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 >

Selecting the most suitable enhanced oil recovery (EOR) technique remains challenging due to severe class imbalance in historical datasets and the limitations of traditional screening criteria. To address data imbalance while preserving domain knowledge, this study proposes a novel machine learning framework that incorporates domain-informed synthetic data generation strictly constrained by established EOR screening criteria. An initial dataset of 583 documented EOR projects was compiled from field reports and public databases. After rigorous cleaning, 575 valid samples were retained and subsequently augmented to 760 balanced instances (class sizes ranging from 60–110 samples per class). T... More >

Deep geothermal resources are environmentally friendly and represent a highly competitive form of clean energy. However, low rock-breaking energy combined with high rock strength results in a low rate of penetration (ROP), which significantly restricts the efficient utilization of geothermal resources. Previous studies have shown that rock failure is primarily caused by shear stress. Therefore, this paper aims to enhance the shear stress level by increasing the impact load and releasing the confining pressure, thereby improving the ROP. Specifically, the rock-breaking efficiency under the coupling of impact load and confining pressure releasing is analyzed to reveal the influence of confinin... More >