Modeling of Heavy-Oil Flow with Regard to Their Rheological Properties

With the depletion of traditional energy resources, the share of heavy-oil production has been increasing recently. According to some estimates, their reserves account for 80% of the world’s oil resources. Costs for extraction of heavy oil and natural bitumen are 3–4 times higher than the costs of extracting light oil, which is due not only to higher density and viscosity indicators but also to insufficient development of equipment and technologies for the extraction, transportation, and processing of such oils. Currently, a single pipeline system is used to pump both light and heavy oil. Therefore, it is necessary to take into account the features of the heavy-oil pumping mode. This paper presents mathematical models of heavy-oil flow in oil-field pipelines. The rheological properties of several heavy-oil samples were determined by experiments. The dependencies obtained were used as input data for a simulation model using computational fluid dynamics (CFD) methods. The modeling condition investigates the range of shear rates up to 300 s−1. At the same time, results up to 30 s−1 are considered in the developed computational models. The methodology of the research is, thus, based on a CFD approach with experimental confirmation of the results obtained. The proposed rheological flow model for heavy oil reflects the dynamics of the internal structural transformation during petroleum transportation. The validity of the model is confirmed by a comparison between the theoretical and the obtained experimental results. The results of the conducted research can be considered during the selection of heavy-oil treatment techniques for its efficient transportation.publishedVersio

System of Comprehensive Energy-Efficient Utilization of Associated Petroleum Gas with Reduced Carbon Footprint in the Field Conditions

This paper considers the issue of associated petroleum gas utilization during hydrocarbon production in remote petroleum fields. Due to the depletion of conventional oil and gas deposits around the globe, production shifts to hard-to-recover resources, such as heavy and high-viscosity oil that requires a greater amount of energy to be recovered. At the same time, large quantities of associated petroleum gas are extracted along with the oil. The gas can be utilized as a fuel for power generation. However, even the application of combined power modes (combined heat and power and combined cooling heat and power) cannot guarantee full utilization of the associated petroleum gas. Analysis of the electrical and heat loads’ graphs of several oil fields revealed that the generated thermal energy could not always be fully used. To improve the efficiency of the fuel’s energy potential conversion, an energy system with a binary power generation cycle was developed, consisting of two power installations—a main gas microturbine and an auxiliary steam turbine unit designed to power the technological objects in accordance with the enterprise’s power load charts. To provide for the most complete utilization of associated petroleum gas, a gas-to-liquid system is introduced, which converts the rest of the gas into synthetic liquid hydrocarbons that are used at the field. Processing of gas into various products also lowers the carbon footprint of the petroleum production. Application of an energy system with a binary power generation cycle makes it possible to achieve an electrical efficiency up to 55%, at the same time maintaining high efficiency of consumers’ energy supply during the year. The utilization of the associated petroleum gas in the developed system can reach 100%.publishedVersio

Improving the energy-efficiency of small-scale methanol production through the use of microturboexpander units

The issue of improving the energy-efficiency of container-based gas chemical plants for methanol production in field conditions is considered. The relevance of the direction is determined by the necessity for development of remote Arctic hydrocarbon fields. The object of research is energy-efficient conversion of waste gases energy and surplus thermal energy in small-scale system of methanol production using technology of synthesis gas generation by non-catalytic partial oxidation of natural gas. Approaches to the design and analysis of structural solutions for microturboexpander units are considered. A technique combining traditional approaches to the calculation of equipment and modeling by the finite element method in ANSYS is proposed. The developed methodology facilitates calculation of design parameters for microturboexpanders and allows taking into account peculiarities of working medium, thermobaric conditions and gas flow characteristics

Gas-Fueled Binary Energy System with Low-Boiling Working Fluid for Enhanced Power Generation

This article discusses methods of enhanced power generation using a binary power system with low-boiling fluid as an intermediate energy carrier. The binary power system consists of micro-gas and steam power units and is intended for remote standalone power supply. Trifluotrichloroethane was considered as the working agent of the binary cycle. The developed system was modeled by two parts in MATLAB Simulink and Aspen HYSYS. The model in Aspen HYSYS calculates the energy and material balance of the binary energy system. The model in MATLAB Simulink investigates the operation of power electronics in the energy system for quality power generation. The results of the simulation show that the efficiency of power generation in the range of 100 kW in the developed system with micro-turbine power units reaches 50%

Development of a Weighted Barite-Free Formate Drilling Mud for Well Construction under Complicated Conditions

Construction of oil and gas wells at offshore fields often involves high formation pressure and the presence of swellable clay rocks in the section. In addition, productivity preservation is also an important aspect. For this purpose, it is necessary to reduce the solids content of the drilling mud. The purpose of this work is to develop, improve, and study compositions of weighted drilling muds with low content of solids, on the basis of organic salts of alkali metals and polymers for the construction of wells prone to rock swelling and/or cavings, as well as drilling fluids for drilling-in the formation. In order to achieve the set goal the following is required: Analysis of existing drilling muds of higher density for drilling wells in unstable rock intervals and for drilling in the productive formation; analysis of experience in using drilling systems on the formic acid salts base and substantiation of requirements for flushing fluids during well construction; development and investigation of drilling mud compositions on the formate base; and the evaluation of inhibiting effect of systems containing organic salts, polymer reagents, and calcium carbonate on clay samples. The developed drilling mud is characterized by a high inhibiting ability that allows minimized mud-weighting by the natural solid phase. This reduces the volume of prepared mud and facilitates the regulation of its properties by reducing the dispersion of drilled cuttings; it eliminates problems related to hydration and the swelling of active clay rocks; and stabilizes unstable argillites prone to caving. The low solids content, low filtration rates, and inhibitory nature of the mud allows high stability of the rheological properties of the mud, and preserves oil and gas reservoir productivity under conditions of elevated formation pressure

Advances in Oil and Gas Production: A Viewpoint

Nowadays, there is a global trend towards “green” industry, which implies the reduction in carbon emissions from various industrial processes [...

Development of a Weighted Barite-Free Formate Drilling Mud for Well Construction under Complicated Conditions

Construction of oil and gas wells at offshore fields often involves high formation pressure and the presence of swellable clay rocks in the section. In addition, productivity preservation is also an important aspect. For this purpose, it is necessary to reduce the solids content of the drilling mud. The purpose of this work is to develop, improve, and study compositions of weighted drilling muds with low content of solids, on the basis of organic salts of alkali metals and polymers for the construction of wells prone to rock swelling and/or cavings, as well as drilling fluids for drilling-in the formation. In order to achieve the set goal the following is required: Analysis of existing drilling muds of higher density for drilling wells in unstable rock intervals and for drilling in the productive formation; analysis of experience in using drilling systems on the formic acid salts base and substantiation of requirements for flushing fluids during well construction; development and investigation of drilling mud compositions on the formate base; and the evaluation of inhibiting effect of systems containing organic salts, polymer reagents, and calcium carbonate on clay samples. The developed drilling mud is characterized by a high inhibiting ability that allows minimized mud-weighting by the natural solid phase. This reduces the volume of prepared mud and facilitates the regulation of its properties by reducing the dispersion of drilled cuttings; it eliminates problems related to hydration and the swelling of active clay rocks; and stabilizes unstable argillites prone to caving. The low solids content, low filtration rates, and inhibitory nature of the mud allows high stability of the rheological properties of the mud, and preserves oil and gas reservoir productivity under conditions of elevated formation pressure

Barite-Free Muds for Drilling-in the Formations with Abnormally High Pressure

This paper discusses problems associated with water-based drilling fluids used for drilling formations with abnormally high pressure. The available solutions are suitable for a narrow range of applications, especially when weighted muds should be used. This paper reviews the experience of searching and developing a new type of drilling mud based on saturated brines. With the referenced papers as the basis, the authors developed compositions of such brine-based drilling muds. A distinctive feature of the considered compositions is the absence of barite, which is often used as a weighting agent. The paper presents a methodology for creating and investigating the proposed drilling fluids. The rheological properties and thermal stability of the muds at various temperatures were studied. The results show that proposed drilling fluids can be efficiently used for drilling formations with abnormally high pressure. It is assumed that the developed muds have greater versatility than analogues

Efficiency Increase of Energy Systems in Oil and Gas Industry by Evaluation of Electric Drive Lifecycle

The efficiency issue of energy systems in the oil and gas industry is a crucial factor nowadays. Energy share in the production costs of oil and gas can reach 50%. Among the most important energy equipment are the electric drives of the pumps, compressors, auxiliary units, etc. The paper considered the lifecycle of the electric drives used at oil and gas fields and evaluated their efficiency parameters during periods of operational wear or malfunctioning. At the same time, the lifecycle of the energy equipment was seen as its technical state during operation. Based on the spectral analysis of the current using the finite Fourier transform (FFT), the main frequency components were identified that characterize the type and level of malfunction, taking into account defined efficiency indicators of the electric drive. A technique for assessing the technical state of an electric drive was proposed based on the normalized levels of the amplitudes of the frequency components. Predictive management of the electric drive was implemented in terms of correcting the control system when a malfunction occurs, providing the required efficiency indicators. Boundaries for the technical state of the electric drive were determined. Recommendations for further operation, terms of maintenance and repair or preventive management were presented

Small-Scaled Production of Blue Hydrogen with Reduced Carbon Footprint

This article reviews a method of hydrogen production based on partial non-catalytic oxidation of natural gas in an original synthesis gas generator. The working principles of the unit are similar to those of liquid-propellant rocket engines. This paper presents a description of the operation and technical characteristics of the synthesis gas generator. Its application in the creation of small-scaled plants with a capacity of up to 5–7 thousand m3/h of hydrogen is justified. Hydrogen production in the developed installation requires a two-stage method and includes a technological unit for producing a hydrogen-containing gas. Typical balance compositions of hydrogen-containing gas at the synthesis gas generator’s outlet are given. To increase the hydrogen concentration, it is proposed to carry out a two-stage steam catalytic conversion of carbon monoxide contained in the hydrogen-containing gas at the synthesis gas generator’s outlet using a single Cu–Zn–cement-containing composition. Based on thermodynamic calculations, quasi-optimal modes of natural gas partial oxidation with oxygen are formulated and the results of material balance calculation for the installation are presented. In order to produce “blue” hydrogen, the scheme of carbon dioxide separation and liquefaction is developed. The conclusion section of the paper contains the test results of a pilot demonstration unit and the recommendations for improving the technology and preventing soot formation