Spontaneous imbibition is the main mechanism responsible for retention of large amounts fracturing fluid during flowback period in shale gas development. Studying will help optimize design and improve accuracy production prediction. Previous experiments have mainly focused on studying relationship between amount liquid imbibed into samples time. However, these could not describe visually saturation distribution along rock samples. In this paper, a chemical potential-dominated flow model...

The objective is to address the issue of gas-carrying particles generated by erosion wear problems in transportation process gas storage reservoir pipelines. In accordance with principles multiphase flow theory, particle discrete phase model, high temperature, pressure, water volume fraction, and other pertinent factors, this paper presents a three-phase gas–liquid–solid mathematical model three-way reservoir. effects content extraction, mass rate, size on tee’s location rate were...

There are few studies on erosion problems in gas storage environments. High-speed gas-carrying sand wells can cause pipeline and subsequent failure. To this end, a numerical model of gas/liquid/solid three-phase under high temperature high-pressure conditions was established. The combines the laws conservation mass, momentum, energy, as well force solid particles. Using established mathematical erosion, simulations were performed to study process column different parameters during injection...

Gas reservoirs play an increasingly important role in oil and gas consumption safety China. To study the problem of erosion wear caused by gas-carrying particles process extraction from storage reservoirs, a mathematical model gas–liquid–solid three-phase reservoir columns was established through theories multiphase flow particle motion. Based on this model, effects water volume fraction, rate, mass size, bending angle location rate pipe were investigated. The findings indicate that when...

Carbonate geothermal reservoirs are widespread in the Beijing-Tianjin-Hebei region, and acidification stands out as most effective method to enhance heat recovery potential of these reservoirs. To understand propagation patterns acidized wormholes thermal reservoirs, a pore-Darcy scale mathematical model acidizing reactions has been established. A normal random distribution function is introduced depict reservoir's heterogeneity. Using finite element method, study simulated impact injection...

The distribution of in-situ stress has significant influence on fracture propagation direction so as to affect the selection fluid backflow technology.The influences longitudinal cracks in direction, caused by vertical interlayer-oil layer, was firstly analyzed.Then, settling rule proppant within fractures during flowing back process analyzed.Meanwhile, bottomhole pressure curves under different nozzle diameters after shut-in were obtained volume balance principle.Therefore, facture closure...

Damage mechanics and rheological are combined to solve the shale sidewall instability problems in oil gas drilling engineering. The microcracks rocks effect caused by physical chemical interplay between inflow fluid underground fluids studied. According nuclear magnetic resonance analysis, experiments theoretical hydration damage variables characterized NMR T2 spectrum established. A creep model for considering is proposed. It shows characteristics evolution process from spreading,...

The production of tight gas wells decreases rapidly, and the traditional method is difficult to accurately predict wells. At present, intelligent algorithms based on big data have been applied in oil well prediction, but there are still some technical problems. For example, error back propagation neural network (BP) has problem finding local optimal value, resulting low prediction accuracy. In order solve this problem, paper establishes output BP optimized with sparrow search algorithm...

In recent years, with the rapid development of salt cavern gas storage reservoir construction in China, characteristics rock reservoirs strong non-homogeneity and many interlayers have brought challenges to dynamic prediction water solution cavity construction. Aiming solve this problem, paper constructs a three-dimensional non-homogeneous water-soluble building model, which takes into full consideration reservoirs, interlayers, temperatures, injection process parameters, among other...

Named entity recognition, a fundamental task in natural language processing, faces challenges related to the sequence labeling framework widely used when dealing with nested entities. The span-based method transforms named recognition into span classification tasks, which makes it an efficient way deal overlapping However, too much overlap among spans may confuse model, leading inaccurate performance. Moreover, mentioned training dataset contains rich information about entities, are not...

This paper carries out a study on the numerical simulation of borehole instability based disturbance state concept. By introducing damage factor into classical Mohr–Coulomb yield criterio, we establish finite element hydro-mechanical coupling model and program relevant field variable by considering elastic–plastic deformation in instability, distribution area, variation porosity permeability with factor, etc. Numerical shows that stability is related to action time drilling fluid wellbore,...

An application of Cyclic Foam Stimulation, which significantly enhances productivity, is introduced. Experimental apparatus for includes a wellbore vessel and reservoir vessel, was designed.

As one of the main numerical methods, boundary element method boasts advantages fast computation speed and high accuracy. Based on considerations influence pressure drop, perforation height, skin coefficient, reservoir radius seepage law, a novel three-dimensional model for vertical wells was established using Laplace transform Stehfest inversion method. The utilized to examine velocity propagation drop amplitude, revealing that near-well area experienced faster than far-well area. During...

Gas transport in shale matrix is complex due to multiple mechanisms and difficult be investigated by macroscopic experiment. For Research Institute (GRI) method, which the most accepted one for gas investigation matrix, apparatus was modified adding an automatic supplement pressurization (AGSP) system, a numerical model considering variation of real property Klinkenberg effect established data interpretation. Then, intrinsic permeability coefficient were effectively obtained maintaining high...

Abstract With the continuous development of oil exploitation, research on industry has gradually shifted from macro to micro. Molecular simulation technology attracted wide attention due its advantages saving costs, shortening experimental period, and realizing limit conditions that are almost impossible under physical conditions. Petroleum workers use molecular model study effects different properties adsorption desorption. The results show capacity CH 4 increases with increase pore size...

Owing to the limitations of physical experiments on heavy oil, this study establishes a mathematical model for oil–water two-phase flow based theory multiphase flow, considering factors such as oil viscosity, mixed velocity, and inlet water cut. Through transient calculations 650 groups flows model, six typical patterns were identified by monitoring pattern cloud images, liquid holdup, probability density function (PDF) holdup: water-in-oil bubble transitional slug oil-in-water very fine...