Robotic reproduction of oil paintings using soft brushes and pigments requires force-sensitive control of deformable tools, prediction of brushstroke effects, and multi-step stroke planning, often without human step-by-step demonstrations or faithful simulators. Given only a sequence of target oil painting images, can a robot infer and execute the stroke trajectories, forces, and colors needed to reproduce it? We present IMPASTO, a robotic oil-painting system that integrates learned pixel dynamics models with model-based planning. The dynamics models predict canvas updates from image observations and parameterized stroke actions; a receding-horizon model predictive control optimizer then plans trajectories and forces, while a force-sensitive controller executes strokes on a 7-DoF robot arm. IMPASTO integrates low-level force control, learned dynamics models, and high-level closed-loop planning, learns solely from robot self-play, and approximates human artists' single-stroke datasets and multi-stroke artworks, outperforming baselines in reproduction accuracy. Project website: https://impasto-robopainting.github.io/
Recent advancements in Multimodal Large Language Models (MLLMs) have demonstrated impressive performance on standard visual reasoning benchmarks. However, there is growing concern that these models rely excessively on linguistic shortcuts rather than genuine visual grounding, a phenomenon we term Text Bias. In this paper, we investigate the fundamental tension between visual perception and linguistic priors. We decouple the sources of this bias into two dimensions: Internal Corpus Bias, stemming from statistical correlations in pretraining, and External Instruction Bias, arising from the alignment-induced tendency toward sycophancy. To quantify this effect, we introduce V-FAT (Visual Fidelity Against Text-bias), a diagnostic benchmark comprising 4,026 VQA instances across six semantic domains. V-FAT employs a Three-Level Evaluation Framework that systematically increases the conflict between visual evidence and textual information: (L1) internal bias from atypical images, (L2) external bias from misleading instructions, and (L3) synergistic bias where both coincide. We introduce the Visual Robustness Score (VRS), a metric designed to penalize "lucky" linguistic guesses and reward true visual fidelity. Our evaluation of 12 frontier MLLMs reveals that while models excel in existing benchmarks, they experience significant visual collapse under high linguistic dominance.
The Qinshui Basin is the main production base of high-rank coalbed methane in China. High-rank coal reservoirs in this region exhibit diverse conditions for coal formation and reservoir development, complex geological structures, low permeability, pronounced reservoir heterogeneity, and significant challenges in reservoir stimulation, which led to early issues such as a low effective resource utilization rate, low gas production per well, and low development profits. By analyzing the characteristics of high-rank coal reservoirs and the development patterns of coalbed methane, this study identifies three key constraints to the efficient development of high-rank coalbed methane: (1) poor precision in selecting areas for efficient development; (2) limited adaptability of development technologies; (3) a mismatch between stimulation processes and coal reservoirs. Investigations into microstructures, coal body structures, in-situ stresses, and fractures—combined with an evaluation of various geological factors’ impact on production—enabled a multidimensional division of development units to identify the geological features of each unit. Consequently, a “five-element” evaluation index system for production potential in efficient development areas was established, and an optimization method for selecting efficient development areas for high-rank coalbed methane was formulated. Analysis suggests that due to the low permeability and strong heterogeneity of high-rank coal, horizontal wells can connect more coal seam fractures, thereby expanding the drainage and pressure-relief areas and reducing the flow resistance of gas and water. This possesses advantages such as high per-well gas production and improved economic benefits. For different geological zones and development stages, in accordance with the principle of “maximizing controlled reserves, maximizing gas production rate, and optimizing economic benefits”, an optimized horizontal well layout technology for high-rank coalbed methane was developed. On this basis, with the objective of “initiating a fracture network, creating new fractures, and controlling reserves”, key technologies were devised—primarily including energy-focused directional perforation, stepwise hydraulic fracturing for incremental production enhancement, a combined application of fine-powder sand, and synchronous well-group interference. At the same time, the process technologies of bridge-plug-and-perforation using active water as the main body and well-group synchronous interference operations were refined, leading to the establishment of a linear fracture network system conducive to gas production, achieving efficient hydraulic fracturing. The application of these research outcomes in the Qinshui Basin has enabled the efficient development of high-rank coal, with daily gas production per horizontal well doubling, the ultimate recoverable reserve per well increasing by 50%, and the productivity attainment rate of newly-built blocks surpassing 90%. When extended to other high-rank coalbed methane blocks in China, these advantages provide technical support and a demonstrative model for strengthening the coalbed methane industry.
Petroleum refining. Petroleum products, Gas industry
Jose Rocher-Gonzalez, Jesus Escudero-Sahuquillo, Pedro J. Garcia
et al.
The interconnection network is a key element in High-Performance Computing (HPC) and Datacenter (DC) systems whose performance depends on several design parameters, such as the topology, the switch architecture, and the routing algorithm. Among the most common topologies in HPC systems, the Fat-Tree offers several shortest-path routes between any pair of end-nodes, which allows multi-path routing schemes to balance traffic flows among the available links, thus reducing congestion probability. However, traffic balance cannot solve by itself some congestion situations that may still degrade network performance. Another approach to reduce congestion is queue-based flow separation, but our previous work shows that multi-path routing may spread congested flows across several queues, thus being counterproductive. In this paper, we propose a set of restrictions to improve alternative routes selection for multi-path routing algorithms in Fat-Tree networks, so that they can be positively combined with queuing schemes.
Sparse continuous policies are distributions that can choose some actions at random yet keep strictly zero probability for the other actions, which are radically different from the Gaussian. They have important real-world implications, e.g. in modeling safety-critical tasks like medicine. The combination of offline reinforcement learning and sparse policies provides a novel paradigm that enables learning completely from logged datasets a safety-aware sparse policy. However, sparse policies can cause difficulty with the existing offline algorithms which require evaluating actions that fall outside of the current support. In this paper, we propose the first offline policy optimization algorithm that tackles this challenge: Fat-to-Thin Policy Optimization (FtTPO). Specifically, we maintain a fat (heavy-tailed) proposal policy that effectively learns from the dataset and injects knowledge to a thin (sparse) policy, which is responsible for interacting with the environment. We instantiate FtTPO with the general $q$-Gaussian family that encompasses both heavy-tailed and sparse policies and verify that it performs favorably in a safety-critical treatment simulation and the standard MuJoCo suite. Our code is available at \url{https://github.com/lingweizhu/fat2thin}.
Based on the displacement discontinuity method and the discrete fracture unified pipe network model, a sequential iterative numerical method was used to build a fracturing-production integrated numerical model of shale gas well considering the two-phase flow of gas and water. The model accounts for the influence of natural fractures and matrix properties on the fracturing process and directly applies post-fracturing formation pressure and water saturation distribution to subsequent well shut-in and production simulation, allowing for a more accurate fracturing-production integrated simulation. The results show that the reservoir physical properties have great impacts on fracture propagation, and the reasonable prediction of formation pressure and reservoir fluid distribution after the fracturing is critical to accurately predict the gas and fluid production of the shale gas wells. Compared with the conventional method, the proposed model can more accurately simulate the water and gas production by considering the impact of fracturing on both matrix pressure and water saturation. The established model is applied to the integrated fracturing-production simulation of practical horizontal shale gas wells. The simulation results are in good agreement with the practical production data, thus verifying the accuracy of the model.
An auxiliary measurement system of nuclear magnetic resonance(NMR)logging tool based on universal acquisition platform was designed to enable the new generation of NMR logging tool to efficiently and accurately acquire information about auxiliary measurement parameters.Based on the universal acquisition platform technology,a detailed analysis was conducted on the necessary parameters and properties in auxiliary measurement of NMR logging tool,and an auxiliary measurement system of NMR logging tool was proposed.The design and realization of the hardware functions(e.g.signal conditioning,multichannel switching and digital-analog conversion)of the auxiliary measurement system,as well as the time sequence of sending auxiliary measurement parameter selection channel commands and reading auxiliary measurement parameter acquisition data,were investigated.The single board test results show that the selection of auxiliary measurement parameter channels and the uploading of acquired data are feasible.The joint debugging test results show that the designed auxiliary measurement system can accurately obtain the information about auxiliary measurement parameters of NMR logging tool,and reflect the actual working status of the tool.The research results provide a technical basis for the design,research and application of auxiliary measurement systems of eccentric,while drilling and through-bit NMR logging tools.
Chemical engineering, Petroleum refining. Petroleum products
Although experimental design and methodological surveys for mono-molecular activity/property has been extensively investigated, those for chemical composition have received little attention, with the exception of a few prior studies. In this study, we configured three simple DNN regressors to predict essential oil property based on chemical composition. Despite showing overfitting due to the small size of dataset, all models were trained effectively in this study.
Ankita Kukshal, Ravi Sharma, Hirak Jyoti Kalita
et al.
Abstract One of the main challenges for healthy hydrocarbon yields from the production wells is the sand production, and its control assumes significant importance for successful production operations. The prime objective remains to control the sand production without compromising on the fluid flow rates. Sand production is conventionally associated with diverse heterogeneous formations, especially poorly consolidated formations. Scrutinizing fluid flow rates at different orientations of perforations is a valuable analysis in controlling the sand production. This study was conducted to examine the case of sand production in a few development wells from Malleshwaram field of the Krishna Godavari (KG) basin in south India and provide alternatives to arrest this sand production. The influence of oriented perforations on fluid flow rates to minimize sanding tendencies was examined. Sand grain diameter was estimated using the distribution plots of the grain sizes obtained from the photomicrographs, and the average value of the grain size was estimated around 100 μm. The fluid flow model was simulated for actual scenario in the hydrocarbon bearing Nandigama formation using finite element modeling (FEM). Sanding tendencies in these formations were studied at varying depletion rates. Critical draw down pressure (CDDP), which is a function of both critical bottom hole pressure and reservoir pore pressure, for well 1 and well 2 is estimated as 4650 Psi and 3400 Psi, respectively, at 0% depletion. CDDP was used to estimate the onset of sanding, and the flow rate for horizontal perforation was calculated as 0.024548 $${\mathrm{m}}^{3}$$ m 3 /sec. Strength parameters, namely the unconfined compressive strength (UCS) and cohesion, were also investigated in all the wells to decipher the formation strength and a possible linkage to sanding. These results present a completely fresh analysis of the sanding potential and the related parameters responsible for it in these formations. Fluid flow rates for the producing reservoir are studied at different set of oriented and sized perforations. It was observed that a hiked flow rate in horizontal perforations maintains the production in a safe and no-sanding zone. This study provides vital information and a workflow for similar heterogeneous complex formations for designing the well completions, augmenting economic production and reinforcing future reservoir management.
The connected media of fault-karst reservoir are fractures, caves and pores, the decrease of pressure will lead to the decrease of permeability and conductivity, which will have an irreversible impact on oil well production. According to the stress-sensitive characteristics of fault-karst reservoir, 72 groups of physical simulation experiments on conductivity are designed and carried out to analyze the stress-sensitive characteristics of different connected media and influencing factors. Based on the results of physical simulation experiment and the theory of porous flow, a numerical inversion model of flow in fractured solution reservoir is established, and the stress sensitivity effect caused by reservoir pressure drop on oil well production is studied. The results show that the pressure drop has great influence on the conductivity, productivity and recovery ability of different connected media. The pressure inflection points of fracture type, karst cave type and pore type are 5.3 %, 20.4 % and 35.1 %, respectively, and the conductivity loss of the first two are 99.7 % and 45.0 %. The conductivity loss of pore type decreases linearly in the test range. The research on the characteristics of pressure drop inflection point provides the basis for reasonable production control and the determination of energy replenishment time, and has important guiding significance for stable production of oil wells.
Petroleum refining. Petroleum products, Gas industry
为提高餐厨废弃油脂制生物柴油的储存稳定性，以餐厨废弃油脂为原料，采用生物酶法制备生物柴油，并向其中添加0.2%的抗氧化剂，测定其在90 d储存过程中酸值、水含量、硫含量及氧化安定性的变化。结果表明：酶法制备的生物柴油各项指标满足GB 25199—2017《B5柴油》中BD100生物柴油S10的技术要求，硫含量最低为2.1 mg/kg；当添加0.2%的抗氧化剂时，生物柴油的氧化安定性由3.6 h提高至12.0 h，储存90 d后，生物柴油的硫含量、酸值、水含量、氧化安定性仍符合国标要求。酶法制备生物柴油工艺易于控制产品的各项指标，且工艺更加绿色环保，通过添加抗氧化剂可提高生物柴油的储存稳定性。To improve the storage stability of biodiesel made from waste cooked oil, with waste cooked oil as raw material, biodiesel was produced by enzymatic process and 0.2% of antioxidant was added to it,then the change of acid value, moisture content, sulfur content and oxidation stability of the biodiesel during 90 d storage were determined. The results showed that the indicators of biodiesel prepared by enzymatic method met the technical requirements of BD100 biodiesel S10 in GB 25199-2017 “B5 Diesel fuels”, with a minimum sulfur content of 2.1 mg/kg.When 0.2% antioxidant was added, the oxidation stability of biodiesel increased from 3.6 h to 12.0 h. After 90 d of storage, the sulfur content, acid value, moisture content and oxidation stability were in line with national standard requirements. Enzymatic preparation process of biodiesel is easy to control the various indicators of the product, the process is more green and environmental protection, and through the addition of antioxidant the storage stability of biodiesel can be improved.
A FALAVAND-JOZAEI, E HAJIDAVALLOO, Y SHEKARI
et al.
The present study aims at investigating the effect of temperature variation due to heat transfer between the formation and drilling fluids considering influx from the reservoir in the underbalanced drilling condition. Gas-liquid-solid three-phase flow model considering transient thermal interaction with the formation was applied to simulate wellbore fluid to calculate the wellbore temperature and pressure and analyze the influence of different parameters on fluid pressure and temperature distribution in annulus. The results show that the non-isothermal three-phase flow model with thermal consideration gives more accurate prediction of bottom-hole pressure (BHP) compared to other models considering geothermal temperature. Viscous dissipation, the heat produced by friction between the rotating drilling-string and well wall and drill bit drilling, and influx of oil and gas from reservoir have significant impact on the distribution of fluid temperature in the wellbore, which in turn affects the BHP. Bottom-hole fluid temperature decreases with increasing liquid flow rate, circulation time, and specific heat of liquid and gas but it increases with increasing in gas flow rate. It was found that BHP is strongly depended on the gas and liquid flow rates but it has weak dependence on the circulation time and specific heat of liquid and gas. BHP increase with increasing liquid flow rate and decreases with increasing gas flow rate.
As a key component of subsea Christmas tree,subsea chokes work in deep water,high pressure and low temperature environment.It is easy to produce natural gas hydrates to block chokes and downstream pipelines due to J-T effect.Therefore,it is very important to study the temperature range downstream of the chokes and compare the hydrate temperature-pressure curves for production safety.In this paper,based on the theories of mass,kinetic energy,energy conservation,heat transfer and fluid mechanics,taking the Cameron subsea chokes as the study object,the subsea choke throttling model was established with natural gas condensate as the medium to study the throttling temperature drop of natural gas through chokes.Fluent software was used to obtain the flow field distribution and temperature distribution of subsea chokes from single-phase methane to gas-liquid two-phase flow.Finally,by using the established model,the effects of inlet pressure,outlet pressure,inlet temperature,gas-liquid ratio and choke opening on the throttling temperature drop and choke flow field distribution were studied.The results show that when fluid passes through the sudden contraction section of subsea chokes,the downstream temperature drops sharply due to J-T effect,and when the temperature drops to a sufficiently low level,hydrate will precipitate and block the pipeline.Controlling the pressure and temperature above the hydrate formation point in production could avoid ice blockage.In addition,the choke opening will indirectly affect the pressure difference,so too small opening is not applicable in operations.The results provide guidance for safe production in deepwater oil and gas fields.
Chemical engineering, Petroleum refining. Petroleum products
The ongoing COVID-19 shocked financial markets globally, including China's crude oil future market, which is the third most traded crude oil futures after WTI and Brent. As China's first crude oil futures accessible to foreign investors, the Shanghai crude oil futures (SC) have attracted significant interest since launch at the Shanghai International Energy Exchange. The impact of COVID-19 on the new crude oil futures is an important issue for investors and policy makers. Therefore this paper studies the short-term influence of COVID-19 pandemic on SC via multifractal analysis. We compare market efficiency of SC before and during the pandemic with the multifractal detrended fluctuation analysis and other commonly-used random walk tests. Then we generate shuffled and surrogate data to investigate the components of multifractal nature in SC. And we examine cross-correlations between SC returns and other financial assets returns as well as SC trading volume changes by the multifractal detrended cross-correlation analysis. The results show that market efficiency of SC and its cross-correlations with other assets increase significantly after the outbreak of COVID-19. Besides that, the sources of its multifractal nature have changed since the pandemic. The findings provide evidence for the short-term impacts of COVID-19 on SC. The results may have important implications for assets allocation, investment strategies and risk monitoring.
We look at optimal liability-driven portfolios in a family of fat-tailed and extremal risk measures, especially in the context of pension fund and insurance fixed cashflow liability profiles, but also those arising in derivatives books such as delta one books or options books in the presence of stochastic volatilities. In the extremal limit, we recover a new tail risk measure, Extreme Deviation (XD), an extremal risk measure significantly more sensitive to extremal returns than CVaR. Resulting optimal portfolios optimize the return per unit of XD, with portfolio weights consisting of a liability hedging contribution, and a risk contribution seeking to generate positive risk-adjusted return. The resulting allocations are analyzed qualitatively and quantitatively in a number of different limits.
In general, fracturing well pattern is used for the development of low-permeability reservoir. This development process relates to the oil-water two phase flow, while the current researches on fracturing well productivity consider more about single phase flow. Based on the consideration of the reservoir anisotropy, threshold pressure gradient and oil-water two phase flow, a prediction method of fracturing well productivity is proposed by numerical method and sweep theory. And then, a contrast between the calculated results of the proposed method and field data is performed to verify the accuracy of the proposed model. The results show that when the water cut is constant, the increase of fracture conductivity results in the increase of the oil production. However,as the conductivity increases, the increase rate of the oil production decreases. The increase of the fracture conductivity also results in the increase of the cumulative oil production. When the conductivity is greater than 0.4 μm2·m, the cumulative oil production increases slowly. When the length of the fracture increases, the seepage resistance near the bottom decreases, so that the oil production increases. The increase of the permeability ratio indicates the planar heterogeneity becoming stronger, so that the productivity of the fractured well reduces showing a poorer water flooding effect. This study provides a theoretical basis for the optimization of the fracturing of the development well pattern by water flooding.
Petroleum refining. Petroleum products, Gas industry
The geological conditions of marine fluvial sedimentary reservoir are very complex.In the process of water flooding development,the remaining oil distribution is dispersed and it is difficult to develop due to different water absorption in the same permeability reservoir.In order to guide the exploration direction of remaining oil in the later stage of each reservoir,the pore throat distribution characteristics and micro percolation characteristics of different permeability reservoirs are studied based on the micro pore throat scale by the mercury injection experiment and micro water drive visualization experiment.The results show that there is a good logarithmic correlation between the average pore throat radius and permeability,and the correlation coefficient is 0.963 5.With the increase of the reservoir permeability,the mean pore throat radius increases gradually,whereas the micro fingering phenomenon of water drive is reduced,and the water flooding process is gradually changing to finger-network-uniform displacement.Both the sweep efficiency and recovery efficiency of each model show an increasing tendency,and the proportion of continuous remaining oil is gradually decreasing.When the permeability increases to 2 228.7×10<sup>-3</sup>μm<sup>2</sup>,both the sweep efficiency and recovery efficiency reach their maximum value,the for is 82.97%,the latter is 66.1%,and the proportion of continuous remaining oil reaches the minimum value of 45.82%.For the reservoirs with permeability of（73.1～1 005.2）×10<sup>-3</sup>μm<sup>2</sup>,the main direction of potential tapping in the later period should be to increase the viscosity of displacement fluid and increase sweep.For reservoirs with permeability of（1 005.2～3 509.6）×10<sup>-3</sup>μm<sup>2</sup>,it turns to be improving oil displacement efficiency.For reservoirs with permeability of（3 509.6～4 040.6）×10<sup>-3</sup>μm<sup>2</sup>,it is appropriate to increase water injection pressure or block large water breakthrough channels to change the direction of injected water,so as to improve the conformance as the main direction of the potential tapping.
Petroleum refining. Petroleum products, Gas industry
In this work we present a formalism of abstract quantum field theory for fat graphs and its realizations. This is a generalization of an earlier work for stable graphs. We define the abstract correlators $\mathcal F_g^μ$, abstract free energy $\mathcal F_g$, abstract partition function $\mathcal Z$, and abstract $n$-point functions $\mathcal W_{g,n}$ to be formal summations of fat graphs, and derive quadratic recursions using edge-contraction/vertex-splitting operators, including the abstract Virasoro constraints, an abstract cut-and-join type representation for $\mathcal Z$, and a quadratic recursion for $\mathcal W_{g,n}$ which resembles the Eynard-Orantin topological recursion. When considering the realization by the Hermitian one-matrix models, we obtain the Virasoro constraints, a cut-and-join representation for the partition function $Z_N^{\text{Herm}}$ which proves that $Z_N^{\text{Herm}}$ is a tau-function of KP hierarchy, a recursion for $n$-point functions which is known to be equivalent to the E-O recursion, and a Schrödinger type-equation which is equivalent to the quantum spectral curve. We conjecture that in general cases the realization of the quadratic recursion for $\mathcal W_{g,n}$ is the E-O recursion, where the spectral curve and Bergmann kernel are constructed from realizations of $\mathcal W_{0,1}$ and $\mathcal W_{0,2}$ respectively using the framework of emergent geometry.