Owing to their high calorific value and sustainable characteristics, natural gas hydrates are expected to serve as a promising alternative energy resource to conventional oil and gas in the near future. Of course, this prospect relies on the premise that hydrates can be developed in a safe and efficient manner. Hydrate-bearing sediments are highly sensitive to temperature and pressure conditions and are therefore particularly vulnerable to disturbances induced by production operation, which may result in challenges such as wellhead instability. In this study, the physical parameters of artificially prepared hydrate-bearing sediments were experimentally characterized to provide a parameter fo... More >

Heavy oil reservoirs often retain substantial remaining oil after polymer flooding with vertical wells due to unfavorable oil-water mobility ratios and reservoir heterogeneity. Although horizontal wells can improve oil displacement efficiency by providing a larger contact area with the formation, systematic studies on the displacement behavior and key influencing factors of polymer flooding in opposed horizontal wells are still lacking. This study addresses this gap by combining two-dimensional physical simulation experiments with Eclipse numerical simulation to investigate the displacement dynamics and remaining oil distribution. The experimental results show that increasing well spacing pr... More >

The morphological transformation of methane hydrates during re-exploitation, caused by depressurization and changes in reservoir environment, significantly impacts hydrate extraction. The present study explores the adsorption and desorption behaviour of methane under different environmental factors by constructing a rock adsorption and desorption device, which can contribute to the efficient extraction of methane during the decomposition of methane hydrates. The findings demonstrate that reservoir temperature strongly promotes methane desorption. Desorption capacity increased markedly above $100^{\circ}\mathrm{C}$, reaching $9.4~\mu\mathrm{g/g}$ at $120^{\circ}\mathrm{C}$, consistent with re... More >

Enthalpy is a key thermodynamic parameter governing energy extraction efficiency in Enhanced Geothermal Systems (EGS). Although Machine Learning (ML) has been widely applied in geothermal modeling, few studies have systematically integrated Response Surface Methodology (RSM) with ML to develop and compare multiple predictive models for enthalpy production. Using datasets from CMG STARS simulations, we developed predictive models based on RSM and four ML techniques (Random Forest, Decision Tree, XGBoost, and Support Vector Machine). A Central Composite Design (CCD) in CMG CMOST established relationships between operational parameters and enthalpy, while Particle Swarm Optimization (PSO) deter... More >

Permafrost is typical temperature-sensitive sediment, and geo-mechanical issues such as wellbore collapse and sand production are prone to occur during the oil and gas development. Therefore, it is crucial to elucidate the patterns and mechanisms of wellbore instability throughout the drilling process and to develop/propose effective control strategies. In this study, based on sensitivity analysis of wellbore stability, a method for determining the safe windows of drilling fluid temperature, density, and salinity was proposed, along with corresponding measures for preventing wellbore collapse. The investigation results indicate that the collapse of sediments around the wellbore was primarily... More >

Hydrocarbon prospectivity in fold-and-thrust belts remains inherently uncertain due to the combined effects of structural complexity and heterogeneous reservoir properties. The Eastern Potwar region of Pakistan, characterized by imbricate thrust systems, anticlines, and synclines, represents a typical example where conventional approaches often fail to adequately constrain reservoir quality. This study integrates seismic interpretation with rock physics modeling to evaluate the hydrocarbon potential of the Missakeswal area. Seismic analysis delineates the structural framework controlling trap development, while rock physics modeling of well log data provides quantitative constraints on litho... More >

This study addresses fracturing performance evaluation during shale oil well flowback by developing a seepage flowback mathematical model and a water-phase evaluation framework. A method calculating effective fracture pore volume via flowback water production data is proposed. Using Well H flowback records, variable-production log-log well test plots and RNP-tm diagnostic charts were constructed for time-dependent fracturing effectiveness quantification. Key findings include: (1) Initial maximum cumulative water production derived from Arps harmonic decline model shows a semilogarithmic relationship between daily/cumulative water output; (2) Unit slope in fracturing fluid flowback indicates... More >

Extended-reach horizontal wells in continental shale formations of the Fuxing Block, southeastern Sichuan Basin, face prominent challenges, including drag and torque exceeding 50 metric tons and difficulties in weight-on-bit (WOB) transfer. Continental shale is characterized by high porosity, high permeability, distinct amphiphilic properties, and rapid performance degradation of oil-based drilling fluids (OBDF). These features lead to the formation of thick filter cakes and compacted cuttings beds, which further exacerbate abnormal drag. Existing research often focuses on single technical aspects, lacking integrated, full-cycle multi-factor coupling analysis. Based on field data from 14 dri... More >