Evolution of the Barents Sea basin and oil and gas potential of coastal zones in the Kola region

The perspectives of development of the Varanger–Timan petroleum basin are considered. The Varanger–Timan oil-and-gas basin was formed in the Riphean and Vendian on the passive continental margin of the East European Plate. Evolution of the Barents–Kara region in the Mesoproterozoic and Neoproterozoic led to a mosaic junction of the lithospheric plates having different ages and having undergone significant alterations during the Caledonian and Variscan orogenies. The spatiotemporal regularities of the interaction between geodynamic processes and conditions providing for the formation of conventional and unconventional hydrocarbon fields are described.     

Conditions of oil source potential formation in the Eocene deposits in the basins of the Crimea and Caucasus regions

The article is dedicated to multidisciplinary studies of organic matter (OM) in Eocene deposits. In the Ciscaucasia region, the mean content of organic carbon in the Kumian deposits is high. A decrease in quality is partly related to the approaching of the displacement source. In the investigated regions of Ciscaucasia and Crimea, hydrogen sulfide contamination of the water column in Eocene basins did not exist. Eocene carbon deposits are characterized by increased and high OM oil source potential. A sharp increase in primary biological production is likely to be related to endogenous processes.     

Coal and coal macerals as source rocks for oil and gas

The role of coals in the generation and migration of hydrocarbons is discussed from the viewpoints of chemistry and petrology. Extract data and considerations of volatile matter and maturity suggests that under geochemical conditions most coals can give rise to oil, as well as gas. A distinction is drawn between release of absorbed oil and formation of hydrocarbons by thermal breakdown of the coal matrix itself. The generation and preservation of oil require not only that suitable lipidic structures be present but that the product oil can escape before being cracked to gas.Exinite, preferably in large discrete particles, is the most oil-prone maceral. Vitrinite can form oil but subsequent migration depends on the availability of cracks and fissures in the coal matrix. The most highly reflecting forms of inertinite (e.g. fusinite) have no inherent capacity to generate oil. Low reflectance inertinite, such as is common in many Australian coals, may have minor source potential.A speculative attempt is made to quantify the oil-generating capacity of coal macerals and mixtures. As a general broad rule, on a weight basis, exinite can produce ten times more oil than vitrinite and a hundred times more than inertinite. Approximate calculations suggest that thermal maturation of coals can account for all the known oil and gas reserves in the Gippsland and Cooper Basins of Australia, even if only 1% of generated hydrocarbons is trapped.     

沁水盆地煤层气气源岩地球化学特征及气源潜力分析

对比研究了山西沁水盆地李雅庄煤矿、寺河煤矿和附城七一煤矿煤岩的地球化学特征,讨论了煤岩的热演化程度、可溶有机质含量、生物标志化合物特征。在此基础上,分析了热成因煤层气与次生生物成因煤层气的气源潜力,对研究区煤层气勘探有实际意义。      

鄂尔多斯盆地南缘古坳陷奥陶系烃源岩与天然气勘探潜力研究

鄂尔多斯盆地南缘古坳陷奥陶系分布广,沉积厚度大,其中泥岩烃源岩厚度10～58 m,泥质碳酸盐岩烃源岩厚度20～285 m.有机质丰度高,有机碳(TOC)含量主要在0.15%～0.25%,烃源岩有机质类型主要为Ⅰ型和Ⅱ_1型。在晚三叠世(相当于延长组沉积期)早期开始生气.在晚三叠世末期进入生气高峰阶段,之后从侏罗纪开始强烈抬升。南缘古坳陷现今所在的鄂尔多斯盆地渭北隆起南部山区天然气保存条件差.没有勘探潜力。而渭北隆起北部地区及与伊陕斜坡南部过渡带地区奥陶系埋深一般超过3000 m.生气时间长.具有良好的成藏条件.是构造气藏和构造-岩性气藏有利的勘探目标区。     

中上扬子地区早古生代烃源岩沉积环境与油气勘探

中上扬子地区早古生代沉积盆地主要表现为克拉通海相盆地(∈-O2)和发育在克拉通之上的隆后盆地(O3-S).由于受区域构造作用、海平面变化以及古气候等主控因素的制约,形成了有利于烃源岩生成的沉积环境,奠定了油气生烃成藏的物质基础.早寒武世,中上扬子地区主要表现为浅海环境,沉积了由上升洋流带来的磷质物质以及分布稳定的黑色页...     

Evaluation of the oil and gas preservation conditions,source rocks,and hydrocarbon-generating potential of the Qiangtang Basin: New evidence from the scientific drilling project

The Qiangtang Basin of the Tibetan Plateau, located in the eastern Tethys tectonic domain, is the largest new marine petroliferous region for exploration in China. The scientific drilling project consisting primarily of well QK-1 and its supporting shallow boreholes for geological surveys (also referred to as the Project) completed in recent years contributes to a series of new discoveries and insights into the oil and gas preservation conditions and source rock evaluation of the Qiangtang Basin. These findings differ from previous views that the Qiangtang Basin has poor oil and gas preservation conditions and lacks high-quality source rocks. As revealed by well QK-1 and its supporting shallow boreholes in the Project, the Qiangtang Basin hosts two sets of high-quality regional seals, namely an anhydrite layer in the Quemo Co Formation and the gypsum-bearing mudstones in the Xiali Formation. Moreover, the Qiangtang Basin has favorable oil and gas preservation conditions, as verified by the comprehensive study of the sealing capacity of seals, basin structure, tectonic uplift, magmatic activity, and groundwater motion. Furthermore, the shallow boreholes have also revealed that the Qiangtang Basin has high-quality hydrocarbon source rocks in the Upper Triassic Bagong Formation, which are thick and widely distributed according to the geological and geophysical data. In addition, the petroleum geological conditions, such as the type, abundance, and thermal evolution of organic matter, indicate that the Qiangtang Basin has great hydrocarbon-generating potential.©2023 China Geology Editorial Office.     

Manganese potential of Neogene rocks in Central Russia (Tambov-Lipetsk region)

Materials related to the manganese potential of Neogene rocks (Sosnovka Formation) in Central Russia are summarized. Concretions and geoides in primary manganese carbonates are most likely early diagenetic formations. However, we cannot also rule out the possibility of their formation after the early diagenetic (catagenetic) stage of sediment transformation. The Tambov-Lipetsk region with manganese potential outlined in this paper is located in an economically favorable setting. Probability of the discovery of commercial manganese oxide deposits in this region is discussed.     

大牛地气田石炭—二叠系烃源岩生烃潜力

大牛地气田上古生界石炭—二叠系烃源岩为煤系烃源岩(主要为煤岩和暗色泥岩),有机质类型以Ⅲ型干酪根为主,烃源岩演化成熟度较高,Ro基本在1.5%左右。烃源岩存在3期生烃演化过程,分别为三叠纪期间、侏罗纪期间和古近纪期间。烃源岩(泥岩+煤岩)累计生烃量为8万多亿m~3,煤岩生烃贡献占85%。石炭—二叠系烃源岩现今累计生烃强度高值区主要分布在大牛地气田的东南部、西北部以及西部地区。     

Absolute dating of igneous rocks of Crimea as reference formations for Bajocian

Because of the fairly homogeneous petrographic and chemical character of the assemblages of the Crimean igneous rocks (plutons), they can be used for an accurate geochronological correlation of the Middle Jurassic. Potassium-argon ages have established the ages of many of the Crimean intrusives as averaging 159 ± 3 m.y. Hypabyssal and effusive rocks (the Bajocian formations) genetically associated with the Crimean intrusives can therefore also be dated as 159 ± 3 m.y. Limits of the Triassic Period should be left at 135 and 180 (perhaps 185) m.y. Younger age determinations of 106 ± 5 m. y. suggest a regional rejuvenation of some of the Crimean intrusives in connection with low temperature hydrothermal metamorphism. Additional work should be carried out to further elucidate this fact. — R.M. Hutchinson.     

山东博兴地区压力系统分析及油气成藏动力学机制

博兴地区沙三段、沙四段油藏普遍具有异常高压。本文利用泥岩声波时差资料研究了地层压力在单井、剖面和平面上的分布特征,异常高压带在各井出现深度大致在2100～ 2500m左右,层位上与沙三段大套泥岩出现有关,剩余流体压力剖面上具有分带性,明显受构造位置、沙三段泥岩以及断层等因素控制,平面上高剩余流体压力值与洼陷区相伴生,且构造陡坡带剩余流体压力梯度值较大,缓坡带剩余流体压力梯度值较小,油气基本聚集于异常压力系统中的相对低压区和常压区。根据异常压力在平面上的分布特点以及油气藏形成特征,将博兴地区的成藏动力学机制划分为自源封闭型成藏动力学机制和它源开放型成藏动力学机制两种类型。     

西藏洞错地堑构造及其对油气的影响

羌塘盆地托纳木地区新生代发育规模较大的洞错地堑构造,走向近南北,长度大于80km,由断隆带和断陷盆地组成,并对研究区地貌和水系格局有明显的控制作用。地堑活动始于中新世,现今仍处于活动之中,其形成可能受深部热动力学机制作用制约。沿地堑正断层存在明显的油气异常,对油气藏具有显著的破坏作用,不利于油气的保存。     

海相碳酸盐岩烃源岩评价的有机碳下限问题

随着勘探程度的提高,深部石油天然气勘探在我国将越来越重要.我国碳酸盐岩地层分布广,埋藏深,其生烃评价是深部石油天然气勘探不可回避的问题.针对我国科学家在这一问题上的争论,提出了海相碳酸盐岩烃源岩评价的三个下限标准,即最低烃源岩的有机碳下限、有效烃源岩有机碳下限和形成大规模油气田的烃源岩有机碳下限.认为以往的争论是最低烃源岩、有效烃源岩下限的争论.通过文献整理、实验研究和计算,认为海相碳酸盐岩普遍存在的Ⅱ型有机质,其最低、有效油源岩的下限值可能在0.1%和0.4%左右,最低、有效气源岩下限可能在0.1%和0.3%左右,大规模油气田形成的TOC应在1%以上.     

豫东地区煤系烃源岩有机质特征与煤系气资源潜力

为了评价豫东地区煤系烃源岩生烃潜力,基于有机碳含量（TOC）、镜质体反射率、干酪根类型及显微组成等测试分析结果,探讨了豫东地区不同区块煤系烃源岩的有机地球化学特征,对比分析了不同区块煤系气资源潜力,提出煤系气勘探有利区块。结果表明：区内煤系烃源岩的有机碳含量偏低（小于1.5%）;干酪根类型以Ⅲ型为主,偶见Ⅱ₂型干酪根,利于生气;煤系经历了中二叠-中晚三叠世和晚侏罗-早白垩世2个大量生烃阶段,烃源岩热演化程度较高,镜质体反射率（R_ran）为1.44%~3.80%,平均2.83%,有机质进入高成熟-过高成熟阶段,生烃量较充足。总体上,区内烃源岩生烃潜力属于差-中级别,砂泥岩储集性能相对较好,含气量高。煤系盖层主要为封盖性好的细砂岩、煤层、泥质岩类,煤系烃源岩气体保存条件好。研究认为研究区的睢西区块烃源岩具有埋藏深度较浅、有效厚度大、孔隙度高、含气量和含气饱和度高、有机质成熟度高的特点,为豫东煤系气勘探的有利区块。     

Reservoir potential of carbonate rocks in the Kutai Basin region,East Kalimantan,Indonesia

Fifteen percent of the exploration wells drilled in the Kutai Basin region were targeted for stratigraphic play-types. Carbonate reservoirs comprise almost 70% of the objectives in these stratigraphic plays. There was need for a better understanding of the carbonate reservoir potential in the region. Accordingly, this study was carried out. The distribution, depositional environment as well as factors controlling the quality of carbonate reservoirs are reviewed and analyzed. Carbonate reservoirs in the study area can be found sparsely throughout the Kutai Basin. Carbonates range in age from Oligocene (Bebulu limestone) to Late Miocene (Dian limestone). The main constituents of these carbonate build-ups are platy-corals, encrusting red algae and larger benthonic foraminifera. Most of the carbonates were deposited in a shallow marine environment (inner to middle shelf) during rises in relative sea level. Highstand system tracts are characterized by well-developed carbonate facies-belts. The carbonate build-ups generally occur as isolated bedded mounds, from a few feet up to 1000 ft in thickness. The preservation of primary porosity is generally poor due to diagenetic processes during burial history, particularly the infilling of pores by non-ferroan calcite cement. The development of secondary porosity is limited, due to the retardation of subsurface fluid flow by non-permeable layers, and the absence of solution effects due to sub-aerial exposure and karstification. Preserved porosities are mainly present as vugs, best developed in coarse-grained shelf-margin facies, which may not have subsequently been completely filled by calcite cement. Early hydrocarbon migration may retard the diagenetic processes and preserve the primary carbonate porosity.     

中国东北地区油气地质特征与勘探潜力展望

中国东北地区发育50多个盆地,规模大小不一,较大的盆地包括松辽、二连、海拉尔盆地和5个跨境盆地。东北地区油气资源潜力巨大,油气储量增幅显著,同时面临油气上产、稳产难度仍然持续加大的现实。本文在深入分析东北地区构造与沉积古地理演化过程的基础上,总结了东北地区构造与沉积协同作用下的成藏组合差异发育特征。进一步结合勘探实践,针对油气勘探中存在的问题,围绕着新领域新层系的工作思路,提出了东北地区油气勘探的方向,包括:松辽盆地中央坳陷带中浅层油气精细勘探,松辽盆地南部深层火山岩油气勘探,松辽盆地西斜坡和北部倾末端油气勘探,东北地区古生界油气勘探,大三江盆地群油气勘探,东北地区页岩油和油页岩资源勘探。为未来东北地区油气资源的勘探部署提供了科学依据。