Kinetics of (TBAF + CO2) semi-clathrate hydrate formation in the presence and absence of SDS

In this communication, the impacts of adding SDS (sodium dodecyl sulfate), TBAF (tetra-n-butylammonium fluoride) and the mixture of SDS + TBAF on the main kinetic parameters of CO₂ hydrate formation (induction time, the quantity and rate of gas uptake, and storage capacity) were investigated. The tests were performed under stirring conditions at T = 5 ℃ and P = 3.8 MPa in a 169 cm³ batch reactor. The results show that adding SDS with a concentration of 400 ppm, TBAF with a concentration of 1–5 wt%, and the mixture of SDS + TBAF, would increase the storage capacity of CO₂ hydrate and the quantity of gas uptake, and decrease the induction time of hydrate formation process. The addition of 5 wt% of TBAF and 400 ppm of SDS would increase the CO₂ hydrate storage capacity by 86.1% and 81.6%, respectively, compared to pure water. Investigation of the impact of SDS, TBAF and their mixture on the rate of gas uptake indicates that the mixture of SDS + TBAF does not have a significant effect on the rate of gas uptake during hydrate formation process.     

Geochemistry of upper Permian siliceous rocks from the Lower Yangtze region, southeastern China: implications for the origin of chert and Permian ocean chemistry

The Permian Chert Event is of great significance to understanding the geological evolution of the entire Permian; however, the origin of widespread chert formation is debated. We report new geochemical data from deep-marine siliceous rocks of the upper Permian Da-long Formation, Lower Yangtze region, southeastern China. Their geochemical results show that these thin-bedded siliceous rocks have a clear biologic origin, with rare to no evidence of hydrothermal influence. The values of Al/(Al + Fe + Mn) and Eu/Eu* are 0.60–0.84 (mean = 0.72) and 0.45–1.08 (mean = 0.77), respectively, and Mn/Ti ratios are relatively low (mean = 0.72). The correlations of La_N/ CeN, La_N/ Yb_N, and Fe₂O₃/ TiO₂ with Al₂O₃/(Al₂O₃ + Fe₂O₃), along with the Ce anomaly, indicate that the Da-long siliceous rocks were deposited at a transitional zone between a continental margin and the open ocean; i.e., relatively close to terrestrial sediment input and far from hydrothermal activity. The accumulation of chert is related to its unique paleogeographic location in an equatorial setting with many submarine paleo-highlands. Intense upwelling and frequent local volcanism are the main factors that promoted the development of siliceous rocks in the studied area. Ocean acidification triggered by large-scale volcanism (Large Igneous Province) during the late Permian led to extensive silica precipitation and preservation.     

The early-middle Miocene submarine fan system in the Pearl River Mouth Basin, South China Sea

Based on a large amount of seismic, drilling and core data, the characteristics of the earlymiddle Miocene submarine fans in the Baiyun Sag, northern South China Sea are investigated. By analyzing the sedimentary processes of submarine fans in SQ21 (SQ21 refers to the 3rd-order sequence with its bottom boundary 21 Ma), a sedimentary model of the sand-rich fans is established and the main factors controlling fan deposition are detailed. The results indicate that from early to middle Miocene the Pearl River Mouth Basin developed seven 3rd-order sequences in all, with each lowstand systems tract (LST) of the sequence corresponding to submarine fans. However, only the fans in SQ13.8 and SQ21 are sand-rich fans, the others being mud-rich fans. The cores reveal that the submarine fans in the Pearl River Mouth Basin developed five lithofacies: (1) mud clast-bearing sandstone, interpreted as channel deposits; (2) typical turbidite sandstones, also interpreted as channel deposits; (3) thin-bedded sandstone and mudstone, interpreted as channel-levee complex deposits; (4) massive sandstones, interpreted as lobe deposits; (5) massive mudstone, interpreted as hemipelagic mud. The sand-rich submarine fans in the Pearl River Mouth Basin mainly developed in LST, and in LST reverse faults were active, which led to the formation of accommodation on the shelf. Different from the theory of classic sequence stratigraphy, the accommodation on the shelf captures terrigenous debris transported by the Pearl River, and the uplift at the edge of shelf serves as a “Linear Source” for the deep water area instead of the Pearl River. Therefore, the fans mainly derived from the eroded debris from the uplift. Factors controlling fan deposition include the basin’s tectonic framework, the evolution of the slope break, relative sea-level changes as well as the evolution of the fault system, and the fans are formed under the combination of the above factors.     

Tectonic evolution and its control over deposition in fault basins: A case study of the Western Sag of the Cenozoic Liaohe Depression, eastern China

The main petroliferous basins in eastern China are Cenozoic fault basins, most of which have experienced two-stage tectonic evolution, i.e., rifting subsidence in the Paleogene and post-rifting thermal subsidence in the Neogene-Quaternary. The episodic tectonic evolution and syndepositional faulting had significant influence on the fault basins in terms of accommodation space, deposition rate, and depositional facies zones. In this study, the tectonic deformation characteristics and the tectonic-depositional evolution of the Western Sag of the Cenozoic Liaohe Depression were investigated by comprehensive analysis of the available geological and geophysical data using the modern theory of tectonic geology and the balanced section technique. The tectonic deformation of the Cenozoic fault basin was characterized by superimposed faults and depression. In addition, there existed relatively independent but still related extensional tectonic systems and strike-slip tectonic systems. The tectonic evolution of the fault basin involved five stages, i.e., initial rifting stage (E2s4), intense faulting stage (E2s3), fault-depression transition stage (E3s1-2 ), differential uplifting stage (E3d), and depression stage (N-Q). According to the characteristics of tectonic development and evolution of the Western Sag, the depositional evolution in the Cenozoic fault basin was divided into two stages, i.e., multi-episodic rifting filling in the Paleogene and post-rifting filling in the Neogene-Quaternary. The former rifting stage was further subdivided into four episodes with different characteristics of depositional development. The episodic faulting controlled the filling process and filling pattern of the Cenozoic Western Sag as well as the development and spatial distribution of associated depositional systems, whereas the syndepositional faults that developed in multiple stages in various tectonic positions controlled the development of depositional systems and sand bodies in the Western Sag. That is, the fault terraces on steep slopes controlled the development of sand bodies, the fault terraces on gentle slopes controlled the development of low-stand fan bodies, and the fault terraces or fault troughs in the central basin controlled the development of fluxoturbidite bodies.     

A compositional model for CO2 flooding including CO2 equilibria between water and oil using the Peng–Robinson equation of state with the Wong–Sandler mixing rule

This paper presents a three-dimensional, three-phase compositional model considering CO₂ phase equilibrium between water and oil. In this model, CO₂ is mutually soluble in aqueous and hydrocarbon phases, while other components, except water, exist in hydrocarbon phase. The Peng–Robinson (PR) equation of state and the Wong–Sandler mixing rule with non-random two-liquid parameters are used to calculate CO₂ fugacity in the aqueous phase. One-dimensional and three-dimensional CO₂ flooding examples show that a significant amount of injected CO₂ is dissolved in water. Our simulation shows 7% of injected CO₂ can be dissolved in the aqueous phase, which delays oil recovery by 4%. The gas rate predicted by the model is smaller than the conventional model as long as water is undersaturated by CO₂, which can be considered as “lost” in the aqueous phase. The model also predicts that the delayed oil can be recovered after the gas breakthrough, indicating that delayed oil is hard to recover in field applications. A three-dimensional example reveals that a highly stratified reservoir causes uneven displacement and serious CO₂ breakthrough. If mobility control measures like water alternating gas are undertaken, the solubility effects will be more pronounced than this example.     

Tectonics-palaeogeomorphology in rift basins: controlling effect on the sequence architecture

The relationship between deposition and tectonics of sedimentary basins has been a significant subject in recent years.Using typical rift basins such as the Nanpu Sag as an example,combined with the analysis of the tectonics-palaeogeomorphology of basins,we undertook a detailed study of the differences of the third-order sequences in different basins,the combination of depositional systems within the sequence framework and the distribution of depocenters and subsidence centers.Our results revealed a significant relationship between the tectonics-palaeogeomorphology of rift basins and the filling styles of sedimentary sequences.The basin structure plays a primary role in controlling the development of the third-order sequences and the boundary of these sequences is easily formed in basins with gentle slopes,shallow water and a small area.The characteristics of the tectonics-palaeogeomorphology of rift basins are dominated by half-grabens of extensional faults,which affect the temporal and spatial combination of sedimentary systems within the sequences as well as the distribution of depocenters and subsidence centers.Based on the development rules of the faults dominating the half-grabens of extensional faults,rift basins are classified into two types： the single fault segmented-linkage type and the multi-fault combination type.The main controlling factors of the temporal and spatial combination of sedimentary systems and the distribution of depocenters and subsidence centers in different basins are different.The characteristics of early segmentation and later linkage of the faults play a critical role in controlling the sedimentary system combination within the sequence framework and the temporal and spatial differences of depocenters and subsidence centers of the single fault segmented-linkage rift basins,while the differences in fault activities are the dominating factors of the multi-fault combination rift basins.     

Hybrid connectionist model determines CO2–oil swelling factor

In-depth understanding of interactions between crude oil and CO₂ provides insight into the CO₂-based enhanced oil recovery (EOR) process design and simulation. When CO₂ contacts crude oil, the dissolution process takes place. This phenomenon results in the oil swelling, which depends on the temperature, pressure, and composition of the oil. The residual oil saturation in a CO₂-based EOR process is inversely proportional to the oil swelling factor. Hence, it is important to estimate this influential parameter with high precision. The current study suggests the predictive model based on the least-squares support vector machine (LS-SVM) to calculate the CO₂–oil swelling factor. A genetic algorithm is used to optimize hyperparameters (γ and σr2) of the LS-SVM model. This model showed a high coefficient of determination (R² = 0.9953) and a low value for the mean-squared error (MSE = 0.0003) based on the available experimental data while estimating the CO₂–oil swelling factor. It was found that LS-SVM is a straightforward and accurate method to determine the CO₂–oil swelling factor with negligible uncertainty. This method can be incorporated in commercial reservoir simulators to include the effect of the CO₂–oil swelling factor when adequate experimental data are not available.     

Phase Behaviour and Physical Properties of Alkane Solvent（s）/CO2N2/DME/Water/Heavy Oil Systems under Reservoir Conditions

The hybrid steam-solvent injection has been considered as a promising technique for enhancing heavy oil/bitumen recovery,while its main mechanisms including the heat transferred and dissolution of solvents （e.g., CH₄,C₂H₆,C₃H₈, C₄H₁₀,CO₂,N₂,and DME）into heavy oil/bitumen to reduce its viscosity and swell it are closely related to the phase behaviour of the solvents/water/heavy oil systems. To allow the seamless integration with the existing reservoir simulators, the traditional cubic equations of state（i.e.,SRK EOS and PR EOS） have been modified and improved to accurately quantify the phase behaviour and physical properties of the aforementioned systems under equilibrium and nonequilibrium conditions. Firstly,a huge database has been built to develop the corresponding alpha functions by minimizing the deviation between the measured and calculated vapour pressures for water as well as non-hydrocarbon and hydrocarbon compounds available from the public domain. Such obtained alpha functions are further validated with enthalpy of vaporization for pure substances, and then the reduced temperature has been optimized and the eccentric factor has been redefined. Finally,a pressure-implicit strategy has been developed to optimize the binary interaction parameters（BIPs）by treating heavy oil as one pseudocomponent （PC） or multiple PCs. Also,the contributions of each solvent to the aforementioned systems have been compared and analyzed within a consistent and unified framework. In addition to new alpha functions for hydrocarbons and water, respectively,the reduced temperature is found to have its optimum value of 0.59 for the two equations of state （EOSs）,while 0.60 is recommended for practical use. Such improved EOSs have been further employed to reproduce the experimentally measured multiphase boundaries （or pseudo-bubble-point pressures）, density,viscosity,（mutual）solubility,and preferential mass transfer for the aforementioned mixtures under equilibrium and nonequilibrium conditions. The swelling effect for the heavy oil can be enhanced due to the addition of C₃H₈ and/or C₄H₁₀ or their mixtures into the CO₂ stream. Due to the existence of water,isenthalpic flash leads to more accurate quantification of multiphase boundaries and physical properties for the hybrid solvent-thermal processes. Each component of a binary or ternary gas mixture is found to diffuse preferentially into heavy oil at high pressures and elevated temperatures in the absence and presence of porous media,while each of them is found to exsolve differently from gas-saturated heavy oil under nonequilibrium conditions.     

Experimental investigation into Fe3O4/SiO2 nanoparticle performance and comparison with other nanofluids in enhanced oil recovery

Nanofluids because of their surface characteristics improve the oil production from reservoirs by enabling different enhanced recovery mechanisms such as wettability alteration, interfacial tension (IFT) reduction, oil viscosity reduction, formation and stabilization of colloidal systems and the decrease in the asphaltene precipitation. To the best of the authors’ knowledge, the synthesis of a new nanocomposite has been studied in this paper for the first time. It consists of nanoparticles of both SiO₂ and Fe₃O₄. Each nanoparticle has its individual surface property and has its distinct effect on the oil production of reservoirs. According to the previous studies, Fe₃O₄ has been used in the prevention or reduction of asphaltene precipitation and SiO₂ has been considered for wettability alteration and/or reducing IFTs in enhanced oil recovery. According to the experimental results, the novel synthesized nanoparticles have increased the oil recovery by the synergistic effects of the formed particles markedly by activating the various mechanisms relative to the use of each of the nanoparticles in the micromodel individually. According to the results obtained for the use of this nanocomposite, understanding reservoir conditions plays an important role in the ultimate goal of enhancing oil recovery and the formation of stable emulsions plays an important role in oil recovery using this method.     

Methods for seismic sedimentology research on continental basins

In contrast to marine deposits, continental deposits in China are characterized by diverse sedimentary types, rapid changes in sedimentary facies, complex lithology, and thin, small sand bodies. In seismic sedimentology studies on continental lacustrine basins, new thinking and more detailed and effective technical means are needed to generate lithological data cubes and conduct seismic geomorphologic analyses. Based on a series of tests and studies,this paper presents the concepts of time-equivalent seismic attributes and seismic sedimentary bodies and a ‘‘four-step approach' for the seismic sedimentologic study of continental basins: Step 1, build a time-equivalent stratigraphic framework based on vertical analysis and horizontal correlation of lithofacies, electrofacies, seismic facies, and paleontological combinations; Step 2, further build a sedimentary facies model based on the analysis of singlewell facies with outcrop, coring, and lab test data; Step 3,convert the seismic data into a lithological data cube reflecting different lithologies by means of seismic techniques; and Step 4, perform a time-equivalent attribute analysis and convert the planar attribute into a sedimentary facies map under the guidance of the sedimentary facies model. The whole process, highlighting the verification and calibration of geological data, is an iteration and feedback procedure of geoseismic data. The key technologies include the following:(1) a seismic data-lithology conversion technique applicable to complex lithology, which can convert the seismic reflection from interface types to rock layers;and(2) time-equivalent seismic unit analysis and a timeequivalent seismic attribute extraction technique. Finally,this paper demonstrates the validity of the approach with an example from the Qikou Sag in the Bohai Bay Basin and subsequent drilling results.     

鄂尔多斯盆地临兴地区上古生界泥岩地球化学特征及地质意义

利用对沉积环境敏感的元素或者元素组合可以定性或半定量地恢复古沉积环境。通过鄂尔多斯盆地临兴地区上古生界31件泥岩样品的主量元素、微量元素以及稀土元素的分析测试,对沉积水体的古盐度、古气候、古水体氧化还原环境以及古物源特征进行了探讨。结果显示：①Ba元素含量以及Sr/Ba比值的变化特征反映古盐度从上石炭统本溪组和下二叠统太原组到下二叠统山西组、中二叠统石盒子组和上二叠统石千峰组明显降低,沉积环境从海相到陆相变化;②Sr含量、Mn含量、Sr/Cu和FeO/MnO指示上古生界从本溪组到石盒子组沉积期的古气候温暖潮湿,但太原组沉积期存在一段干旱期,石千峰组沉积期为干旱气候;③V/Cr、Ni/Co以及REE等对沉积水体氧化还原环境的指示性较差,通过泥岩颜色和有机质含量可推断上古生界水体由本溪组、太原组以及山西组的还原环境转化为石盒子组和石千峰组的氧化环境;④临兴地区具有明显的轻稀土富集特征,但从本溪组到石千峰组,轻稀土的富集性变差,Ce含量表现为基本正常或轻微负异常,Eu表现为"V"型逐渐变弱的负异常;⑤上古生界的CIA指数显示物源区受到中等-强烈风化。综合稀土元素分析表明,临兴地区的物源来自鄂尔多斯盆地北部的阿拉善-阴山古陆。     

尼日尔Termit盆地Yogou组泥岩地球化学特征及沉积背景

Yogou组泥岩是Termit盆地主要的烃源岩之一。为了揭示Termit盆地Yogou组沉积时期物源属性、物源区的构造背景及其沉积环境,通过对4口井20块泥岩样品的主量元素、微量元素和稀土元素测试,对Yogou组泥岩的元素地球化学特征进行了综合分析。结果显示： Yogou组上部以被动大陆边缘物源为主,下部以长英质物源为主,物源区处于大陆岛弧的构造背景条件下。Yogou组中-上部沉积时期水体盐度相对较低,为海陆过渡相沉积;Yogou组下部沉积时期水体盐度较高,为海相沉积。CIA指数、Sr/Cu值等指标表明,Yogou组沉积时期研究区处于湿热的气候条件;V/（V+Ni）等指标说明,Yogou组沉积时期水体处于厌氧环境。     

下扬子地区古生界硅岩地球化学特征及成因

下扬子地区的 3 套区域性烃源岩（下寒武统、中二叠统以及上二叠统）均发育灰黑色层状硅岩,硅岩地球化学特征及成因的研究对认识该区烃源岩的沉积环境具有重要意义。通过对下扬子无为-南陵地区 4 条典型地质剖面（下寒武统青阳青坑剖面、二叠系巢湖平顶山剖面、巢湖马家山剖面以及泾县昌桥剖面）的硅岩主量元素和稀土元素的地球化学特征进行研究,结果发现：下寒武统硅岩为纯硅质岩;二叠系硅岩部分样品含少量泥质成分;下寒武统黄柏岭组、中二叠统孤峰组以及上二叠统大隆组硅岩均存在 Ce 负异常,而这 3 个层段的 Eu 异常明显不同。 根据研究区古生界硅岩的 MnO/TiO₂ 值、Fe₂O₃/TiO₂Al₂O₃/（Al₂O₃+Fe₂O₃）关系以及稀土元素特征,综合判断上二叠统大隆组硅岩沉积背景为大陆边缘浅海,而下寒武统和孤峰组层状硅岩沉积于海盆中,其沉积环境与大隆组硅岩相比,更远离陆源影响。根据研究区 3 个层段的硅岩 Al/（Al+Fe+Mn）值、Al-Fe-Mn 三角散点图以及稀土元素特征,判断研究区下寒武统硅岩为热水沉积成因硅岩,上二叠统硅岩为典型生物成因硅岩,中二叠统孤峰组硅岩为生物和热水混合成因硅岩。     

玛湖地区三叠系克拉玛依组浅水辫状河三角洲沉积特征

近年来,玛湖地区三叠系克拉玛依组的多口井获得工业油气流,展现了该地区中浅层较大的勘探潜力。为了查明玛湖地区克拉玛依组沉积体系特征,明确主要砂体的成因和分布,开展了岩心观察、物源分析、沉积相研究、砂体平面展布规律及控制因素研究。结果表明：①克拉玛依组沉积时期,准噶尔盆地处于坳陷湖盆演化阶段,玛湖地区由"多隆多凹"逐渐转化为"大型缓坡"背景,在此基础上发育四大物源体系,主要为浅水辫状河三角洲沉积,三角洲前缘水下分流河道砂体为主要储集体类型;②克拉玛依组下段的砂体主要集中于底部,与泥岩呈互层状,在夏子街、黄羊泉等主物源区较为发育;③克拉玛依组上段的砂体主要发育于顶部,三角洲砂体呈叠瓦状向湖盆中心进积,延伸较远。克拉玛依组下段砂体与上段厚层暗色泥岩形成的储盖组合和克拉玛依组顶部砂岩与白碱滩组巨厚泥岩形成的储盖组合均为有利勘探领域。该研究成果对玛湖地区克拉玛依组的油气勘探具有指导意义。     

川西北地区海相烃源岩地球化学特征、分布规律及天然气勘探潜力

川西北地区为近年来四川盆地天然气勘探的热点地区,但时至今日对该区海相烃源岩的地球化学特征和分布仍缺乏全面的研究。选取8条露头剖面对川西北地区下震旦统陡山沱组、上震旦统灯三段、下寒武统筇竹寺组、下志留统龙马溪组、中泥盆统、中二叠统茅口组、上二叠统龙潭组/吴家坪组和大隆组8套海相烃源岩进行了系统的有机地球化学分析,探讨了该区天然气勘探潜力。筇竹寺组优质烃源岩厚度最大,可达80 m,其次是上二叠统龙潭组/吴家坪组和大隆组,厚度可达20~30 m,其他层系优质烃源岩厚度均较薄。从有机质丰度来看,陡山沱组、筇竹寺组、龙马溪组、龙潭组/吴家坪组和大隆组总有机碳含量(TOC)大于3%的发育优质烃源岩,灯三段、中泥盆统、茅口组有机碳含量整体偏低。从下寒武统筇竹寺组至上二叠统大隆组烃源岩干酪根碳同位素值逐渐增高,陡山沱组、灯三段和筇竹寺组烃源岩δ¹³C值小于-30.0‰,有机质类型以Ⅰ型为主,龙潭组/吴家坪组与大隆组烃源岩δ¹³C值主要分布在-28.0‰~-26.0‰之间,有机质类型以Ⅱ2型为主,其他介于两者之间。川西北地区除广元矿山梁、朝天二叠系和朝天泥盆系的烃源岩处于成熟阶段之外,大部分地区处于过成熟阶段,主要以生干气为主。多套高丰度烃源岩的发育奠定了川西北地区海相天然气资源丰富,以筇竹寺组和上二叠统烃源岩为气源的含气系统是川西北地区未来天然气勘探的关注领域。     

湘中坳陷涟源凹陷湘页1井大隆组页岩气地质特征

为评价湘中坳陷涟源凹陷二叠系大隆组页岩气成藏地质条件,部署实施了该区首口以大隆组为目的层的页岩气参数井——湘页1井。充分利用湘页1井钻井、岩心、测井及分析测试资料,开展大隆组岩石矿物组成特征、沉积特征、有机地球化学特征、储集物性特征、含气性等地质条件分析。研究结果表明:湘页1井大隆组页岩形成于缺氧的较深水台盆相沉积环境,有利于页岩发育和有机质保存,优质页岩厚度大(TOC大于2%的页岩厚92.8m)、有机质丰度高(TOC为0.41%~10.47%,平均为3.91%)、热演化程度适中(R_o为1.50%~1.72%,平均为1.58%),微观孔隙结构以中孔和大孔为主,微裂缝发育,页岩脆性指数高,两向水平主应力差值小,有利于压裂形成复杂网络裂缝,具备形成页岩气藏的基本地质条件;保存条件是影响页岩含气性的关键因素,湘页1井大隆组页岩进入生烃期以后,经历了3期明显的构造抬升剥蚀,以致现今埋藏浅,距离剥蚀区近,向斜构造页岩气易横向逸散,同时腐殖型干酪根产烃率相对较低也影响其含气性。构造形态宽缓、埋深较大、远离剥蚀区、翼部发育反向逆断层有利于残留向斜型页岩气富集。     

湖北鹤峰地区二叠系大隆组黑色岩系成因——来自鹤地1井的元素地球化学证据

为明确湖北鹤峰地区二叠系大隆组的沉积环境特征及黑色岩系的成因,开展了鹤地1井黑色岩系详细的元素地球化学分析。结果表明,大隆组缺氧的还原环境控制了有机质的富集,其早期沉积环境相对较稳定,为贫氧且富含H₂S的还原环境,而中-晚期则呈明显波动变化的贫氧-缺氧环境。大隆组沉积期上升流的发育提供了大量的富营养物质,导致沉积水体缺氧,产生较高的古生产力。与同生断裂有关的热水上涌主要造成自生白云石和钠长石形成、硅质生物溶蚀再胶结作用,促使有机质发生热演化,对页岩气无不利影响。大隆组局部发育的层状硅质岩具有生物成因和自生化学沉淀成因2种类型。     

鄂尔多斯盆地东南部下二叠统山西组二段物源体系及沉积演化模式

早二叠世是鄂尔多斯盆地海陆变迁的关键时期,其中下二叠统太原组沉积期由于发育稳定的碳酸盐岩地层,其陆表海沉积环境得到了大多数学者的认可,而对于下二叠统山西组的沉积环境与沉积体系的认识则存在着较大的争议。为此,在研究该盆地东南部区域构造背景与周缘古陆特征的基础上,结合岩石、重矿物与稀土元素的组成特征,分析了该区山西组二段(以下简称山2段)的物源体系,并依据地层、古生物、沉积构造、古盐度等分析结果,判别其沉积环境并建立了沉积演化模式。结果表明:(1)山2段沉积期发育南、北两大物源体系,其中北物源主要来自古阴山褶皱造山带,南部物源则来自祁连—北秦岭造山带,延安南部宜川—富县一带是上述两大物源的交汇区;(2)该区自早二叠世太原末期—山西早期发生区域性海退,海水自东南方向退出,山2段沉积期仍受到海侵作用的影响;(3)延安以北地区发育三角洲沉积体系,其以南地区则发育障壁岛海岸沉积体系;(4)该区山西组沉积在平面上具有"岸线频繁迁移,水体影响范围广"的特点,垂向上多套储集砂岩体与泥岩、煤层频繁交替转换,形成了良好的源储配置关系。     

丽水凹陷古新统微量元素地球化学特征及其地质意义

采用电感耦合等离子体质谱分析仪测试了丽水凹陷古新统泥岩样品的微量元素含量,综合分析了岩石微量元素的富集程度、组合特征以及变化规律等地球化学特征。结果表明,丽水凹陷古新统泥岩的微量元素含量及其比值变化主要与研究区物源供应和沉积成岩环境有关;丽水凹陷古新世的构造环境为活动大陆边缘;古新世早期沉积环境为干热气候环境,晚期主要为温湿—干热—温湿交替变化气候环境;古新统泥岩的母岩主要为酸性岩浆岩。     

南黄海盆地青岛坳陷二叠系、三叠系地震属性及其地质意义

新一轮的战略性油气地质调查工作在南黄海盆地崂山隆起新近系之下发现了疑似海相地层的有效地震反射,但因针对海相地层的勘探程度低（无井、地震测线稀）等原因,其地层属性至今依然不清楚。本文利用青岛坳陷有限的钻井资料,结合新采集有限的二维地震资料,对青岛坳陷二叠系、三叠系进行了地震属性提取及分析,认为其地震属性特征为：上二叠统龙潭组和大隆组总体表现为中-强振幅、偏低频、平行-近平行较密集地震反射;下三叠统下青龙组为中振幅、中-高频、平行-近平行密集地震反射;下三叠统上青龙组则为弱振幅或空白反射、低-中频、平行-近平行地震反射。预测上二叠统及中-下三叠统主要残存分布于青岛坳陷东侧靠近崂山隆起及勿南沙隆起的部位,并据此推测在崂山隆起及勿南沙隆起区可能残存,是值得探索的勘探领域。对于钻井稀少的低勘探程度区,利用地震多属性分析技术及地震属性特征来识别与预测勘探目的层的分布,对于早期勘探评价具有重要现实意义。