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Copyright 2012, Society of Petroleum Engineers This paper was prepared for presentation at the SPE Annual Technical Conference and Exhibition held in San Antonio, Texas, USA, 8-10 October 2012. This paper was selected for presentation by an SPE program committee following review of information contained in an abstract submitted by the author(s). Contents of the paper have not been reviewed by the Society of Petroleum Engineers and are subject to correction by the author(s). The material does not necessarily reflect any position of the Society of Petroleum Engineers, its officers, or members. Electronic reproduction, distribution, or storage of any part of this paper without the written consent of the Society of Petroleum Engineers is prohibited. Permission to reproduce in print is restricted to an abstract of not more than 300 words; illustrations may not be copied. The abstract must contain conspicuous acknowledgment of SPE copyright. Abstract The effect of downward and upward pipe inclinations on flow characteristics for high viscosity oil-gas two-phase flow was experimentally studied.
- Production and Well Operations > Well & Reservoir Surveillance and Monitoring > Production logging (1.00)
- Facilities Design, Construction and Operation > Pipelines, Flowlines and Risers > Pipeline transient behavior (0.94)
- Reservoir Description and Dynamics > Reservoir Fluid Dynamics > Multiphase flow (0.75)
- Reservoir Description and Dynamics > Improved and Enhanced Recovery (0.72)
Abstract This paper presents the results of a modeling study for paraffin deposition under single-phase turbulent flow conditions. Analysis on flow loop deposition data is presented for various crude oils such as South Pelto crude oil, Garden Banks condensate and Trans Alaska Pipeline System (TAPS) crude oil. A new closure relationship simulating shear effects is proposed. The experimental data were obtained under single-phase turbulent flow conditions using different types of crude oils on different test facilities at TUPDP (Tulsa University Paraffin Deposition Projects). These data were used to develop a correlation which can be used to predict the relative difference between the estimated wax mass deposition rate and mass diffusion rate from Fick's law as a function of the Nusselt and Sherwood numbers representing the heat and mass transfer characteristics under turbulent flow conditions. Uncertainty analysis was conducted on this correlation and most of the data points fall within the range of ±25%. Model predictions have been compared using a film mass transfer model and equilibrium model. It is observed that the film mass transfer model always over predicts the deposition rate. But the equilibrium model can both under predicts and over predicts the deposition rate. The results presented in this paper can be used to improve the accuracy of paraffin deposition model predictions under turbulent flow conditions.
- North America > United States > Texas (0.28)
- North America > United States > Alaska (0.24)
- Europe > Norway > North Sea > Northern North Sea > North Viking Graben > PL 054 > Block 31/6 > Troll Field > Sognefjord Formation (0.99)
- Europe > Norway > North Sea > Northern North Sea > North Viking Graben > PL 054 > Block 31/6 > Troll Field > Heather Formation (0.99)
- Europe > Norway > North Sea > Northern North Sea > North Viking Graben > PL 054 > Block 31/6 > Troll Field > Fensfjord Formation (0.99)
- (9 more...)
- Production and Well Operations > Well & Reservoir Surveillance and Monitoring > Production logging (1.00)
- Production and Well Operations > Production Chemistry, Metallurgy and Biology > Inhibition and remediation of hydrates, scale, paraffin / wax and asphaltene (1.00)
- Facilities Design, Construction and Operation > Flow Assurance > Precipitates (paraffin, asphaltenes, etc.) (1.00)
It is a privilege for me to serve as Chairman of the Technical Advisory Committee. On behalf of BHR Group and the Organizing Committee, I would like to welcome you to BHR Group's 8th North American Conference on Multiphase Technology in Banff, Canada. Once again, we have a very diverse International delegation representing International and National Oil and Gas Operators, Service and Consulting Companies, Equipment Manufacturers, and Software Developers. The delegation includes multiple generations reflecting a thriving community of multiphase flow technology experts. I keep the attendee lists of past BHR Group conferences. I have recently looked through the lists. The lists include many legends and talented people who have helped shape not only the advancement of the science and technology of multiphase flow but also have contributed to Society at large by enabling new hydrocarbon resources through technological advancements. I am honored to present, one of the legends of our industry, Dr. Dendy Sloan as our Keynote Speaker for this conference. Dr. Sloan is Professor Emeritus of Chemical Engineering at the Colorado School of Mines. He is the foremost authority in the Hydrates field. Hydrates are considered as one of the important flow assurance problems, if not the most, to be managed in Multiphase Production. Professor Sloan will share his knowledge and wisdom with a talk titled "Developing acomprehensive understanding and model of hydrate in multiphase flow: From laboratorymeasurements to field applications". This conference and its counterpart, BHR Group's Multiphase Production Technology Conferences held in Europe every other year, have been the most educational, intellectually stimulating, and technically fulfilling conferences serving our industry since 1983. I certainly hope that most of you agree with me. One can see the evolution of our industry through BHR Group's Multiphase Production Technology conferences.
- North America > United States > Colorado (0.26)
- North America > Canada > Alberta > Census Division No. 15 > Improvement District No. 9 > Banff (0.26)
Abstract The objective of this project is to measure and observe high-viscosityoil/water/gas three-phase flows in horizontal and upward vertical pipes, andcompare the experimental results with existing models to identify the gaps. Inthis study, oil with viscosities between 0.15 and 0.57 Pa•s (150 and 570 cP)corresponding to temperatures from 37.8 to 15.6 °C (100 to 60 °F), filtered tapwater and natural gas at 2.59 MPa (375 psig) pressure are used as the threephases. Superficial oil and water velocities range from 0.1 to 1.0 m/s andsuperficial gas velocity varies from 1.0 to 5.0 m/s. The internal diameter ofthe pipe is 5.25-cm (2.067 in). The experimental measurements include pressuregradient and liquid holdup. The flow pattern and slug characteristics areobserved and the images are recorded with a high speed video camera systemthrough a high pressure sapphire window. The experimental results are comparedwith the predictions of Zhang and Sarica (2006) unified model, and thediscrepancies are identified. Introduction Heavy oil, extra heavy oil together with bitumen constitutes about 70% of theworld's total oil reserve. They are discovered and produced all around theworld and have become one of the most important future hydrocarbon resourceswith ever increasing world energy demand and depletion of conventional oils. However, the high viscosity of heavy oils poses many challenges for itsproduction and transportation. Three-phase flow of oil, water and gas is of particular importance for the oilindustry. It frequently occurs in wells, risers and flowlines before reachingthe downstream processing facilities. The water can be introduced either due tothe connate water condensation or water steam injection for enhanced oilrecovery at the later stage of production. Understanding of the three-phaseflow phenomena is necessary in order to better design the production andtransportation systems. Most of the previous experimental researches, model andcorrelation developments were conducted using low-viscosity conventional oilsor other liquids. Açikgöz et al. (1992) carried out the first experimentalinvestigation of three-phase flow patterns in horizontal pipes. Pan et al.(1995) performed similar horizontal experiments. The tests were conducted at 5bar pressure and in a 38.0-m long horizontal, 7.62-cm ID pipe. Woods et al.(1998) reported oil/water/air upward vertical flow in a 2.52-cm ID Perspex pipewith a 1.8-m test section. Nine flow patterns were identified based onvisual/video observations and pressure techniques. Langsholt et al. (2001)studied oil/water/gas flows in steeply inclined pipes. Hewitt (2005) studiedthree-phase oil/water/air flows in a 38.0-m long, 7.62-cm ID stainless steelpipes. Keskin et al. (2007) proposed a two step classification method foroil/water/gas three-phase flow patterns. 12 flow patterns were identified forhorizontal and slightly inclined flows.
- Research Report > New Finding (1.00)
- Research Report > Experimental Study (1.00)
Abstract This manuscript presents a systematic methodology to determine the optimalcritical velocity for sand transport on-the-fly for a given field operatingcondition. Using publicly-available experimental data on sand transport andsand transport models, the methodology combines data clustering andoptimization approaches with statistical analysis. The data clusteringalgorithm is used to select the representative data points that lie closest tothe operating condition, and then, the parameters of the sand transport modelsare fine-tuned using unconstrained optimization with the representative data. Using statistical analysis, the fine-tuned models are compared to identify theones that are most applicable and provide accurate velocity predictions for thegiven operating condition. Upon applying the methodology to a field operatingcondition, the sand transport velocity for the operating condition, assuggested by the methodology, are consistent. Introduction Sand transport models are used to predict the critical velocity, defined as therequired "fluid velocity for particle motion" [1], in order for the fluid to beable to transport the sand particles in the pipe. The transport of the sandparticle must take place in order to prevent the accumulation of sandparticles, which is of importance, as the accumulation of sand particles inpipes can have consequences, such as blockage in the pipeline [2], theprevention of corrosion inhibitors from reaching the bottom of the pipe [3], and erosion due to the decreased flow area in the pipe [4]. In industrialapplications, sand transport models are used to provide a reasonable estimatefor the operating velocity of existing pipelines to ensure that the sandparticles are transported. Due to the wide range of possible operatingconditions that exist, and the different possible mechanisms for particletransport, many sand transport models were developed by different authorsthroughout the years. Fig. 1 shows the critical velocity predictions of 40 sand transport models fora field operating condition, which will be referred as the case study for theremainder of this manuscript. The case study corresponds to solid/liquid flowwith a particle concentration of 5 lbm/1000 bbl, a fluid density of 850 kg/m3,a fluid viscosity of 15 cp, a particle density of 2630 kg/m3, and a particlediameter of 60 µm, for flow in a horizontal pipe with a diameter of 8.25inches. As can be seen from Fig. 1, the values of the predicted sand transportvelocity vary over four orders of magniture. Therefore, out of these 40 models, it is necessary to identify the ones that will provide accurate and consistentvelocity predictions for the given operating condition. This manuscript presents a mechodology, which, on-the-fly, determines the sandtransport models that provide accurate and consistent critical velocitypredictions for an operating condition. In what follows, the details of themethodology are summarized. Then, the methodology is used to determine the sandtransport velocity for the case study, and the results are discussed. Finally, the last section provides concluding remarks and the future directions of thecurrent study. Methodology Our database contains 478 sand transport data for gas/solid flow and 161 sandtransport data for liquid/solid flow, for a total of 639 data points, all ofwhich were obtained from open literature [1, 2, 5-19], where the authors whoconducted the studies were interested in quantifying the sand transportvelocity for different sets of operating conditions. In addition, for thevelocity predictions, 40 sand transport models were considered, and similar tothe sand transport data, the models are also publicly available from theliterature [1-4, 7, 9-11, 18, 20-47], and the models were developed to predictthe velocity required for transporting solids given an operating condition.
- Research Report > New Finding (0.68)
- Research Report > Experimental Study (0.46)
- Reservoir Description and Dynamics (1.00)
- Data Science & Engineering Analytics > Information Management and Systems (1.00)
- Production and Well Operations > Well & Reservoir Surveillance and Monitoring > Production logging (0.66)
- Facilities Design, Construction and Operation > Flow Assurance > Solids (scale, sand, etc.) (0.66)
Abstract Crude oil, having a paraffin nature, has been studied extensively in thesmall-scale flow loop at Tulsa University Paraffin Deposition Projects (TUPDP). The effects of turbulence/shear and thermal driving force on wax depositioncharacteristics were experimentally studied using a waxy crude oil from theGulf of Mexico. The test matrix consisted of a total of 15 experiments whichinclude 12 short term tests and 3 long term tests. The tests were conductedunder different operating conditions with a wide range of Reynolds numbers from3,700 to 20,500. The shear stress ranged from 5.4 to 53.9 Pa. It was observed that paraffin deposition is highly dependent on the thermaleffective driving force which is the temperature difference between oil bulkand initial inner pipe wall and also on turbulence effects. The depositthickness obtained using both the pressure drop method and a direct measurementwas found to decrease with increasing shear stress and decreasing thermaldriving force. The wax content showed a gradual increase with an increase inflow rate. For the short term tests, the deposit mass with no entrained oilseemed to increase and then decrease with an increase in initial shear stressand decrease in effective thermal driving force whereas the total deposit masswas found to decrease with an increase in initial shear stress or decrease ineffective thermal driving force. Introduction When crude oil flows through the subsea and production pipelines, the oiltemperature drops due to the colder surroundings. It has been observed throughexperiments and postulated in literature that when the bulk temperature of thecrude oil in pipes is higher than the wall temperature, there exists adissolved wax concentration gradient between the bulk oil and the pipe wall. The n-paraffin components are considered to be mainly responsible for waxdeposition (Benallal et al. 2008). When the pipe wall temperature goes belowthe wax appearance temperature (WAT) of the oil, the liquid wax diffusestowards the wall. The liquid wax diffused towards the pipe wall crystallizes on the wall surface orat the interface between the bulk and deposit. The wax deposit may eventuallyblock the pipes. Hence, it is imperative to accurately predict wax depositionunder different operating conditions. The main problems associated with waxdeposition are the increased pressure drop in the pipeline, reducedproductivity and the risk of getting a pig stuck during regular maintenanceoperations. The current paraffin deposition models can predict wax depositioncharacteristics with high confidence under zero or low shear rate conditionswhile they can grossly over predict and under predict paraffin deposition underturbulent flow or high shear conditions. Understanding of the physics behindparaffin deposition in single phase can help accurately model the behavioraiding in the prediction of paraffin deposition and in deciding the piggingfrequency.
- North America > United States > Oklahoma (0.28)
- North America > United States > Texas (0.28)
- Research Report > New Finding (0.64)
- Research Report > Experimental Study (0.50)
- Production and Well Operations > Well & Reservoir Surveillance and Monitoring > Production logging (1.00)
- Production and Well Operations > Production Chemistry, Metallurgy and Biology > Inhibition and remediation of hydrates, scale, paraffin / wax and asphaltene (1.00)
- Facilities Design, Construction and Operation > Flow Assurance > Precipitates (paraffin, asphaltenes, etc.) (1.00)