Paraffin Deposition Research Articles

Assessment of cellulose substituted with varying short/long, linear/branched acyl groups for inhibition of wax crystals growth in crude oil

The deposition of paraffin on the pipeline surface during crude oil transportation is a significant issue for oil industries. In this regard, the demand for adequate methods of wax deposition has gained considerable attention. In the current work, five cellulose esters were synthesized with varied chain short/long and linear/branched in a homogeneous medium and characterized by various analytical techniques. The ability of all cellulose esters to change wax crystal's structure and pour-point and yield stress reduction was observed by cross-polarized microscope, pour-point measurement, differential scanning calorimetry, and rheology. It was noticed that the paraffin crystallization temperature and pour-point had decreased significantly with long/linear side chain esters. The efficiency to reduce yield stress was found to correlate with the nature of the side chain. Long/linear side chain esters with 0.3 wt% are more effective in stabilizing the paraffin/asphaltene gel formation, thereby improving the flowability of waxy oil. The computational calculations also support all the findings at a molecular level.

Experimental study and modelling of asphaltene deposition on metal surfaces with superhydrophobic and low sliding angle inner coatings

Inner coatings have emerged as a novel technique to prevent the deposition of paraffin, wax, scale, and corrosion of pipelines during oil production and transport. Few studies addressed this technique for preventing asphaltene deposition. In this study, two superhydrophobic inner coatings, including polytetrafluoroethylene (PTFE) coating and nanosilica coating, were fabricated on metal surfaces and the asphaltene deposition on these coated surfaces was examined. A model oil solution was prepared using asphaltene and heptol and the effect of static and dynamic flow states on the amount of asphaltene deposition on uncoated electrodes, PTFE coated electrodes, and nanosilica coated electrodes were investigated. The results showed that the PTFE coating is more effective in reducing asphaltene deposition than nanosilica coating. The PTFE coating could reduce 56% of the deposition in a static state and more than 70% in a dynamic state at an asphaltene concentration of 2000 ppm. For PTFE coating in a dynamic state, the deposition rate is negligible in long times. In addition, it was found that the type of flow state affects the asphaltene deposition kinetics. The results demonstrate that, in the static state, the nth-order kinetics model, and in the dynamic state, the double exponential models are in best agreement with the experimental data.

CONTROL OF THE HEATING CABLE OPERATION BASED ON A MATHEMATICAL MODEL OF HEAT AND MASS TRANSFER PROCESSES IN AN OIL WELL

The paper considers the problem of controlling the process of thermal dewaxing of oil and gas wells using a heating cable. An axisymmetric mathematical model of heat and mass transfer processes in an oil well is proposed, the implementation of which makes it possible to estimate the temperature distribution on the wall of a pumping compressor pipe, to determine the area of ​​possible deposition of asphalt-resin-paraffin substances and the necessary conditions to prevent their formation. The mathematical model is a system of differential equations based on the laws of conservation of energy, mass and momentum. Considers the basic principles of heating cable control used in modern thermoelectric installations. The inefficiency of these methods is shown, which leads to increased energy consumption and accelerated aging of the heating cable. A fundamentally new algorithm for controlling the operation of a heating cable is proposed, based on modeling the processes of heat and mass transfer in an oil well. The use of this algorithm makes it possible to obtain with a sufficiently high accuracy the temperature distribution inside the well and determine the required heating time and power to prevent the deposition of asphalt-resin-paraffinic substances on the walls of the tubing. The control algorithm is implemented taking into account the technological parameters of production, which have a significant impact on the temperature distribution in the well, and adapts to their possible change caused by the heterogeneity of the oil and gas reservoir. The proposed heating cable control algorithm makes it possible to reduce energy consumption, which is the main disadvantage of thermal dewaxing of oil wells using resistive heating, and to prevent premature equipment failure caused by possible overheating of the heating cable line. The results presented in the work can be useful in the development and operation of oil and gas wells complicated by asphalt-resin-paraffin deposits. Application of the proposed mathematical model makes it possible to evaluate the efficiency of thermal dewaxing of wells with a heating cable at the stage of field development and draw conclusions about the effectiveness of this method of combating paraffin deposits. The control algorithm based on the proposed mathematical model makes it possible to effectively use the equipment and reduce capital costs for electricity and well turnaround.

Influences of the Water Cut of Pumping Oil and the Mineralization of the Associated Water on the Rate of Sludging

The problem of the formation of organic deposits on the inside surfaces of borehole equipment and oilfield pipelines, which is urgent for all active oil fields, was considered in the study. The formation of these deposits leads to decreased lifespans for oilfield equipment and accidents involving oil pipelines and wells. The aim of our work was to estimate the dependencies of the organic deposition’s formation-rate factor on the water cut of the investigated water–oil emulsion and the mineralization of the water phase. Examination via generation of asphaltene–resin–paraffin deposits on the surfaces of cold rods was carried out with a “Cold Finger” CF-4 unit. Coefficients of specific oil sludging, fluid sludging and rate sludging have been determined. It has been defined that in the definite oilfields, the rate of sludging does not increase as the water content in the emulsion increases. As water-phase mineralization increases, this value remains practically constant.

Peculiarities of the operation of the oil pipeline in the process of its cleaning from paraffin deposition

Purpose: Improving the technology of cleaning the inner surface of the main oil pipelines from paraffin deposition by specifying the hydrodynamic parameters of the movement of the cleaning device in the cavity of the pipeline, by more accurate prediction of the time of its approach to the final point of purification. Design/methodology/approach: Performing theoretical researches and application of mathematical modelling methods in order to establish the regularities of the cleaning device movement in the oil pipeline. Findings: Regularities of changes in the capacity of the pipeline, the speed of the cleaning process, the specific energy consumption for oil transportation as a function of the linear coordinates of the place and time of the cleaning device movement in the pipeline were established. Research limitations/implications: The next stage of research is to establish the influence of the characteristics of the viscoplastic fluid of the paraffin plug on the additional resistance and the mode of the cleaning device movement in the pipeline. Practical implications: It was developed the method that allows predicting the capacity and energy efficiency of the pipeline operation for each point in time of the process of cleaning from paraffin deposition. Originality/value: The originality of the method is the taking into account the additional hydraulic resistance of the paraffin plug and the available energy resources of oil pumping stations on the hydrodynamic process of moving the cleaning device in the oil pipeline.

A REVIEW OF VARIOUS POUR POINT DEPRESSANTS USED FOR FLOW ASSURANCE IN OIL INDUSTRIES

Crude oil needs to be transported from oil wells to refinery and storage facilities in one form or another to ultimately become end use products. After the successful extraction of oil from the ground it is mostly transported through pipelines where the crude oil experiences various changes in its physical and chemical properties. These rheological changes may cause numerous flow assurance problems such as wax and paraffin deposition which ultimately restricts the flow of oil. Chemical additives such as Pour Point depressants (PPDs) are used in this case for the efficient transportation of crude oil by lowering the Wax Deposition Temperature (WAT). Hence, in order to enhance the knowledge about PPDs, the mechanism of various types of Pour Point Depressant for aiding the flow of crude oil while transportation were discussed in this paper.

Development of a Paraffin Deposition Primary Diagnosis Program for Oil Field Production Facilities

본 연구에서는 파라핀 침적으로 유동안정성 문제 발생이 예상되는 유전 시설에서 파라핀 침적 양상을 예측하고 화학제 주입량 및 유정보수 주기를 제안하는 프로그램을 개발하였다. 수치해석에 기반하여 파라핀 침적량 및 침적위치를 진단한 후, 시뮬레이션 결과를 학습한 기계학습 방법을 통해 예측 결과의 신뢰성을 검증하였다. 개발된 프로그램은 파라핀 문제가 있는 생산현장에서 안정적으로 생산목표를 유지할 수 있는 솔루션을 제공하는 기능이 포함되어 있어, 영세한 중소규모 유전에서 초기의 파라핀 침적 양상을 진단할 수 있는 툴로 활용할 수 있다. 이를 통한 현장 운영 계획 수립 및 수익성 개선에 효율적으로 활용될 수 있는 프로그램이라고 판단된다.

Определение минимальных мероприятий в скважине по предотвращению образования асфальтосмолопарафиновых отложений

An analysis of the formation of asphaltene resin paraffin deposits is presented, criteria for assigning wells to subgroups of the complications type are considered, and a classification of complications in oil production is proposed. Oil is a complex and varied mixture of various hydrocarbons, both light and heavy, in thermodynamic equilibrium under reservoir conditions. In some fields, oil production is not accompanied by the formation of asphaltene resin paraffin deposits on the downhole pumping equipment, while in others it is complicated by them. Methods of preventing the deposition of asphaltene resin paraffin deposits and methods of dealing with them are considered, the research work done to substantiate the use of chemical reagents to prevent the formation of complications in oilproducing wells is presented, the minimum measures for subgroups of the proposed classification, complicated by asphaltene resin paraffin deposits of the fund, are presented. The methods for determining the effectiveness of the asphaltene resin paraffin deposits inhibitors, developed in the PermNIPIneft branch of LLC LUKOIL-Engineering, were briefly presented, on the basis of which the studies were carried out. The results of studies on the selection of reagents and determination of their effectiveness for the production well stock complicated by asphaltene resin paraffin deposits were considered. It was found that during wells operation where the physicochemical properties changed, the effectiveness of the inhibitor significantly decreased and did not reach the efficiency criterion of 75%. So, in oil production it is necessary to periodically, at least once every three years, check the effectiveness of the selected reagents, as well as analyze changes in such parameters of the processed object as: change in the physicochemical properties of the fluid; geological and technical measures at the well; significant increase, decrease in production; involvement or isolation of interlayers, production facilities; changes in reservoir, bottomhole pressure during operation. Approaches for wells are proposed: where, as a result of research, the criterion of the effectiveness of chemical reagents has not been achieved, it is necessary to select other methods to avoid the complication.

Исследование температурных условий образования органических отложений в продуктивном пласте при скважинной добыче парафинистой нефти

The paper presents the studies results of the temperature conditions for the formation of organic (asphalt-resin-paraffinic) deposits in the productive formation during the downhole production of paraffinic oil, including the results of experimental studies to assess the temperature of oil saturation with paraffin in the pore space of reservoir rocks. The studies were carried out in order to substantiate and develop a technology for preventing such deposits in the "reservoir - well" system. The results of filtration and rheological studies showed that for the same oil, the wax saturation temperature in the pore space of the reservoir rock could exceed the value of this parameter in the free volume. It was found that for the investigated solutions (models of highly paraffinic oils), the phase transition of paraffin from liquid to solid state, the formation of wax crystals in the pore space occured at a temperature 3-4° C higher than in the free volume. The results of tomographic studies of the core material, performed before and after filtration of a paraffin-containing solution through it with a decrease in temperature, showed that the open porosity of rock samples decreased on average four times due to the clogging of their pore space with paraffin. Based on the results of the filtration experiment and computed tomography, a digital core model was created, which allowed modeling the fluid flow in the pore space of the rock before and after the formation of paraffin deposits in it. The calculations results of the changes dynamics in the thermal field around the injection well confirmed the probability of cooling the bottomhole zone of the well to a temperature equal to the temperature of the onset of wax crystallization, as well as the probability of the cold water front advancing to neighboring production wells, which could cause a significant decrease in the productivity due to the formation of paraffin deposits in pore space of reservoir rocks. The research results are recommended to be taken into account when developing oil fields in conditions of possible formation of organic (asphalt-resin-paraffinic) deposits in the productive formation. This will make it possible to more reliably predict and effectively prevent its formation in the "reservoir - well" system.

Study on the practice of downhole dewaxing by in situ generated heat

In situ heat systems are a technology that effectively solves paraffin deposition and improves oil recovery. Generally, the oxidation–reduction reaction of sodium nitrite and ammonium chloride generates a large amount of heat to promote the melting of paraffin. An in situ heat system combined with an acid-resistant fracturing fluid system can form an in situ heat fracturing fluid system, which solves the problem of the poor reformation effect caused by cold damage during the fracturing process of low-pressure and high-pour-point oil reservoirs. In this paper, with the goals of system heating up to 50 °C, a low H+ concentration, a high exotherm, and reduction of the toxic and harmful by-product NOX, the preferred in situ heat system was found to comprise 1.6 mol/L ammonium chloride, 1.0 mol/L sodium nitrite, and 0.8% hydrochloric acid. The effect of five factors on the heat production of the reaction was studied experimentally, and a reaction kinetic equation for the in situ heat system was proposed based on the results. The results showed that increasing the concentration of the reactants and lowering the ambient temperature produced more heat. The in situ heat system was used to conduct a crude oil cold damage elimination experiment, and the results of the removal experiments verified that the system could effectively but not completely reduce the cold damage. Overall, the in situ heat fracturing fluid system formed by the preferred in situ heat system combined with an acid-resistant fracturing fluid system could avoid cold damage in the formation during construction and increase the output.

The use of esters as an inhibitor to prevent asphalt-resinous paraffin deposits

This article discusses the problem of asphalt-resinous-paraffin deposits in production and tubing pipes. As a rule, these deposits help to reduce the debit of the well with the subsequent failure of the sucker rod or electric centrifugal pumps that are installed at the wellhead. For this reason, the fight against asphaltene-resinous-paraffin deposits is an urgent research task. We considered the chemical method of exposure to asphaltene deposits, in particular with the use of esters, which are part of inhibitors. Today, a wide range of varieties of inhibitors is known that are used as substances that slow down physicochemical processes; the word inhibitor itself comes from lat. “Inhibere”, which means “delay, slow down”. Of the currently available inhibitors, an ester-based inhibitor has been proposed that can be used initially to prevent the accumulation of asphaltene deposits.

Analysis of the Structure of Viscous Oil Flow for the Development of a System to Prevent the Formation of Paraffin Deposits in Pipelines

The detection of paraffin deposits in the systems of main oil pipelines today is a very important problem, since they lead to emergency oil spills, environmental disasters and economic losses both for the enterprise and for the country as a whole. This work is aimed at studying the physicochemical properties of asphaltic resin paraffins, as well as the mechanism of phase transition from liquid to crystalline. Such studies make it possible to estimate the absorption coefficient of the paraffin phase, which was previously not possible due to the complex nature of oil, consisting of hydrocarbons and many organic compounds of various molecular weights, and to provide high-precision non-contact measurements of the concentration of suspended asphalt-resin-paraffins in the oil flow in the pipeline. The analysis of the morphology and chemical composition of paraffins of various deposits is carried out, the dependence of the phase transition depending on the temperature gradient is determined.

Autonomous complex for electro-thermal heating of oil wells fed by a photovoltaic installation

Paraffin deposits are a serious problem causing complications in oil production. This article describes the creation of a complex operatingonphotovoltaic installations to combat paraffin deposits. The authors offer an innovative method for accurate calculation of the parameters of photovoltaic installations, taking into account changes in total solar radiation, geographical and climatic conditions, the angle of inclination of solar panels, characteristics of the power source, and oil parameters. Measurements of solar radiation are carried out on the basis of mathematical and simulation modeling in Matlab Simulink. The results of the studies confirm the adequacy of the proposed method of oil well heating. This method of electric heating has a simple design and does not require underground works and well shutdown. Thus, it will improve the efficiency of oil production, prevent the formation of paraffin deposits, and ensure energy savings by reducing power losses and electricity consumption.

In-silico research of the influence of gas injection into the subsea crude oil pipeline on the paraffin solid phase deposition

The aim of the article is presenting of the preliminary results of simulations showing behaviour of paraffin deposits in submarine pipelines. The described parameters for changing the deposition of the solid paraffin phase with the flow of crude oil through the submarine pipeline inside the subsea system: subsea wellhead – platform processing system. The research includes considerations of the behaviour of paraffins in the presence of the injected gas phase. Author recommends using of phenomenon as an alternative way of securing submarine pipelines operating on the Baltic Sea. This analyse informs that the paraffin’ deposit is possible to adjust of it’s thickness buy using agents other than purely chemical paraffin point temperature depressants. It is supposed here that main impact on paraffin deposition behaviour get decreasing of sediments thickness on the walls of the submarine pipeline in the analysed sections. The reservoir fluid composition used in the simulation was taken from B3 fluid PVT analysis owned by LOTOS Petrobaltic S.A. General composition was used in Leda Flow 2.5 computer analysis in courtesy of Kongsberg Company.

The substantiation of the influence of asphalt resin paraffin oil residue on the asphalt concrete technology

Based on scientific research and experimental tests, it has been proved that solid waste from oil fields in the Kyzylorda region based on asphalt resin paraffin sediment (ARPS) is close and binding in its chemical composition to the main component of the asphalt-concrete mixture of the road surface. And the most effective method of disposal and neutralization of oil waste was chosen. In this article, it is proposed to develop an asphalt-concrete technology based on asphalt-resinous paraffin deposits. The issue of increasing the reserves of raw materials for the production of durable asphalt concrete and reducing the amount of oil-containing waste in the fields due to the sale of solid oil-containing waste will be considered. Based on the study, the composition of asphalt-resinous paraffin deposits was analyzed by IR spectroscopy. The infrared (IR) absorption spectrum was captured in the IR-Fourier spectrometer. The results of the study showed the suitability of asphalt-resinous paraffin deposits for use as organic binders to dense asphalt concrete of type «B» grade III for IV-V road climatic zones recommended for applying top layers of coating on roads of technical category IY.

Development of methods for determining the relative weight of physical factors in pipeline paraffinization

The paper is devoted to the development of a system for predicting pipeline paraffinisation, which is a matter of urgency in oil transportation to ensure resource-saving and facilitating sustainable development of the oil industry. The paper focuses on the composition analysis of measuring instruments, the combined use of which can fix the values of all physical parameters right at the time of paraffin formation. To date, the need for such measurements is due to the absence of a precise model for the process of formation of paraffin deposits and correlating dependencies between the process of paraffinisation and physical factors causing it, as well as the absence of possibility to create a forecasting system without this information. Its creation has become possible as a result of introducing advanced methods for measuring the degree of pipeline paraffinisation and oil stream viscosity, critical for the aforesaid data collection. The paper discusses the process of pipeline paraffinisation, presents the selected methods for measuring the desired values, as well as describes the required measuring equipment. The developed system of sensors is characterized by the absence of contact with the medium being measured, full automation, and minimum number of elements. Economically feasible stages of the system development and implementation were selected.

Technical and economic analysis of the proposed method of utilization of asphalt resin paraffin deposits (ARPD) in the composition of organomineral waterproofing material

Currently, for many construction industries promising becomes the creation of waterproofing materials on the basis of integrated management natural oily raw material, as well as improvement of traditional materials. Choice of material depends on the working conditions of a hydraulic installation, categories of reliability construction, its structures, the availability of local building materials, method of work and of technical and economic indices of construction. In this paper described economic and technical efficiency of using asphalt resinous paraffin deposits as a main composition of organomineral material for antifiltration screen. In this paper described technology of preparing oil waste sludge pit, where asantifiltration screen is used polymerorganic screen based on asphalt resin paraffin deposits (ARPD) and polymer material. Processing of oil waste and reducing their formation is a significant problem from the ecological point of view and requires new ecological and technological solutions. In this research paper analyzes the results of world practical experiments on the application of waste and presents technical solutions for the use of waste that are suitable for future application. The feature of this work is obtaining waterproofing materials based on asphalt – resin -paraffin deposits and polymer, moreover the improvement of its physicochemical properties. The results of experimental laboratory testing of the effects of aggressive components of waste on the physical and mechanical properties of the material made from polymerorganic and cement mixture are presented.

Selection of effective solvents against asphalteneresin-paraffin deposition in the Uzen oilfield

Deposition of asphaltenes, resins and paraffins in underground well equipment has always been one of the major challenges in the production of highly paraffinic oil at the Uzen field. This problem still remains extremely urgent, and measures to combat these complications are quite costly.
 Paraffin deposition processes in wells and field equipment complicate oil production and lead to oil losses, as well as accidents and equipment downtime. For these reasons, it becomes necessary to conduct a laboratory research on the selection of effective solvents against paraffin deposition and methods for their removal.

Study the impact of Difron 4201 depressor additive on formation of paraffin deposition in laboratory conditions

The impact of Difron 4201 depressor additive on the asphaltene deposits on metallic surface has been studied for the first time in laboratory conditions via "coldfinger" method. The experiments were carried out in various temperatures of "coldfinger” and different concentrations of Difron 4201 depressor additive. The experiment lasted 3 hours. The amount of deposited paraffin in different times (0, 20, 40, 60, 80, 100, 120 minutes) on the coldfinger surface was specified via the analytical balance and it was defined that with decreasing temperature of the coldfinger the amount of oil sediments on the surface increases and the intensity of deposition decreases by time, and stabilizes after 120 minutes. As a result of the mass dependence of asphaltene deposits on the concentration of depressor additive, it was defined that with increasing concentration of the additive in the oil, the amount of deposits decreases and in the 900 g/t concentration, the maximum level of deposit reduction is observed. The efficiency of depressor additive and the maximum percentage of paraffin sediments on coldfinger surface has been estimated based on the obtained results of experiments. The highest effect was observed in the concentration of 900 g/t concentration of Difron 4201 depressor additive (85 %). Depending on the temperature of coldfinger the maximum percentage of paraffin sediments on the coldfiner surface was equal to 0 оC – 12.8, 5 оC – 9.16, 10 оC – 6.76, 15 оC – 5.82, 20 оC – 5.04, 25 оC – 2.96, 30 оC – 1.63.

THE INFLUENCE OF ASPHALT RESIN PARAFFIN OIL RESIDUE ON ASPHALT CONCRETE TECHNOLOGY

Based on scientific research and experimental tests, it has been proved that solid waste from oil fields in the Kyzylorda region based on asphalt resin paraffin sediment (ARPS) is close and binding in its chemical composition to the main component of the asphalt-concrete mixture of the road surface. And the most effective method of disposal and neutralization of oil waste was chosen. The ARPS formed from the use of oil at the Kumkol field was studied, which includes asphaltenes 3 ... 8%; resins-13 ... 20%; fats-34...65%; mechanical impurities-20...49%; water-1...5%. In this article, it is proposed to develop an asphalt-concrete technology based on asphalt-resinous paraffin deposits. The issue of increasing the reserves of raw materials for the production of durable asphalt concrete and reducing the amount of oil-containing waste in the fields due to the sale of solid oil-containing waste will be considered. Based on the study, the composition of asphalt-resinous paraffin deposits was analyzed by IR spectroscopy. The infrared (IR) absorption spectrum was captured in the IR-Fourier spectrometer IR Prestige-21. The absorption spectra of asphalt-tar-paraffin deposits recorded by the IR spectrometer show the structure of hydrocarbons in the methyl (2954-2852 cm-1), methylene (1463-1377 cm-1), and methine (721 cm-1) groups. The analysis shows that the composition of solid oil waste generated at the fields consists mainly of paraffin hydrocarbons.The results of the study showed the suitability of asphalt-resinous paraffin deposits for use as organic binders to dense asphalt concrete of type" B " grade III for IV-V road climatic zones recommended for applying top layers of coating on roads of technical category IY. Replacing scarce commercial bitumen with oil waste will significantly reduce the cost of commercial products, as well as simplify the process of preparing the mixture and prevent environmental pollution with harmful substances released from oil.