The Silurian Kepingtage Formation of Tarim Basin is an important deep clastic reservoir. Exploration practice shows that the reservoirs are generally characterized by extremely low porosity and permeability, exhibiting strong mineral composition and physical property heterogeneities. The study of heterogeneity and its effect on oil charge is of great significance to the understanding of oil migration and accumulation in such reservoirs and thus is crucial to oil exploration. Therefore, based on identification and quantitative statistics of thin sections, SEM, and homogenization temperature measurements, this study was designed to examine the relationship between diagenetic evolution and oil emplacement in the Silurian Kepingtage Formation in S9 Block in Tarim Basin. The control of differential diagenesis and physical property evolution on oil charge process are discussed. It is found that the sandstones with fine grain size and high content of ductile grains (>20%) have experienced strong mechanical compaction, the porosity decreases rapidly in the early stage of burial. The densification process has been completed before the first period of oil charge so that no oil was found in the reservoir. In contrast, sandstones with relatively coarse grain size and low ductile grain content have better porosity and permeability properties, which are generally oil-bearing. This kind of sandstone generally experienced two periods of oil charge. Apart from moderate compaction, multiple diagenesis events were also observed, including quartz cementation, calcite cementation, and dissolution. Before the early period of oil charge, the diagenesis events are dominated by moderate compaction, chlorite cementation, and dissolution, and the reservoir property is still high. It seems that the time of late period oil charge is relatively long. With the growth of multiple types of authigenic minerals such as quartz, calcite, and illite after or sometimes synchronously occurred with the late period oil charge, the porosity gradually decreases.

Artificial ground freezing technology is the most important construction method of complex water-bearing soft clay rock. The thermodynamic properties of soft clay rock are important evidence for the design and construction of space resources development, and the variable hydrothermal parameter can directly affect the uncertain thermodynamic properties of soft clay rock. In this work, an array of field experiments on the soft clay rock are carried out, and the anisotropic spatial variations of hydrothermal parameters of soft clay rock are obtained. The statistical variability characteristics of variable hydrothermal parameters are estimated. A stochastic coupling model of soft clay rock with heat conduction and porous flow is proposed, and the uncertain thermodynamic properties of soft clay rock are computed by the self-compiled program. Model validation with the experimental and numerical temperatures is also presented. According to the relationship between anisotropic spatial variations and statistical variability characteristics for the different random field correlation models, the effects of the autocorrelation function, coefficient of variation, and autocorrelation distance of variable hydrothermal parameters on the uncertain thermodynamic properties of soft clay rock are analyzed. The results show that the proposed stochastic analysis model for the thermal characteristics of soft clay rock, considering the spatial variability of frozen soil layers, is scientifically reasonable. The maximum standard deviation of average thickness is 2.33 m, and the maximum average temperature is 2.25 °C. For the autocorrelation function, the most significant impact comes from DBIN. For the coefficient of variation, the most significant impact comes from thermal conductivity. Different variations of hydrothermal parameters have different effects on the standard deviation of soft clay rock temperature. The biggest influence is the thermal conductivity, while the lowest influence is the specific heat capacity.

车排子-莫索湾古隆起是准噶尔盆地腹部的正向构造单元, 油气成藏条件优越, 其形成演化过程对于挤压环境下"凹中隆"格局的变形史有较大的指示意义。本文通过区域构造分析和地震资料精细解释明确了车排子-莫索湾古隆起的构造特征及演化过程, 通过砂箱实验模拟揭示了古隆起的成因机制。研究结果表明, 古隆起以古潜山形式存在于盆地腹部, 在白垩系沉积前为轴向NE-SW的宽缓背斜, 脊线高点位于征1井附近, 南北两端弯曲, 整体成"S"形。古隆起的演化可分为四个阶段: 中侏罗世前的基底调整稳定期; 中侏罗世在西北缘边界挤压下盆地腹部缓慢隆升雏形期; 晚侏罗世古隆起快速隆升形成期; 白垩纪-新生代受盆地南缘控制整体南倾改造期。受中、晚侏罗世达尔布特断裂左行走滑作用影响, 扎伊尔山系派生SE向挤压应力导致的远程传递作用使盆地腹部发育平缓的背斜, 隆起轴线与西北缘断阶带走向近平行; 乌伦古地块南界的右行剪切作用使得古隆起轴线向北东弯曲, 盆地边界形态及南缘挤压剪切造成古隆起上升并转向。古隆起在油气成藏过程中具有较好的聚油作用, 尽管后期形态改造造成了原有油气藏部分被破坏, 但也导致油气向北西运移并聚集。本文研究认为, 该地区今后的油气勘探方向应以岩性及构造-岩性复合油气藏为主。

The Jurassic reservoirs in the Fukang Sag of the Junggar Basin exhibit heterogeneous overpressure. As the mechanisms underlying overpressure generation remain poorly constrained, this poses challenges for accurate pre-drilling-pressure prediction and hinders a comprehensive understanding of hydrocarbon accumulation processes. Through integrated analysis of measured pressure, mud weight, and well-logging curves, this study delineates distinct overpressure characteristics in sandstones and identifies the well-logging response to overpressure in mudstones. By coupling the loading-unloading response with the analysis of geological conditions conducive to overpressure, we differentiate the overpressure-generating mechanisms between sandstones and mudstones and assess their implications for deep petroleum exploration. The study reveals significant vertical heterogeneity in pressure regimes, with sandstones exhibiting pressure coefficients ranging from 1.2 to 1.8, locally exceeding 2.1. Strong overpressure preferentially develops in isolated sand bodies linked to deep source kitchens via oil-source faults. The logging response of overpressured mudstones shows high acoustic transit time, high neutron, and low resistivity, deviating from the normal compaction trend, yet demonstrates progressive density increases attributable to chemical compaction processes. Overpressure points with pressure coefficients between 1.2 and 1.4 align with the loading curve dominated by disequilibrium compaction. The overpressure with a pressure coefficient exceeding 1.4 correlates with abrupt unloading responses indicative of fault-transferred overpressure in sandstones. Our results highlight that overpressured fluid migration via faults is a critical process in hydrocarbon migration, with large-magnitude overpressured reservoirs being readily formed near oil-source faults. Multi-overpressure mechanisms create a complex pore-pressure distribution in deep layers, challenging conventional pressure-prediction models. These insights advance predictive models for pore pressure and provide a robust framework for optimizing exploration strategies in the Fukang Sag.

The thermal history of carbonate successions is fundamental to constraining hydrocarbon generation and reservoir diagenesis, yet traditional proxies such as vitrinite reflectance and apatite fission-track analysis are often inapplicable to marine carbonates because organic matter and suitable heavy minerals are scarce. This study evaluates an integrated carbonate isotope (Δ₄₇) thermometry and in situ U-Pb geochronology approach using a micrite matrix and three dolomite-bearing samples from the Upper Permian Changxing Formation in the Yuanba area, northern Sichuan Basin, southwestern China. The measured apparent clumped isotope temperatures (TΔ₄₇) range from 127.8 to 174.6 °C. The micrite matrix yields a U-Pb age of 257 ± 1.2 Ma, consistent with an early depositional or syndepositional origin, whereas the dolomite samples yield younger diagenetic ages. Coupling these time–temperature constraints with an exchange–diffusion model for solid-state reordering provides a preliminary, well-scale thermal scenario for the sampled intervals. The preferred model suggests rapid heating during Late Permian–Early Triassic and Middle Jurassic burial, followed by peak heating to approximately 220 °C in the Late Cretaceous at modeled maximum burial depths exceeding 8000 m, and subsequent cooling during Yanshan–Himalayan uplift and denudation. A conditional maturity model predicts that the underlying Wujiaping Formation source rocks entered the main gas-generation window (1.3% < Ro < 2.6%) by the Middle Jurassic and became overmature during peak heating in the Late Cretaceous. This dual-proxy framework is promising for carbonate-dominated petroleum systems but requires validation with a larger sample set and independent thermal indicators.