Viscous Crude Oil Production Facilitated by Flow Improver Technology: A Holistic Chemical Approach with Successful Field Application

2021 ◽  
Author(s):  
James Alexander McRae ◽  
Bianca Daniela Covarrubias Rosas

Abstract This paper describes the approach taken to evaluate and successfully treat flow assurance challenges associated to high viscosity produced fluids in an oil producing field, offshore Gulf of Mexico. The first section of the paper outlines primary evaluation criteria: discussing base line modeling of crude oil characteristics at various points of the production system, laboratory analyses, detailed explanation of the chemistries considered for reducing the viscosity, and the strategy to remediate multiple flow assurance challenges with subsequent performance testing. The second section presents field trial data from the application of the selected flow improver and its longer-term performance. Initial evaluation of high viscosity was required due to deposition of asphaltene, high levels of emulsion, increased pressure and resultant decrease in production All of these production issues caused increased spending on fluids treatment in a field that is mature and becoming more marginal to produce. Initial analysis of the produced fluid did not result in an immediate, clear approach to address the concern, without considering the multiple factors that can contribute to flow assurance challenges. Organic deposition, such as waxes and asphaltenes, were found to increase fluid viscosity and worsen highly stabilized emulsions. Crude oil/water emulsions also cause increased viscosity and needed to be addressed as part of any holistic solution. Each issue was studied and experimented on its own and in combination to ensure there was no reductive effect in a final chemical application that needed to treat them all. Successful field application of the selected flow improver technology exceeded the performance at laboratory scale achieving over 30% reduction in total fluid viscosity over long-term field deployment with associated benefits to the offshore operator which will be elaborated further in this paper. As an outcome of this field trial, this paper also presents a proposed generic approach in devising chemical solutions for treatment of high viscosity fluids.

2021 ◽  
Author(s):  
Ferdio Giffary ◽  
Achmad Anggawirya Alimin ◽  
Bambang Heru Susanto

SPE Journal ◽  
2021 ◽  
pp. 1-13
Author(s):  
Biswadeep Pal ◽  
Tarun Kumar Naiya

Summary Pour-point depressants (PPDs) were synthesized from natural sources and used in waxy crude oil transportation to reduce the pour point and improve flow. A biodegradable PPD (BPPD) was synthesized and tested to mitigate crude oil flow assurance problems in the present work. The transesterification process was used to synthesize coconut oil ethyl ester (COEE, termed as BPPD). Fourier transform electron spectroscopy (FTIR), proton nuclear magnetic resonance (H-NMR), and microscopic analysis were performed for better understanding of mechanisms for both BPPD and a commercially available PPD named PPD-A. The pour point of crude oil was reduced by 12 and 9°C after the addition of 800 ppm BPPD and PPD-A, respectively. The microscopic analysis confirms that the crystals of wax converted to very fine and dispersed particles during mixing of additives, which in turn increase flowability. BPPD performs better to reduce interfacial tension than PPD-A. The maximum reduction of 19% in interfacial tension was observed after the addition of 800 ppm BPPD. BPPD alters the wettability of the pipeline surface from intermediate wet to water-wet within 60 seconds, which results in reduced slip velocity and consequently lessens the deposition of wax. As a result, crude oils will not stick to the wall of the pipe surface and will experience less resistance to flow through pipelines. FTIR analysis indicated that long-chain alkane and aromatic groups are responsible for a higher pour point, and their concentration level was reduced after the addition of BPPD. The viscosity of crude oil was reduced by almost 94% after the addition of 800 ppm BPPD with crude oil, which in turn minimizes pumping costs for crude oil. As a result, the total project cost was reduced substantially. Biodegradability tests confirm that the BPPD is biodegradable and nontoxic. Due to its biodegradability and nontoxic nature, BPPD has a promising capacity to be used in the petroleum industry for easier pipeline transportation of waxy crude.


1990 ◽  
Vol 258 (1) ◽  
pp. G65-G72 ◽  
Author(s):  
P. J. Sirois ◽  
G. L. Amidon ◽  
J. H. Meyer ◽  
J. Doty ◽  
J. B. Dressman

The influence of particle size, particle density, fluid viscosity, and fluid flow rate on the gastric emptying of nondigestible solids was investigated in five dogs with chronically placed fistulas. Six hundred and fifty particles of 13 different size and density combinations were administered simultaneously with 500 ml of either normal saline or low-, medium-, or high-viscosity polymer solutions. The canine stomach was found to discriminate between these solids on the basis of size and density at all levels of viscosity above saline. The observed patterns of emptying are consistent with the hypothesis that gastric emptying of nondigestible solids is governed in part by hydrodynamics and correlate well with the gastric-emptying coefficient (GEC), a dimensionless grouping of variables that takes the form GEC = (Dpy/Dp) [g(rho f - rho p)Dp2]/[eta (nu)] where [g(rho f - rho p)] is particle buoyancy consisting of fluid (rho f) and particle (rho p) densities and g, the gravitational constant; (Dp) is the particle diameter, (Dpy) the estimated pyloric diameter, eta the fluid viscosity, and (nu) the average linear velocity of fluid exiting the stomach.


Author(s):  
Bo Xu ◽  
Qing Miao ◽  
Hao Lan ◽  
Feng Yan ◽  
Donglei Liu

More than 80% crude oils produced in China has a high content of wax. Pipeline transportation for such high waxy Chinese crude has a serious safety risk due to its characteristics of high gel point (up to 30 degree) and high viscosity below the wax appearance temperature. In the case of pipeline shutdown the crude cools down. After a certain amount of time, depending on the crude oil properties, the crude oil temperature plot file, the hydraulic data as well as the pipeline construction and environmental related data, the required pressure to restart the pipeline might exceed the maximum allowable operation pressure (MAOP) which makes the restart of operation become very difficult or even impossible. To mitigate the safety risk in case of the pipeline shutdown or to avoid congeal accident, determining the safe time after which the pipeline is still able to restart is necessary. However, the complexity of the presented problem lies in the uncertainty of the operation parameters and the environmental related data, such as the uncertainly of the flow rate and natural temperature. A method is developed to predict the safe time based on the uncertainty of parameters. In the method, the field data is firstly collected, then processed and analyzed to obtain the static rules of these data. By doing so, the complexity of uncertainty is successfully handled. The method is then applied to two pipelines, the results show that the safety of the pipeline is ensured and the energy consumption is also significantly reduced.


2021 ◽  
Author(s):  
Luiz Pastre ◽  
Jorge Biazussi ◽  
William Monte Verde ◽  
Antonio Bannwart

Abstract Although being widely used as an artificial lift method for heavy oil field developments, Electrical Submersible Pump (ESP) performance in high viscous applications is not fully understood. In order to improve knowledge of pump behavior under such conditions, Equinor has developed stage qualification tests as part of the technical requirements for deploying ESPs in Peregrino Field located offshore Brazil and has funded a series of research efforts to better design and operate the system more efficiently. Qualification tests were made mandatory for every stage type prior to field deployment in Peregrino. It is known that the affinity laws don´t hold true for high viscosity applications. Therefore, extensive qualification tests are required to provide actual stage performance in high viscous applications. Test results are used to optimize ESP system design for each well selecting the most efficient stage type considering specific well application challenges. In addition, the actual pump performance improves accuracy in production allocation algorithms. A better understanding of ESP behavior in viscous fluid application helps improving oil production and allows ESP operation with higher efficiency, increasing system run life. Shear forces inside ESP stages generate emulsion that compromises ESP performance. Lab tests in controlled environments have helped Equinor to gather valuable information about emulsion formation and evaluate ESP performance in conditions similar to field application. Equinor has funded studies to better understand two-phase flow (oil-water) which allowed visualization and investigation of oil drops dynamics inside the impeller. In addition, experimental procedures were proposed to investigate the effective viscosity of emulsion at pump discharge and the phase inversion hysteresis in the transition water-oil and oil-water emulsion. In addition to qualification tests and research performed to better understand system behavior, Equinor has developed and improved procedures to operate ESP systems in high viscous applications with emulsion production during 10 years of operation in Peregrino field. Such conditions also impose challenges to ESP system reliability. Over the years, Equinor has peformed failure analysis to enhance ESP system robustness which, combined with upper completion design, have improved system operation and reliability decreasing operating costs in Peregrino field.


Author(s):  
Le Xie ◽  
Qi-An Wang ◽  
Xian-Jin Luo ◽  
Zheng-Hong Luo

Abstract Solid particle dispersion and chemical reactions in high-viscosity non-Newtonian fluid are commonly encountered in polymerization systems. In this study, an interphase mass transfer model and a finite-rate/eddy-dissipation formulation were integrated into a computational fluid dynamics model to simulate the dispersion behavior of particles and the mass transfer–reaction kinetics in a condensation polymerization-stirred tank reactor. Turbulence fields were obtained using the standard k–ε model and employed to calculate the mixing rate. Cross model was used to characterize the rheological property of the non-Newton fluid. The proposed model was first validated by experimental data in terms of input power. Then, several key operating variables (i.e. agitation speed, viscosity, and particle size) were investigated to evaluate the dispersive mixing performance of the stirred vessel. Simulation showed that a high agitation speed and a low fluid viscosity favored particle dispersions. This study provided useful guidelines for industrial-scale high-viscosity polymerization reactors.


2003 ◽  
Vol 47 (7-8) ◽  
pp. 243-250 ◽  
Author(s):  
T. Kose ◽  
A. Miyagishi ◽  
T. Mukai ◽  
K. Takimoto ◽  
M. Okada

Biodegradation rates of polycyclic aromatic hydrocarbons (PAHs) in spilled oil stranded on tidal flats were studied using model reactors to clarify the effects of NAPL on the biodegradation of PAHs in stranded oil on tidal flat with special emphasis on the relationship between dissolution rates of PAHs into water and viscosity of NAPL. Biodegradation of PAHs in NAPL was limited by the dissolution rates of PAHs into water. Biodegradation rate of chrysene was smaller than that for acenaphthene and phenanthrene due to the smaller dissolution rates. Dissolution rates of PAHs in fuel oil C were smaller those in crude oil due to high viscosity of fuel oil C. Therefore, biodegradation rates of PAHs in fuel oil C were smaller than those in crude oil. Biodegradation rates of PAHs in NAPL with slow decrease rate like fuel oil C were slower than those in NAPL with rapid decrease like crude oil. The smaller decrease rate of fuel oil C than crude oil was due to higher viscosity of fuel oil C. Therefore, not only the dissolution rate of PAHs but also the decrease rates of NAPL were important factors for the biodegradation of PAHs.


2018 ◽  
Vol 18 (05) ◽  
pp. 1850043 ◽  
Author(s):  
S. V. FROLOV ◽  
S. V. SINDEEV ◽  
D. LIEPSCH ◽  
A. BALASSO ◽  
P. ARNOLD ◽  
...  

The majority of numerical simulations assumes blood as a Newtonian fluid due to an underestimation of the effect of non-Newtonian blood behavior on hemodynamics in the cerebral arteries. In the present study, we evaluated the effect of non-Newtonian blood properties on hemodynamics in the idealized 90[Formula: see text]-bifurcation model, using Newtonian and non-Newtonian fluids and different flow rate ratios between the parent artery and its branch. The proposed Local viscosity model was employed for high-precision representation of blood viscosity changes. The highest velocity differences were observed at zones with slow recirculating flow. During the systolic peak the average difference was 17–22%, whereas at the end of diastole the difference increased to 27–60% depending on the flow rate ratio. The main changes in the viscosity distribution were observed distal to the flow separation point, where the non-Newtonian fluid model produced 2.5 times higher viscosity. A presence of such high viscosity region substantially affected the size of the flow recirculation zone. The observed differences showed that non-Newtonian blood behavior had a significant effect on hemodynamic parameters and should be considered in the future studies of blood flow in cerebral arteries.


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