum accumulation in northern Qaidam Basin

Based on the results of fluid inclusion study(microscopic characteristics,homogenization temperatures and grains with oil inclusions),the pool-forming time of the Nanbaxian and Mabei 1 oilfields in northern Qaidam Basin was discussed in this paper.Fluid inclusions in northern Qaidam Basin are relatively abundant,including aqueous inclusions and hydrocarbon inclusions.These inclusions are small(5-10 μm),and mainly distributed in quartz fissures,overgrowths and cementations.The abundances of grains with oil inclusions(GOI) are commonly low.The GOI values of most samples are between 2.0%-10.5%,and those of about 40 percent of total samples exceed 5%.The homogenization temperatures of fluid inclusions in different samples are markedly dissimilar,indicating that these inclusions were formed in different periods.According to the measured homogenization temperatures of fluid inclusions and in combination with burial history and thermal evolution history,the Nanbaxian and Mabei 1 oilfields are deduced,which have experienced two hydrocarbon charging periods,with the former of N1-N21 and N22-N23,and the latter of N1 and N1 end-N2,respectively.

塔里木盆地顺北地区东西部海相油气成藏差异

塔里木盆地顺北地区东西部海相油气成藏差异明显,自东向西油气主要表现为由富到贫,勘探风险明显加大。通过对满加尔坳陷西缘的顺北东部和阿瓦提坳陷东缘的顺北西部油气成藏的分析,对比海相油气成藏条件的差异性,明确二者成藏差异的原因。以顺北1、4、8号断裂带东北段为代表的顺北东部近年来不断获得高产,油气多期成藏,油气富集特征明显;但阿瓦提坳陷东缘的顺北西部钻探结果不理想,表现为以早期成藏为主,且油气成藏规模不大。顺北东西部存在烃源层分布条件、生烃演化史、烃源资源规模、成藏期及成藏模式等差异,主要表现为东部多源多期成藏和西部单源单期成藏。顺北东部紧邻满加尔生烃坳陷区,长期处于四源供烃条件,属于多源多期成藏;而顺北西部要么是本地的寒武系玉尔吐斯组烃源岩早期成藏,要么是阿瓦提坳陷奥陶系烃源岩晚期成藏,属于单源单期成藏。阿瓦提东缘英买力油田及近年来英西1井奥陶系的突破表明,阿瓦提海相油气以海西晚期成藏为主,喜马拉雅期成藏为辅。阿瓦提坳陷周缘烃源岩发育相对较差,海相油气藏分布局限,油气资源规模也有限。

北部湾盆地海中凹陷成藏关键要素及成藏模式

海中凹陷经几十年勘探虽点上有发现,但因成藏关键要素不明勘探陷入了停滞。该文为寻求其勘探规模突破方向,在成凹、成烃研究的基础上,深化成藏关键要素研究,建立了海中凹陷成藏模式,指出了规模突破的勘探有利区带。研究认为:海中凹陷油气成藏关键要素是近生烃中心、圈源时空匹配佳、油气输导条件好、优质储层发育。北部陡坡带是各成藏关键要素匹配最佳区,是海中最有利的勘探区带。研究成果为寻求海中凹陷规模油气突破指明了方向。

底水油藏水平井变密度射孔设计及应用

利用水平井开发底水油藏过程中,底水快速突破、油井提早见水是影响水平井开发效益的关键因素。针对采用射孔完井的水平井,通过在水平段不同部位采用不同的射孔密度,实现均衡各部位见水时间、延长无水采油期的目标。建立了考虑射孔密度、井眼轨迹、井筒流动压降、渗透率各向异性等影响因素的水平井分段产量和见水时间计算方法,基于此计算方法对东海海域XH井进行了变密度射孔方案设计。实际应用表明,建立的计算方法预测见水时间的准确性较高,变密度射孔能够提升无水采油期产油量,在一定程度上节约完井费用,提升水平井综合开发效益。

山地气象因子对烤烟生育期及青枯病的影响

为探明主要气象因子对山地烤烟生长发育进程的限制与影响,优化烤烟生育期,做好烟草青枯病的预测预报和合理防控,通过连续2年的烤烟主栽品种‘云烟87’、‘K326’、‘HN2146’的不同移栽期大田试验,探索生育期变化规律,研究日照及温度与烤烟生育期、青枯病的关系。结果表明:(1)烤烟团棵期和旺长期随移栽期延迟而显著减少,其原因是温度随移栽期推迟而显著升高,使生育进程加快;累积日照时数的减少有随生育时间缩短而变化的趋势。(2)温度、日照对烤烟的主要效应时期在团棵期与旺长期,主要影响在现蕾以前,其中温度是影响湘西烤烟生育期的关键因子。(3)平均日照时数与平均气温是影响生育期的主要因子,其中关键主要因子是平均气温。(4)青枯病重点防治期为烟叶移栽63 d之前且均温未达21.82℃之前,重点预防期为均温未达18.77℃之前且烟叶移栽42 d之前。温度对于指导青枯病的预测预报和防治具有重要意义。

气候变化对临沂冬小麦主要生育期的影响及适播期研究

为了研究气候变化对临沂市冬小麦生产的影响,确定合理播期和适宜的田间管理措施。利用2001—2021年临沂市气象资料和农业农村部门苗情调查数据,同时参考1962—2000年临沂市历史天气数据,采用线性趋势性预测对小麦生育期温度、积温以及主要生育期日期和持续时间进行变化规律分析。结果表明:临沂市冬小麦适播期和各生育期均对气候变化发生了不同的响应,适播期为10月8—19日,最佳播期为10月11—14日;分蘖期出现反复降温频率变高,促进了小麦冬前抗寒锻炼,利于形成壮苗;冬前积温增多和越冬期延迟,间接推迟了适播期,为上一季玉米晚收创造了条件;返青大幅提前和返青后积温显著增加,大幅缩短了小麦停止生长和越冬时间,增加了冬小麦实际生长时间,有利于冬小麦苗情转化;拔节期大幅提前,使小麦更容易遭受晚霜冻(冷)害和倒春寒;4月和5月温度下降为小麦抽穗、扬花、灌浆提供了更好的气候条件,特别是5月温度下降既减少了干热风的发生机率又利于小麦后期灌浆。确定了临沂市冬小麦适播期,为小麦全生育期田间管理和高产栽培提供了依据。

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.

聚煤期植物作用下的煤系旋回沉积

煤系特征的还原色和突发性、阶段性间断—充填相间的非渐变旋回沉积,明显不同于其他沉积地层。为探究其成因,引用“将今论古”原理,一方面,调查现代植物的生存潜力,植物对地表碎屑的稳固作用,以及植物涵养水源、调节气候等宏观环境效应;另一方面,通过古生物、地层、煤系、煤层、煤质等研究成果,分析地质历史时期植物的发生、发展、繁盛、衰落的演替历程,以及各聚煤期的形成演化。运用比较沉积学方法将二者分阶段不同功能进行类比,经过一系列证据链推演,推导出聚煤期是植物演替更新后发展到鼎盛阶段的产物,当时的植物异常繁盛,具有强劲的拓殖能力和群体效应。各聚煤期植物规模化发展,已经从脆弱的遭受河流、海浪、潮汐等流体的冲刷、改造的被动阶段,回归到主动限制河流的侧蚀、迁移、汇聚,以及压制海浪、潮流的高度,是由个体生存发展为群体效应的过程,是从现代脆弱的植物生态反演到聚煤期强劲的控盆植被系统的依律回溯过程,是植物功能潜力的充分展现,是质的飞跃。聚煤期植被主导下,陆源碎屑库的累积和崩溃,控制盆地碎屑萎缩与扩张、煤系突发间断性沉积,致使煤层向盆缘分岔变薄以致尖灭、煤层中断续沉积角砾岩、同生多阶性带状砂体、陆表海多重障壁体系、约代尔旋回等特殊沉积。聚煤期植物作用的研究,填补了煤地质学空白,能够对煤地质勘查与研究中出现的一些异常现象给予合理的解释。

东营凹陷岩性油藏成藏期次与成藏过程

东营凹陷岩性油藏分布规律复杂,成藏时期存在差异,从而影响了对岩性油藏形成和分布规律的深入认识。综合运用东营凹陷的构造演化史及岩性圈闭形成史、烃源岩主要生排烃史和流体包裹体均一温度等资料,对东营凹陷岩性油藏的成藏期次、成藏过程、成藏阶段和不同期次岩性油藏的平面分布规律进行了系统研究。研究结果表明:东营凹陷岩性油藏的成藏期次主要有两期,即古近纪东营组沉积末期和新近纪馆陶组-明化镇组沉积时期,且以馆陶组-明化镇组沉积时期为主要成藏期;不同成藏期次的岩性油藏具有一定的分布规律:第一期分布于生油洼陷,为岩性油藏,其包裹体均一温度分布较宽,油气充注持续时间长,具有两期充注的特点;第二期分布于断裂带和斜坡带,为构造-岩性油藏和岩性油藏,其包裹体均一温度分布较窄,油气成藏时间较晚,主要为馆陶组-明化镇组沉积时期充注;东营凹陷岩性油藏的形成具有明显的阶段性,可以划分为成藏准备、成藏和保存3个阶段。

轮南古隆起控油理论及其潜山准层状油气藏勘探

针对塔里木盆地轮南古隆起奥陶系潜山油气勘探的难点,应用新的学科理论和技术方法,系统研究轮南古隆起对奥陶系潜山油气聚集成藏的控制作用,建立轮南古隆起控油、潜山整体含油局部富集的理论体系。古隆起是油气长期运移的指向区,古隆起控制岩溶缝洞型储集体发育、输导体系的形成和潜山油气的多期成藏。提出轮南古隆起奥陶系风化壳岩溶型准层状油气藏新模式,认为受风化壳岩溶储集体的控制,油气富集在潜山表层150m深度范围内。同时,形成了该类油气藏勘探开发配套技术,如高精度三维地震储集体预测及酸压储集体改造技术、非均质碳酸盐岩油气藏井点优选及不规则井网开发技术等。

英买力地区中生界—新生界油气藏石油包裹体特征及成藏期次

明确油气的成藏期次及成藏演化历史是当前英买力地区中生界—新生界油气藏勘探亟待解决的关键问题。利用石油包裹体岩相学、微束荧光光谱和显微测温技术,对英买力地区中生界—新生界石油包裹体特征和油气成藏期次开展了详细研究。结果表明：样品中主要观察到发蓝色、蓝白色、亮黄色、弱黄色荧光的石油包裹体;荧光光谱的主峰波长主要集中在470-490nm和510-540nm,分别指示近蓝白色和近黄色2种荧光的石油包裹体组合。其中,近黄色石油包裹体的红绿商Q在0.48-0.65,色度指数CIE-X和CIE-Y值在0.345-0.360和0.358-0.375,对应盐水包裹体的均一温度主峰值在80-90℃;近蓝白色石油包裹体的红绿商Q在0.20-0.51,色度指数CIE-X和CIE-Y值在0.302-0.333和0.325-0.352,对应盐水包裹体的均一温度主峰值在120-130℃。结合埋藏史、热演化史模拟结果,明确了英买力地区中生界—新生界油气藏具有2期成藏过程：第1期在8-5 Ma,以形成常规油藏为主,成熟度相对较低,石油包裹体发近黄色荧光;第2期在3 Ma以来,以形成凝析油气藏为主,成熟度较高,石油包裹体发近蓝白色荧光。

柳沟庄—窟窿山油藏储集层裂缝类型及特征

根据岩心描述、薄片观察、X CT扫描以及钻井、测井等资料 ,研究了酒西盆地青西坳陷柳沟庄—窟窿山油藏裂缝性储集层的类型及特征 ,分析了控制裂缝发育的地质因素及裂缝对油气的控制作用 ,认为储集层裂缝有 3种基本类型 ,即构造裂缝、构造溶蚀缝和饼状破裂 ,主要受构造应力场及构造位置等因素的控制。根据裂缝形态、充填特征及其相互关系 ,裂缝的形成主要有 3个期次 ,其中喜马拉雅运动晚期形成的第三期裂缝对油气运移和聚集最有效。研究结果表明 ,裂缝是柳沟庄—窟窿山油藏主要的储集空间和控制油气富集的因素。图 6表 2参

中国最老古油藏——中元古界下马岭组沥青砂岩古油藏

从冀北坳陷下马岭组(Qnx)沥青砂岩与火成岩侵入体的共存关系入手,利用有机岩石学、同位素年代学方法准确厘定Qnx沥青砂岩油藏的成藏时限。根据野外调查、实验室薄片镜下观察及浅钻结果,在前人已发现Qnx底砂岩油苗/沥青点的基础上,新发现Qnx油苗/沥青点31处(其中肉眼可见黑色沥青点21处),基本查明了Qnx沥青砂岩油藏平面分布规律并命名了4个古油藏:平泉双洞、凌源龙潭沟、宽城芦家庄和宽城塌山古油藏。根据沥青含量,采用体积法估算Qnx沥青砂岩古油藏的规模在7×108～10×108 t。大量样品的有机岩石学分析发现,Qnx沥青砂岩中发育两类具有不同反射率特征的固体沥青,在固体沥青中发现了类天然焦结构,首次以直接证据证实Qnx底砂岩沥青遭受过严重的热蚀变效应。Qnx辉长辉绿岩斜锆石SHRIMP U-Pb测年结果为1 327 Ma±2 Ma,限定Qnx沥青砂岩油藏的成藏时间为1 400～1 327 Ma,确定Qnx沥青砂岩油藏是迄今为止中国最古老的油藏。