Journal of Petroleum Science and Engineering最新文献

{"title":"An accelerated process-based method for the accurate computation of relative permeability from direct simulations of two-phase flow on micro-computed tomography images of porous media","authors":"Faruk O. Alpak,&nbsp;Nishank Saxena","doi":"10.1016/j.petrol.2022.111095","DOIUrl":"10.1016/j.petrol.2022.111095","url":null,"abstract":"<div><p><span><span><span><span>Pore-scale forces have significant effects on the macroscopic behavior of multi-phase flow through </span>porous media. We develop a robust and accurate accelerated process-based method for the computation of </span>relative permeability<span> from direct simulations of pore-scale two-phase flow on micro-computed tomography images. In the pressure drop calculation, we take advantage of an existing analysis that establishes a relationship between pore-scale forces and Darcy-scale pressure drops using an energy-conservation approach. We establish a thermodynamically consistent approximation of Darcy-scale viscous pressure drops as the rate of </span></span>energy dissipation per unit flow rate of each flowing phase for the first time within the context of a free-energy </span>lattice Boltzmann method (LBM). In addition, we propose and test a new computationally efficient partial-mirror periodic boundary condition for a fully coupled visco-capillary pore-scale flow simulator based on a free-energy LBM. The new boundary condition is imposed only in the main flow direction and significantly reduces the computational cost of the process-based relative-permeability computation protocol at a small compromise on accuracy.</p><p>We first compute primary-drainage and subsequent imbibition<span> relative permeability curves for a reservoir sandstone rock sample. We use this real-reservoir dataset to validate the pressure drop computation method and the partial-mirror periodic boundary condition. We then simulate the entire drainage and imbibition cycle using an extensively studied Berea sandstone dataset. We quantitatively demonstrate that pore-scale direct numerical simulation-based relative permeability curves computed with our novel process-based method agree well with experimental steady-state relative permeability measurements. We also quantitatively demonstrate that the new partial-mirror periodic boundary condition accelerates the relative permeability computations 4 to 13 times.</span></p></div>","PeriodicalId":16717,"journal":{"name":"Journal of Petroleum Science and Engineering","volume":"220 ","pages":"Article 111095"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43037685","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Pressure transient analysis of horizontal wells in multibranched fault-karst carbonate reservoirs: Model and application in SHB oilfield","authors":"Wenyang Shi ,&nbsp;Jian Cheng ,&nbsp;Yongchuan Liu ,&nbsp;Min Gao ,&nbsp;Lei Tao ,&nbsp;Jiajia Bai ,&nbsp;Qingjie Zhu","doi":"10.1016/j.petrol.2022.111167","DOIUrl":"10.1016/j.petrol.2022.111167","url":null,"abstract":"<div><p><span><span>Current flow models for fault-karst reservoirs are mostly described as a single fault formation, which cannot be applied in recent-developed multibranched fault-karst reservoirs. This paper established a novel analytical model to investigate pressure response behavior of a horizontal well in multibranched fault-karst reservoirs. The model is able to describe the influence of the physical properties and spatial structure of fracture-cave system on pressure transient response. The flow model considers different flow behaviors in each region, which includes </span>Darcy flow<span> (gravity included) in fault-fracture, large-scale storage flow in karst-cave, and Poiseuille-law-based horizontal laminar flow<span> in the horizontal wellbore, respectively. These assumptions enable the model to match complex situations in multibranched fault-karst reservoirs. Then, the model was retrograded to compare with a single fault-karst reservoir model to verify its accuracy. Further, the solutions were graphed on log-log plots, and we discussed the effect of fluids mobility, formation storability, and structure characteristics (e.g., length, angle, depth, distance) of fracture-cave branches on </span></span></span>transient pressure responses. Results show that (a) the number of fracture-cave branches in a reservoir can be directly observed by counting the number of V-shaped appearances on the pressure derivative curve. (b) The exact shut-in time when V-shape appears is affected by volume and distance between two neighboring fracture-cave branches. (c)The characteristics of the V-shape are affected by fluid mobility, formation storability, and length of fracture region. (d) The slope of the pressure derivative curve in the boundary-dominated flow regime can be used to evaluate the gravity effect. (e) The pressure response behavior exhibits a near-well effect when a horizontal well commingled production in the multibranched fault-karst reservoir. Finally, we applied our model and resulting observations to analyze pressure build-up data tested from SHB Oilfield, which demonstrated a workflow to identify the number of fault-karst branches and also to estimate reservoir properties.</p></div>","PeriodicalId":16717,"journal":{"name":"Journal of Petroleum Science and Engineering","volume":"220 ","pages":"Article 111167"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46703344","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Study of the trapping mechanism of merging drops moving under thermocapillary migration on a surface with wettability contrast","authors":"Gloire Imani ,&nbsp;Lei Zhang ,&nbsp;Chao Xu ,&nbsp;Hai Sun ,&nbsp;Yongfei Yang ,&nbsp;Jun Yao","doi":"10.1016/j.petrol.2022.111172","DOIUrl":"10.1016/j.petrol.2022.111172","url":null,"abstract":"<div><p><span><span><span>Trapping of drops due to wettability contrast in porous materials emerges in a variety of subsurface and manufacturing applications. In </span>carbon capture and storage, carbon dioxide must be trapped in order to avoid its release into the atmosphere, while trapped oil must be displaced. Both carbon dioxide and oil can exist as drops in </span>porous media<span><span>. The migration of a single drop attached to a wall can be hindered if the wall surface has a different wettability. However, the trapping condition becomes more complicated in the presence of two or more drops. In this work, we aim to study the trapping mechanism during thermocapillary migration of a merging drop on a heterogeneous surface. To do so, numerical simulations have been performed using the Front-Tracking/Finite Volume Method, where the Navier-Stokes equations are coupled with the conservation equations. The generalized Navier boundary condition (GNBC) has been used as the slip model to remove the viscous singularity. The combined finite-volume and tracking method is able to deal with different types of discontinuities in compressible or </span>incompressible fluid<span> flows, as e.g., interfaces. The material properties of the drop and the ambient fluid are different, and surface tension depends on the temperature. The results have shown that there exist three regimes characterizing the motion of merging drops, including the passage of the leading drop, the trapping of the merging drop, and the partial trapping, which correspond to the trapping of the leading drop but the passage of the merging drop. We show that there is a critical wettability contrast at which the merging drop gets trapped. The effects of </span></span></span>Marangoni number<span><span> (Ma) and viscosity ratio are investigated. The critical wettability contrast decreases with the increase of Ma number and the regime shift as a function of the viscosity and Marangoni number. These findings have implications for the design of geological carbon dioxide storage, improvement of oil recovery and </span>microfluidic device development.</span></p></div>","PeriodicalId":16717,"journal":{"name":"Journal of Petroleum Science and Engineering","volume":"220 ","pages":"Article 111172"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44644285","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Field-scale simulation of gas hydrate dissociation behavior in multilayered sediments under different depressurization conditions","authors":"Seo-Yoon Moon ,&nbsp;Hyo-Jin Shin ,&nbsp;Jong-Se Lim","doi":"10.1016/j.petrol.2022.111221","DOIUrl":"10.1016/j.petrol.2022.111221","url":null,"abstract":"<div><p><span><span>When a gas hydrate<span> reservoir is depressurized for gas production, the production tendency and dissociation behavior may differ depending on conditions such as the bottom hole pressure and </span></span>depressurization rate. Gas hydrate dissociation is a complex process that involves the transfer of materials and heat, and on-site analysis based on laboratory-scale results is critical. In the present study, a field-scale numerical analysis was performed to reflect the conditions of the Ulleung Basin in the East Sea of </span>Korea. The dissociation behavior, which varies depending on the conditions in the gas hydrate-bearing sediment, was analyzed under various conditions of bottom hole pressure and depressurization rate. This study also identified the effects of depressurization conditions on gas hydrate saturation. As the bottom hole pressure decreased and the depressurization rate increased, the production rate and cumulative production of gas and water increased, and the radius of the pressure propagation effect at the beginning of production increased. In sediments with a gas hydrate saturation of ≥70%, the pressure propagation was unstable and the dissociation rate was low. These results can serve as preliminary data for the field production of gas hydrates in the Ulleung Basin.</p></div>","PeriodicalId":16717,"journal":{"name":"Journal of Petroleum Science and Engineering","volume":"220 ","pages":"Article 111221"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45290303","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mechanical formation damage control in permeability Biot’s effective stress-sensitive oil reservoirs with source/sink term","authors":"Fernando Bastos Fernandes ,&nbsp;Arthur Martins Barbosa Braga ,&nbsp;Antônio Luiz S. de Souza ,&nbsp;Antônio Cláudio Soares","doi":"10.1016/j.petrol.2022.111180","DOIUrl":"https://doi.org/10.1016/j.petrol.2022.111180","url":null,"abstract":"<div><p><span>Geomechanical effects monitoring on reservoir rock and fluid properties response during the oil production curve are essential to improve oil recovery in a petroleum field. Incorporating geomechanics to flow models become the mathematical formulation regarding well-test and </span>reservoir engineering<span><span> more realistic because geomechanical parameters, e.g., in situ and overburden stress<span>, as well as Biot’s coefficient, play a fundamental role in pressure response. Hence, permeability stress-sensitive oil reservoirs are the scope of various research in the petroleum industry for minimizing formation damage during drilling, completion, and stimulation operations. In this context, mechanical formation damage control plays a key role in preventing early-permeability loss that may result in reservoir compaction and oil field disinvestments. This work develops a new analytical solution for the nonlinear hydraulic </span></span>diffusivity<span><span> equation (NHDE) with instantaneous point-source/sink effects in permeability effective stress-sensitive oil reservoirs. The proposed model considers Biot’s effective stress change in the permeability response, and a new deviation factor is derived from comparing the nonlinear effect concerning the constant permeability classical solution and a decoupled case available in the literature. The calibration methodology is performed using a numerical simulator named IMEX®, widely used in formation evaluation works, and the results presented high convergence. The findings of this study allowed us to notice the role of overburden stress, </span>oil flow rate, deviation factor, and Biot’s coefficient in permeability change during production in the diagnostic plots. Thereby, the modeling developed in this paper becomes a useful and attractive tool for predicting and monitoring permeability loss, oil flow rate specification, and reservoir history matching.</span></span></p></div>","PeriodicalId":16717,"journal":{"name":"Journal of Petroleum Science and Engineering","volume":"220 ","pages":"Article 111180"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50185601","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Structural characteristics of pores and fractures during lignite pyrolysis obtained from X-ray computed tomography","authors":"Weizhen Liu ,&nbsp;Shiwei Niu ,&nbsp;Haibo Tang","doi":"10.1016/j.petrol.2022.111150","DOIUrl":"10.1016/j.petrol.2022.111150","url":null,"abstract":"<div><p><span>In-situ mining of lignite requires dehydration, </span>pyrolysis<span><span><span>, gasification, and other stages. The injected fluid, dehydrated water, and pyrolysis products are transported in the developing pores and fractures. The internal structure and properties of lignite change significantly under the joint action of temperature and fluid pressure. In this study, X-ray computed </span>tomography (X-CT) was used to scan lignite samples in the temperature range of 25°C–450 °C. </span>Grayscale images<span> and three-dimensional reconstruction images of the internal structure were obtained to investigate the evolution of the internal pore structure during lignite pyrolysis. It is found that the porosity of lignite increased as the temperature rose from 25 °C to 250 °C. The porosity was 6.54% at 250 °C. At 350 °C, the porosity decreased to 2.45% due to channel blockage and softening of the coal. At 450 °C, the pyrolysis of the lignite organic matter resulted in numerous large and interconnected honeycomb pore clusters. At this temperature, the porosity was 16.02%. X-CT and nuclear magnetic resonance enabled detailed and quantitative characterization of the internal structure of lignite. The research results provide theoretical and technical information on the evolution of migration channels in lignite for the potential improvement of in-situ pyrolysis and gasification efficiency of in-situ lignite mining.</span></span></p></div>","PeriodicalId":16717,"journal":{"name":"Journal of Petroleum Science and Engineering","volume":"220 ","pages":"Article 111150"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49398408","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of lithological variations on the performance of artificial intelligence techniques for estimating total organic carbon through well logs","authors":"Khaled Maroufi ,&nbsp;Iman Zahmatkesh","doi":"10.1016/j.petrol.2022.111213","DOIUrl":"10.1016/j.petrol.2022.111213","url":null,"abstract":"<div><p><span>By the expansion of production from source-related unconventional petroleum resources<span>, accurate approximation of Total Organic Carbon<span> (TOC) through well logs has become progressively important. Accordingly, recent studies have mainly focused on increasing the precision of TOC estimation by using different types of AI techniques<span> and/or optimizing algorithms. Along with utilizing these approaches, this study emphasized on removing an unaddressed source of error inherited from lithological heterogeneity with the same goal. Like organic matter quantity, lithological variations within a source interval also induce well log responses, which may interfere with the training process of Artificial Intelligence (AI) techniques. In the present research, the effect of lithological variations on the performance of TOC estimators was evaluated by employing Adaptive Neuro Fuzzy Inference System (ANFIS) and Multilayer </span></span></span></span>Perceptron<span><span> network (MLP). Firstly, ANFIS and MLP models were constructed and trained using a database containing different lithologies (original models). Then, a new methodology was developed based on modeling the relationship between log data and TOC values for each type of lithology (litho-based method). The result showed that the litho-based method estimates more reliable and accurate TOC values, proving the adverse effect of lithological variations on the original models. Furthermore, the litho-based ANFIS models provide the most promising results. Since metaheuristic algorithms are usually employed to optimize AI techniques, Genetic Algorithm (GA) and </span>Particle Swarm Optimization<span> (PSO) were also implemented into the original models (hybrid models). Accuracy of TOC values estimated by the hybrid models is slightly higher than those derived from the original models. However, these hybrid approaches are not as efficient as the litho-based method. Applicability of the proposed approach was guaranteed by performing it over Pabdeh source rocks in a well of SW Iran. Based on its high efficiency, the newly developed litho-based method can be used as a powerful tool to reliably evaluate unconventional hydrocarbon resources, as well as the potential of the conventional petroleum sources. Moreover, it can be utilized, instead of/along with traditional optimization approaches, to approximate other geochemical factors as well as petrophysical parameters from log data.</span></span></p></div>","PeriodicalId":16717,"journal":{"name":"Journal of Petroleum Science and Engineering","volume":"220 ","pages":"Article 111213"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42541341","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A volumetric-smoothed particle hydrodynamics based Eulerian-Lagrangian framework for simulating proppant transport","authors":"Huiying Tang ,&nbsp;Zhicheng Wen ,&nbsp;Liehui Zhang ,&nbsp;Junsheng Zeng ,&nbsp;Xiao He ,&nbsp;Jianfa Wu ,&nbsp;Jian Zheng","doi":"10.1016/j.petrol.2022.111129","DOIUrl":"https://doi.org/10.1016/j.petrol.2022.111129","url":null,"abstract":"<div><p>Different numerical methods<span><span> have been applied to simulate the proppant transport<span><span> in petroleum engineering, which can be roughly categorized as the Eulerian-Eulerian and Eulerian-Lagrangian models. Recently, a hybrid Eulerian-Lagrangian (E-L) approach, the multiphase particle-in-cell (MP-PIC) method, has been successfully applied to model large-scale proppant transport problems by introducing the concept of parcels (clusters of particle). In the MP-PIC method, particle-particle interaction force is expressed as the gradient of particle stress. The calculation of this gradient strongly depends on the interpolation between particle properties and Eulerian grids, which could lead to problems such as non-physical particle suspension, particle agglomeration and non-conserved interparticle interactions. In this study, a new method, the volumetric-smoothed particle </span>hydrodynamics (V-SPH) method, is proposed to improve the calculation accuracy of the particle-particle interaction forces in the original MP-PIC method. In the V-SPH method, the calculation of the particle </span></span>stress gradient<span> no longer depends on the background Eulerian grids and the conservation of the interparticle stress is also guaranteed. In this paper, detailed introduction of the V-SPH based Eulerian-Lagrangian framework is provided. The reliability of the proposed V-SPH method is validated against both the numerical and experimental results in literature. By comparing with the original MP-PIC method, we observe that the non-physical particle agglomeration, as well as non-physical particle suspension problems can be well solved with the proposed new model. In addition, the impact of some key parameters in the V-SPH method on simulation results are also investigated. The choice of the PPP (number of particles per parcel) and the treatment of boundary particle deficiency are found to play important roles in model accuracy and efficiency. The V-SPH method proposed in this work can provide more accurate results than the original MP-PIC method, especially in the regions of dense proppant concentration, with comparable computing efficiency. With proper treatment of boundary deficiencies, it is promising to be used in more complex field-scale proppant transport problems.</span></span></p></div>","PeriodicalId":16717,"journal":{"name":"Journal of Petroleum Science and Engineering","volume":"220 ","pages":"Article 111129"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50185979","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dynamic effect of gas initial desorption in coals with different moisture contents and energy-controlling mechanism for outburst prevention of water injection in coal seams","authors":"Chaojie Wang ,&nbsp;Xiaowei Li ,&nbsp;Lutan Liu ,&nbsp;Zexiang Tang ,&nbsp;Changhang Xu","doi":"10.1016/j.petrol.2022.111270","DOIUrl":"https://doi.org/10.1016/j.petrol.2022.111270","url":null,"abstract":"<div><p><span>In view of the continuous occurrence of coal and gas outbursts (hereafter as ‘outbursts’), and the dynamic behavior and quantitative mechanism of water injection in </span>coal seams<span> preventing outbursts are not still unclear. In the study, the characterization of mechanical action and expansion energy release of gas initial desorption (GID) in coals with different moisture contents is revealed to clarify the influence of moisture on gas dynamic effect in coals. The results show that during the GID of gas-containing coals, the increased moisture content will decrease the pressure and momentum of gas from coals significantly. And the gas pressure reduction rate shows an increasing trend, with the decreasing reduction rate of gas momentum. Therefore, the ability of gas damaging coals with high moisture contents is weakened by reducing the degree of pressure-induced mechanical action on the coal surface and the impact intensity on the cracks in coals. Meanwhile, the gas-released cumulative expansion energy from the coals is significantly reduced, with the decreasing increase rate of the gas energy. Therefrom, the moisture in the coal masses synthetically weakens the dual effects of pressure attribute and expansion effect of gas decreasing the damage ability of gas to coals, which can prevent the further development of outburst preparation process. It is concluded that the correlation between moisture content and the initial expansion energy of released gas is linearly and negatively correlated. For moisture content with the every 1% increase in coal masses of Xuehu Coal Mine, the energy decreases by about 11% on average. Accordingly, the quantitative water injection in coal mining face is carried out to eliminate the local abnormal zone containing gas.</span></p></div>","PeriodicalId":16717,"journal":{"name":"Journal of Petroleum Science and Engineering","volume":"220 ","pages":"Article 111270"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50185990","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of eccentricity with different shape wellbores on the flushing efficiency of drilling fluid filter cake","authors":"XiaYu Zhang ,&nbsp;Yang Bai ,&nbsp;Jiang Du ,&nbsp;Chuan Lu ,&nbsp;LiKun Fan ,&nbsp;Jian Song ,&nbsp;Zhen Li ,&nbsp;ShiHao Zhang ,&nbsp;XingGuo Zhang","doi":"10.1016/j.petrol.2022.111112","DOIUrl":"10.1016/j.petrol.2022.111112","url":null,"abstract":"<div><p><span>The effective flushing of a drilling fluid filter cake is crucial for improving the zone isolation of cement sheaths during cementing operations, some studies have researched the flushing law of filter cake in circular wellbore, however, only a few have studied the flushing law and mechanism of elliptical wellbore and the irregularity of elliptical wellbore may lead to the increase of the non-uniformity of filter cake that may result in different flushing results than the circular wellbore. In this study, a filter cake formation and flushing experimental system is developed for circular and elliptical wellbore, and the formation and flushing experiments of drilling fluid filter cake in circular and elliptical wellbore are conducted, the flushing law and mechanism of drilling fluid filter cake in circular and elliptical wellbore are obtained by combining the computational fluid dynamics (CFD) simulation calculation results with the experimental results. The results revealed that the filter cake flushing efficiency of the same drilling fluid and displacement were primarily affected by the thickness of the initial drilling fluid filter cake, shear strength, wellbore shape, </span>wall shear stress<span> and eccentricity, the initial thickness and shear strength were higher, the filter cake flushing efficiency was lower, the wall shear stress of the flushing fluid was higher, the flushing efficiency of the filter cake was higher, and the change in wellbore shape and eccentricity led to an uneven distribution of annular velocity and reduced the flushing efficiency of the filter cake. The method and conclusion enable to gain an understanding for improving the flushing efficiency of the drilling fluid filter cake and forms a basis for the design of flushing fluids in cementing operations.</span></p></div>","PeriodicalId":16717,"journal":{"name":"Journal of Petroleum Science and Engineering","volume":"220 ","pages":"Article 111112"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46856373","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}