This study investigates the phase behavior of methane, ethane, and their binary mixture in both bulk and 5 nm slit-like pores with silica, anhydrite, calcite, dolomite, and montmorillonite walls using grand canonical Monte Carlo simulation (GCMC). The results show that vapor densities increase and, liquid densities decrease with the reduction of the pore width for both pure components and binary mixtures. The critical pressure and temperature decrease significantly in confined systems compared to bulk systems, with the rate of decrease varying depending on the type of surface. The response of critical density to surface type is distinct, and the critical density can be higher or lower than that in bulk systems. Furthermore, the dew point pressure of the confined binary mixture between two surfaces of silica, anhydrite, calcite, dolomite, and montmorillonite is higher than its value in bulk systems, while the bubble point pressure in confined systems can be lower, equal, or more than its value in bulk systems, depending on the pore surface and temperature.
Petroleum refining. Petroleum products, Engineering geology. Rock mechanics. Soil mechanics. Underground construction
Benakashani Fatemeh, Tavakoli Hossein, Soltani Elias
Expanding the cultivation of underutilized oilseed crops on marginal lands necessitates innovative agronomic strategies to maintain lipid quality while ensuring stable yields. This study explored the use of living mulch systems for the sustainable production of black cumin (Nigella sativa L.), a promising yet weed-sensitive oilseed crop, in salt-affected soils in Iran. Through a two-year field experiment, the effectiveness of berseem clover (Trifolium alexandrinum L.) and barley (Hordeum vulgare L.) mulches, paired with strategic mowing timings, was evaluated. The results showed that berseem clover mulch significantly reduced the biomass of dominant weeds including Amaranthus retroflexus, Chenopodium album, and Portulaca oleracea, by 47–74.3% compared to weedy control plots. The highest reduction (74.3%) observed in plots with T. alexandrinum living mulch mowed before the black cumin flowering stage. The oil yield of black cumin cultivated under berseem clover living mulch (with post-establishment mowing) increased by 12.4% relative to weed-free control plots. Concurrently, the fatty acid profile improved, with a 3.47% increase in unsaturated fatty acids and a 13.35% higher unsaturated-to-saturated fatty acid ratio compared to the control. These results demonstrate a dual improvement in both oil yield and quality under the living mulch system. The optimal management strategy involved removing berseem clover after crop establishment, which led to a 12.4% and 45.7% increase in oil yield compared to the weed-free and weedy plots, respectively. These findings provide the first evidence-based protocol for managing weeds in black cumin under saline conditions, offering oilseed producers an ecological alternative to herbicides that maintains both yield quantity and lipid quality in marginal environments.
Objective Hydrogen energy has drawn significant attention as the strategy of energy transition pushing forward, making it essential to establish reliable hydrogen transmission systems. For the construction of hydrogen service pipelines, it is vital to evaluate the risk of material failure due to hydrogen embrittlement in pipes. Hydrogen embrittlement occurs when hydrogen comes into contact with pipeline steel through a process consisting of six steps, among which hydrogen generation and adsorption lack of well-developed theories, leading to disparities among scholars in their understanding of the hydrogen adsorption mechanism. Therefore, studying the dissociative adsorption mechanism of hydrogen on pipeline steel is particularly crucial. Methods Focusing on hydrogen generation and adsorption, this paper presents a systematic review of the dissociative adsorption mechanism of hydrogen on pipeline steel. Lennard-Jones potential curves are incorporated to illustrate the interaction process between hydrogen and the iron surface. The dissociative adsorption modes of hydrogen on the iron surface were simulated and calculated leveraging thermodynamics and density functional theory. By analyzing orbital bonding and charge transfer, the dissociative adsorption mechanism of hydrogen on the iron surface was identified. This paper summarizes three influencing factors in the dissociative adsorption of hydrogen: the environment, the surface, and the hydrogen itself, while proposing corresponding methods to inhibit the dissociative adsorption of hydrogen. Results Hydrogen was found to be adsorbed on the surface of pipeline steel through activated dissociation into hydrogen atoms, which then enter the pipes. This process follows the primary mechanism in which orbital hybridization between H2 and Fe leads to the rupture of the H-H bonds and the subsequent formation of H-Fe bonds. Several factors were observed to influence the dissociative adsorption of hydrogen to varying degrees, including hydrogen concentration, hydrogen flow state, gas impurities, temperature, and the condition of the iron surface. Based on these findings, three methods were proposed to enhance hydrogen resistance: coating, corrosion films, and protective gas. All these methods aim to prevent hydrogen from coming into contact with pipeline steel and causing embrittlement from the perspective of surface adsorption, with the protective gas method identified as the most economical and convenient option. Conclusion This research clarifies the specific process of H2 dissociative adsorption on the surface of pipeline steel. Future research is recommended to explore the dissociative adsorption of hydrogen under multi-factor coupling conditions, to identify economical and effective hydrogen resistance options. These outcomes will establish a foundation for the integrity management of hydrogen service pipelines and ensure the safety of pipes in contact with hydrogen.
The buried-hill basement reservoirs of oilfields in Chad demonstrate low pressure and low production of oil production wells.To improve the well production,gas injection is required to replenish the formation energy.However,the reservoirs are filled due to sand production in upper layers after the open-hole development wells are converted to gas injection wells.A lower completion string consisting of an expandable tube hanger and an open-hole packer was run in Well BX20 in buried-hill reservoir of Block B,Chad,for a pilot test of recompletion technology.The test results show that the designed recompletion string is set successfully in one trip,with the entire operation period of 10 d,which is 7 d less than the average operation period of traditional recompletion technology,corresponding to US$200 000 of workover costs or more saved.After the recompletion,the casing is effectively sealed and protected from damage caused by high-pressure gas injection,ensuring the wellbore integrity of the open-hole gas injection wells.The gas injection pressure reaches 20 MPa,and the daily gas injection rate reaches 2 000 m<sup>3</sup>/h.The proposed recompletion technology is proved suitable for gas injection wells in basement reservoirs in Chad,and has a demonstration effect on the development of similar oilfields.
Chemical engineering, Petroleum refining. Petroleum products
XU Yandong, TAO Shan, HE Hui, WAN Xiaoyong, ZOU Ning, YUAN Hongfei
The fault-affected karst system in the north of Shuntuoguole low uplift, Tarim basin, Shunbei oilfield has obvious vertical development and heterogeneity. Due to the large vertical depth of the reservoir, the influence of gravity can not be ignored in the process of fluid flow. Considering that the reservoir is composed of small-scale fracture, large-scale cavity and large-scale channeling path, and the initial pressure at different depths varies with the depth, a large-scale fracture-vuggy well test model considering gravity is established combined with the principle of seepage mechanics and the equipotential body theory. The Laplace transform method was used to address this issue and the typical model plate and parameter sensitivity analysis plate were drawn. The results show that the fluid flow needs to overcome more resistance when gravity is taken into account, and the positions of dimensionless pressure and its derivative curves are higher in the middle and later stages. When accounting for the seepage effect in small-scale fractured reservoirs, distinct flow characteristics emerge: Linear flow in channeling paths, Transitional flow in large cavities, Quasi-steady flow in large cavities, and Radial flow in fractured reservoirs. The slope of the dimensionless pressure and its derivative curve of the former is between 0 and 0.5. The dimensionless pressure derivative curves of the latter two decrease slowly and then rise slowly. The applicability and validity of the model are further corroborated through case studies. This research not only enriches the fracture-vuggy well test model literature but also provides a solid theoretical foundation for interpreting well test data in vertical fracture-vuggy reservoirs with significant depth.
Petroleum refining. Petroleum products, Gas industry
The inter-well connectivity calculated from reservoir dynamic production data reflects formation heterogeneity quantitatively. Currently, the calculated inter-well connectivity between pair wells is mainly used as a tool for water flood management but not for quantitative reservoir characterization. This study proposes an innovative, dynamic data integration workflow that can integrate inter-well connectivity with a static reservoir model. In the workflow, the first step is calculating the inter-well connectivity vectors from the reservoir pairwise injector and producer wells. The second step covers interpolation in the domain of interest. The third step is to update the permeability model based on the Bayesian updating method. The result of this study shows that integrating the calculated inter-well connectivity with the static models enhances model reliability and it also provides an insight to deeper geological understanding reflected from dynamic data integration in reservoir modeling.
Oils, fats, and waxes, Petroleum refining. Petroleum products
大豆原油在储存两年的过程中，受光、热等环境因素的影响发生氧化反应，稳定性下降，酸值增加，过氧化值呈阶段性变化，油色深暗，形成较稳定的胶体层，增加精炼的难度和炼耗，精炼成品油出现返色返味,白土等辅料消耗增加。采用化学精炼对储备轮换大豆原油进行精炼，对精炼工艺操作要求和注意事项进行阐述，并进行应用效果分析，发现相比单纯精炼储备轮换大豆原油，将浸出大豆原油和储备轮换大豆原油按35∶ 65比例混合进行精炼，可减少辅料用量，降低炼耗，延长精炼成品油的货架期，降低精炼成本。The crude soybean oil has been stored for 2 years that have been affected by environmental factors such as light and hot, the oxidizing reaction occurs. The stability of the crude soybean oil decreases, the acid value increases, and the peroxide value changes in stages, the colour turns to darker and the relatively stable colloid layers is formed, which increases the difficulty and consumption of refining, and the refined oil appears color and odor reversions, and the consumptions of clay and other auxiliary materials increases. Chemical refining was adopted to refine reserve rotation crude soybean oil, and the operational requirements and precautions for the refining process were elaborated and the application effects were analyzed. It was found that compared with refining reserve rotation crude soybean oil alone, refining by mixing crude leached soybean oil and reserve rotation crude oil in a ratio of 35∶ 65 could reduce the amount of auxiliary materials and refining consumption, extend the shelf life of refined product oil, and decrease refining costs.
Harry K. Robson, H. Saul, Valerie J. Steele
et al.
Abstract Ceramic containers, intentionally deposited into wetlands, offer detailed insights into Early Neolithic culinary practices. Additionally, they are key for ascertaining the Neolithisation process in Denmark since they appear to form a typo-chronological sequence. Here, we use a combination of organic residue analysis (ORA) of pottery alongside Bayesian chronological modelling of the radiocarbon dates obtained on these vessels to explore the initial stages of votive deposition in wetlands, a practice that stretches from the Mesolithic to the onset of Christianity in Northern Europe. We consider 34 Early-Middle Neolithic (c. 3900–2350 cal BC) ‘bog pots’ from Denmark, of which 20 have ORA data, and 26 have been dated directly. Carbonised surface residues and absorbed lipids from powdered sherds were analysed using a combination of bulk carbon and nitrogen stable isotope analysis, gas chromatography-mass spectrometry (GC–MS) and GC-combustion-isotope ratio MS (GC-C-IRMS). The molecular and isotopic compositions of the analysed samples revealed the presence of aquatic, ruminant carcass and dairy fats as well as plant waxes with the majority containing mixtures thereof. Dairy fats were present from the onset of the Funnel Beaker culture, whilst aquatic foods, prevalent at the close of the preceding Mesolithic period, continued to be processed in pottery for the following thousand years.
There is a close relationship between the evolution of the Cambrian–Ordovician paleo-uplifts and their hydrocarbon accumulation in the Southwest Tarim Depression. Using regional 2D seismic data interpretation, the structural morphology of the top of the Ordovician carbonate rocks in the Southwest Tarim Depression at different historical geologic stages is mapped. Combined with analysis of the discovered oil and gas reservoirs, the regularity of the hydrocarbon distribution in the Southwest Tarim Depression is investigated. Research shows that the evolution of the Cambrian-Ordovician paleo-uplifts in the Southwest Tarim Depression can be divided into four stages: (1) formation of the paleo-uplifts, (2) steady subsidence of the eastern paleo-uplift, (3) migration and adjustment of the western paleo-uplift and (4) strong subsidence and extinction of the paleo-uplifts. The Cambrian-Ordovician strata in the Southwest Tarim Depression experienced a seesaw-like structural reconstruction from an early north-dipping slope to a late south-dipping slope. During the structural reconstruction process, a pivot zone was located at the position of the current Maigaiti Slope, proving favorable for hydrocarbon accumulation and preservation. The fault zones in the eastern and western paleo-uplifts of the Maigaiti slope finalized during the Late Hercynian Period were favorable to preserving paleo-oil reservoirs. In contrast, the fault zones in the northern margin of the Maigaiti Slope, where the current tectonic uplift is located, were favorable for the accumulation of gas reservoirs.
Inna N. Ponomareva, Vladislav I. Galkin, Dmitriy A. Martyushev
One of the major tasks of monitoring production well operations is to determine bottom-hole flowing pressure. The overwhelming majority of wells in the Perm Krai are serviced using borehole pumps, which makes it difficult to take direct bottom-hole flowing pressure measurements. The bottomhole filtration pressure (BHFP) in these wells is very often determined by recalculating the parameters measured at the well mouth (annulus pressure, dynamic fluid level depth). The recalculation is done by procedures based on analytically determining the characteristics of the gas-liquid mixture in the wellbore, which is very inconsistent to perform due to the mixture's complex behavior. This article proposes an essentially different approach to BHFP measurements that relies on the mathematical processing of the findings of more than 4000 parallel mouth and deep investigations of the oil production wells of a large oil-production region. As a result, multivariate mathematical models are elaborated that allow reliably determining the BHFP of oil-production wells in operation.
Oils, fats, and waxes, Petroleum refining. Petroleum products
Concrete is a strong and hard material used for construction but it can undergo corrosion as a result of water permeation inside the concrete structures. As together with water many aggressive substances get inside the concrete structures, the surface absorbability of concrete is an important factor determining the stability of concrete constructions [1, 2]. One of the effective methods of concrete protection from the adverse effects of water is covering its surface with a protecting coat restricting the permeation of aggressive agents. The silicon-based compounds, such as silanes, siloxanes and silicones have been often applied in building industry [3]. Organofunctional alkoxysilanes are monomeric silicon compounds that as a result of hydrolysis and condensation produce a stable polysiloxane coating that covers the pore surface. The coating restricts the water permeation but permits free permeation of vapor towards outside of a given concrete element [4]. Another approach applied in order to restrict the adverse effect of water on concrete is the addition of hydrophobic admixtures at the stage of its production [5]. The hydrophobic agents such as fatty acids, their salts (soap), vegetable oils, wax emulsions and animal fats, change the surface tension in pores and cracks, which limits water permeation [5-7]. Our earlier papers present the synthesis of alkoxysilyl derivative based on rapeseed oil (RPTMS) by the reaction of nucleophilic substitution of 3-chloropropyltrimethoxysilane with appropriate sodium salts (rapeseed soap) [8]. The obtained silane has been used for production of wood [8] and steel [9] surface coating protecting from the adverse effect of water. In this paper we report on an alternative method of synthesis of the above-mentioned silane (RPTMS) from the commercially available oleic acid (OPTES) and propose its use for making concrete surface coating protecting from water permeation inside its structure.
Regular internal and external detection on oil and gas pipelines is helpful for timely and accurate detection of pipeline corrosion defects, and to take appropriate maintenance and replacement measures and effectively reduce the occurrence probability of corrosion accidents. Focusing on the problems of external corrosion, internal corrosion, stress corrosion cracking, and external corrosion of crossing sections, the development status of corrosion detection technology and related standards for oil and gas pipelines was elaborated, the principles and engineering applications of trenchless detection technologies such as transient electromagnetic detection, ultrasonic guided wave detection, and magnetic stress detection were introduced, the problems existing in the application and management of corrosion detection technology for oil and gas pipelines in China were summarized, and the demands for future development were discussed from the aspects of management improvement and technology upgrading. In terms of management improvement, it was proposed to build a unified technical specification, data management platform and professional corrosion detection efficiency evaluation team. As for technology upgrading, it was suggested to continuously carry out research on stress corrosion cracking detection and assessment technology, initiate research on microbial corrosion mechanism and detection technology, carry out research on pinhole corrosion defect detection and verification technology, and develop combined internal and external detection tools.
The PLET is the core product of deep-water oil and gas field development, whose technologies have long been monopolized by foreign countries. To master the key technologies for the design, manufacture, testing and installation of deep-water PLET and realize the complete localization of the product, according to the application characteristics of deep-water PLET, relying on the trial project of a gas field in the South Sea of China, a split PLET engineering prototype for water depth 500 m is designed and developed. After completing the conventional land test, considering the environmental conditions of China's South Sea area, offshore installation and function test are carried out in the 330 m water depth of Lufeng sea area. The test results show that the ROV can clearly read the numbers, letters and valve switch position indications on the engineering prototype. The underwater valve is smoothly operated by ROV. The switch position indication is accurate, and the overall valve function is complete. The switch pins of the lock arms on both sides of the deep-water PLET engineering prototype are easy to operate. The lock arms on both sides are normally opened and closed. The PLET body can be correctly located in the anti-sinking board foundation, and the pipeline part does not tilt. The separation from the anti-sinking board foundation and recovery to the deck of the PLET body is smooth. All test results meet the design index requirements. The research results have important reference significance for the technical research and product development of deep-water PLET and other deep-water production facilities.
Chemical engineering, Petroleum refining. Petroleum products