Water saturation is one of the most critical yet often underappreciated petrophysical parameters in reservoir characterization. A wide range of petrophysical and reservoir engineering computations that lead to crucial field development decisions, including reserve estimation, waterflooding efficiency calculation, and capillary pressure deduction, rely on its accurate determination. This study demonstrates how machine learning techniques can forecast reservoirs' fluid saturation and pressure distribution. This study describes a deep learning-based proxy modeling technique for accurately predicting reservoir pressure distribution and fluid (oil, water, and gas) saturation during water flooding in single-layer heterogeneous reservoirs. This study used recurrent neural networks (RNNs) and convolutional neural networks (CNNs) to build a proxy model. This work indicates that compared to simulation outcomes, computer-based machine learning algorithms can accurately predict fluid (oil, water, and gas) saturation and pressure distribution. The stated accuracy was evaluated numerically and graphically, and error analysis between various machine learning approaches and simulated results was utilized.

Accurate prediction of oil-based drilling fluid (OBD) behavior under high-temperature, high-pressure (HTHP) conditions in ultra-deep wells is essential for ensuring well control safety. However, research on the volumetric expansion of OBD in HTHP wellbores remains limited. This study develops a mathematical model to predict the expansion characteristics of OBD in HTHP wellbores, incorporating temperature- and pressure-dependent variations in rheological properties, thermophysical parameters, and density. The model is solved using discretization and the successive over-relaxation (SOR) method. Laboratory experiments were conducted to measure the rheology and density of OBD at different initial densities under varying temperature and pressure conditions. Binary mathematical models describing density and rheology as functions of temperature and pressure were established. The results indicate that the rheological properties of OBD exhibit consistent trends across different initial densities. Apparent viscosity (AV) and plastic viscosity (PV) decrease with increasing temperature and gradually stabilize, while both increase with rising pressure. The density of OBD decreases due to thermal expansion at elevated temperatures and increases due to thermal contraction at lower temperatures. Temperature exerts a greater effect on OBD density than pressure. Model validation using field data from an ultra-deep well confirms the accuracy of the proposed approach. During drilling and tripping operations, changes in mud pit volume occur due to temperature fluctuations; however, these changes are relatively slow compared to the rapid volume changes associated with wellbore influx. It is recommended to suspend the use of drilling fluid cooling devices before pulling out of hole (POOH) operations to minimize mud pit volume fluctuations. These findings provide theoretical guidance for accurate bottom-hole temperature prediction and improved drilling strategy optimization.

To meet the operational requirements of slip-type packers within TP140V casing in ultra-deep wells and enhance the anchoring performance and load-bearing capacity of the packer's anchoring mechanism during setting, this paper focuses on the study of tooth-embedded slips. The Abaqus finite element software was used to analyze the stress and contact pressure distribution patterns in key components such as the embedded teeth, casing, and slip base during the anchoring process of tooth-embedded slips. An orthogonal experimental method was employed to optimize the structural parameters of segmented tooth-embedded slips. Based on the results of the orthogonal experiments, the optimal combination of slip structural parameters was obtained: the front-end distance was 12 mm, the tooth installation spacing was 24 mm, the dip angle of the groove was 76.5°, the groove depth was 6.8 mm, and the slip wedge angle was 13°. After optimization, the maximum Von Mises stress in the slip base was reduced from 1080 MPa to 512.2 MPa, the embedding depth decreased from 0.2156 mm to 0.1338 mm, and the maximum contact pressure at the tooth tips dropped from 4247 MPa to 2965 MPa. Compared to the pre-optimization values, these reductions were 52.6%, 37.9%, and 30.2%, respectively. Moreover, the optimized casing bite depth and tooth-tip contact pressure exhibited a more uniform axial distribution. Additionally, physical prototypes of the optimized slips were manufactured and subjected to laboratory tests, which demonstrated that the axial bearing capacity of the slips could reach 450 kN, capable of withstanding axial loads in a 152.5-mm inner diameter casing under a downhole pressure environment of 100 MPa. The research findings in this paper provide a theoretical reference for optimizing the structural parameters of tooth-embedded slips within TP140V steel grade casing.

This study aims to develop a low-cost and environmentally friendly multifunctional thinning agent for water-based mud (WBM) from tea leaf extract (TLE). Matured tea leaves that are not used for tea production were collected, processed, and boiled in distilled water to release the extracts and prepare the liquid thinning agent. The resultant TLE was characterized using Fourier Transform Infrared spectroscopy (FTIR). Rheological properties were measured at two temperature conditions (35 ℃ and 70 ℃) with varying concentrations of TLE, and the findings were compared with the widely used thinning agent potassium lignite (PL) under all test conditions. In addition, the density, pH, filtration control, and lubricating properties were evaluated under ambient conditions. The findings revealed that TLE, under all test conditions, exhibited better thinning performance than potassium lignite. At the temperature of 35 ℃, when used at 1% concentration, TLE reduced apparent viscosity, plastic viscosity, yield point, initial and final gel strength by 23.94%, 21.57%, 27%, 76.99%, and 24.44%, respectively, compared to 12.89%, 16.34%, 8.44%, 39.82%, and 7.94% using the same concentration of potassium lignite. Compared to the ambient condition, the effectiveness of TLE in controlling rheology was found to be more pronounced at higher temperatures. Moreover, TLE at different concentrations significantly improved the filtration and lubricating properties of the mud. The addition of TLE reduced the mud cake thickness by a maximum of 44.44% and the coefficient of friction by a maximum of 40.7%. The comprehensive investigation and comparison with potassium lignite suggest that TLE can be effectively used as a multifunctional, non-toxic, and low-cost thinning agent for water-based drilling fluids.

Geopolymers are promising alternatives to Portland cement due to their lower carbon footprint, superior mechanical strength, durability, and reduced shrinkage. However, inconsistent data and significant variations in experimental results highlight the uncertainty surrounding the reaction mechanisms of clay-based geopolymers (CBGs) in high-temperature oil wells. This review provides critical insights into these mechanisms and summarizes CBG synthesis methods. It explores the reaction processes of CBGs under high-temperature oil well conditions and analyzes the variables influencing these mechanisms. This review also examines the application of CBGs in oil wells, focusing on the challenges and potential solutions. Laboratory studies show that Portland cement degrades at temperatures above 300 ℉ (150 ℃), while CBGs maintain their integrity and strength at temperatures up to 1500 ℉ (815 ℃). This makes them particularly suitable for high-temperature geothermal wells and high-pressure, hightemperature oil well cementing. The dominant reaction mechanisms of CBGs include chemical reactivity, dissolution, gelation, polymerization, and growth. These findings highlight the potential of CBGs in addressing the challenges of high-temperature oil wells, thereby paving the way for further research in this area.

To maintain the integrity of internal floating roof tanks, curb environmental pollution and guarantee the safety of tank farms, it is important to determine the oil flow features that impact the floating roof during the oil receiving process, especially when the floating roof falls to the bottom of the tank. In this study, the finite volume, volume of fluid (VOF), and realizable k-ε turbulence models and the pressure implicit with splitting of operators (PISO) algorithm were adopted to establish a three-dimensional physical model of an internal floating roof tank and simulate the oil receiving process. A pressure test platform was then set up to validate the model's viability. The flow field characteristics and influencing properties of the impact of the liquid against the floating roof under different oil inlet velocities, initial liquid levels, medium densities, and tank diameters were analyzed and compared. The results showed that increasing the oil inlet velocity and medium density led to the maximum pressure and the impact force at different moments of the liquid against the floating roof also increasing. An increase in the oil inlet velocity, led to greater turbulence on the opposite the inlet, and higher pressure at the edge of the floating roof in the upper area opposite the inlet. At an oil inlet velocity of 4.0 m/s, the maximum pressure was 135.5 kPa and the maximum impact force peak was 13.967 MN. The initial liquid level increase had little influence on the liquid's impact on the floating roof, and the high pressure zone was at the edge of the floating roof opposite the inlet. When the initial level was 0.5 m, the maximum pressure was 135.81 kPa and the maximum impact force peak was 14.021 MN. As the density of the medium increased, the greater the turbulence on the inlet relative side and the higher pressure at the edge of the floating roof in the upper area of the inlet relative side. When diesel was the medium, the maximum pressure was 154.9 kPa and the maximum impact force peak was 15.999 MN. As the diameter of the tank increased, the maximum pressure of the floating roof impacted by the liquid reduced, but the impact force increased. The slower the turbulence on the inlet relative side, the greater the maximum pressure zone of the floating roof. When the tank volume was 1000 m³, the maximum pressure was 135.5 kPa. When the tank volume was 10,000 m³, the maximum impact force peak was 81.978 MN. Considering the above, a low velocity, a low-density light oil, and an internal floating roof tank with a small diameter are recommended for engineering operations that involve receiving oil. Further increased safety precautions at the edge of the floating roof opposite the inlet are needed. In sum, the findings of the study offer theoretical justifications and a technical reference for optimizing the structural design of floating roofs and the oil receiving and delivering process.