Yandy Scientific Press
Not a member yet
641 research outputs found
Sort by
Experimental study on the isothermal adsorption of methane gas in natural gas hydrate argillaceous silt reservoir
Get PDFGas hydrate occurs in hydrate reservoirs in a solid form. At present, the conventional exploitation method is to decompose solid hydrate and then extract the resulting gaseous gas. Therefore, the occurrence law of gas in a reservoir is of great significance for the study of gas hydrate seepage and productivity. Adsorption, as an important occurrence mode, has been widely concerned in the research on shale reservoirs. However, the adsorption problem in hydrate reservoirs has not received enough attention. In this paper, the existence of adsorption in a hydrate reservoir has been experimentally confirmed for the first time. Based on the argillaceous silt of a natural gas hydrate reservoir in the South China Sea, the pore structure and adsorption characteristics of argillaceous silt were experimentally studied, and the results were compared with those of typical shale reservoirs. The modified Langmuir and Dubinin-Radushevich equations were used to fit the adsorption data, and the suitable adsorption model of argillaceous silt was established and optimized. The results showed that the inhomogeneous slit pores are dominant in argillaceous silt, and they are formed by the accumulation of lamellar particles. Compared with shale, the adsorption capacity of argillaceous silt is weak under the same conditions. However, adsorption is a spontaneous exothermic reaction, and the ambient temperature of argillaceous silt is much lower than that of shale. Therefore, it is possible for argillaceous silt to achieve an adsorption capacity comparable to that of shale. The modified Langmuir model can be used to simulate argillaceous silt adsorption at low pressure, while under medium and high pressures, the modified Dubinin-Radushevich model performs better. The adsorption capacity of argillaceous silt is affected by moisture. When the water content is 20%, the Langmuir adsorption capacity and the Dubinin-Radushevich maximum adsorption capacity decreases by 21.88% and 13.67%, respectively, which is far less than the influence of moisture on shale adsorption, as reported in the literature.Cited as: Qi, R., Qin, X., Lu, C., Ma, C., Mao, W., Zhang, W. Experimental study on the isothermal adsorption of methane gas in natural gas hydrate argillaceous silt reservoir. Advances in Geo-Energy Research, 2022, 6(2): 143-156. https://doi.org/10.46690/ager.2022.02.0
A new upscaling method for microscopic fluid flow based on digital rocks
Get PDFThis report presents our new findings in microscopic fluid flow based on digital rocks. Permeability of digital rocks can be estimated by pore-scale simulations using the Stokes equation, but the computational cost can be extremely high due to the complicated pore geometry and the large number of voxels. In this study, a novel method is proposed to simplify the three-dimensional pore-scale simulation to multiple decoupled two- dimensional ones, and each two-dimensional simulation provides the velocity distribution over a slice. By this decoupled simulation approach, the expensive simulation based on the Stokes equation is conducted only on two-dimensional domains, and the final three- dimensional simulation of Darcy equation using the finite difference method is very cheap. The proposed method is validated by both sandstone and carbonate rock samples and shows significant enhancement in the computational speed. This work sheds light on large-scale microscopic fluid flow based on digital rocks.Document Type: Research highlightCited as: Liao, Q., Xue, L., Wang, B., Lei, G. A new upscaling method for microscopic fluid flow based on digital rocks. Advances in Geo-Energy Research, 2022, 6(4): 357-358. https://doi.org/10.46690/ager.2022.04.1
Effect of viscosity and heterogeneity on dispersion in porous media during miscible flooding processes
Get PDFIn this paper, a mathematical model has been developed to quantitatively examine the effect of viscosity and heterogeneity on dispersion in porous media at the pore scale during miscible flooding processes. More specifically, the Navier-Stokes equation and advection-diffusion equation are coupled with supplementary equations to describe the solvent transport behaviour. Two-dimensional heterogeneous models are numerically developed as a function of porosity and permeability, assuming that the grain sizes satisfy normal distribution. In addition, the performance of miscible hydrocarbon gas injection in heterogeneous porous media is comprehensively evaluated. It is found that a larger aspect ratio (ratio of pore throat size) in the single non-flowing pore model results in a greater asymmetry of the concentration curve. As for single non-flowing pore models and heterogeneous models, the dispersion coefficients increase with the expansion of the non-flowing domain. Both the heterogeneity of porous media and the variable viscosity of th fluid mixture contribute to the asymmetry of the concentration curve in the heterogeneous model. A negative correlation is established between the sorting coefficients of pore throat size and the power-law coefficients. As for slug injection, the injected solvent slug size along the longitudinal direction does not effectively influence the longitudinal length of the mixing zone for a given porous medium and fluids, though the Peclet number and the porosity greatly affect the length and concentration distribution of the mixing zone.Cited as: Bai, Z., Song, K., Fu, H., Shi, Y., Liu, Y., Chen, Z. Effect of viscosity and heterogeneity on dispersion in porous media during miscible flooding processes. Advances in Geo-Energy Research, 2022, 6(6): 460-471. https://doi.org/10.46690/ager.2022.06.0
Leakage simulation and acoustic characteristics based on acoustic logging by ultrasonic detection
Get PDFThe detection of casing leakage in oil and gas wells or water injection wells is an important element of wellbore integrity management. Ultrasonic technology is suitable to detect and identify the position of leakage in oil and gas well shafts, providing engineering guidance for subsequent treatment. In this paper, the finite element calculation model of casing leakage in oil and gas wells is established by using the computational fluid dynamics method, and the large eddy simulation model and Ffowcs Williams-Hawkings acoustic model are utilized to simulate the casing leakage condition. The acoustic pressure signals of each monitoring point on the inner axis of the pipeline are obtained, and the influences of the pipeline pressure difference, the leakage hole diameter and the pipeline fluid on the leakage acoustic field are analyzed. The simulation results indicate that the acoustic pressure level measured on the pipeline axis rises with the increase of pipeline pressure difference and leakage hole diameter. The size and variation rule of acoustic pressure level also vary with the type of pipeline fluid. Overall, the results obtained show that ultrasonic logging can accurately locate and detect tubing leakage, and they provide theoretical guidance for practical casing leakage detection, assisting with wellbore integrity management.Cited as: Li, J., Wan, J., Wang, T., Yuan, G., Jurado, M. J., He, Q. Leakage simulation and acoustic characteristics based on acoustic logging by ultrasonic detection. Advances in Geo-Energy Research, 2022, 6(3): 181-191. https://doi.org/10.46690/ager.2022.03.0
Lattice Boltzmann pseudopotential multiphase modeling of transcritical CO2 flow using a crossover formulation
Get PDFThis report summarizes our recent implementation of a crossover formulation in the lattice Boltzmann method and its application in modeling transcritical CO2 sequestration in water-saturated porous media. A crossover enhancement of the Peng-Robinson equation of state increases the accuracy in predicting fluid properties in transcritical conditions, which is relevant in modeling CO2 sequestration. The crossover formulation leads to the prediction of liquid-vapor coexistence curves closer to experimental data. The formulation was validated with several tests and applied to model the displacement of H2O with CO2 in a homogeneous porous medium in multiple conditions. This investigation provides a promising strategy for improving the accuracy of the lattice Boltzmann method in modeling transcritical CO2 sequestration in aquifers using realistic transcritical conditions.Cited as: Ashirbekov, A., Kabdenova, B., Kuljabekov, A., Monaco, E., Wang, L., Rojas-Solórzano, L. Lattice Boltzmann pseudopotential multiphase modeling of transcritical CO2 flow using a crossover formulation. Advances in Geo-Energy Research, 2022, 6(6): 539-540. https://doi.org/10.46690/ager.2022.06.1
Formation damage mechanism of a sandstone reservoir based on micro-computed tomography
Get PDFFormation damage caused by well drilling, completion, oil testing, oil recovery, and stimulation seriously affects oil and gas production, the evaluation of which plays an important role in the process of oilfield development. Thus, it is necessary to study formation damage mechanism from micro scale. In this study, two sets of displacement experiments were conducted using two sandstone samples and two chemical reagents. Each set was divided into three processes: first formation water injection, reverse chemical reagents injection and second formation water injection. According to the results of displacement experiments, the permeability changes of two sandstone samples were analyzed and the formation damage rates of different experimental processes were calculated respectively. In addition, we analyzed the formation damage of the two samples from the macroscopic aspect according to the changes of inlet pressure curves. We compared the pore structure changes of sandstone samples at different experiment processes by computed tomography (CT) images, and found the particle migration phenomenon. Based on the core sensitive regions observed by CT images, the pore network models of the sensitive regions were extracted to quantitatively characterize the change of pore structure parameters (pore radius, throat radius, coordination number and tortuosity). Finally, we designed a two-dimensional microscopic seepage channel model according to the real core structure. The flow rule of solid particles in fluid was simulated by finite element method, and the reason of reservoir clogging was analyzed. Through this study, we found that the injection of chemical reagents increased the inlet pressure and led to the decrease of core permeabilities. There was a negative correlation between the export rate of particle migration and matrix deformation degree.Cited as: Wang, Z., Li, H., Lan, X., Wang, K., Yang, Y., Lisitsa, V. Formation damage mechanism of a sandstone reservoir based on micro-computed tomography. Advances in Geo-Energy Research, 2021, 5(1): 25-38, doi: 10.46690/ager.2021.01.0
An exploratory multi-scale framework to reservoir digital twin
Get PDFIn order to make full use of the information provided in the physical reservoirs, including the production history and environmental conditions, the whole life cycle of reservoir discovery and recovery should be considered when mapping in the virtual space. A new concept of reservoir digital twin and the exploratory multi-scale framework is proposed in this paper, covering a wide range of engineering processes related with the reservoirs, including the drainage, sorption and phase change in the reservoirs, as well as extended processes like injection, transportation and on-field processing. The mathematical tool package for constructing the numerical description in the digital space for various engineering processes in the physical space is equipped with certain advanced models and algorithms developed by ourselves. For a macroscopic flow problem, we can model it either in the Navier-Stokes scheme, suitable for the injection, transportation and oil-water separation processes, or in the Darcy scheme, suitable for the drainage and sorption processes. Lattice Boltzmann method can also be developed as a special discretization of the Navier-Stokes scheme, which is easy to be coupled with multiple distributions, for example, temperature field, and a rigorous Chapman-Enskog expansion is performed to show the equivalence between the lattice Bhatnagar-Gross-Krook formulation and the corresponding Navier-Stokes equations and other macroscopic models. Based on the mathematical toolpackage, for various practical applications in petroleum engineering related with reservoirs, we can always find the suitable numerical tools to construct a digital twin to simulate the operations, design the facilities and optimize the processes.Cited as: Zhang, T., Sun, S. An exploratory multi-scale framework to reservoir digital twin. Advances in Geo-Energy Research, 2021, 5(3): 239-251, doi: 10.46690/ager.2021.03.0
Paleoenvironment and chemostratigraphy heterogenity of the Cretaceous organic-rich shales
Get PDFThe Cretaceous Qingshankou Formation in the Songliao Basin is rich in shale oil resources, which has become one of the most important exploration targets of lacustrine shale oil in China. Based on X-ray fluorescence element analysis, X-ray diffraction analysis, total organic carbon, rock pyrolysis, scanning electron microscope and nitrogen adsorption, the Paleoenvironment was reconstructed by comprehensive utilization of integrated prediction error filter analysis of chemical stratigraphy, and its relationship with organic geochemistry, mineralogy and pore structure was discussed. The results indicated that the Qingshankou Formation was deposited in the environment with fresh water-brackish water, semi-deep/deep water and strong reduction. The evolution of Paleoenvironment during the deposition of Qingshankou Formation changed from bottom to top, with increasing water depth, decreasing salinity and oxygen content. Paleosalinity was positively correlated with total organic carbon, residual hydrocarbon and carbonate mineral content. From bottom to top, the contents of carbonate and chlorite decreased, while the contents of plagioclase and clay minerals increased slightly. The pores were dominated by intra-illite pores, intra-I/S mixed-layer pores and intra-pyrite pores. Some intra-plagioclase pores and calcite dissolution pores were developed, and the organic matter pores are slightly few. Nitrogen adsorption data showed that the dominate pore size was 40-53 nm. This study clarifies the Paleoenvironmental evolution of the Qingshankou Formation, and may shed lights on lacustrine shale oil accumulation and sweet-spotting.Cited as: Guan, M., Wu, S., Hou, L., Jiang, X., Ba, D., Hua, G. Paleoenvironment and chemostratigraphy heterogenity of the Cretaceous organic-rich shales. Advances in Geo-Energy Research, 2021, 5(4): 444-455, doi: 10.46690/ager.2021.04.0
Prediction of spontaneous imbibition in fractal porous media based on modified porosity correlation
Get PDF Spontaneous imbibition plays a significant role in different technical applications, and several analytical models have been proposed for predicting the fluid imbibition mass into porous media based on the fractal theory. Herein, these previous models are reconsidered in view of the obvious difference between the effective porosity and the areal porosity of porous media. Firstly, an implicit equation for fractal tortuosity is proposed and a modified correlation for the areal porosity is presented; then, a semi-analytical prediction model for fluid imbibition mass with gravity pressure is derived; finally, comparisons of predictions among several previous models with the present model are carried out. The modeling results show consistency with the experimental data published in the literature.Cited as: Li, Y., Yu, D., Niu, B. Prediction of spontaneous imbibition in fractal porous media based on modified porosity correlation. Capillarity, 2021, 4(1): 13-22, doi: 10.46690/capi.2021.01.02
Petroleum rock mechanics: An area worthy of focus in geo-energy research
Get PDFRock mechanics is a discipline that studies the stress, strain, failure, stability, and reinforcement of rocks under the action of external factors (such as load, fluid flow, and temperature changes). It is not only a branch of mechanics but also an interdisciplinary engineering subject. This discipline requires knowledge of applied mathematics, solid mechanics, fluid mechanics, geology, soil mechanics, and civil engineering, etc., and the main purpose is to solve engineering problems that arise from anthropogenic or natural processes concerning rock physics. Petroleum, a complex mixture of hydrocarbons that occurs in subsurface rocks in liquid, gaseous, or solid form, includes oil, natural gas, and the viscoelastic solid bitumen. Literally, “petroleum” means “rock oil” from Latin, in which the word “petra” means “rock” or “stone” while “oleum” corresponds to “oil”.The upstream of the petroleum industry mainly includes the processes of petroleum geophysical prospecting, drilling & completion, fracturing, injection & production, and storage. Each of the abovementioned phases is directly related to rock mechanics, and for some of these stages, the success of the project directly depends on the mechanical behavior of the subsurface rocks.· In the stage of petroleum geophysical exploration, it is necessary to ascertain the intrinsic correlation between petrophysical properties and field parameters related to geophysical exploration methods, e.g., how rock elastic moduli will affect wave propagation during acoustic porosity logging, which is conducive to improving the accuracy of reservoir identification and explaining the oil and gas occurrence states as well as physical parameters of the reservoir.· In the drilling and completion stage, rock mechanics is the main theoretical basis to ensure wellbore stability and prevent sand production or casing damage. At this stage, it is necessary to establish mechanical models through analytical or numerical methods to reveal the mechanical mechanisms of wellbore instability, sand production, and casing damage for various well types such as vertical, inclined, horizontal, and lateral wells. Consequently, controlled measurements can be made to ensure the stability and integrity of the borehole.· Fracturing is a key technology for the efficient development of low-permeability oil and gas reservoirs. Based on the theories of rock fracture mechanics and fluid mechanics, the evaluation metric of rock fracability can be proposed, the crack propagation pattern of complex reservoir rocks during hydraulic fracturing can be revealed, and the process and parameters of hydraulic fracturing can be optimized based on computer simulation of hydraulic fracturing.· Fluid injection and production can usually be regarded as a pure fluid transport problem in reservoir engineering contexts. But the reservoir rock is, after all, an elastoplastic material rather than a rigid body. Therefore, in order to accurately predict oil and gas production and optimize injection and production protocols, reservoir thermo-hydromechanical coupling theory has been incorporated into reservoir simulation and geo-stress evolution analysis. By formulating different rock constitutive models, fluid transport models, and multi-physics coupling algorithms, integrated simulations of reservoir fluid pressure and solid stress fields can be achieved.· Large-scale underground gas storage is an important measure to ensure the safe production of oil and gas. In the stage of site selection and operating parameter design, it is necessary to study the sealing efficiency of the caprock and the stability of the nearby faults based on rock mechanics and fluid-solid coupling theories, so as to determine the safety window for all the operating parameters during gas storage.· In the design of salt cavern gas storage projects, rock mechanics analysis is necessary for salt cavern stability evaluation, injection pressure optimization, and geological disasters prevention, such as land subsidence and induced seismicity. In addition to the issues mentioned above, natural gas hydrate extraction, enhanced heavy oil recovery, and shale gas/oil reservoir development also involve complex thermal-hydraulic-mechanical-chemical coupling mechanisms.Nowadays, the development of oil and gas reservoirs is getting deeper and deeper. For example, some wells in the Tarim Oilfield in Xinjiang, have been drilled more than 8,000 meters in depth. At the same time, rock mechanics is playing an increasingly important role in the oil and gas industry with the increasing development of unconventional oil and gas reservoirs. In the coming period, the research of petroleum rock mechanics will focus on:· Rock mechanical properties and behaviors under high temperature and high pressure and their influences on reservoir productivity;· The propagation and control of hydraulic fractures in complex reservoirs, as well as new and efficient fracturing methods for shale oil and gas reservoirs;· Improved reservoir rock thermal-hydraulic-mechanical chemical multi-physics coupling algorithms;· High temperature and high pressure physical experiments of reservoir rock under multi-physics conditions;· Accurate and efficient computational algorithms and simulator development for multi-physics coupling problems.Certainly, with the in-depth intersection and integration of various related disciplines, 3D printing technology, artificial intelligence algorithm and other technologies have been introduced into petroleum rock mechanics, and numerous new research directions are emerging.The papers published in this virtual special issue are closely related to petroleum rock mechanics and have important significance in both theoretical and practical aspects. In these 16 articles, the research on the modeling and simulation of permeability variation is mainline. Coupled multi-scale and multi-physics characterization, as well as the related simulation methods are the focus of attention. The purpose of the included researches is to discover and explain the mechanisms governing the exploitation of geological resources and ultimately provide guidance for engineering practice.We hope that while reading and citing these papers, colleagues will think profoundly and deepen the research in this area, and jointly promote the development of petroleum rock mechanics.Cited as: Yang, C., Liu, J. Petroleum rock mechanics: An area worthy of focus in geo-energy research. Advances in Geo-Energy Research, 2021, 5(4): 351-352, doi: 10.46690/ager.2021.04.01Contributions to the virtual special issue-listing of articles arranged as follows:Andhumoudine, A. B., Nie, X., Zhou, Q., et al. Investigation of coal elastic properties based on digital core technology and finite element method. Advances in Geo-Energy Research, 2021, 5(1): 53-63.Anyim, K., Gan, Q. Fault zone exploitation in geothermal reservoirs: Production optimization, permeability evolution and induced seismicity. Advances in Geo-Energy Research, 2020, 4(1): 1-12.Chai, Y., Yin, S. 3D displacement discontinuity analysis of in-situ stress perturbation near a weak fault. Advances in Geo-Energy Research, 2021, 5(3): 286-296.Chen, S., Ding, B., Gong, L., et al. Comparison of multi-field coupling numerical simulation in hot dry rock thermal exploitation of enhanced geothermal systems. Advances in Geo-Energy Research, 2019, 3(4): 396-409.Faraji, M., Rezagholilou, A., Ghanavati, M., et al. Breakouts derived from image logs aid the estimation of maximum horizontal stress: A case study from Perth Basin, Western Australia. Advances in Geo-Energy Research, 2021, 5(1): 8-24.Jia, D., Qiu, Y., Li, C, et al. Propagation of pressure drop in coalbed methane reservoir during drainage stage. Advances in Geo-Energy Research, 2019, 3(4): 387-395.Lei, G., Liao, Q., Chen, W., et al. Stress dependent gas-water relative permeability in gas hydrates: A theoretical model. Advances in Geo-Energy Research, 2020, 4(3): 326-338.Li, J., Yu, T., Liang, X., et al. Insights on the gas permeability change in porous shale. Advances in Geo-Energy Research, 2017, 1(2): 69-73.Li, L., Liang, W., Lian, H., et al. Compressed air energy storage: characteristics, basic principles, and geological considerations. Advances in Geo-Energy Research, 2018, 2(2): 135-147.Liu, R., Jiang, Y., Huang, N., et al. Hydraulic properties of 3D crossed rock fractures by considering anisotropic aperture distributions. Advances in Geo-Energy Research, 2018, 2(2): 113-121.Nguyen, T.S. Thermo-Hydro-Mechanical-Chemical processes in geological disposal of radioactive waste – An example of regulatory research. Advances in Geo-Energy Research, 2018, 2(2): 173-189.Wang, F., Gong, R., Huang, Z., et al. Single-phase inflow performance relationship in stress-sensitive reservoirs. Advances in Geo-Energy Research, 2021, 5(2): 202-211.Wei, Q., Wang, Y., Han, D., et al. Combined effects of permeability and fluid saturation on seismic wave dispersion and attenuation in partially-saturated sandstone. Advances in Geo-Energy Research, 2021, 5(2): 181-190.Yang, Y., He, Y., Zheng, Q. An analysis of the key safety technologies for natural gas hydrate exploitation. Advances in Geo-Energy Research, 2017, 1(2): 100-104.Ye, D., Liu, G., Gao, F., et al. A multi-field coupling model of gas flow in fractured coal seam. Advances in Geo-Energy Research, 2021, 5(1): 104-118.Zhang, T., Li, Z., Adenutsi, C.D., et al. A new model for calculating permeability of natural fractures in dual-porosity reservoir. Advances in Geo-Energy Research, 2017, 1(2): 86-92.