Petroleum Science最新文献

{"title":"A novel optimization scheme for structure and balance of compound balanced beam pumping units using the PSO, GA, and GWO algorithms","authors":"Jie Wang ,&nbsp;Quan-Ying Guo ,&nbsp;Cheng-Long Fu ,&nbsp;Gang Dai ,&nbsp;Cheng-Yu Xia ,&nbsp;Li-Qin Qian","doi":"10.1016/j.petsci.2025.01.007","DOIUrl":"10.1016/j.petsci.2025.01.007","url":null,"abstract":"<div><div>The beam pumping unit (BPU) remains the most stable and reliable equipment for crude oil lifting. Despite its simple four-link mechanism, the structural design of the BPU presents a constrained single-objective optimization problem. Currently, a comprehensive framework for the structural design and optimization of compound balanced BPUs is lacking. Therefore, this study proposes a novel structural design scheme for BPUs, aiming to meet the practical needs of designers and operators by sequentially optimizing both the dynamic characteristics and balance properties of the BPUs. A dynamic model of compound balanced BPU was established based on D'Alembert's principle. The constraints for structural dimensions were formulated based on the actual operational requirements and design experience with BPUs. To optimize the structure, three algorithms were employed: the particle swarm optimization (PSO) algorithm, the genetic algorithm (GA), and the gray wolf optimization (GWO) algorithm. Each newly generated individuals are regulated by constraints to ensure the rationality of the outcomes. Furthermore, the integration of three algorithms ensures the increased likelihood of attaining the global optimal solution. The polished rod acceleration of the optimized structure is significantly reduced, and the dynamic characteristics of the up and down strokes are essentially symmetrical. Additionally, these three algorithms are also applied to the balance optimization of BPUs based on the measured dynamometer card. The calculation results demonstrate that the GWO-based optimization method exhibits excellent robustness in terms of structural optimization by enhancing the operational smoothness of the BPU, as well as in balance optimization by achieving energy conservation. By applying the optimization scheme proposed in this paper, the CYJW7-3-23HF type of BPU was designed, achieving a maximum polished rod acceleration of ±0.675 m/s² when operating at a stroke of 6 min⁻¹. When deployed in two wells, the root-mean-square (RMS) torque was minimized, reaching values of 7.539 kN·m and 12.921 kN·m, respectively. The proposed design method not only contributes to the personalized customization but also improves the design efficiency of compound balanced BPUs.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"22 3","pages":"Pages 1340-1359"},"PeriodicalIF":6.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143760150","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Insights into the pore structure and hydrocarbon accumulation of lacustrine organic-rich shales","authors":"Xiao-Jiao Pang ,&nbsp;Gui-Wen Wang ,&nbsp;Yong-Jia Zhang ,&nbsp;Da-Li Yue ,&nbsp;Hong-Bin Li ,&nbsp;Li-Chun Kuang ,&nbsp;Chao-Liu Li","doi":"10.1016/j.petsci.2024.12.005","DOIUrl":"10.1016/j.petsci.2024.12.005","url":null,"abstract":"&lt;div&gt;&lt;div&gt;With the development of unconventional hydrocarbon, how to improve the shale oil and gas recovery become urgent. Therefore hydraulic fracturing becomes the key due to the complicated properties of the reservoirs. The pore structure not only plays an essential role in the formation of complex fracture networks after fracturing but also in resource accumulation mechanism analyses. The lacustrine organic-rich shale samples were selected to carry out petrophysical experiments. Scanning Electron Microscopy (SEM) and X-ray Diffraction were performed to elucidate the geology characteristics. MICP, 2D NMR, CT, and N&lt;sub&gt;2&lt;/sub&gt; adsorption were conducted to classify the pore structure types. The contribution of pore structure to oil accumulation and hydrocarbon enrichment was explained through the N&lt;sub&gt;2&lt;/sub&gt; adsorption test on the original and extracted state and 2D NMR. The results show that micropores with diameter less than 20 nm are well-developed. The pore structure was divided into three types. Type I is characterized by high porosity, lower surface area, and good pore throat connectivity, with free oil existing in large pores, especially lamellation fractures. The dominant nano-pores are spongy organic pores and resources hosted in large pores have been expelled during high thermal evolution. The content of nano-pores (micropores) increases and the pore volume decreases in Type II pore structure. In addition, more absorbed oil was enriched. The pore size distribution of type II is similar to that of type I. However, the maturity and hydrocarbon accumulation is quite different. The oil reserved in large pores was not expelled attributed to the relatively low thermal evolution compared with type I. Structural vitrinite was observed through SEM indicating kerogen of type III developed in this kind of reservoir while the type of kerogen in pore structure I is type II. Type III pore structure is characterized by the largest surface area, lowest porosity, and almost isolated pores with rarely free oil. Type I makes the most contribution to hydrocarbon accumulation and immigration, which shows the best prospect. Of all of these experiments, N&lt;sub&gt;2&lt;/sub&gt; adsorption exhibits the best in characterizing pores in shales due to its high resolution for the assessment of nano-scale pores. MICP and NMR have a better advantage in characterizing pore space of sandstone reservoirs, even tight sandstone reservoirs. 2D NMR plays an essential role in fluid recognition and saturation calculation. CT scanning provides a 3D visualization of reservoir space and directly shows the relationship between pores and throats and the characteristics of fractures. This study hopes to guide experiment selection in pore structure characterization in different reservoirs. This research provides insight into hydrocarbon accumulation of shales and guidance in the exploration and development of unconventional resources, for example for geothermal and CCUS reservoirs.&lt;/div&gt;&lt;/","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"22 3","pages":"Pages 957-976"},"PeriodicalIF":6.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143760317","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Damage mechanism analysis of polymer gel to petroleum reservoirs and development of new protective methods based on NMR technique","authors":"Dao-Yi Zhu,&nbsp;Jiong Zhang,&nbsp;Tao Zhang,&nbsp;Ying-Qi Gao,&nbsp;Si Guo,&nbsp;Yong-Liang Yang,&nbsp;Jia-Mai Lu","doi":"10.1016/j.petsci.2024.12.004","DOIUrl":"10.1016/j.petsci.2024.12.004","url":null,"abstract":"<div><div>Polymer gels are widely used in water control and enhanced oil recovery in oil fields. However, the damage mechanism of polymer gels to layers with remaining oil and not requiring plugging and corresponding protective measures are unclear. In this paper, we investigated polymer gels' damage and protection performance through static gel-breaking experiments and dynamic plugging and oil recovery evaluations on rock cores. Moreover, nuclear magnetic resonance (NMR) technology was combined to analyze the damage performance of polymer gels on cores from the pore scale. In addition, a protective technique based on gel breakers for layers with remaining oil and not requiring plugging was proposed. Results showed that when polymer gels were injected into heterogeneous cores, they plugged high-permeability layers while also penetrating low-permeability layers. When the damage to the low-permeability layers was not alleviated, the conformance and oil displacement efficiency were significantly reduced. When the concentration of ammonium persulfate was 2%–5%, the gel-breaking time was shortest and the residue was very minimal. Therefore, ammonium persulfate could be used as a gel breaker and reservoir protective material. Furthermore, after injecting ammonium persulfate into heterogeneous reservoir cores, the gel damage on the face of low-permeability layers was relieved. Consequently, the improvement in sweep efficiency was achieved, showing the re-activation of the remaining oil in medium-low permeability layers. Therefore, the low-permeability layer protection process and core experiment study based on gel-breaking agents proposed in this study were suggested to provide a new technique for the field application of conformance modification agents, aiming to achieve higher recovery degrees.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"22 3","pages":"Pages 1225-1233"},"PeriodicalIF":6.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143760144","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An integrated multi-scale approach for transient analysis of multi-well horizontal pad with well interference in shale gas reservoirs: Methodology and case study","authors":"Hong-Yang Chu ,&nbsp;Si-Dong Fang ,&nbsp;Zhi-Qiang Ren ,&nbsp;Jian-Dong Zou ,&nbsp;Ran Bi ,&nbsp;Wei-Yao Zhu ,&nbsp;W. John Lee","doi":"10.1016/j.petsci.2024.12.022","DOIUrl":"10.1016/j.petsci.2024.12.022","url":null,"abstract":"<div><div>Shale gas, as a clean, low-carbon, and abundant unconventional natural gas resource, plays a crucial role in achieving clean energy transformation and carbon neutrality. The Fuling shale gas reservoir in Sichuan Basin stands out as China's most promising area for shale gas exploration and recovery. However, the continuous recovery of shale gas in the southern Sichuan Basin has led to well interference events in hundreds of wells, with the furthest well distance reaching over 2000 m. This study introduces a multi-scale approach for transient analysis of a multi-well horizontal pad with well interference in shale gas reservoirs. The approach utilizes Laplace transform technology, boundary element theory, and the finite difference method to address the complexities of the system. Well interference is managed using the pressure superposition principle. To validate the proposed multi-scale method, a commercial numerical simulator is employed. The comprehensive pressure behavior of a multi-well horizontal pad in a shale gas reservoir is analyzed, encompassing wellbore storage effect, skin effect, bilinear flow, linear flow, pseudo-radial flow of primary fractures, well interference period, dual-porosity flow, pseudo-radial flow of the total system, and boundary-dominated flow. A case study is conducted on the typical well, the well with the longest production history in the Fuling shale gas reservoir. The rate transient analysis is conducted to integrate up to 229 days of shale gas production daily data and wellhead pressure data, enabling the generation of pressure behavior under unit flow rate. The results indicate that the linear flow, transitional flow, and boundary-dominated flow are more likely to be observed in the actual data. Secondary fractures are considered to be the primary pathways for fluid migration during well interference events. The evaluated formation permeability is 2.58 × 10⁻² mD, the well spacing is 227.8 m, the diffusion coefficient is 1.49 × 10⁻⁴, and the skin factor is 0.09.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"22 3","pages":"Pages 1155-1170"},"PeriodicalIF":6.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143760230","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Coupling mechanism analysis of CO2 non-Darcy flow in multi-scale reservoirs: A case study of the life-cycle process of fracturing-development in shale oil reservoirs","authors":"Zhen-Hua Rui ,&nbsp;Hai-Yang Deng ,&nbsp;Ting Hu ,&nbsp;Guang-Long Sheng ,&nbsp;Malcolm Wilson ,&nbsp;Birol Dindoruk ,&nbsp;Shirish Patil","doi":"10.1016/j.petsci.2024.12.018","DOIUrl":"10.1016/j.petsci.2024.12.018","url":null,"abstract":"<div><div>With policy support for carbon capture, utilization, and storage (CCUS), an integrated approach that combines energy storage fracturing, CO₂-enhanced oil recovery (EOR), and storage emerges as a promising direction for the shale oil industry. The process of energy storage fracturing induces significant changes in the pressure and saturation of the medium. However, conventional simulations often overlook the effects of fracturing and shut-in operations on the seepage field and production performance. Furthermore, fractured shale reservoirs exhibit complex non-Darcy flow characteristics due to intricate pore structures and multi-scale porous media. A comprehensive understanding of flow mechanisms is essential for effective reservoir development and CO₂ storage. This study establishes a multi-component simulation model that encompasses the life-cycle of fracturing, shut-in, production, and CO₂ huff-n-puff processes, thereby ensuring the continuity of the seepage field. The model accounts for the effect of nano-confinement on phase behavior by modifying the equation of state. Furthermore, the flux term is adjusted to incorporate Maxwell–Stefan diffusion, pre-/post-Darcy flow, and stress sensitivity. The embedded discrete fracture model (EDFM) is employed to simulate multiphase flow within multi-scale media, and the results from the validation model align satisfactorily with those derived from ECLIPSE. Mechanism analysis indicates that the interaction of multiple mechanisms significantly influences both production and storage performance. Under the multi-mechanism coupling, the cumulative oil production increased by 12.01%, while the utilization and storage factors increased by 62.93% and 8.93%, respectively. The role of molecular diffusion in shale oil reservoirs may be overstated, contributing only a 0.26% enhancement in oil production. Simulation results show that the energy storage fracturing strategy can increase oil production and net present value by 12.47% and 15.07%, respectively. Sensitivity analysis indicates that the CO₂ injection rate is the main factor affecting the recovery factor, followed by CO₂ injection time and the number of cycles, with fracturing fluid volume having the least impact. This study develops a multi-process, multi-mechanism simulation framework for multi-scale shale oil reservoirs. This framework provides a robust evaluation system for CCUS-EOR, facilitating informed decision-making in fracturing stimulation, development planning, and parameter optimization.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"22 3","pages":"Pages 1171-1199"},"PeriodicalIF":6.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143760231","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Morpho-dynamics in fan deltas: Effect of topography on flow transformation, facies distribution and graded profile evolution, a case study in XLG fan delta","authors":"Hong-Wei Sun ,&nbsp;Shun-Li Li ,&nbsp;Pan Li ,&nbsp;Chao-Fan Wei ,&nbsp;Zhan-Teng Wu ,&nbsp;Long-Jv Hai","doi":"10.1016/j.petsci.2024.12.028","DOIUrl":"10.1016/j.petsci.2024.12.028","url":null,"abstract":"&lt;div&gt;&lt;div&gt;Fan deltas are usually constructed through episodic flood event with debris flow transforming to hyper-concentrated flow during sediments proceeding. However, the role of topography in controlling the flow transformation and sediments aggradation has been less studied. This constrain studies of sediment distribution and understanding of graded profile. For lake basin sequences, geomorphological control is much stronger than lake level rise and fall. Under extreme conditions, sediments can still prograde when the lake level rises. Therefore, describing the influence of geomorphology on the flow transformation and stacking pattern of the lobes can provide a deeper understanding of the controlling factors of the lake basin stratigraphy sequence. Xiligou lake (XLG) fan delta from Xisai Basin provides an optimal case for addressing this issue. Three lobes developed on the XLG fan delta with significant differences in their morphologies, architectures, lithofacies, sediment distributions and topographies. Through trenching, drone photography, and satellite data, we analyzed the structure of the sediments and the distribution of sedimentary facies. Based on the analysis of debris flow and hyper-concentrated flow deposits, two transformation models corresponding to different topographies were established. Sediment unloading is caused by a frictional reduction or a sudden momentum loss in the sediments flow's carrying capacity, allowing the debris flow transforms to hyper-concentrated flow and then to stream flow during the movement. The role of topography in controlling sediment flow transformation and sediment distribution is clarified through forces analysis of sediment grain. The topographic gradient of the linear slope is constant, so the direction of fluid movement is consistent with the topographic direction. Therefore, sediment flows move on linear slope without collision with the bed and there is no sudden loss of momentum. The gradual or sudden reduction in topographic gradient of concave slopes forces a constant or sudden change in the direction of fluid movement, which facilitates the unloading of sediments and the transformation of flow. The sudden change of topography forces unloading of viscous component, and the non-viscous component pass over to form hyper-concentrated flow, often accompanied by remobilized large gravels. The graded profile was an equilibrium between the dynamics and resistance of sediment transport. Changes in lake level affect the graded profile by changing the elevation of sediment transport, which is the total gravitational potential energy. The instantaneous graded profile and temporary graded profile are different scales of equilibrium corresponding to hydrodynamic equilibrium and depositional trend respectively. This study reveals the role of geomorphological dynamics in controlling sedimentary body progradation, thus providing a new perspective on the analysis of lake basin stratigraphy sequence.&lt;/div&gt;&lt;/","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"22 3","pages":"Pages 1021-1040"},"PeriodicalIF":6.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143760320","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental investigation into CO2 huff-n-puff in low-permeability heavy oil reservoirs: Role of fractures","authors":"Di Zhu ,&nbsp;Bin-Fei Li ,&nbsp;Lei Zheng ,&nbsp;Maen M. Husein ,&nbsp;Zheng-Xiao Xu ,&nbsp;Bo-Liang Li ,&nbsp;Zhao-Min Li","doi":"10.1016/j.petsci.2024.11.015","DOIUrl":"10.1016/j.petsci.2024.11.015","url":null,"abstract":"<div><div>Low-permeability heavy oil reservoirs are characterized by poor flowability, generally mandating hydraulic fracturing to commence production. CO₂ huff-n-puff in fractured reservoirs is an effective enhanced oil recovery method. This paper uses nuclear magnetic resonance imaging to elucidate the role of propped and unpropped fractures on CO₂ huff-n-puff in cores under different confining pressures. In presence of fractures, significant improvement in the rate of early stage oil recovery is observed, up to 0.255 mL/min. Fractures enlarge the contact area between CO₂ and the heavy oil, hence improve CO₂ dissolution and oil flowability. Fractures improve oil recovery from micropores, small pores, and mesopores, as well as reduce CO₂ consumption ratio. The oil recovery factor in propped fractures is significantly higher than that in unpropped fractures, and with higher oil recovery from small pores and mesopores. The oil recovery in fractured cores noticeably decreases with increasing confining pressure. The extent of fracture closure increases and the matrix pore throats compress under pressure leading to lower apparent permeability. The decrease in oil recovery factor is more pronounced in unpropped fractured cores. A relationship between the apparent permeability of the fracture aperture is derived based on the modified cubic law of percolation to quantitatively characterize the fracture. Additionally, both the reduction in heavy oil viscosity and the increase in experimental temperature and pressure can improve the CO₂ huff-n-puff oil recovery factor in fractured cores.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"22 3","pages":"Pages 1200-1213"},"PeriodicalIF":6.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143760232","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Formation mechanism and reservoir quality evaluation in tight sandstones under a compressional tectonic setting: the Jurassic Ahe Formation in Kuqa Depression, Tarim Basin, China","authors":"Dong Li ,&nbsp;Gui-Wen Wang ,&nbsp;Kang Bie ,&nbsp;Jin Lai ,&nbsp;De-Wen Lei ,&nbsp;Song Wang ,&nbsp;Hai-Hua Qiu ,&nbsp;Hong-Bo Guo ,&nbsp;Fei Zhao ,&nbsp;Xing Zhao ,&nbsp;Qi-Xuan Fan","doi":"10.1016/j.petsci.2024.12.026","DOIUrl":"10.1016/j.petsci.2024.12.026","url":null,"abstract":"<div><div>The northern structural belt of Kuqa Depression is adjacent to the South Tianshan orogenic belt, which are characterized by complex geological conditions. The reservoir quality of the Jurassic Ahe Formation is controlled by sedimentation, diagenesis, and tectonics, and show complex pore structure and strong heterogeneity, thereby hindering effective natural gas exploration and development. Core, thin sections, cathodoluminescence (CL), scanning electron microscopy (SEM), conventional well logs and image logs are used to characterize the petrological characteristics and pore systems. Then a comprehensive analysis integrating sedimentation, diagenesis, and tectonics is performed to unravel the reservoir formation mechanism and distribution of reservoir quality. Results show that reservoir properties are generally environmentally selective. Coarse grained sandbodies (gravelly sandstones) formed in high depositional-energy have the best physical properties, while fine sandstone and mudstone with low depositional energy is easily to be tightly compacted, and have poor reservoir quality. Porosity usually decreases with compaction and cementation, and increases due to dissolution. Clay minerals filling pores result in a deterioration of the pore structure. Microfracture formed by fracturing can connect the matrix pores, effectively improving the reservoirs’ permeability. The differential distribution of fractures and in-situ stress plays an important role in modifying reservoir quality. The in-situ stress has obvious control over the matrix physical properties and fracture effectiveness. The matrix physical properties are negatively correlated with the value of horizontal stress difference (Δ<em>σ</em>). As the value of Δ<em>σ</em> increases, the pore structure becomes more complex, and the macroscopic reservoir quality becomes poor. The smaller the strike divergence between the natural fracture and SH_max, the lower the value of Δ<em>σ</em> in the fracture layers is, and the better the fracture effectiveness is. Under the control of ternary factors on the reservoir, sedimentation-diagenesis jointly affect the matrix reservoir quality, while fractures and in-situ stress caused by tectonism affect the permeability and hydrocarbon productivity of the reservoir. Affected by ternary factors, reservoir quality and hydrocarbon productivity show obvious differences within the various structural location. Reservoir quality in tight sandstones can be predicted by integrating sedimentation, diagenesis, and tectonics (fracture and in-situ stress) in a compressional tectonic setting like Kuqa Depression. The research results will provide insights into the efficient exploration of oil and gas in Kuqa Depression as well as similar compressional tectonic settings elsewhere.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"22 3","pages":"Pages 998-1020"},"PeriodicalIF":6.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143760319","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluation of cement density utilizing through-casing X-Ray logging method","authors":"Ji-Lin Fan ,&nbsp;Qiong Zhang ,&nbsp;Ya Jin ,&nbsp;Quan-Wen Zhang","doi":"10.1016/j.petsci.2024.11.004","DOIUrl":"10.1016/j.petsci.2024.11.004","url":null,"abstract":"<div><div>In the evaluation of cementing quality, quantitatively assessing cement density is crucial along with identifying the cementation degree at the interface using acoustic logging. While the ¹³⁷Cs-based formation density logging method is well-suited for density calculation, its reliance on open-hole environmental measurements poses challenges when inspecting cement density. This work focuses on the quantitative calculation of cement density while considering the radioactive hazards to the environment caused by ¹³⁷Cs source. The proposed approach utilizes a measurement system consisting of an X-Ray source and four gamma detectors. The gamma spectrum characteristics of each detector are analyzed, and the energy spectrum recorded by each detector is distinguished by different energy windows. A forward model is established to relate the gamma counts of each energy window to the formation and cement parameters. By employing a regularized Newton's method based on optimization technique, cement density can be calculated with a controllable error margin of within 0.015 g/cm³. Furthermore, even though X-Ray detection has lower sensitivity to formation parameters compared to ¹³⁷Cs, this method is capable of estimating formation density. Overall, the proposed approach enables the quantitative calculation of cement density and semi-quantitative calculation of formation density, therefore is of significance to the comprehensive evaluation of cementing quality.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"22 3","pages":"Pages 1041-1050"},"PeriodicalIF":6.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143760321","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mechanism of proppant transport and deposition in rough intersecting fractures after offshore fracturing","authors":"Biao Yin ,&nbsp;Yi-Shan Lou ,&nbsp;Shan-Yong Liu ,&nbsp;Yan Zhang","doi":"10.1016/j.petsci.2025.01.008","DOIUrl":"10.1016/j.petsci.2025.01.008","url":null,"abstract":"<div><div>To accurately analyze proppant transport in rough intersecting fractures and elucidate the interaction mechanisms among liquid, particles, and rough walls, this study reconstructed a numerical model of fractures in inhomogeneous reservoirs with varying brittleness index (BI). Various auto-correlation Gaussian rough fracture models were created using Matlab to assess roughness through the fractal dimension method. This research innovatively combined Boolean operations to establish three-dimensional rough fracture models, incorporating (Computational Fluid Dynamics) CFD-DEM (Discrete Element Method) with a bidirectional method for cosimulation. The proppant transport in fractures was categorized into three zones based on the difference in the turbulent kinetic energy. Artificially induced fracture roughness increases fluid retention and turbulence, causing plugging effects and limiting proppant flow into branch fractures. Additionally, compared with the superior deposition and significant support effects of the spherical proppant, the low-sphericity proppant traveled farther under fracturing fluid, inducing more pronounced plugging near curved fracture intersections; the variation in fracture intersection angles primarily impacted the wall shear stress within the flow field, indicating smaller angles led to higher shear energy at the intersection. Compared with the intersection angle of 30°, the height and area deposited in the 90° branch fracture increased by 52.25% and 65.33%, respectively; notably, injecting proppant from smaller to larger particles (S:M:L) and a low velocity effectively ensured fracture conductivity near the wellbore at joint roughness coefficient (JRC) ≥46 while achieving satisfactory placement in the branch fracture, making it a recommended approach.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"22 3","pages":"Pages 1270-1288"},"PeriodicalIF":6.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143760147","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}