哈拉哈塘地区东河砂岩段-角砾岩段沉积模式探讨

塔北的哈拉哈塘地区是东河砂岩油气勘探的重点地区,该地区目前已发现并探明了东河塘和哈得4两个东河砂岩油气藏,油气储量丰富,显示出良好的勘探前景。基于哈拉哈塘地区东河砂岩段和角砾岩段的岩性段穿时沉积现象异常明显,根据层序地层学原理和方法对哈拉哈塘地区东河砂岩段一角砾岩段进行了重新分层和对比,在层序分层等时地层框架的基础上重新进行了东河砂岩段一角砾岩段沉积模式研究,弄清该地区地层分布规律、演化规律、砂体分布及储层分布规律对该地区的油气勘探具有重要指导意义。     

Deep water clastic reservoirs in the Gulf of Mexico: A depositional model

A conceptional model has been developed relating the deposition of thick sand sequences in deep water regions of the Gulf of Mexico to episodes of high volume Mississippi River discharge. In accordance with the model, coarse sand units are deposited by turbidity currents as submarine fans on the lower slope and in the deep basin during periods of rapid glacial melting. These sands are predicted to be more extensive and cleaner than those deposited under glacial and interglacial conditions. Evidence supporting this interpretation is provided from projections of the high rates of river discharge and sediment transportation at the end of the Wisconsin glacial epoch.     

Stratigraphic division and depositional processes for the Mesozoic basin in Northern South China Sea

This paper divided the age of Mesozoic strata in the Northern South China Sea into epochs by the stratigraphic correlation between land and sea areas. A Mesozoic stratigraphic profile from South China to the northern continental slope of the South China Sea was constructed by ground and seismic surveys. The depositional process was illustrated by the chronostratigraphic framework of the Mesozoic basin, and the oil and gas exploration prospect was discussed. Results indicate that the depositional process from the initial transgression in the Late Triassic to the Mesozoic maximum flooding event that occurred in the Early Jurassic period formed a continuous transgression when the depositional environment varied from littoral to semi-closed gulf and shelf. After this maximum flooding event, a continuous marine regressive process developed, including seawater withdrawal from the South China epicontinental region at the end of the Early Jurassic period, seawater withdrawal to the outer shelf of the Northern South China Sea at the end of the Early Cretaceous period, and seawater withdrawal to the slope trough at the end of the Cretaceous period. Research achievement not only connects major Mesozoic geological events but also specifies the time nodes of such events. Thus, an investigation of this event is significant to the Mesozoic tectonic evolution study of the South China Sea and Paleo-Pacific Ocean.     

An approach to estimate gas hydrate saturation from 3-D heterogeneous resistivity model: A study from Krishna-Godavari basin,Eastern Indian offshore

A method is proposed to estimate gas hydrate saturation from three dimensional (3-D) heterogeneous model of resistivity simulated using resistivity log. Pure gas hydrates are highly resistive compared to the host sediments, and their presence in the pore space of sediments increase the resistivity of the formation. The anomalous increase of resistivity is used as a proxy for the delineation of gas hydrates using the resistivity log. A 3-D heterogeneous resistivity model has been constructed from one dimensional resistivity log in Krishna Godavari (KG) basin, eastern Indian offshore. The simulated model contains all small scale variation in resistivity of the reservoir and maintains all properties associated with covariance, like root mean square fluctuation, characteristic scales and fractal dimension of the observed log. We have estimated volumetric hydrate saturation using the three dimensional simulated model. The porosity used for estimating hydrate saturation is calculated from the simulated density field generated using the observed density log. Estimated average gas hydrate saturation is about 9.84% of the pore volume over a 1000 m × 1000 m x 131 m cubic meters area.     

Palynofacies classification of submarine fan depositional environments: Outcrop examples from the Marnoso-Arenacea Formation,Italy

Basin floor fans contain some of the largest deep-water hydrocarbon accumulations discovered, however they also demonstrate extremely complex stratigraphic architecture, understanding of which is crucial for maximum recovery. Here we develop a new method, based upon palynofacies analysis, for the distinction of the different depositional environments that are commonly associated with basin floor fans. Previous studies and our sedimentological analysis allow good confidence in the discrimination of the different depositional environments of the outcropping Marnoso-Arenacea Formation fan system. One hundred and thirty-five samples were collected from mudstones in conjunction with sedimentary logging of 871 m of outcrops. Six lithofacies associations are described and interpreted to represent lobe axis, lobe fringe, fan fringe, contained interlobe, basin plain, and starved high depositional sub-environments. Palynofacies of these elements demonstrate turbidites to be rich in terrestrial organic matter, with sixteen categories of matter recognised. The abundances and proportions of particles varies between sub-environments, with lobe axis deposits containing the largest, densest particles, with a transition to ever smaller and lighter particles moving toward the basin plain. Fuzzy C-means statistical analysis was used to explore this trend. Distribution of organic matter is not random, but is dominated by hydrodynamic sorting and sequential fall-out of particles as turbidity currents passed across the basin. This allows a palynofacies classification scheme to be constructed to assist the identification of depositional environments of submarine fans, which may be combined with subsurface data to assist reservoir characterisation.     

A sub-salt structural model of the Kelasu structure in the Kuqa foreland basin,northwest China

The Kuqa foreland basin, adjacent to the South Tianshan Mountains, is a major hydrocarbon accumulation basin in Western China. The Kelasu structural belt is the focus for hydrocarbon exploration in the basin due to the presence of ramp-related anticline traps and a thick salt seal. The model of the Kelasu sub-salt structure is still contentious because of the structural complexity and poor seismic imaging below the salt layer. The area–depth–strain (ADS) method is applied to the southern part of the Kelasu Fault, a regional fault that cuts basement rocks. The ADS results are consistent with the seismic data, which indicate that both thin-skinned thrusting and basement-involved deformation occur within the Kelasu structure, with the Kelasu Fault acting as the boundary between the two regions of contrasting deformation. The ADS results also suggest that the depth of the lower detachment of the thin-skinned thrust belt is 9.5–10 km, which may correspond to the base of the Triassic. The Kelasu structure has undergone approximately 8.15–10.76 km of horizontal shortening in the east and 16.34 km in the west of the structure.     

Morphosedimentary features and recent depositional architectural model of the Cantabrian continental margin

Multibeam bathymetry, high (sleeve airguns) and very high resolution (parametric system-TOPAS-) seismic records were used to define the morphosedimentary features and investigate the depositional architecture of the Cantabrian continental margin. The outer shelf (down to 180–245 m water depth) displays an intensively eroded seafloor surface that truncates consolidated ancient folded and fractured deposits. Recent deposits are only locally present as lowstand shelf-margin deposits and a transparent drape with bedforms. The continental slope is affected by sedimentary processes that have combined to create the morphosedimentary features seen today. The upper (down to 2000 m water depth) and lower (down to 3700–4600 m water depth) slopes are mostly subject to different types of slope failures, such as slides, mass-transport deposits (a mix of slumping and mass-flows), and turbidity currents. The upper slope is also subject to the action of bottom currents (the Mediterranean Water — MW) that interact with the Le Danois Bank favouring the reworking of the sediment and the sculpting of a contourite system. The continental rise is a bypass region of debris flows and turbidity currents where a complex channel-lobe transition zone (CLTZ) of the Cap Ferret Fan develops.The recent architecture depositional model is complex and results from the remaining structural template and the great variability of interconnected sedimentary systems and processes. This margin can be considered as starved due to the great sediment evacuation over a relatively steep entire depositional profile. Sediment is eroded mostly from the Cantabrian and also the Pyrenees mountains (source) and transported by small stream/river mountains to the sea. It bypasses the continental shelf and when sediment arrives at the slope it is transported through a major submarine drainage system (large submarine valleys and mass-movement processes) down to the continental rise and adjacent Biscay Abyssal Plain (sink). Factors controlling this architecture are tectonism and sediment source/dispersal, which are closely interrelated, whereas sea-level changes and oceanography have played a minor role (on a long-term scale).     

Low energy, low latitude wave-dominated shallow marine depositional systems: examples from northern Borneo

The depositional environments of the wave-dominant successions in the middle to late Miocene Belait and Sandakan Formations in northwestern and northern Borneo, respectively, were determined based on grain size distributions, sedimentary structures and facies successions, as well as trace and microfossil assemblages. Generally, progradational shoreface successions in the Belait Formation were deposited in very low wave energy environments where longshore currents were too weak to generate trough cross-bedding. Shoreface sands are laterally continuous for several km and follow the basin contours, suggesting attached beaches similar to the modern Brunei coastline. In contrast, trough cross-bedding is common in the coarser Sandakan Formation and back-barrier mangrove swamp deposits cap the progradational succession as on the modern northern Dent Peninsula coastline, indicating barrier development and higher wave energy conditions than in the Belait Formation. The Borneo examples indicate that barrier systems that include significant tidal facies form under higher wave energy conditions than attached beaches with virtually no tidal facies. Also, Borneo’s low latitude climate promotes back-barrier mangrove which reduces tidal exchange and reduces tidal influence relative to comparable temperate climate systems. The results of the study indicate that depositional systems on low energy, wave-dominated coasts are highly variable, as are the sand bodies and facies associations they generate.     

辽西凸起南段沙河街组双向物源沉积模式及油气勘探意义

古近系储层发育程度一直是制约辽西凸起南段勘探突破的关键因素。运用钻井地质、磷灰石裂变径迹分析、三维地震等基础资料,针对辽西凸起南段沙河街组储层发育问题,开展精细古热史-构造演化分析、古地貌半定量刻画,对目标区沙河街组储层进行预测,结果表明：辽西凸起南段主要经历了新生代早期构造抬升、古近纪沙河街组沉积期构造沉降、东营组沉积期构造反转和新近纪构造定型4个演化时期;断裂体系可划分为长期活动型、早断早衰型、晚断晚衰型3种断裂类型;辽西凹陷具有“盆满砂溢”的先天供源条件,构造演化的分段性特征又造成辽西凸起南段形成了特殊的“链状岛湾”沉积地貌,既可以为围区提供物源,形成近源沉积体,又可以形成较大的可容纳空间,汇聚来自于辽西凹陷满溢的砂体,在辽西凸起上形成了双向供源沉积模式。以上认识推动了旅大4-3油田的油气勘探评价,且对凸起围区的油气勘探具有较好的借鉴意义。     

Objectives of fisheries management: case studies from the UK, France, Spain and Denmark

The main objectives of fisheries management are generally similar throughout the world. These are often stated in policy documents such as the Common Fisheries Policy and the Magnuson–Stevens Fishery Conservation and Management Act. However, at the local level often the key objectives of management are more detailed, characterised by both the overriding management structure and the status and type of fishery concerned. In this paper, we consider case study fisheries from the UK, France, Spain and Denmark to compare some of the various types of fisheries and fisheries management systems that exist in the European Union. From this, we define the key objectives for each management system.     

Present-day 3D structural model of the Po Valley basin,Northern Italy

A 3D structural model of the Po Valley basin (Northern Italy) was built by integrating the dataset available from the public domain (DEM, wells, isobath-maps, cross-sections, outcrop-trends).The model shows the complex foredeep-foreland architecture across the basin, from the Moho level to the topography while illustrating the top Basement, top Triassic, top Mesozoic and base-Pliocene surface-grid structures.The results, by model slicing and isopach-map reconstruction, suggest that the deep Moho architecture and the original tectonics of the ancient Adria-Po Valley passive continental margin are key factors in controlling the current structures type, orientation and distribution, at any of the shallowest levels across the basin. In particular, the analysis of the final 3D Mesozoic geometries against the pre and post-Alpine trends confirms the structural interference between the mutually perpendicular Triassic–Jurassic extensional structures and the Tertiary compressional ones, this being evident from the regional to the oil-field scale.Despite the model uncertainty, mainly related to its dimension versus the original non-homogeneous dataset quality and distribution, the final geo-volume offers, for the first time in the region, a continuous three-dimensional visualization of the Po Valley tectonic architecture. It provides, simultaneously, a powerful tool for the reviewing of the basin structures and the potential support to future applications for both industry and academia.     

边缘海盆地断层差异演化成因的数值模拟：以西湖凹陷平北斜坡带为例

东海陆架盆地中生代以来的成盆过程中,发育了大量陆倾控盆断裂,其发育模式与形成演化与东亚其他边缘海盆地差异明显。前人关注东海陆架盆地迁移特征,而忽略了断层差异演化的形成机制,对断层发育过程控制因素缺少深入研究。西湖凹陷平北斜坡带北部为海倾断层组成的断阶区,南部为陆倾断层组成的半地堑区,断裂差异演化指示着东海陆架盆地的成盆过程。本文通过离散元数值模拟,模拟陆倾和海倾断层的形成及演化,以探讨断层几何发育特征的控制因素。结果表明,岩性差异对斜坡带断层演化有较大影响,较高抗剪强度岩层破裂易产生陆倾控盆断裂,而低抗剪强度岩石则易形成向海倾断层。应力作用方向是区域差异演化的重要控制因素,岩石强度相同,应力作用方向相反时,断层倾向相反。盆地形成过程中发育众多凹陷斜坡,但坡度不是断层差异演化的主导因素。平北斜坡带和边缘海盆地的差异演化可能是由基底强度差异或应力方向差异导致的。本文利用离散元数值模拟平北斜坡带断裂差异演化过程,为东海盆地构造演化机制及边缘海盆地的形成提供了思路和理论依据。     

Navy Fan,California Borderland: Growth pattern and depositional processes

Navy Fan is a Late Pleistocene sand-rich fan prograding into an irregularly shaped basin in the southern California Borderland. The middle fan, characterized by one active and two abandoned “distributary” channels and associated lobe deposits, at present onlaps part of the basin slope directly opposite from the upper-fan valley, thus dividing the lower-fan/basin-plain regions into two separate parts of different depths. Fine-scale mesotopographic relief on the fan surface and correlation of individual turbidite beds through nearly 40 cores on the middle and lower fan provide data for evaluating the Late Pleistocene and Holocene depositional processes.     

Wrench-related folding: A case study of Bohai Sea basin,China

Wrench motion is relatively common in basins but often goes undetected because of its subtle structural imprint. Even so wrench-related folding is of significance in petroleum exploration and development. Based on the Riedel shear nomenclature, we apply the model of wrench-related folding to deformation in the Bohai sea basin. The folding related to R-shears, T-tensional structural systems (T-systems) and C-compressive structural systems (C-systems) in a Riedel shear model are discussed. The R-system related folding results from differential movements between the two sides of fault blocks, in map view the fold is oriented (90°-φ/2) (in the initial deformation stage) or more than (90°-φ/2) from the principle displacement zone (PDZ), where φ is the angle of internal friction. The T-system related folding is related to the rollover of the hanging wall, and in map view the fold is initiated at 45° from the PDZ in the initial deformation stage. The C-system related folding is resulted from the compression induced by a wrench action, in map view the fold was oriented 45° from initial deformation in the PDZ. Bohai Sea basin fold orientations fit our models, and the wrench-related folds play important roles in oil and gas accumulation.     

东海丽水凹陷西次凹明月峰组海底扇沉积特征及沉积模式

东海陆架盆地丽水凹陷古新统明月峰组发育典型的海底扇沉积,且已获得工业油气发现。该文利用现有地震地质资料,运用层序地层学理论方法,总结出丽水凹陷的海底扇沉积模式。海底扇沉积相标志包括：岩心主要表现为滑塌揉皱、包卷层理、泄水构造、块状砂岩、黑色泥岩撕裂屑、漂砾、砂注等构造;C-M图主要表现为重力流沉积特征;结构成熟度和成分成熟度中等—差。扇体地震反射结构主要为顺物源方向双向下超,垂直物源方向丘状反射特征,平面地震属性显示为典型扇形。丽水凹陷明月峰组由低位体系域、水进体系域和高位体系域组成,其中海底扇发育在低位体系域,在扇体近端发育多个下切谷,下切谷下切规模较大;坡折主要划分为断裂坡折和沉积坡折,其中断坡坡度较大,坡度7.2°左右,沉积坡折坡度较小,一般在5°左右,与下切谷相对应在谷口形成一系列的扇体,沟–坡–扇耦合关系良好。扇体规模较大,单个扇体面积最大124 km2,整个低位域由6个扇体组成,展示了丽水凹陷良好的岩性圈闭勘探前景。本次研究根据扇体的成因特点建立明月峰组低位域时期沟–坡–扇沉积模式,对指导勘探寻找出岩性圈闭和开创丽水凹陷油气勘探新局面具有一定意义。     

Tidal eddies in a semi-enclosed basin: a model study

A modeling study has been carried out to support a Marine Management Plan for the Gulf of Kachchh, India and here the hydrodynamic part of the programme is described. The hydrodynamic model accurately predicts the tides and tidal currents present in the Gulf and these have been validated with the measured data, albeit at only a few locations. The time averaged residual currents obtained from the model for one lunar cycle clearly reproduce the complex, small-scale, topographically induced flows with several eddies. The existence of a dynamic barrier along Sikka-Mundra section, which divides the Gulf into two distinct dynamic systems, is very evident. The model is further used to predict the movement of surface floating particles launched at different locations in the Gulf, as an aid to determining floating pollutants. The results indicate that industries discharging wastes upstream of the barrier should use extreme caution, as these will remain in the vicinity for at least one lunar cycle.     

Depositional model for a prograding oolitic wedge,Upper Jurassic,Iberian basin

Facies architecture and bedding patterns of the Kimmeridgian Pozuel Formation (Iberian Basin) evidence that this 50–70-m thick oolitic-grainstone unit conforms to the Infralittoral Prograding Wedge (ILPW) model instead of the classic models used for interpreting oolitic grainstones sandbodies on carbonate ramps or platforms (i.e., bank-margin shoal complexes, beaches and beach ridges).Ten lithofacies have been distinguished in the Pozuel Formation: 5–10° dipping clinobedded oolitic grainstone foresets passing to tabular oolitic packstones-grainstones, which interfinger the muddy basinal bottomsets. Landwards, the clinobeds pass into subhorizontal topsets composed of trough cross-bedded to structureless oolitic grainstones; oolitic-skeletal grainstones with stromatoporoids and coral-stromatoporoid-microbial mounds. Siliciclastic lithofacies and oncolitic/peloidal packstones occur at the innermost position. These lithofacies stack in strike elongated, 5–20-m thick, 0,5–2 km dip-oriented wide, aggradational-progradational packages with complex sigmoid-oblique geometries.Lithofacies, depositional geometries and stacking pattern permit to summarize the main characteristic of such Upper Jurassic oolitic infralittoral prograding wedge potentially to be applied in other oolitic sandbodies both in outcrops and subsurface: 1) sediment production within the wave action zone, 2) grainstone-dominated textures, 3) prograding basinward onto basinal muds, 4) laterally (strike) extensive, paralleling the shoreline, 5) variable thickness, commonly of few tens of meters, 6) broadly sigmoidal to oblique internal architecture, with topsets, foresets and bottomsets, 7) dip of foresets close to the angle of repose, 8) topsets deposited in shallow-water, extending through the shoreface, from the shoreline down to the wave base, 9) mounds, either microbial or skeletal, may occur in the topsets.The coated-grains factory was along the high-energy, wave-dominated outer platform (topset beds), from where the mud was winnowed and the grains transported both landward to the platform interior, and seaward to the platform edge, from were the grains cascaded down the slopes as grain flows and mass flows, forming clinobeds. This genetic model can be applied to other grain-dominated lithosomes, some of them forming hydrocarbon reservoirs, e.g., the Jurassic Hanifa Formation and some Arab-D (e.g., Qatif Field) in Arabia, the Smackover Formation in northern Louisiana and south Arkansas, the Aptian Shuaiba Formation (e.g., Bu Hasa Field) and the Cenomanian Mishrif Formation (e.g., Umm Adalkh Field) of the Arabian Gulf.     

Mathematical model for the dynamics of radionuclides,heavy metals,and petroleum hydrocarbons in the Arctic basin

This paper discusses a mathematical model for the dynamics of pollution in the Arctic basin, considering spatial non-uniformities in the distribution of ecological and hydrodynamic parameters. The model features blocks simulating contaminant fluxes through the tropic chains. The results of numerical experiments are provided which demonstrate the model's capability to predict and assess the dynamics of heavy metals, radionuclides, and petroleum hydrocarbons in the Arctic basin. The model is adaptable to a global model. Climatic phenomena and anthropogenic forcing are described in the form of scenarios.Translated by Vladimir A. Puchkin.     

Structural styles and depositional architecture in the Triassic of the Ninian and Alwyn North fields: Implications for basin development and prospectivity in the Northern North Sea

Interpretation of well-calibrated three-dimensional seismic volumes, sedimentological analysis and electrical well-log correlations from the Ninian and Alwyn North fields challenge the long-held view that Mid-Late Jurassic extensional faults in the East Shetland Basin represent a simple reactivation of older (Triassic) fault systems. Restoration for the effects of the younger, predominantly eastward-dipping, Mid-Late Jurassic structures clearly demonstrates that Triassic precursors had a steep, westerly dip. In contrast to the eastern flank of the Viking Graben (e.g. Troll and Oseberg areas), where the west-dipping Triassic structures are reutilised in the Mid-Late Jurassic, those of the East Shetland Basin have largely been dissected and rotated during the later event. Those west-dipping faults that did see later movement appear to have simply acted as minor antithetic structures to the throughgoing east-dipping ones.The Triassic normal fault patterns actively controlled sediment thicknesses and facies distribution within the Lunde and Teist Formations in the basin. Use of seismic stratigraphic surfaces, calibrated by biostratigraphy and chemostratigraphic markers, provides strong evidence that the Triassic depocentres are spatially offset from their Mid-Late Jurassic counterparts. The combination of structural, stratigraphic and sedimentary effects reveal the existence of an emergent deeper Triassic play opportunity in footwall locations to the Mid-Late Jurassic normal faults, which has the potential to extend the life of what is otherwise mature acreage.