Reservoir controlling differences between consequent faults and antithetic faults in slope area outside of source: A case study of the south-central Wenan slope of Jizhong Depression, Bohai Bay Basin, East China

The control effects of different occurrence faults on oil and gas accumulation and distribution in the outer slope area of oil and gas reservoirs were studied taking the south-central Wen’an slope of the Jizhong depression in the Bohai Bay Basin as an example.Based on 3D seismic data and the distribution of oil and water,the controlling differences between consequent fault and antithetic fault were analyzed and compared from the formation and evolution rule of faults and the formation mechanism of fault traps,including development positions of the consequent fault traps and antithetic fault traps,oil and gas distribution horizon adjusted by fault and formation period of fault traps.The differences between consequent faults and antithetic faults in controlling reservoirs have three main aspects:(1)Consequent fault traps and antithetic fault traps are in different positions,the consequent fault traps are at the segmented growing point in the hanging wall of"hard-linkage"faults,while the antithetic fault traps are developed in the position with the largest throw in the footwall because of tilting action;(2)The two kinds of faults result in different oil and gas distribution vertically,oil and gas adjusted by consequent faults is distributed in a single layer or multi-layers,while oil and gas adjusted by antithetic faults occur in single layers;(3)The two kinds of fault traps are formed in different periods,the consequent fault traps are formed at the time when the related faults enter the stage of"hard-linkage",while the antithetic fault traps are formed at the beginning of the fault active period.

Differential Hydrocarbon Enrichment and its Main Controlling Factors in Depressions of the Bohai Bay Basin Differential Hydrocarbon Enrichment and its Main Controlling Factors in Depressions of the Bohai Bay Basin

Significant differential hydrocarbon enrichment occurs in depressions in a petroliferous basin.There are multiple depressions in the Bohai Bay Basin, and each depression as a relatively independent unit of hydrocarbon generation, migration and accumulation, contains significantly different hydrocarbon generation conditions and enrichment degree. On the basis of previous documents and a large number of statistical data, this work comparatively analyzed the differential hydrocarbon enrichment and its major controlling factors in depressions of the Bohai Bay Basin. The results show that depressions in the Bohai Bay Basin have various hydrocarbon enrichment degrees, and can be categorized into four types, namely enormously oil-rich, oil-rich, oily and oil-poor depressions. In general, the enormously oil-rich and oil-rich depressions are distributed in the eastern part of the basin along the Tan-Lu and Lan-Liao faults, whereas depressions in the western part of the basin are poor in hydrocarbons. Moreover, the vertical distribution of hydrocarbons is also highly heterogeneous, with Pre-Paleogene strata rich in hydrocarbons in the northern and western depressions, Paleogene strata rich in hydrocarbons in the entire basin, and Neogene strata rich in hydrocarbons in the off-shore areas of the Bohai Bay Basin. From early depressions in onshore areas to the late depressions in offshore areas of the Bohai Bay Basin, the source rocks and source-reservoir-cap rock assemblages gradually become younger and shallower, and the hydrocarbon resource abundance gradually increases. Hydrocarbon supplying condition is the key factor constraining the hydrocarbon enrichment for different depressions,while the main source-reservoir-cap rock assemblage, sufficient hydrocarbons and the transportation capacity of faults control the vertical distribution of hydrocarbons. The main factors controlling hydrocarbon enrichment are different for different layers. The hydrocarbon supplying condition of source rocks is the key controlling factor, whereas the source-reservoir configuration, the main sourcereservoir-cap rock assemblages, and the fault transportation are the main factors of hydrocarbon enrichment in the Paleogene, Paleogene and Neogene, respectively.

Tectonic development of subtle faults and exploration in mature areas in Bohai Sea,East China

Based on the theory of structural analysis,the characteristics and structural patterns of subtle faults are studied using 3D seismic data of the Bohai Sea to analyze the development process and origin of the subtle faults.A method of identifying subtle faults is proposed,forming a complete system for analyzing origins of subtle faults in the Bohai Sea.The complex strike-slip fault patterns under the strike-slip and extension stress background,diverse formation rocks,and strong neotectonic movement are the reasons for the development of subtle faults.According to the tectonic origin and development location,the subtle faults in Bohai Sea can be divided into 12 types in the three categories of strike slip dominant,extension dominant and strike slip and extension composite,and the different types of subtle faults occur in different regions of the Bohai Sea.Unreasonable variation of sedimentary stratum thickness,inherited distortion or even abrupt change of stratum occurrence,zonation of plane fault combination and the variation of oil-water system in the same structure with no-lithologic change are the important signs for identifying subtle faults in Bohai Sea.The subtle faults greatly enlarge the size of the structural trap groups,and areas with dense subtle faults are often active area of hydrocarbon migration and accumulation and favorable exploration zones,which have strong control on the hydrocarbon accumulation.The identification method for subtle faults has guided the exploration in the mature areas of Bohai Sea effectively,with a number of large and medium oil and gas fields discovered,such as Bozhong 29-6 and Penglai 20-2.

Strike-Slip Faults and Their Control on Differential Hydrocarbon Enrichment in Carbonate Karst Reservoirs: A Case Study of Yingshan Formation on Northern Slope of Tazhong Uplift, Tarim Basin

Objective Oil and gas are abundant in the Ordovician Yingshan Formation carbonate karst reservoirs on the northern slope of Tazhong uplift in the Tarim Basin, and have extremely complicated oil-gas-water distribution, however. The difference in burial depth of the reservoirs between east and west sides is up to 1000 m. Water-bearing formations exist between oil- and gas-bearing formations vertically and water-producing wells are drilled between oil- and gas-producing wells. Macroscopically, oil and gas occur at low positions, while water occurs at high positiona on the northern slope of Tazhong uplift. The mechanism of differential hydrocarbon enrichment in heterogeneous reservoirs is by far not clarified, which has affected the efficient exploration and development of oil and gas fields in this area.

Seismic hazard assessment of Tehran,Iran with emphasis on near-fault rupture directivity effects

Many destructive earthquakes happened in Tehran, Iran in the last centuries. The existence of active faults like the North Tehran is the main cause of seismicity in this city. According to past investigations, it is estimated that in the scenario of activation of the North Tehran fault, many structures in Tehran will collapse. Therefore, it is necessary to incorporate the near field rupture directivity effects of this fault into the seismic hazard assessment of important sites in Tehran. In this study, using calculations coded in MATLAB, Probabilistic Seismic Hazard Analysis （PSHA） is conducted for an important site in Tehran. Following that, deaggregation technique is performed on PSHA and the contribution of seis- mic scenarios to hazard is obtained in the range of distance and magnitude. After identifying the North Tehran fault as the most hazardous source affecting the site in 10000-year return period, rupture directivity effects of this fault is incorporated into the seismic hazard assessment using Somerville et al. （1997） model with broadband approach and Shahi and Baker （2011） model with narrowband approach. The results show that the narrowband approach caused a 27% increase in the peak of response spectrum in 10000-year return period compared with the conventional PSHA. Therefore, it is necessary to incorporate the near fault rupture directivity effects into the higher levels of seismic hazard assessment attributed to important sites.

Hydrocarbon migration and accumulation along the fault intersection zone-a case study on the reef-flat systems of the No.1 slope break zone in the Tazhong area, Tarim Basin

Understanding hydrocarbon migration and accumulation mechanisms is one of the key scientif ic problems that should be solved for effective hydrocarbon exploration in the superimposed basins developed in northwest China. The northwest striking No.1 slope break zone, which is a representative of superimposed basins in the Tarim Basin, can be divided into five parts due to the intersection of the northeast strike-slip faults. Controlled by the tectonic framework, the types and properties of reservoirs and the hydrocarbon compositions can also be divided into five parts from east to west. Anomalies of all the parameters were found on the fault intersection zone and weakened up-dip along the structural ridge away from it. Thus, it can be inferred that the intersection zone is the hydrocarbon charging position. This new conclusion differs greatly from the traditional viewpoint, which believes that the hydrocarbon migrates and accumulates along the whole plane of the No.1 slope break zone. The viewpoint is further supported by the evidence from the theory of main pathway systems, obvious improvement of the reservoir quality （2-3 orders of magnitude at the intersection zone） and the formation mechanisms of the fault intersection zone. Differential hydrocarbon migration and entrapment exists in and around the strike- slip faults. This is controlled by the internal structure of faults. It is concluded that the more complicated the fault structure is, the more significant the effects will be. If there is a deformation band, it will hinder the cross fault migration due to the common feature of two to four orders of magnitude reduction in permeability. Otherwise, hydrocarbons tend to accumulate in the up-dip structure under the control of buoyancy. Further research on the internal fault structure should be emphasized.

Adaptive fault-tolerant control based on boundary estimation for space robot under joint actuator faults and uncertain parameters

Since the joint actuator of the space robot executes the control instructions frequently in the harsh space environment,it is prone to the partial loss of control effectiveness(PLCE)fault.An adaptive fault-tolerant control algorithm is designed for a space robot system with the uncertain parameters and the PLCE actuator faults.The mathematical model of the system is established based on the Lagrange method,and the PLCE actuator fault is described as an effectiveness factor.The lower bound of the effectiveness factors and the upper bound of the uncertain parameters are estimated by an adaptive strategy,and the estimated value is fed back to the control algorithm.Compared with the traditional fault-tolerant algorithms,the proposed algorithm does not need to predetermine the lower bound of the effectiveness factor,hence it is more in line with the actual engineering application.It is proved that the algorithm can guarantee the stability of the closed-loop system based on the Lyapunov function method.The numerical simulation results show that the proposed algorithm can not only compensate for the uncertain parameters,but also can tolerate the PLCE actuator faults effectively,which verifies the effectiveness and superiority of the control scheme.

Control of Facies and Potential on Jurassic Hydrocarbon Accumulation and Prediction of Favorable Targets in the Hinterland Region of the Junggar Basin

Exploration practices show that the Jurassic System in the hinterland region of the Junggar Basin has a low degree of exploration but huge potential, however the oil/gas accumulation rule is very complicated, and it is difficult to predict hydrocarbon-bearing properties. The research indicates that the oil and gas is controlled by structure facies belt and sedimentary system distribution macroscopically, and hydrocarbon-bearing properties of sand bodies are controlled by lithofacies and petrophysical facies microscopically. Controlled by ancient and current tectonic frameworks, most of the discovered oil and gas are distributed in the delta front sedimentary system of a palaeo-tectonic belt and an ancient slope belt. Subaqueous branch channels and estuary dams mainly with medium and fine sandstone are the main reservoirs and oil production layers, and sand bodies of high porosity and high permeability have good hydrocarbon-bearing properties; the facies controlling effect shows a reservoir controlling geologic model of relatively high porosity and permeability. The hydrocarbon distribution is also controlled by relatively low potential energy at the high points of local structure macroscopically, while most of the successful wells are distributed at the high points of local structure, and the hydrocarbon-bearing property is good at the place of relatively low potential energy; the hydrocarbon distribution is in close connection with faults, and the reservoirs near the fault in the region of relatively low pressure have good oil and gas shows; the distribution of lithologic reservoirs at the depression slope is controlled by the distribution of sand bodies at positions of relatively high porosity and permeability. The formation of the reservoir of the Jurassic in the Junggar Basin shows characteristics of favorable facies and low-potential coupling control, and among the currenffy discovered reservoirs and industrial hydrocarbon production wells, more than 90% are developed within the scope of facies- potential index FPI〉0.5, while the FPI and oil saturation of the discovered reservoir and unascertained traps have relatively good linear correlation. By establishing the relation model between hydrocarbon- bearing properties of traps and FPI, totally 43 favorable targets are predicted in four main target series of strata and mainly distributed in the Badaowan Formation and the Sangonghe Formation, and the most favorable targets include the north and east of the Shinan Sag, the middle and south of the Mobei Uplift, Cai-35 well area of the Cainan Oilfield, and North-74 well area of the Zhangbei fault-fold zone.

塔里木盆地顺北地区顺北84X井超千米含油气重大发现及其意义

塔里木盆地顺北中部北东向走滑断裂带长期处于油气运聚富集的优势区,顺北8号走滑断裂带实钻揭示沿断裂带发育断控缝洞型油气藏,顺北84X井纵向上沿断裂带含油气高度高达1088 m,揭示断控缝洞型油气藏含油气高度大、不受现今构造高低控制。为查明断控缝洞型油气藏含油气高度的主控因素,立足顺北中部奥陶系碳酸盐岩油气藏的成藏地质条件和钻探成果,开展顺北84X井的储层、圈闭及成藏特征等石油地质条件分析,为深化断控缝洞型油气藏认识和向深层评价拓展提供支撑。研究表明:①走滑构造破碎是致密碳酸盐岩成储的关键,其储层发育深度不受碳酸盐岩地层埋深的控制,在近9000 m的埋深条件下仍发育断控缝洞型储集体;②上覆巨厚泥岩盖层顶封、两侧致密灰岩侧封、走滑断裂平面分段和纵向分层变形是形成断控缝洞型圈闭的关键;③油-源对比分析表明油气来自寒武系玉尔吐斯组烃源岩,证实了前期顺北中、东部“寒武多期供烃、构造破裂成储、原地垂向输导、晚期成藏为主、走滑断裂控富”的成藏模式的合理性。顺北84X井的发现揭示塔里木盆地超深层致密碳酸盐岩发育受走滑断裂控制,储层纵向深度大,油气充注足,超深层勘探潜力巨大。

断裂封闭性研究现状及发展趋势

断裂控油气作用主要表现在其对油气运移、聚集过程及分布规律的影响,其实质是断裂封闭性问题。断裂封闭性往往是受多种因素控制的,不同地区不同层系在不同地质时期的断裂封闭机制与封闭性主控因素差异较大。目前,断裂封闭性、封闭机理与评价方法还没有形成完整的研究体系,其评价的精度也有待提高。依据全面系统地调研断裂封闭性方面近年来的研究热点,归纳总结了断裂封闭机理,分析了断裂封闭主控因素,梳理了断裂封闭性评价方法,讨论了断裂封闭性研究中面临的实际问题,并提出了未来研究发展趋势。目前,断裂的封闭机理可以分为垂向和侧向封闭机理,前者包括断裂面封闭机理和断裂带排替压力差封闭机理,后者包括砂泥对接封闭机理、泥岩涂抹形成的侧向封闭机理和断裂带高排替压力封闭机理。断裂发育特征、断裂两盘岩性、应力场环境以及压实、胶结、溶蚀等成岩作用是影响断裂封闭性的主要因素,不同因素对断裂封闭性的作用方式不同,断裂在不同位置、不同时期的封闭性有着明显的差别。断裂封闭性评价研究方法可归结为以下4类:(1)传统地质学方法,包括定性分析和半定量分析;(2)数学地质方法,涵盖逻辑信息法、非线性映射分析法、模糊综合评判法、灰色关联分析法等;(3)构造应力场数值模拟及断裂封闭性相关参数计算法;(4)地球化学方法。碳酸盐岩地层断裂启闭机制与封闭性评价、应力和流体及其耦合作用对断裂封闭性的影响机制、多因素的断裂封闭性综合定量评价、断裂封闭性的时空演化及通源能力评估等是未来断裂封闭性研究的发展方向。

塔里木盆地超深层走滑断控油气藏研究进展与趋势

在塔里木盆地开辟了超深层走滑断控油气藏勘探开发领域,但断控油气藏极为复杂,难以效益开发,亟需加强油气藏基础地质研究。走滑断控油气藏具有非均质性强、储集层与流体分布复杂、油气产量变化大及采收率低的共性,不同地区走滑断控油气藏的断裂、储集层、成藏与流体存在较大的差异,面临一系列勘探开发难题。建立了差异成因的走滑断裂破碎带及其控储模型,揭示了沿走滑断裂带“相-断-溶”三元复合控储、连片差异规模发育的成储机制;构建了“源-断-储-盖”四元耦合成藏、“小藏大田”的走滑断控油藏模型,揭示了超深层走滑断控油藏的形成与保存机理。突破了克拉通盆地弱走滑断裂难以形成走滑断控大规模储集层与大油气田的理论认识局限,明确了克拉通盆地走滑断裂系统大规模发育的成因机制、走滑断裂破碎带差异成储成藏机理与油气富集规律。

塔里木盆地麦盖提斜坡罗探1井奥陶系断控岩溶新类型油气藏勘探突破及意义

塔里木盆地麦盖提斜坡罗探1井在奥陶系碳酸盐岩获得勘探新突破,是麦盖提斜坡奥陶系断控岩溶新类型油气藏的首次勘探突破,标志着斜坡区发现一个重要的战略接替领域。结合区域钻井、测井、地震等资料,开展罗探1等井分析化验资料的综合分析,对麦盖提斜坡奥陶系碳酸盐岩的成藏条件进行再认识。麦盖提斜坡奥陶系碳酸盐岩断控岩溶储层的形成主要与走滑断裂活动相关,是麦盖提斜坡三类主要成储模式之一;麦盖提斜坡目前已发现油气均来自寒武系玉尔吐斯组烃源岩,基底古构造控制了下寒武统的沉积和烃源岩的分布;斜坡区存在加里东期、海西期—印支期和喜马拉雅期3期油气充注成藏过程,烃源岩、古构造演化及通源断裂控制油气复式聚集成藏,断裂活动期次、断穿层系决定了油气富集层系与油气藏性质。麦盖提斜坡奥陶系走滑断裂十分发育,延伸距离累计可达1000km以上,控制了断控岩溶储层和油气藏的分布,平面上具有明显的分区特征,资源规模大、可部署性强,展示出巨大的勘探潜力,是塔西南地区规模油气勘探发现和战略接替的重要现实领域。

青藏高原1990年以来的M_W≥6.5强震事件及活动构造体系控震效应

深入认识青藏高原陆陆碰撞-挤出构造体系作用下的强震活动特点及未来强震活动趋势,对于区域防震减灾具有重要科学意义。统计分析青藏高原及邻区1900年以来的M≥6.0强震活动发现,青藏高原自1950年西藏墨脱—察隅8.6级大地震以来正处于新一轮相对缓慢的地震能释放期,但1990年以来的强震发生率和地震释放能显示出逐步增高趋势,并可能预示下一轮地震能快速释放期的临近。活动构造体系控震分析表明,青藏高原陆陆碰撞-挤出构造体系中的“多层次挤出-旋转活动构造体系”构成了1990年以来新一轮M_W≥6.5强震活动的主要控震构造,尤其是其中的巴颜喀拉挤出构造单元的强震活动最为显著,指示其目前正处于构造活跃状态,而且这一状态可能仍将持续。综合研究认为,在区域强震活动趋势分析中,充分认识活动构造体系控震效应,将有助于更好地分析判断区域未来强震时空迁移过程及最可能出现的构造部位。考虑到当前强震活动过程中,青藏高原“多层次挤出-旋转活动构造体系”的未来强震活动趋势仍会持续,需要重点关注挤出块体边界上3条大型左旋走滑断裂带,阿尔金—祁连—海原断裂系、东昆仑断裂带和鲜水河—小江断裂带的未来强震危险性,其次是断块内部断裂。

苏北盆地盐城凹陷盐③断裂带构造演化及其控圈作用

盐(3)断裂带位于苏北盆地盐城凹陷中,断裂带及周边区域发生过多期伸展-走滑复合的构造演化,控制圈闭的时空有效性。为阐明这些构造圈闭对油气差异聚集的影响,需先明确盐(3)断裂带在各时期的演化过程,并研究构造变形对圈闭的控制作用。本文基于盐城凹陷高精度三维地震资料,揭示主要断层和周边褶皱的几何学形态和运动学特征;结合断距回剥法定量恢复断层分段生长过程,进一步利用古构造图分析各期次的褶皱变形规律,解析各期次构造演化性质以及控圈作用。结果表明,盐(3)断裂带经历3个主要演化阶段:(1)泰州—阜宁期(K_(2)t—E_(1)f_(4))NW向伸展控制盐(3)正断层西段孤立生长、东段发生软连接,此时主干断裂的控陷作用不明显,圈闭不发育;(2)阜宁期末发生短期快速的压扭作用,造成盐(3)断层再活动,同时形成一系列的NW向共轭剪切断层,此时沿着盐(3)断裂带形成了一系列的圈闭;(3)戴南—盐城期(E_(2)d-Ny)发生SN向东强西弱的伸展,控制盐(3)断裂带东部再活动,并对圈闭进行调整。整体而言,盐城凹陷的构造活动强度具有“早强晚弱,东强西弱”的差异性,随着研究区构造应力场的不断变化,圈闭的构造幅度、面积逐渐缩小,构造高点也逐渐往SW向转移。

塔里木盆地塔北地区多期断裂差异匹配控制下超深岩溶缝洞储层成藏特征

超深断控岩溶缝洞型油藏是塔北地区重要油藏类型,探讨多期构造活动与深层油气成藏匹配关系对区域油气勘探具有重要意义。基于哈拉哈塘油田、金跃油田和富满油田连片地震资料,以野外地质露头断裂特征为指导,采用多种地震精细解释手段,分期、分级、分段刻画研究区断裂。基于研究区中寒武统玉尔吐斯烃源岩认识,结合加里东期、海西期和喜马拉雅期3期成藏的特点,将研究区走滑为主的控藏断裂划分为加里东早期、加里东中晚期、海西晚期和喜马拉雅期。进一步分析多期断裂继承性关系、通源特点和调整作用等,结合多种类型岩溶缝洞型储层的开发现状,探讨了研究区走滑断裂控制下的岩溶缝洞型储层成藏差异性。结果表明:(1)研究区油气藏关键因素是油源断裂通源性与后期断裂的调整作用,将加里东早期正断裂系统定义为源内断裂,加里东晚期形成的走滑断裂系统定义为源外断裂,源内断裂利于寒武系烃源岩排烃,源外断裂进一步沟通烃源岩实现油气运移成藏,基于这种认识建立4种通源模式;(2)结合研究区存在加里东晚期、海西期和喜马拉雅期3个主力生烃期的认识,海西晚期部分北西向走滑断裂继承性发育至二叠系,对加里东期油藏有一定的破坏和调整作用,喜马拉雅期部分北东向走滑断裂系统继承性发育至新近系,对早期油气藏起破坏和调整作用,建立了3种调整样式;(3)根据断裂匹配关系,建立6种走滑断裂控藏等级,并将研究区加里东中晚期走滑断裂带逐一划分,叠合开采现状图显示差异控藏断裂与油气生产情况匹配度较高;(4)选择发育断裂与岩溶共同控储的研究区,建立多期断裂系统与多种类型岩溶缝洞油气藏的匹配关系,并将认识成功应用于研究区井位勘探中,取得较好效果,为受控于走滑断层的岩溶缝洞油气藏勘探开发提供一定指导意义。

特提斯洋与古亚洲洋协同演化控制下的塔里木台盆区油气富集效应

显生宙特提斯洋和古亚洲洋2大构造域演化历史对塔里木盆地产生了巨大的影响,其效应包括原型盆地的形成与沉积充填过程及油气成藏与调整改造等。原特提斯洋和古亚洲洋分别经历了扩张、俯冲-消减和关闭-碰撞造山过程。特提斯域经历了原特提斯、古特提斯和新特提斯3个阶段,具有此消彼长的关系。古亚洲洋在新元古代—古生代多陆-岛-洋的格架下经历了复杂的伸展—聚敛过程。受特提斯洋(昆仑-阿尔金分支洋)和古亚洲洋(南天山洋分支)协同演化控制,塔里木盆地经历了新元古代—早古生代和晚古生代—新生代2个从伸展—聚敛的巨型盆地旋回,与海平面升降和气候旋回匹配,形成了优质烃源岩、多类型规模性储层和盖层,构成了油气形成的优越物质基础。特提斯洋和古亚洲洋多圈层协同演化控制的油气富集效应体现在:①多类型盆地原型与后期构造改造决定了塔里木台盆区不同部位油气成藏与富集的差异性;②北部坳陷广泛分布的优质烃源岩,是塔北—顺托—塔中地区大型油气富集区形成的基础;③多期构造运动伴随的构造破裂与古岩溶作用造就了断控缝洞型和岩溶缝洞型2类各具特点且规模发育的储集体;④区内构造与地温场差异演化决定了油气聚集区内油气相态与次生改造的规律性变化。台盆区大型古隆起和不整合面、走滑断裂带、高能相带及其叠加区是油气有利目标区。

渤东凹陷新生代伸展-走滑叠合断裂时空差异演化模式及控藏效应

以三维地震精细解释为基础,通过构造剖面恢复,系统分析了渤东凹陷新生代伸展-走滑叠合断裂的时空差异演化特征及控藏作用。研究结果表明:(1)渤东凹陷新生代广泛发育以NNE向为主干、NE向为派生、NW向为叠加的伸展-走滑叠合断裂体系,可划分为强伸展-弱走滑断裂和强走滑-弱伸展断裂2类;整体具有深浅分层、南北分段的特征,纵向上,古近系主要发育强伸展-弱走滑断裂,断裂大而稀,新近系—第四系主要发育强走滑-弱伸展断裂,断裂小而密;平面上,同一断裂在不同段的构造组合样式存在差异。(2)研究区新生代伸展-走滑叠合断裂的演化主要表现为北部断裂活动强度“早强晚弱”,中部断裂继承性持续发育,南部断裂活动强度“早弱晚强”;演化模式分为初始断陷(孔店组—沙四段沉积期)、强烈断陷(沙三段—东营组沉积期)和走滑坳陷(馆陶组—平原组沉积期)3个阶段,初始断陷阶段,NNE—NE向强伸展与弱走滑叠合,NE向强伸展-弱走滑断裂为主控,NW向先存断裂活化,分割凹陷;强烈断陷阶段,NNE—NE向强伸展与弱走滑叠合,NNE向强伸展-弱走滑断裂变为主控,NW向断裂活动减弱或停止;走滑坳陷阶段,NNE向强走滑与弱伸展叠合,断裂不控制沉积,但对地层展布具有调整作用。(3)研究区伸展-走滑叠合断裂的发育演化与油气成藏密切相关,整体具有“早期伸展控源、晚期走滑控运、多期叠加控圈”的特征,东部斜坡带是油气运聚的有利区。

顺北1号走滑断裂带分段差异活动特征及其控藏效应

塔里木盆地塔中北坡众多大型走滑断裂带是近年油气勘探开发的重点,文中通过对顺北1号走滑断裂带三维地震资料精细解释,综合前人研究成果及油气勘探实践,探讨了顺北1号走滑断裂带的差异活动特征及其控藏效应。研究表明:1)顺北1号走滑断裂带主要发育于下古生界,为一条大型左行走滑断裂带,平面展布具有分层差异性,在下古生界为线性展布,在上古生界呈雁列式展布。2)顺北1号走滑断裂带分段差异活动特征明显,研究区内可划分出张扭、压扭和纯走滑等3类12段。3)顺北1号走滑断裂带经历了多期构造演化,其中,加里东中期Ⅰ幕、加里东中期Ⅲ幕、加里东晚期—海西早期为顺北1号走滑断裂带的关键活动时期,此后的深埋阶段构造相对稳定,断裂活动微弱。4)顺北1号走滑断裂带沟通了寒武系优质烃源岩与奥陶系有利储集体,断裂带的分段差异活动造成了不同断裂段的断溶体发育程度的差异及油藏规模的差异。实钻数据表明,张扭段和压扭段油气富集程度高,纯走滑段较低。此外,主断裂与分支断裂交叉处通常高产,推测分支断裂规模及活动强弱控制了其油气富集程度。

深层—超深层海相碳酸盐岩成储成藏机理与油气藏开发方法研究进展

基于钻井、地震、测井、测试以及实验分析等新资料,针对中西部叠合盆地深层—超深层海相碳酸盐岩层系成储、成藏和油气藏高效开发面临的关键科学问题开展持续攻关。研究表明:(1)断裂主导形成的储集体和古老层系白云岩储层是深层—超深层海相碳酸盐岩两类重要的储层;以断裂为主导形成的规模储集体,根据成因可进一步分为3种类型:断裂活动过程中构造破裂形成的缝洞储集体、致密碳酸盐岩受断裂和流体双重改造形成的储集体与早期丘滩等高能相带受断裂和流体改造形成的储层;优势丘滩相、早期白云石化和溶蚀、酸性流体环境、膏盐岩封盖和超压是优质白云岩储层形成和保持的关键。(2)中国中西部叠合盆地海相碳酸盐岩层系富有机质页岩主要发育于被动陆缘深水陆棚、碳酸盐缓坡等环境中,构造-热体制是控制深层—超深层油气藏赋存相态的重要因素,改造型动力场控制中西部叠合盆地深层—超深层海相碳酸盐岩油气成藏与分布。(3)普光等高含硫酸性气田开发过程中硫析出堵塞井筒,采用井筒溶硫剂配合连续油管解硫堵效果明显;基于沉积模拟的双重介质建模数模一体化技术可以精细刻画水侵前缘空间展布及变化,并据此提出气井全生命周期调、排、堵控水对策。(4)超深断控缝洞油气藏开发过程中,储层应力敏感,渗透率随压力下降而显著降低,产量递减较快;凝析气藏相态变化快,压降显著影响凝析油采出程度;据此提出“注水+注天然气”重力驱油藏开发方法和“高注低采”天然气驱凝析气藏开发方法;采用分层次约束、逐级地质建模和流-固-热耦合的复合介质数值模拟有效提高了油气藏开发生产动态模拟的预测精度。