Summary By using an acrylamide (AM)-acrylamide propyl sulfonate (AMPS) copolymer crosslinked with hydroquinone (HQ) and hexamethylenetetramine (HMTA), a stable gel was prepared at 150℃ in simulated brine salinity of 25×104 mg/L. The gelation time, strength, thermal stability were investigated, the results indicated that dosage crosslinker key factor controlling time gel. When polymer concentration more than 0.7 wt% concentrations HQ HMTA 0.2 wt%, respectively, aged under high temperature for...

As one of the key status gas in shale reservoir, adsorption accounts for considerable percentage total amount. Due to complexity and nanostructure it is very challenging represent through traditional methods. However, integration fractal theory molecular dynamics (MD) simulation may provide a new perspective understanding such micro-phenomenon happening it. The purpose this paper investigate phenomenon kerogen. By using MD grand canonical Monte Carlo (GCMC) algorithm, methane 2, 5...

Summary A high-strength gel was prepared by crosslinking a high-concentration but low molecular weight polyacrylamide-tert-butyl acrylate (PAtBA) copolymer with polyethyleneimine (PEI), and the various factors affecting gelling were systematically evaluated. The results showed that, besides concentration of polymer crosslinker, PEI, pH value salinity gelant, temperature all affected gelation time, strength, stability. High-strength PAtBA-PEI gels could be stable for more than 240 days in...

Shales or mudstones are fine grained and layered reservoirs, which leads to strong shale permeability anisotropy. Shale has a wide pore-size distribution, pores with different diameters contribute differently the apparent of shales. Therefore, understanding anisotropy multiscale gas reservoirs is an important aspect model evaluate production from In this paper, novel for presented calculate in arbitrary direction three dimensional space. A numerical valid entire Knudsen’s range (continuum...

The great amount of solid particles contained in a weighting agent is major cause the problems both rheology properties and damage control mechanism an oil-based drilling fluid (OBM). Therefore, proper type can be solution for application OBM. In this study, three agents that have been commonly used with OBM, namely, standard barite, submicron barite superfine manganese ore, are studied. Rheological OBM degree formation assessed regard to agents. also studied aspects particle size,...

This paper presents two representative models to analyze the flow dynamic of multi-scale porous medium in hydraulic fractured horizontal shale gas wells. In this work, considering characteristic mechanisms (multi-scale space, desorption and diffusion), equations are established. After that, (discrete fracture model dual-porosity model) tailored our issues. Solved by control-volume finite element method (CVFEM), influences network system on productivity reservoirs analyzed detail. Based...

In this paper, we modelled the electrical transport behaviour of bimodal carbonate rocks from a reservoir in China using dual-pore networks. One basic assumption, generally supported by experimental data and microstructure observations samples, was that low porosity, monomodal had same properties structure as microporous matrix high samples. We assumed homogeneous always interconnected but connectivity pore size distribution macropore system randomly variable. Both systems were supposed to...

A novel type curve is presented for oil recovery factor prediction suitable gas flooding by innovatively introducing the equivalent water-gas cut to replace water cut, comprehensively considering impact of three-phase flow (oil, gas, water), and deriving theoretical equations based on Tong's curve. The ratio cumulative underground volume production total produced fluids. Field data numerical simulation results are used demonstrate feasibility new verify accuracy with field cases. both...

Abstract Carbonate reservoir is one of the important in world. Because characteristics carbonate reservoir, horizontal well and acid fracturing have become a key technology for efficiently developing reservoir. Establishing corresponding mathematical models analyzing transient pressure behaviors this type well‐reservoir configuration can provide better understanding fluid flow patterns formation as estimations parameters. A model oil‐water two‐phase multiple‐fractured with multiple...

The multiscale pore size and specific gas storage mechanism in organic-rich shale reservoirs make transport such complicated. Therefore, a model that fully incorporates all mechanisms employs an accurate numerical method is urgently needed to simulate the production process. In this paper, unified of apparent permeability was first developed, which took into account multiple influential factors including slip flow, Knudsen diffusion (KD), surface diffusion, effects adsorbed layer, stress...

A series of corrosion problems caused by high-temperature, high-pressure and high-acid gas environments has been an issue in oil production for a long time. During the development field, petroleum pipe is subjected to many aspects corrosion, mechanism complicated condition coexistence H2S/CO2. Based on study problem associated with formate packer fluid Southwest China, three kinds steels were studied prevention alloy G3/N80 steel/TP110SS steel. The shows that rate low, but severe...

Flow in extremely low permeability shale gas reservoirs undergoes a transition from Darcy regime to other flow regimes including slip flow, and free molecular due the significant effect of collisions with pore walls on transport. These various shales their actual production are not clearly understood, multi-fractured horizontal wells crucial for economic unconventional resources. Therefore, numerical model which is valid entire Knudsen range (continuum flow) has been developed, gas–water...

Stimulated reservoir volume (SRV) is a key parameter affecting the post-fracturing production of ultra-low permeability reservoirs. Accurate prediction SRV shape and size vital significance for pre-fracturing stimulation design effect evaluation. In this paper, an equivalent mathematical model simulating two-dimensional growth proposed by integrating fracture width equation, tensor conversion, cubic law calculation method porosity with mass conservation equation injected fluid in natural...

Oil-based drilling fluid is widely used in tight sandstone well and shale recent years, performance advantages of borehole stability formation protection are the main reason to promote its use. According development existing research, oil-based still existed serious damage, could not catch attention developers. The study chose Keshen Block as research object, analyzed reservoir characteristics, evaluated rock wettability, damage oil trapping, mechanisms fluid. Based on characteristics fluid,...

Studies of rock stress sensitivity are mainly focused on experimental and data processing methods, the mechanism cannot be adequately explained using specific pore shape models. This study, based a random network simulation, explains for first time. Based model theory, hydraulic conductivity equation, dimensionless radius effective equation partially saturated used to generate three-dimensional QT platform. The simulation results show that influence becomes more significant as aspect ratio...