Science Bulletin, Год журнала: 2024, Номер unknown
Опубликована: Ноя. 1, 2024
Язык: Английский
ACS Omega, Год журнала: 2023, Номер 8(50), С. 47540 - 47559
Опубликована: Дек. 8, 2023
The Qaidam Basin is a prominent oil and gas exploration production base of NW China's Jurassic coal-bearing strata. Coal-bearing mudstones are important source rocks for unconventional reservoirs can record valuable paleoenvironment paleoclimate information. Here, geochemical analysis including total organic carbon (TOC), sulfur, isotopic composition, rock pyrolysis, X-ray diffraction, major trace elements were carried out on mudstone samples from the Middle strata Dameigou section in to reveal paleoclimatic paleoenvironmental conditions during deposition their controls matter accumulation. Results show that Shimengou formations include three significant stages based average TOC values (3.32%, Stage I; 0.87%, II; 4.42%, III) bottom top. Stages I II mainly derived terrestrial higher plants, while has mixed sources plant debris lower aquatic organisms III. Paleoclimate parameters indicate deposited under humid warm conditions, climate changed semiarid before turning dry hot varying characteristics different have also been reconstructed. Our results suggest accumulation was primarily controlled by redox paleoproductivity controlling factor
Язык: Английский
Процитировано
4
Energy Exploration & Exploitation, Год журнала: 2022, Номер 41(1), С. 3 - 18
Опубликована: Июль 25, 2022
The study on the Zhangjialiang No. 2 coal of Middle Jurassic Yan'an Formation in northeastern Ordos Basin has been analyzed by gas chromatography-mass spectrometry (GC-MS) to determine geochemical characteristics and reconstruct palaeovegetation palaeoclimate changes. distribution n-alkanes is mainly unimodal, with a medium high molecular weight. Pr/Ph ratio (2.03–10.6) most samples. values Tm/Ts are between 1.42 4.92, predominance C 29 over 27 steranes found for These parameters indicate that all samples were deposited an oxidizing freshwater environment, organic matter was derived from terrestrial higher plants, small amount aquatic organisms. Thermal maturity such as 31 22S/(22S + 22R) homohopane, 30 αβ/(αβ βα) hopane, together total carbon (TOC) contents (43.1% - 58.6% (except floor 2-13)) detected 17β(H)-22, 29, 30-trisnorhopane (βTm), suggest have relatively low early stage. Besides, gymnosperm-derived biomarkers, including labdane, norpimarane, isopimarane, phyllocladane, abietane, rimuane, ent-beyerane, ent-kaurane, vegetation during Yan’an characterized conifers.
Язык: Английский
Процитировано
4
Palaeoworld, Год журнала: 2023, Номер 33(4), С. 1044 - 1064
Опубликована: Июнь 17, 2023
Язык: Английский
Процитировано
2
Frontiers in Earth Science, Год журнала: 2022, Номер 10
Опубликована: Сен. 9, 2022
The organic-rich shales of the Chang 7 Member in Yan’an Formation area, Ordos Basin is a hot spot for lacustrine shale gas exploration. In this paper, taking area as an example, main controlling factors accumulation and prediction “sweet spots” are systematically carried out. results show that Yanchang has complete generating conditions. Shale requires three necessary elements, namely source, reservoir good preservation dynamic hydrocarbon generation process reservoirs established according to thermal simulation experiments generation, mechanism catalytic degradation under background low evolution degree revealed. enriched authigenic pyrite can catalyze organic matter with activation energy, thereby increasing rates low-mature-mature stage. Different types pores at different scales (2–100 nm) form multi-scale complex pore network. Free dissolved laminar micro-scale pores, adsorbed nano-scale thick shales, silty laminates improve physical properties reservoir. This because structure better conditions favorable migration oil molecules. thickness between 40 120 m, which exceeded effective expulsion limit (8–12 m). At end Early Cretaceous, excess pressure was above 3 MPa. present, horizontal wells daily production more than 50,000 cubic meters distributed areas high pressures during maximum burial depth.
Язык: Английский
Процитировано
3
Geological Journal, Год журнала: 2024, Номер 59(6), С. 1724 - 1742
Опубликована: Апрель 21, 2024
The Early‐Middle Jurassic is one of the crucial coal‐forming geologic periods in world and an important target for hydrocarbon exploration Turpan‐Hami Basin, China. paleoenvironment vegetation reconstruction have been investigated using elemental geochemistry palynological analysis to reveal paleoclimate evolution. A total 48 genera pteridophyte spore 35 gymnosperm pollen were identified, 5 assemblages longitudinally divided, which showed significant differences geochemical behaviours. was a transition from suboxidation anoxia then oxidation environment under freshwater conditions. paleowater northern Taibei Sag deeper than that southern part during Middle Jurassic, coincided with sedimentary background sublacustrine fan north shallow braided river delta south. paleovegetation evolved mixed lowland–upland forest Hettangian‐Toarcian, lowland fern Aalenian‐Bajocian, upland conifers early Bathonian, Cheirolepidiaceae late Bathonian‐Callovian. Toarcian Bathonian‐Callovian arid climate Hettangian‐Pliensbachian Aalenian‐Bajocian warm‐humid responses continued global warming events intensification East Asian monsoon circulation, respectively. influence aridification event on response will be delayed due gradual southward migration depositional centre.
Язык: Английский
Процитировано
0
Science Bulletin, Год журнала: 2024, Номер unknown
Опубликована: Ноя. 1, 2024
Язык: Английский
Процитировано
0