Field Pilot Test Research Articles

DEVELOPMENT OF TEST BENCH FOR EVALUATION OF RESISTANCE OF INTERNAL PROTECTIVE TUBING COATINGS TO INORGANIC SALT DEPOSITS

The formation of inorganic deposits on the working surface of oil and gas equipment is one of the most common causes of failures in oil and gas fields. Inorganic salt deposits formed in tubing reduce pipeline throughput capacity and lead to equipment failure. Thus, the problem of salt formation in tubing is relevant and requires the search for optimal methods to solve it. There are a large number of methods aimed at preventing the formation of inorganic scale and at removing the resulting scale from tubing. The methods of removal of scale from the tubing are expensive, time-consuming, and they require a shutdown at the oil production facility. Therefore, it is preferable to use methods for preventing salt formation in tubing pipes.One of the methods for preventing salt formation in oil production is the use of internal protective coatings of the NKT. It is important to understand that the use of coatings to prevent salt formation is not a universal method, individual selection of the protective coating is required for each object. In addition, at the moment, the effectiveness of the use of protective coatings as a measure to prevent salt formation in the tubing has not been fully proven. The selection of an effective internal coating (to prevent salt formation on the surface of the equipment) using pilot field tests is an expensive and long procedure, so it is necessary to develop a laboratory method and specialized testing equipment to solve this problem. This paper reviewed the existing test equipment to assess its potential for laboratory dynamic testing of tubing coatings under saline conditions. Based on the advantages and disadvantages of existing equipment, the «Stand for assessing the resistance of coatings to inorganic salt deposits» was developed. This article describes the development of the «Test Bench for Evaluation of Coating Resistance to Inorganic Salt Deposits,» which can be used to assess the possibility of using protective tubing coatings to prevent the formation of inorganic salt deposits on the inner surface of pipes.

Design of an axial hydrocyclone for preliminary water separation using CFD, RSM, and SUS

Preliminary water separators can effectively solve the problem of high-water-cut produced fluids in oil wells. In this study, we propose a co-design method for the serialization of an axial inlet preliminary water separator based on the combination of cyclone separation theory, computational fluid dynamics (CFD) simulations, response surface method (RSM) optimization, experimental verification, and a scale-up strategy (SUS). For an inlet water cut ≥ 70%, the water separation rate was ≥ 50% and the oil concentration of heavy phase outlet (HPO) was ≤ 1000 mg/L. The indoor experimental results indicated that the performance of the preliminary water separator could achieve better results obtained through the CFD simulation results were taken as sample points and the optimal structural size was found by machine learning method (MLM). The field pilot test results showed that the Hy similarity criterion based SUS did not affect the separation effect. For water cut in the range of 85.0–92.7%, the water separation rate was ≥ 50% and the HPO oil concentration was < 1321.6 mg/L. Our results can provide reference and guidance for the design and optimization of hydrocyclones for preliminary water separation of oilfield produced fluids.

Professional Development to Improve Responsible Beverage Service Training: Formative Research Results and Protocol for a Randomized Controlled Trial.

Improved interventions are needed to reduce the rate of driving while intoxicated. Responsible beverage service (RBS) training has reduced service to intoxicated patrons in licensed premises in several studies. Its efficacy might be improved by increasing the proper application and continued use of RBS with a professional development program in the 3 to 5 years between the required RBS retraining. This study aims to develop and evaluate a professional development component for an RBS training that aims to improve the effectiveness of the web-based training alone. In a 2-phase project, we are creating a professional development component for alcohol servers after completing an RBS training. The first phase involved formative research on the feasibility, acceptability, and potential effectiveness of components. Semistructured interviews with owners and managers of licensed establishments and focus groups and a survey with alcohol servers in New Mexico and Washington State examined support for RBS and the need for ongoing professional development to support RBS. A prototype of a professional development component, WayToServe Plus, was produced for delivery in social media posts on advanced RBS skills, support from experienced servers, professionalism, and basic management training. The prototype was evaluated in a usability survey and a field pilot study with alcohol servers in California, New Mexico, and Washington State. The second phase of the project will include full production of the professional development component. It will be delivered in Facebook private groups over 12 months and evaluated with a sample of licensed premises (ie, bars and restaurants) in California, New Mexico, and Washington State (n=180) in a 2-group randomized field trial (WayToServe training only vs WayToServe training and WayToServe Plus). Licensed establishments will be assessed for refusal of sales to apparently intoxicated pseudopatrons at baseline and 12 months after the intervention commences. Although owners and managers (n=10) and alcohol servers (n=43) were favorable toward RBS, they endorsed the need for ongoing support for RBS for servers and identified topics of interest. A prototype with 50 posts was successfully created. Servers felt that it was highly usable and appropriate for themselves and the premises in the usability survey (n=20) and field pilot test (n=110), with 85% (17/20) and 78% (46/59), respectively, saying they would use it. Servers receiving the professional development component had higher self-efficacy (d=0.30) and response efficacy (d=0.38) for RBS compared with untreated controls. Owners, managers, and servers believed that an ongoing professional development component on RBS would benefit servers and licensed premises. Servers were interested in using such a program, a large majority engaged with the prototype, and servers receiving it improved on theoretic mediators of RBS. Thus, the professional development component may improve RBS training. ClinicalTrials.gov NCT05779774; http://tinyurl.com/4mw6d2vk. DERR1-10.2196/49680.

Exploring Potential of Gellan Gum for Enhanced Oil Recovery.

Extensive laboratory and field tests have shown that the gelation response of gellan gum to saline water makes it a promising candidate for enhanced oil recovery (EOR). The objective of this mini-review is to evaluate the applicability of gellan gum in EOR and compare its efficiency to other precursors, in particular, hydrolyzed polyacrylamide (HPAM). At first, the "sol-gel" phase transitions of gellan gum in aqueous-salt solutions containing mono- and divalent cations are considered. Then the rheological and mechanical properties of gellan in diluted aqueous solutions and gel state are outlined. The main attention is paid to laboratory core flooding and field pilot tests. The plugging behavior of gellan in laboratory conditions due to "sol-gel" phase transition is discussed in the context of conformance control and water shut-off. Due to its higher strength, gellan gum gel provided ~6 times greater resistance to the flow of brine in a 1 mm-width fracture compared to HPAM gel. The field trials carried out in the injection and production wells of the Kumkol oilfield, situated in Kazakhstan, demonstrated that over 6 and 11 months, there was an incremental oil recovery of 3790 and 5890 tons, respectively. To put it into perspective, using 1 kg of dry gellan resulted in the incremental production of 3.52 m3 (or 22 bbls) of oil. The treatment of the production well with 1 wt.% gellan solution resulted in a considerable decrease in the water cut up to 10-20% without affecting the oil flow rate. The advantages and disadvantages of gellan compared to HPAM are analyzed together with the economic feasibility of gellan over HPAM. The potential for establishing gellan production in Kazakhstan is emphasized. It is anticipated that gellan gum, manufactured through fermentation using glucose-fructose syrup from Zharkent and Burunday corn starch plants, could be expanded in the future for applications in both the food industry and oil recovery.

Study on total residual oxidant decay in long-distance seawater intake pipeline of cooling system

Electrochlorination is often used for biofouling control along the water intake pipeline of seawater cooling system, but with the increasing of pipeline length, this process needs to be further improved. In this study, the dynamic circulation and field pilot test were used to simulate the long-distance seawater intake pipeline, investigating total residual oxidant (TRO) decay and its influencing factors by comparing the bench test. The results showed that intermediate dosing could increase terminal TRO, but also reduce the CT value, resulting in decline of local inactivation effect. The initial concentration of dynamic cycle test was higher than that of bench test under the same terminal TRO, and the difference value between the two was affected by holding time. When the initial concentration was greater than 8.5 mg L−1, TRO decay rate was proportional to the seawater flow rate and inversely proportional to the initial concentration. The initial concentration of 8.5–10 mg L−1 could meet TRO decay requirement under 3 h holding time, and the dosing concentration could be reduced to 6 mg L−1 when the temperature was low. The results provided important guidance for the actual operation of biofouling control in long-distance water intake pipelines of cooling system.

Laboratory tests and field pilot of foam-assisted deoxidized-air flooding in a low-permeability sandstone reservoir

Foam-assisted deoxidized-air flooding is a promising technique for improving oil recovery, particularly in low-permeability oil reservoirs. However, significant differences in displacement efficiency have been observed. A comprehensive program including field pilot analysis in Wuliwan oil reservoir, a low-permeability reservoir in China, and laboratory experiments was initiated to investigate the displacement mechanism of foam-assisted deoxidized-air flooding. We carried out a series of laboratory experiments of foam-assisted deoxidized-air flooding with different gas–liquid ratios at different water cut stages, while using nuclear magnetic resonance technology to monitor the distribution of crude oil in pores. The results revealed that increasing gas–liquid ratio enhanced oil recovery during the high water cut stage, but reduced it during the middle water cut stage. The differences in oil recovery at different water cut stage appear to be linked to changes of the displacement mechanism. We indeed observed that oil was produced from a wide range of pores at the high water cut stage, but only from the macropores at the middle water cut stage. The field pilot analysis supported our conclusion based on the experimental findings, that foam-assisted deoxidized-air flooding using an appropriate gas–liquid ratio can efficiently lower water cut and enhance oil production at different water cut stages. The combination of laboratory and field pilot tests used here can serve as a template for future studies in other oil reserves.

Field pilot testing and reservoir simulation to evaluate processes controlling CO2 injection and associated in-situ fluid migration in deep coal

A key strategy for reducing global CO2 emissions is geologic sequestration of CO2. Deep, unmineable coal seams have been proposed as possible targets for CO2 injection and storage because of the global distribution of coal resources, and relative security of CO2 storage associated with CO2 adsorption. However, the current paradigm is that near-injector permeability loss caused by pure CO2 adsorption-induced coal swelling limits the effectiveness of this process making coal a less than an ideal target for CO2 injection/sequestration.In order to test the viability of CO2 injection and storage in deep coal seams, and evaluate processes controlling CO2 injection, migration and storage therein, a field pilot was implemented in the Mannville Coal (∼1500 m depth) of Alberta, Canada. An additional objective of the field pilot was to quantify the migration of water and natural gas away from the CO2 injection well, an important mechanism used to improve the performance of the pilot operator's enhanced hydrogen recovery (EHR™) process. To achieve these multiple objectives, a vertical injection well and closely-spaced offsetting vertical observation well were drilled, cored, and completed in the Mannville coal seams, and instrumented with pressure sensors to monitor both the coal and bounding zones during injection testing. Periodic fluid sampling at the observation well allowed for quantification of CO2 plume and fluid migration. Pre-CO2 injection/falloff testing was performed with water at variable injection rates/pressures to assess coal permeability/porosity changes without the complication of CO2-coal interaction. CO2 injection/falloff tests were then performed at increasing CO2 injection rates to assess the combined impact of injection pressure/CO2 rate and CO2-coal interaction (e.g., adsorption) on injectivity. All tests were history-matched with a numerical reservoir simulator; the calibrated model was used to study the key controls on CO2 storage, CO2 plume migration, in-situ fluid displacement, and injectivity.A key finding from simulation of the pilot results is that, for the Mannville coals in the study area, permeability increases caused by coal natural fracture dilation during injection outweigh permeability decreases caused by CO2 adsorption-induced coal swelling, resulting in an injectivity index increase with CO2 injection rate. In addition, the coals exhibit strong anisotropy in permeability and geomechanical properties; ignoring coal anisotropy in the simulation model causes coal swelling effects to be overestimated, resulting in an underestimate in CO2 plume extent.From the pilot results and analysis, it can be concluded that the deep Mannville coal could be a viable target for CO2 storage.

Current status and development trends of CO2 storage with enhanced natural gas recovery (CS-EGR)

CO2 storage with enhanced gas recovery (CSEGR) technology is a pivotal solution to mitigate the greenhouse effect and respond to national energy conservation and emission reduction policies. This involves injecting CO2 into gas reservoirs for storage and using it to displace gas into producing wells to enhance production. This paper provides a comprehensive analysis of the primary mechanisms of CO2 storage in gas reservoirs, quantifies the long-term contribution of these, and summarizes the methods used to evaluate CO2 storage potential. The mechanisms of the displacement of natural gas by CO2 are explained and two technical difficulties are addressed: the degree of CO2-natural gas mixing and competitive adsorption and displacement of CO2-CH4. Besides, the main factors affecting CSEGR are studied thoroughly, and the currently typical CSEGR field pilot tests across the word are considered along with CSEGR economic policy research. This paper then identifies the current challenges and future trends in CSEGR development. The results show, firstly, in the later stage of gas reservoir development, high rates of CO2 injection at the bottom of the gas reservoir and CH4 production at the top can significantly enhance gas recovery. Secondly, in previous studies, the degree of CO2-natural gas mixing has been studied more in sandstones and carbonates, while CO2-CH4 competitive adsorption has been studied more in shales and coal seams. The results of all these studies demonstrate the feasibility of CSEGR. Thirdly, Four major storage mechanisms interact to stabilize CO2 storage in gas reservoirs, but there is no systematic method to evaluate the CO2 storage potential. Finally, among recent experimental and simulation studies, CSEGR analytic techniques that consider complex formation conditions need to be further explored. Additionally, combining CSEGR with geothermal energy development in high temperature gas reservoirs presents a promising avenue for exploration.

Coupled TMD modeling of cryogenic treatment of borehole in coal under confinement

Cryogenic fracturing using liquid nitrogen (LN2) is a waterless fracturing technology that is under extensive research nowadays given the high demand of environmental-friendly development of unconventional oil and gas resources. Excluding the exerted hydraulic pressure, the initiation and propagation of cryogenic fractures in rock materials largely depend on thermal stress generated by LN2 and the rock properties. So far, there are quite a few experimental studies elaborating on the cryogenic fracturing process of coal rocks; however, modeling studies on the topic are still very preliminary with no damage quantification. This study first set up a coupled thermo-mechanical (TM) modeling procedure by solving the heat conduction and rock mechanics equations in a serial manner and incorporating the maximum principal stress failure criterion. Then the numerical stability of this modeling procedure was examined through time step and grid resolution tests, and the model accuracy was corroborated by analytical solutions. Furthermore, the damage criterion was quantitatively validated against our experimental observations. Using this thermo-mechanical damage (TMD) modeling procedure, a systematic examination of the effects of key factors on cryogenic circulation treatment of coal rock borehole was carried out using realistic parameters. Trends and patterns of the cryogenic damage upon key factors, including realistic temperature boundary with the Leidenfrost effect, Young's modulus, thermal expansion coefficient, Poisson's ratio, specific heat capacity, density, thermal conductivity, in-situ stresses, and initial temperature of the coal rocks have been revealed and discussed. The modeling results herein are of great significance to understand the mechanisms of cryogenic fracturing of coal rocks, and this TMD modeling procedure could be further expanded to evaluate and optimize cryogenic treatment process of coal seams in field pilot tests.

Optimization of operational strategies for rich gas enhanced oil recovery based on a pilot test in the Bakken tight oil reservoir

Horizontal well drilling and multistage hydraulic fracturing have been demonstrated as effective approaches for stimulating oil production in the Bakken tight oil reservoir. However, after multiple years of production, primary oil recovery in the Bakken is generally less than 10% of the estimated original oil in place. Gas huff ‘n’ puff (HnP) has been tested in the Bakken Formation as an enhanced oil recovery (EOR) method; however, most field pilot test results showed no significant incremental oil production. One of the factors affecting HnP EOR performance is premature gas breakthrough, which is one of the most critical issues observed in the field because of the presence of interwell fractures. Consequently, injected gas rapidly reaches adjacent production wells without contacting reservoir rock and increasing oil recovery. Proper conformance control is therefore needed to avoid early gas breakthrough and improve EOR performance. In this study, a rich gas EOR pilot in the Bakken was carefully analyzed to collect the essential reservoir and operational data. A simulation model with 16 wells was then developed to reproduce the production history and predict the EOR performance with and without conformance control. EOR operational strategies, including single- and multiple-well HnP, with different gas injection constraints were investigated. The simulation results of single-well HnP without conformance control showed that a rich gas injection rate of at least 10 MMscfd was needed to yield meaningful incremental oil production. The strategy of conformance control via water injection could significantly improve oil production in the HnP well, but injecting an excessive amount of water also leads to water breakthrough and loss of oil production in the offset wells. By analyzing the production performance of the wells individually, the arrangement of wells was optimized for multiple-well HnP EOR. The multiwell results showed that rich gas EOR could improve oil production up to 7.4% by employing conformance control strategies. Furthermore, replacing rich gas with propane as the injection gas could result in 14% of incremental oil production.

Mobilization pilot test of PCE sources in the transition zone to aquitards by combining mZVI and biostimulation with lactic acid

The potential toxic and carcinogenic effects of chlorinated solvents in groundwater on human health and aquatic ecosystems require very effective remediation strategies of contaminated groundwater to achieve the low legal cleanup targets required. The transition zones between aquifers and bottom aquitards occur mainly in prograding alluvial fan geological contexts. Hence, they are very frequent from a hydrogeological point of view. The transition zone consists of numerous thin layers of fine to coarse-grained clastic fragments (e.g., medium sands and gravels), which alternate with fine-grained materials (clays and silts). When the transition zones are affected by DNAPL spills, free-phase pools accumulate on the less conductive layers. Owing to the low overall conductivity of this zone, the pools are very recalcitrant. Little field research has been done on transition zone remediation techniques. Injection of iron microparticles has the disadvantage of the limited accessibility of this reagent to reach the entire source of contamination. Biostimulation of indigenous microorganisms in the medium has the disadvantage that few of the microorganisms are capable of complete biodegradation to total mineralization of the parent contaminant and metabolites. A field pilot test was conducted at a site where a transition zone existed in which DNAPL pools of PCE had accumulated. In particular, the interface with the bottom aquitard was where PCE concentrations were the highest. In this pilot test, a combined strategy using ZVI in microparticles and biostimulation with lactate in the form of lactic acid was conducted. Throughout the test it was found that the interdependence of the coupled biotic and abiotic processes generated synergies between these processes. This resulted in a greater degradation of the PCE and its transformation products. With the combination of the two techniques, the mobilization of the contaminant source of PCE was extremely effective.

DEVELOPMENT OF TECHNOLOGY FOR CLEANING THE BOTTOM-HOLE ZONE OF THE FORMATION FROM ASPHALT-RESINOUS DEPOSITS

The article considered the process of operation of wells, paraffin oil, causing a serious problem during the operation of the well. Physico-chemical methods providing an increase in displacement and coverage coefficients simultaneously for the extraction of film and capillary–retained oil from flooded reservoirs. At the same time, by adding special chemicals to water, it is possible to create solutions that reduce: the interfacial surface tension of water, thereby changing the ratio of the displacing and displaced phase mobility. For this kind of issues, pilot field studies and testing of the optimal technology for cleaning the bottom-hole formation zone (BFZ) from deposits of asphaltene-resinous substances were carried out and 6 production wells were selected for this purpose. Further, the criteria of wells for conducting pilot field tests of the technology for cleaning bottom-hole zones of wells from asphaltene-resinous substances are recommended. A composite composition with a high solvent capacity in relation to asphaltene-resinous substances was selected, the results of laboratory studies to determine the effectiveness of hydrocarbon solvents were given. The volume of the solvent composition was calculated for all selected wells. It is recommended that for processing for each well, a "Plan for processing the bottom-hole zone of the well" was drawn up, and a recommendation was also given that the processing of the BFZ should be carried out without extracting the underground equipment of the well (tubing columns with a pump).

Recent Advances and Perspectives of CO2-Enhanced Coalbed Methane: Experimental, Modeling, and Technological Development

Carbon dioxide (CO2)-enhanced coalbed methane recovery (CO2-ECBM) is a critical way to increase methane production and reduce greenhouse gas (CO2 and CH4) emissions. As captured CO2 is continuously injected in the coal seams, a low cost of CO2 sequestration and high efficiency of CH4 recovery can be achieved via the flooding and replacing effects driven by the injected CO2 flow. Scientific insights into the complex process of CO2-ECBM in experiments, modelings, and technological developments need to be made to propose appropriate countermeasures. This review first highlights the progress of CO2-ECBM under laboratory conditions, e.g., the binary gas competitive adsorption and gas displacement experiments in the macroscale and porous structure tests using technologies of nuclear magnetic resonance (NMR), scanning electron microscopy (SEM), and computed tomography (CT) in the microscale. Then, the advances of mathematical models for changing in coal permeability and porosity during CO2-ECBM are reviewed, accompanying with the multi-field and multi-phase coupling responses of competitive sorption, diffusion, gas–water seepage, heat transfer, and solid deformation. Furthermore, the field pilot tests of CO2-ECBM in various countries and regions are also covered to reveal the key technical challenges confronted with the development of CO2-ECBM technology. The perspectives in experiments, models, and field pilots of CO2-ECBM are made, which include but are not limited to the following: conducting a core CH4/CO2 flooding test under in situ conditions, modeling CO2-ECBM with real fractures/faults and coal failure, developing a new method for gas migration and leakage monitoring in the field, and enacting relevant standards, laws, and regulations to promote CO2-ECBM.

Characteristics of TOC Treatment for Industrial Wastewater Treatment -Characteristics of Industrial Wastewater TOC Treatment Status and TOC Treatment by Ozone and Advanced Oxidation Process-

Objectives:As the organic pollutant indicator is changed from COD&lt;sub&gt;Mn&lt;/sub&gt; to TOC and the demand for TOC treatment of industrial wastewater increasing, the current situation of TOC treatment of wastewater discharge facilities of each industrial category is analyzed, and it is intended to consider the possibility of residual TOC treatment by ozone and advanced oxidation process.Methods:To review the TOC treatment situations of wastewater discharge facilities of each industrial category, the field survey data (46 sites) by Environment Ministry and Korea Environment Corporation were analyzed according to inflow TOC concentrations, direct/indirect discharge type, and main treatment process of wastewater treatment facilities. To review the characteristics of TOC treatment by ozone and advanced oxidation processes, previous studies and the results of field pilot tests conducted by ozone companies were comprehensively analyzed.Results and Discussion:The TOC treatment level varies depending on the inflow TOC concentrations to each industrial wastewater treatment facility, direct/indirect discharge type depending on the location of the wastewater treatment facilities, and the main treatment process of the wastewater treatment facility. In particular, the TOC removal rate differed by more than 20% depending on the presence or absence of biological treatment. The wastewater treatment facilities that require additional treatment of residual TOC were divided as follows (1) when the facility has biological treatment as main process, increasing unexpected inflow TOC load in treatment facilities or the condition of the biological treatment become worsen. (2) when the facility has phy-chemical treatment as main process, increasing unexpected inflow TOC load. (3) extending the replacement cycle of activated carbon to save maintenance cost. The advance oxidation process decomposes easily by OH radicals through the radical substitution of unsaturated hydrocarbons and aromatic compounds, so the removal rate of TOC by the O&lt;sub&gt;3&lt;/sub&gt;+H&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;2&lt;/sub&gt; advanced oxidation pilot test was 14.7~93.5%, higher than that of ozone oxidation. The specific ozone consumption per TOC removal amount (O&lt;sub&gt;3&lt;/sub&gt;/ΔTOC) by O&lt;sub&gt;3&lt;/sub&gt;+H&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;2&lt;/sub&gt; advanced oxidation is 8.5~22.5mgO&lt;sub&gt;3&lt;/sub&gt;/mgTOC, which is 1/5 of that of ozone oxidation only. In addition, comparing ozone demand by COD&lt;sub&gt;Mn&lt;/sub&gt; and TOC removal, ozone demand of O&lt;sub&gt;3&lt;/sub&gt;+H&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;2&lt;/sub&gt; advanced oxidation to remove TOC is 2.7 to 4.3 times compared to that by O&lt;sub&gt;3&lt;/sub&gt; oxidation to remove COD&lt;sub&gt;Mn&lt;/sub&gt;.Conclusion:In order to reduce residual TOC from industrial wastewater effluent, it is necessary to secure stability of the existing main treatment process in preparation for load fluctuations, and the technologies research on complex advanced oxidation processes, hybrid advanced oxidation processes, and pretreatment technology to reduce ozone demand is needed for economical field application.

ЭФФЕКТИВНОСТЬ ПРИМЕНЕНИЯ АВТОМАТИЧЕСКИХ УСТАНОВОК КОМПЕНСАЦИИ РЕАКТИВНОЙ МОЩНОСТИ В НЕФТЕПРОМЫСЛОВЫХ ЭЛЕКТРИЧЕСКИХ СЕТЯХ

The relevance One of the key directions of innovative development of the electric power industry until 2035 is the transition to digital active-adaptive networks with a distributed intelligent automation and control system. In this regard, in conditions of increasing demands for improving the quality of electricity and reducing losses in networks, it is necessary to improve the voltage and reactive power regulation system in electric networks, which should be based on the widespread use of modern means of regulating voltage and reactive power, as well as automatic control systems, including centralized ones. The main effect of reducing technical losses in electric networks, as shown by the energy survey of FGC UES JSC, the experience of foreign electric grid companies and the analysis of the modes of operation of the Unified National Electric Grid, can be obtained by optimizing the established modes of operation of the electric grid in terms of reactive power and voltage levels in automatic mode, provided that the condition of regulating devices is constantly monitored. The absence of a system for remote monitoring of the parameters of power factor correction devices in the power supply systems of enterprises leads to untimely detection and elimination of failures in the operation and operation of the network without power factor correction. Aim of research To analyze the energy parameters of the power supply system of oil production facilities, to identify deviations of voltage values and power factor from regulatory requirements. To investigate the effectiveness of the use of low-voltage automatic power factor correction units in the power supply system of an oil-producing enterprise. Research methods The study of scientific literature, field research at oil pumping facilities, energy surveys, computer modeling. In order to identify the technical and economic efficiency of the use of low-voltage automatic power factor correction units, pilot field tests were conducted in one of the oil and gas producing enterprises of the Tatneft PJSC. Results Energy surveys of in-field pumping facilities, oil treatment and reservoir pressure maintenance of Tatneft PJSC have shown that the value of reactive power in the networks of power supply systems of these enterprises significantly exceeds the standard. As a result of pilot field tests, it was revealed that the use of automatic power factor correction units in automatic mode ensures the stabilization of the power factor at the level of standard values, excluding under-compensation or overcompensation of reactive power, while reducing electricity consumption by an average of 2.4 %. The remote monitoring system allows you to monitor the operating mode and technical condition of all elements of the capacitor plant, timely perform maintenance of contactors to ensure the operability of the installation.

Enhancing Well Performance and Economic Value via Better Well Completion Design—A Delaware Basin Case Study

Summary Operator H’s wells on University Lands acreage in the Delaware Basin were completed with a perforation cluster spacing of around 45 ft and a fracturing fluid volume of about 25 bbl/ft. However, other operators in this area used half or even smaller perforation cluster spacing and a few times more fluid. As a result, the estimated ultimate recovery (EUR) of non-Operator H wells is about 18% higher than that of Operator H’s wells in the Wolfcamp Formation, indicating that Operator H’s completion design can be greatly improved. Therefore, our objective in this work is to locate a better completion design for Operator H’s wells and increase the economic value of the operator and the landowner. An integrated fracturing→well performance→economics workflow is implemented to optimize the completion design for Operator H’s wells. First, a 3D geological and geomechanical model is built and calibrated with historic multiwell multistage completion and production data. A decline curve analysis (DCA) is also performed to double-check our history-matching (HM) model. Then, we use an unconventional fracturing model to simulate fracture propagation and proppant transport for multiple wells on the same pad under various completion designs. The resultant complex fracture network is converted into unstructured gridblocks for reservoir-performance simulation. Finally, economic analysis is incorporated to evaluate the net present value (NPV)and internal rate of return (IRR) to identify the optimal completion design. Numerical results show that with the same amount of fluid and proppant, halving perforation cluster spacing gives shorter and more nonuniform fractures. Doubling the fluid volume creates 40% more fracture area in our target area and activates more microfractures along the wellbore. Also, a smaller stage spacing significantly improves cluster efficiency and well production. For the Wolfcamp Formation in the Delaware Basin, tighter cluster spacing (10–20 ft) with higher fluid volume (75–90 bbl/ft) plus a smaller stage spacing (~120 ft) greatly improves fracturing efficiency and well performance. Our recommended optimal completion design would increase Operator H’s NPV10 by USD 226 million on its undeveloped Wolfcamp A Formation (WCA). With the latest modeling technologies, we model the complex fracture propagation and associated well performance and efficiently identify a better completion design with economic analysis. Compared to multiple field pilot tests needed, the integrated workflow in this work helps operators significantly reduce the time and financial cost to optimize completion design and can be easily adapted to other unconventional wells given their unique data set.

Carbon neutral oil assessment using a dual-porosity compositional model in unconventional reservoirs

The combined use of CO2 for enhanced oil recovery (EOR) and decarbonization has not been viewed favorably by environmentalists because the combustion of oil emits CO2. However, the use of CO2 for EOR and the consequential decarbonization is a viable and practical option that can be viewed as a win-win situation given other alternatives. Thus, we embarked on this study to assess the benefits of the process by modeling its application in the Niobrara and Codell unconventional formations in the Wattenberg Field of the Denver-Julesburg (DJ) Basin, Colorado. The modeling results provide an inexpensive substitute for the current non-existing field pilot tests. Modeling the reservoir geology and production performance in the unconventional resources of the DJ Basin is challenging because of the presence of numerous faults, micro-fractures, and macro-fractures. In this numerical model study, we used much large fracture permeabilities and compaction coefficients in the vicinity of major faults and we obtained hydraulic fracture dimensions and properties from a credible geomechanics simulator GOHFER. Seismic data, well logs, cores, PVT analyses, and field production data were integrated to construct the numerical flow model. The input reservoir permeabilities for the model were obtained from the rate transient analyses (RTA) of production data. After achieving a history match of production data for eleven wells, theoretical RTAs were conducted on each well using the modeled pressure and flowrate data to calculate the formation permeabilities to confirm the simulation accuracy. Despite the complexity of the well completion and reservoir heterogeneity in the model, the RTA analyses of the model production results for all eleven wells yielded the input reservoir permeability within an acceptable error tolerance. Moreover, a term named “Carbon Neutrality Index (CNI)” is defined in this research where CNI = 0 indicates carbon neutrality while negative CNI values indicates that the produced incremental EOR oil is carbon negative and there is a net decrease in carbon emission. When our validated numerical model was used to simulate a 4-year huff-n-puff CO2-EOR process, the results yielded a positive CNI value—indicating that the EOR oil was not perfectly carbon neutral. However, the stored CO2 divided by the CO2 generated from burning the incremental EOR oil is 0.82 — indicating that there is 82% reduction in CO2 emissions per bbl of EOR oil when compared with the emissions of one barrel of conventionally produced oil. Thus, CO2-EOR in the DJ Basin unconventional reservoirs is an effective decarbonization method.

Progress and prospects of carbon dioxide capture, EOR-utilization and storage industrialization

Carbon dioxide capture, EOR-utilization and storage (CCUS-EOR) are the most practical and feasible large-scale carbon reduction technologies, and also the key technologies to greatly improve the recovery of low-permeability oil fields. This paper sorts out the main course of CCUS-EOR technological development abroad and its industrialization progress. The progress of CCUS-EOR technological research and field tests in China are summarized, the development status, problems and challenges of the entire industry chain of CO2 capture, transportation, oil displacement, and storage are analyzed. The results show a huge potential of the large-scale application of CCUS-EOR in China in terms of carbon emission reduction and oil production increase. At present, CCUS-EOR in China is in a critical stage of development, from field pilot tests to industrialization. Aiming at the feature of continental sedimentary oil and gas reservoirs in China, and giving full play to the advantages of the abundant reserves for CO2 flooding, huge underground storage space, surface infrastructure, and wide distribution of wellbore injection channels, by cooperating with carbon emission enterprises, critical technological research and demonstration project construction should be accelerated, including the capture of low-concentration CO2 at low-cost and on large-scale, supercritical CO2 long-distance transportation, greatly enhancing oil recovery and storage rate, and CO2 large-scale and safe storage. CCUS-EOR theoretical and technical standard system should be constructed for the whole industrial chain to support and promote the industrial scale application, leading the rapid and profitable development of CCUS-EOR emerging industrial chain with innovation.

The investigation of geochemical and geomechanical properties in surface paste disposal by pilot‑scale tests

ABSTRACT Today, seepage control in tailings dams has become an important problem due to the increased production in mining sites. Although very techniques have been developed to solve this problem, research in this field continues. The reason for this is that there is an ongoing search for a one hundred percent successful method to prevent seepage. In this study, the geochemical and geomechanical properties of paste material stored by the surface paste disposal (SPD) method were investigated by pilot field tests. To determine the effects of cement and pozzolanic materials on the geochemical and geomechanical properties of the paste, 2 different pilot-scale storage designs were observed for about 1 year, with no additives (reference) and binder added to some layers (cement and fly ash). Based on the data derived from the former laboratory investigations and with no additives and with a few layers of cement and fly ash, the two different designs were applied on a pilot scale near the existing tailings dam of a currently active mining enterprise. These designs were observed in inland conditions for about 1 year to determine the effects of seasonal changes on the material. The seepage analysis, surface crack densities, microstructural properties, consolidation, and cohesion values of these designs, which are directly exposed to atmospheric effects, were determined during the study period. According to the results obtained, the use of cement improved the volume compressibility coefficient of the material by approximately 25% compared to the reference design. However, the use of fly ash alongside cement improved the volume compressibility coefficient by about 75%. In conclusion, the use of cement made the material more resistant to external factors, and the usability of fly ash, which was used at a 50% replacement ratio with cement to bring down the cost, for long-time storage in the industry was demonstrated within the scope of the study.

Development of a hydrocarbon completion system for wells with low bottomhole temperatures for conditions of oil and gas fields in Eastern Siberia

The paper presents the results of investigations on the influence of low bottomhole temperatures in the intervals of productive formations on the technological properties of solutions used for drilling and completion of wells in order to determine the possibility of increasing gas recovery coefficient at the field of the “Sila Sibiri” gas pipeline. The analysis of technological measures determining the quality of the productive horizon drilling-in was carried out. It was found out that the dispersion of bridging agent in the composition of the hydrocarbon-based drilling mud selected from the existing methods does not have significant influence on the change in the depth of filtrate penetration into the formation in conditions of low bottomhole temperatures. The main reason for the decrease in the near-bottomhole zone permeability was found out – the increase in plastic viscosity of the dispersion medium of the hydrocarbon-based drilling mud under the influence of low bottomhole temperatures. A destructor solution for efficient wellbore cleaning from hydrocarbon-based solution components in conditions of low bottomhole temperatures was developed. The paper presents the results of laboratory investigations of hydrocarbon-based drilling mud and the developed destructor solution, as well as its pilot field tests. The mechanism of interaction between the destructor solution and the filter cake of the hydrocarbon-based drilling mud ensuring the reduction of the skin factor in the conditions of the geological and hydrodynamic structure of Botuobinsky, Khamakinsky and Talakhsky horizons of the Chayandinskoye oil and gas condensate field has been scientifically substantiated.