Elemental logging evidence for paleoenvironmental reconstruction of the ordovician strata in the Western Ordos basin, China.

The Ordovician carbonate succession in the western Ordos Basin, China, represents an important target for unconventional hydrocarbon exploration, particularly shale gas in the Wulalike Formation. In this study, we utilize high-resolution elemental logging data from MJ1 well to reconstruct the paleoenvironmental evolution of the basin and evaluate the controlling factors on organic matter enrichment. Major and trace element distributions reveal distinct geochemical signatures across stratigraphic units, reflecting variations in lithology, productivity, redox conditions, paleoclimate, salinity, and water depth.

Modeling and application of production metering for electric pump wells without downhole pressure measurement devices.

To address the issues of low frequency and high costs associated with the current manual production measurement for ESP wells in the Tarim Oilfield, a study was conducted to develop a digital production measurement method for ESP wells. Based on the principle of energy conservation, where the input power of the pump equals the output power of the motor, and incorporating parameters such as surface tubing and casing pressure, motor current, and motor/ pump performance curves, with viscosity correction of the pump performance curve, a corrected power calculation method was proposed. A digital production measurement mathematical model was established.

Quantitative Analysis of the Formation and Evolution of Underpressure in Tight Sandstone Reservoirs in the Craton Basin: The Chang 7 Member in the A Area of the Ordos Basin.

The Ordos Basin is a typical craton basin. Underpressure exists in the tight sandstone reservoirs of the Chang 7 member of the Upper Triassic Yanchang Formation in the Yishan slope of the basin. However, overpressure was verified in these reservoirs during the Early Cretaceous period, and the evolution process from overpressure to underpressure is still unclear.

Identification and comparative genomic analysis of two Bacillus subtilis producing antifungal lipopeptide.

Bacillus subtilis demonstrates functional diversity through production of structurally distinct lipopeptides, demonstrating significant potential for biocontrol applications. Two high-yield lipopeptide-producing strains, SL-2(7216.4 mg/L) and L6(3462.

Evaluation of Oil Displacement by Polysaccharide Fermentation Broth of Under Extreme Reservoir Conditions.

In the development of high-temperature and high-salinity oil fields, biopolymer scleroglucan flooding technology faces significant challenges. Traditional scleroglucan products exhibit poor injectability and high extraction costs. This study investigated the application potential of the original fermentation broth of exopolysaccharides (EPS) produced by microorganisms in a simulated high-temperature and high-salinity oil reservoir environment.

Experimental study of the effect of natural fracture curvature on hydraulic fracture propagation behavior.

The interaction mechanism between hydraulic fractures (HF) and natural fractures (NF) constitutes a critical research focus in hydraulic fracturing optimization. This study systematically investigates the influence of NF curvature on HF propagation behavior through large-scale true triaxial hydraulic fracturing physical simulations. The experiments were conducted on artificial rock specimens containing prefabricated fractures with varying curvature parameters.

Mechanisms of Intermolecular Interactions and Molecular Dynamics in Anionic and Nonionic Surfactant Microemulsions.

This study investigates the molecular interactions and self-assembly behaviors in microemulsions formed by alkanes, alcohols, a nonionic surfactant (C12E5), and anionic surfactants (SDBS, SDS). Utilizing quantum mechanical weak interaction analysis and molecular dynamics simulations, we explore the weak interaction forces, thermal stability, and conformation of surfactant molecules at the interface membrane. Radial distribution function (RDF) and molecular polar surface area (MPSA) analyses reveal how hydrophilic group structures influence water molecules, while reduced density gradient (RDG) diagrams provide insights into microscopic interactions.

Coupled Evolution of Oil Content and Pore Structure of the Qingshankou Formation Shale, Songliao Basin, Northeastern China: Insights from Thermal Simulation Experiments.

Oil content estimation and pore characterization of shale are crucial for identifying sweet spots in shale plays. Despite extensive research, the correlation between retained hydrocarbon characteristics and pore evolution in shale with thermal maturity remains controversial. This study employs an integrated approach, combining thermal simulation experiments with multiple analytical techniques, to investigate organic geochemical characteristics and pore structure evolution across different maturity stages.

Nonequilibrium Phase Behavior of Condensate Gas Flow in Porous Media.

The description and quantification of condensate gas flow in porous media are often inadequate when considering nonequilibrium phase behavior. This study presents a systematic approach that integrates experimental research with advanced mathematical techniques. A pressure depletion test conducted on a long core demonstrates that a higher condensate recovery can be achieved with faster pressure drop rates.

Enrichment Mechanism of Organic Matter in the Marine-Continental Transitional Shale of the Taiyuan Formation in Ordos Basin, China: Control of the Paleoenvironment.

With the growing recognition of substantial exploration potential in transitional shale gas, increasing attention has been directed toward organic-matter-rich transitional shale. Although previous studies have primarily examined the characteristics of organic matter, basin depositional environments, and individual geochemical parameters, detailed analyses of depositional microfacies remain limited. Furthermore, the integration of geochemical analyses with sedimentological characteristics has been insufficient, leading to a limited understanding of the factors controlling the organic matter enrichment in transitional shale.

A case study of reservoir characterization and modeling for tidal-dominated estuary reservoir in Ecuador.

The Oriente Basin, as part of the retro-arc foreland basin system, develops tidal-dominated estuary, where the LU layer exhibits complex sedimentary characteristics in lateral that brings great uncertainty to reservoir characterization using only wells. As a result, it is essential to investigate the sedimentary characteristics of the tidal-dominated estuary by incorporating seismic data. First, four electrofacies are established to characterize the logging response of various lithology combinations in an estuary setting.

Geostress in the Ordovician system of the northern segment of the Shunbei No. 4 fault zone based on finite element simulation.

The principal focus of geostress studies in the Shunbei area has been on stress measurements, one-dimensional stress profiles, and the stress distribution across planes. However, research on the three-dimensional (3-D) geostress field of the Ordovician system is relatively lacking, and investigations into the stress states of faults have not yet been conducted, thereby hindering the progress of oil and gas exploration and development in this area. This article comprehensively utilizes geological, logging, and seismic data to establish a high-resolution 3-D structural geological model.

Quantitative reconstruction of phase states and evolution of condensate and gas in the western Kelasu Thrust Belt, Kuqa Depression, Tarim Basin.

Various oil-gas reservoirs have been discovered in the Lower Cretaceous Beshijiqike Formation in the western Kelasu Thrust Belt, Kuqa Depression, Tarim Basin. However, uncertain evolutionary characteristics, physical properties, and formation process for diverse phase states hinder further petroleum exploration and development. In this study, we reconstructed models of phase state evolution of six wells integrating PVT simulation and basin modeling.

Device-Driven Service Allocation in Mobile Edge Computing with Location Prediction.

With the rapid deployment of edge base stations and the widespread application of 5G technology, Mobile Edge Computing (MEC)has gradually transitioned from a theoretical concept to practical implementation, playing a key role in emerging human-machine interactions and innovative mobile applications. In the MEC environment, efficiently allocating services, effectively utilizing edge device resources, and ensuring timely service responses have become critical research topics. Existing studies often treat MEC service allocation as an offline strategy, where the real-time location of users is used as input, and static optimization is applied.

Paleoenvironment reconstruction and differential OM enrichment mechanism of the Upper Triassic Chang 7 member source rocks in the Ordos Basin.

The organic-rich mudstones within the lacustrine deposits of the Chang 7 member in the Ordos Basin are recognized as the primary source rocks of the Mesozoic petroleum system. Previously, scholars have extensively investigated the formation processes of high-quality source rocks in the deep lake facies of the southern part of the basin. However, systematic studies on the differential enrichment of organic matter in the Chang 7 member across the entire basin are lacking.

Effect of the Codetermined Seepage Ability by Varying Hydrate Saturation and Rock-Matrix Permeability on Depressurized Gas Coproduction in Hydrate Reservoir with an Underlying Free-Gas Layer.

Within hydrate reservoir, depressurization in the underlying free-gas layer could facilitate efficient gas coproduction, provided that its overall seepage ability is conducive to pressure propagation. Such overall seepage ability is codetermined by hydrate saturation ( ) and rock-matrix permeability (), and varies across different hydrate reservoirs and even at different locations of the same reservoir. In this study, we designed an experiment/simulation integrated approach to investigate the effect of the codetermined overall seepage ability by varying hydrate saturation and rock-matrix permeability on depressurized gas coproduction.

Screening and Evaluation of CO Thickening Agents Based on Molecular Dynamics Simulation Technology.

CO is one of the main methods for improving recovery. The low viscosity and density of CO lead to issues such as viscous fingering and gravitational override during the displacement process, which can cause gas channeling and premature breakthrough in reservoirs. These problems severely affect sweep and displacement efficiencies, thereby reducing the recovery of CO flooding.

Hydrocarbon migration and accumulation simulation: A review and a novel multi-scale quantitative numerical simulation method.

The simulation of hydrocarbon migration and accumulation is critical for understanding petroleum systems, yet existing methods face significant limitations, particularly in unconventional reservoirs. Traditional physical experiments are constrained by scale, complexity, and difficulty in reproducing real subsurface conditions, while conventional numerical simulation models struggle to capture the multi-scale dynamics of fluid flow in low-permeability formations. Many current approaches fail to incorporate key microscopic mechanisms, such as capillary effects, wettability alterations, and multi-phase interactions, leading to inaccuracies in predicting hydrocarbon accumulation.

Experimental study on isothermal adsorption and desorption characteristics and influencing factors of transitional facies shale gas.

Methane adsorption and desorption are important for shale gas storage and production, but the effects of shale, temperature, pressure, and water content are not fully understood. This study looks at methane adsorption and desorption in shale gas reservoirs under different temperature, pressure, and water conditions. It highlights how water molecules compete for adsorption sites, reducing adsorption capacity.

Study on the Mechanism of Swept Volume Expansion of a Nanoparticle-Polymer Compound Flooding System in Low-Permeability Reservoirs.

With the advancement of oil field development, oil and gas exploration has gradually shifted to low-permeability reservoirs. When polymer flooding is applied in these reservoirs, the primary challenge is that polymer molecules have a larger size and struggle to enter the pore spaces in the reservoir. To address this issue, this study utilizes a nanocomposite polymer flooding system, leveraging the synergistic effects of nanometer-sized particles to reduce the size of polymer aggregates and thus improve displacement efficiency.

Mesozoic Tectonic Setting and Evolution in Kuqa Depression of the Tarim Basin: A Study of Detrital Zircons and Geochemistry.

Kuqa Depression is an important oil-bearing tectonic unit in the Tarim Basin, and the Mesozoic tectonic setting is of great significance for hydrocarbon exploration in the deep-seated strata of the depression. In this paper, the Mesozoic tectonic setting and evolution processes of Kuqa Depression have been studied by using petrology, seismic interpretation, zircon chronology, and geochemistry methods, combined with the analysis of rock properties and age composition of potential provenance areas. The results show that the zircon ages of the sandstones of Triassic Taliqike Formation range from 251 to 2816 Ma, the zircon ages of the sandstones from the Jurassic Yangxia and Ahe formations range from 241 to 2600 Ma, and most of the zircon ages are concentrated in 241-485 Ma.

Using Mg isotopes to constrain the formation temperature of dolomite.

The "dolomite problem" has long been a significant challenge in sedimentology, particularly regarding the determination of dolomite formation temperatures, a subject that remains highly debated. Magnesium (Mg) isotopes, due to their stability in dolomite during diagenesis and the strong relationship between isotopic equilibrium fractionation and temperature, present a promising tool for estimating the formation temperatures of dolomite. In this study, we analyzed the Mg isotope composition (δMg) of various dolomite samples from the Ediacaran to Ordovician in the Tarim Basin, China, to assess the potential of Mg isotopes as a thermometer for dolomite formation.

Permafrost thawing under overlaying salt water.

Thawing of permafrost substantially affects the local environment and global energy balance. When salt water overlays permafrost, Rayleigh-Darcy (R-D) instability emerges because of the density mismatch and regulates melting (thawing) dynamics. Contrary to expectations that a higher Rayleigh number () would amplify instability, our experiments revealed fingering and stable melting fronts at low and high , respectively.

Genetic mechanism of bicyclic sesquiterpanes in Upper Triassic source rock of Yinan 2 well from the Kuqa Depression of Tarim Basin, China.

Bicyclic sesquiterpanes are widely distributed in terrigenous sedimentary organic matter and are serve as valuable biomarker in the field of organic geochemistry. However, their formation and evolution, especially in geological conditions, are still poorly understood. In the present study, a series of bicyclic sesquiterpanes, including C-C rearranged and regular compounds with generally dominant isomers of 4,4,8,8,9-pentamethyl-trans-decalin, 8(β)H-drimane, and 8(β)H-homodrimane, have been detected in approximately 230-m-thick Upper Triassic source rocks from the Yinan 2 well in the Kuqa Depression of Tarim Basin, NW China.

Features of Karst Paleogeomorphology and Sedimentary Environment of Ordovician Majiagou Formation in Eastern Ordos Basin.

The formation and evolution of carbonate weathering crust-type reservoirs are closely linked to paleokarst processes. This study aims to restore and analyze the karst paleogeomorphology and sedimentary environment of the Ma2 and Ma3 sections in the eastern Ordos Basin, using the compensation thickness impression method. The Ma3 section is characterized by widespread distribution and considerable thickness, with clear inheritance among the sublayers and minimal variation in thickness across the section.