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Abstract This paper presents an experimental study on pipelining of Shanjiasi heavy crude oil as oil-in-water emulsions. Viscosity reductions of more than three orders of magnitude were achieved in laboratory by emulsification. Field trials were then made in three 4-in. gathering lines 101, 160 and 241 meters long respectively. A chemical solution was injected into the gathering line at the wellhead. Drag reductions of 40-80% were achieved provided that the formed emulsions had an injected water fraction of 0.2-0.4 and the chemical concentration was at 0.35-0.5% (based on injected water). It was also found that drag reduction was more significant at a low temperature and for a highly viscous heavy oil. A big difference existed between rheological data obtained from the field trials and those from laboratory experiments, and possible reasons were discussed. Introduction Shanjiasi Oilfield of Shengli Petroleum Administration is one of the major heavy oilfields in China. Since the oilfield was put into production by steam soak, a number of difficulties have arisen in production and pipelining of the 13.5 API heavy oil for its high viscosity, 10,000 mPa.s at 50C. A waxy crude from a nearby oilfield is injected down the well annulus to reduce viscosity of the produced fluid for the time being. produced fluid for the time being. Shanjiasi heavy oil is planned specially for producing highway grade bitumen. Investigation showed that the addition of waxy crude might deteriorate Ditumen quality. As an alternative, the light and of the heavy crude itself from refinery will be added in place of the currently used waxy crude. However, this will result in additional cost and increased light hydrocarbon loss. Traditionally, heating has been used for reducing the viscosity of the pumped fluid, but it has the disadvantage of significant equipment cost and fuel consumption as well as difficulty in restarting after shutdown. The oil-in-water emulsion technology seems more attractive. It shows many advantages over beating and dilution, and has been proved effective elsewhere for the production and pipelining of heavy oils and bitumens Since 1985, we have undertaken a research project on pipelining heavy oils as project on pipelining heavy oils as oil-in-water emulsions at the university of Petroleum, China. Laboratory results were quite encouraging, with a substantial reduction of heavy oil viscosity at 30C from 115,000 mPa.s to 100 mPa.s for an emulsion of 70:30 oil to water ratio. A joint study group between the University of Petroleum and the 3rd Division of Binnan Oil Production Department, Shengli Petroleum Administration was then established to evaluate the feasibility of the technology in heavy oil production. P. 911
- North America > United States (0.47)
- Asia > China > Shandong Province (0.25)
- Water & Waste Management > Water Management > Constituents > Oil/Grease/Xylene/Methanol (1.00)
- Energy > Oil & Gas > Upstream (1.00)
- Asia > China > Shandong > Shanjiasi Field (0.99)
- North America > United States > Louisiana > China Field (0.97)
Publication Rights Reserved This paper to be presented at the 36th Annual California Regional Fall Meeting of the Society of Petroleum Engineers of the AIME in Bakersfield, California on November 4–5, 1965 and is considered the property of the Society of Petroleum Engineers. Permission to publish is hereby restricted to an abstract of not more than three hundred words with no illustrations unless the paper is specifically released to the press by the editors of the Journal of Petroleum Technology for the Executive Secretary. Such abstract shall contain conspicuous acknowledgment of where and by whom the paper is presented. Publication elsewhere after publication in the Journal of Petroleum Technology or the Society of Petroleum Engineers Journal is granted on request providing proper credit is given that publication and the original presentation of the paper. Discussion of this paper is invited. Three copies of any discussion should be sent to the Society of Petroleum Engineers Office. Such discussion may be presented at the above meeting and with the paper may be considered for publication in one of the two Society of Petroleum Engineers magazines. Abstract Knowledge of the nature of emulsions and demulsification is important in resolving any emulsion. The theory of emulsions and demulsification is reviewed. The method of treating emulsions, chemicals, heat, electricity and time are discussed; how they influence the emulsion and how they are applied in actual operation. The treating of emulsions produced by thermal recovery operations follows the same pattern as used for other emulsions. However, it is necessary to increase the magnitude of some or all of the applied factors. Introduction The expansion of the use of thermal stimulation methods has brought with it an increase in the severity of produced emulsions. In-situ combustion produces unusually large quantities of emulsion stabilizing elements. Materials removed from the formation by steam tend to stabilize emulsions. Difficulty is encountered in removing steam condensate from crude. These and other factors contribute to the difficulty encountered in treating thermally stimulated production. These emulsions are not different in character from others but they are different in degree. Therefore, a better understanding of emulsification and demulsification will provide a basis for establishing a treating program to handle such emulsions. All crude oils, regardless of their origin, contain certain characteristics which tend to make them emulsifiable. Therefore certain principles must be adhered to when treating any emulsion. Our first step then will be a review and discussion of the theory of emulsification and demulsification. An emulsion by definition is a stable dispersion of one liquid in another. Not every mixture or dispersion of water in oil is an emulsion. The dispersion must be a stable one. A dispersion characterized by very small water drops is said to be a tight emulsion (Figure 1); one characterized by large water drops is a loose emulsion (Figure 2). In the oil field, where water and oil are the two liquids, two types of emulsions are formed. They are the oil-in-water and water-in-oil emulsions. Since the water-in-oil type is more common, this discussion will center around it with a brief review of the oil-in-water emulsion later.
Abstract Heavy (viscous) crude oils have become an increasingly important source of hydrocarbons in many parts of the world. Transport of these viscous crudes from the source to the refinery can be a problem. In a number of producing areas, a pipeline is problem. In a number of producing areas, a pipeline is in place, but the line was designed for lighter (less viscous) crudes. Pipeline transport can be effected by heating, dilution with lighter fractions, or thermal viscosity breaking. All of these techniques are expensive and are not practical in many situations. Techniques are needed to reduce the pumping costs without significantly increasing the handling costs at either end of the pipeline. High oil content oil-in-water emulsions have been shown to be a viable alternative to the techniques mentioned above. Dramatic decreases in viscosity can be achieved while transporting a fluid which has an oil content of 70% or greater. A knowledge of the rheological behavior of these emulsions, under both laboratory and field conditions, is important. In this study, four different viscous crude oils were used. The viscosities ranged between 2000 and 500,000 (estimated) centipoise (2.0 to 500 Pa s). The emulsions ranged from 60 to 72.5% oil in tap water stabilized with an emulsion stabilizer. Rheological measurements were carried out with a tube flow viscometer equipped with three tube sizes and a concentric cylinder viscometer (Rheometrics Pressure Rheometer). The data obtained showed that Pressure Rheometer). The data obtained showed that the shear stress-shear rate behavior of the emulsions are highly dependent on oil droplet size. For a given oil concentration, the non-Newtonian character and the apparent viscosity increased with decreasing droplet size. The majority of the emulsions showed shear thinning behavior at low shear rates (below 50 s to the -1) and Newtonian behavior at shear rates above 1000 s to the -1. These data show that the power law model is insufficient for the whole range of shear rates. A three parameter model needs to be considered. Results show parameter model needs to be considered. Results show that oil droplet size is the dominant factor in the behavior of emulsions. The influence of mixing intensity and duration while preparing the emulsion and emulsifier concentration on the resulting droplet size were investigated. Pipe flow data were collected for scale-up studies. Data were collected in both the laminar and turbulent flow regimes. This study reveals that careful laboratory testing and scale-up is needed prior to the designing of pipeline systems for the transport of heavy crude oils as emulsions. Introduction There are vast reserves of heavy crude to be produced around the world. For instance, the produced around the world. For instance, the Venezuelan Orinoco Oil Belt is estimated to have 2 × 10 to the 12 barrels of heavy crude oil in place. Emulsions are of utmost importance in production and transport of heavy crudes. Many researchers are now seeking ways to apply emulsions to improve both the recovery and transport of crude oil. Unless methods of producing and transporting these crudes can be found, producing and transporting these crudes can be found, a significant source of hydrocarbons will remain inaccessible to the world. The pipeline transport of heavy crudes is difficult because of their low mobility and high viscosity. Several methods to facilitate the flow of heavy crudes have been used. Cutting the viscous oils with lighter fractions of hydrocarbons is one common technique. However, this procedure involves the use of relatively large amounts of expensive hydrocarbon solvents to transport a relatively cheap material. The practice also requires that a source of the light hydrocarbon solvents be available, which, in many instances, is inconvenient. P. 393
- Research Report > New Finding (1.00)
- Research Report > Experimental Study (1.00)
- Well Drilling > Drilling Fluids and Materials > Drilling fluid selection and formulation (chemistry, properties) (1.00)
- Reservoir Description and Dynamics > Improved and Enhanced Recovery (1.00)
- Production and Well Operations > Well & Reservoir Surveillance and Monitoring > Production logging (1.00)
- Production and Well Operations > Production Chemistry, Metallurgy and Biology > Downhole chemical treatments and fluid compatibility (1.00)
Summary Viscous crudes often are produced by means of a low-viscosity hydrocarbon diluent to decrease viscosity of the produced fluid in the tubing and the flowlines. Rod-pump difficulties may result from the slow fall of the rod string caused by high fluid viscosity. The use of a diluent reduces these rod-fall and associated flow problems. Our goal was to replace the diluent completely with a water/surfactant system without increasing the flowline pressures. This was accomplished with a produced water/surfactant mixture, However, in one field we found that using a combination of diluent, surfactant, and water was the most economical way to produce the crude. The crude is dispersed in a water-external system so that the viscosity is decreased appreciably. We initially evaluated different chemicals in the laboratory. Later tests were on individual wells, a 6-well pilot, and finally a I5-well pilot. Economics of the new system are projected to be more favorable than those of using diluent alone. This system can be used not only for heavy crudes but also for waxy crudes that have high pour points and are thus difficult to produce. It allows a lower pumping cost because of reduced viscous drag and can be more economical than some diluent systems. Introduction Our previous work described various techniques for reducing the viscosity of waxy crudes that are also applicable to heavy crudes. In addition to the preparation of oil and water emulsions, these techniques included:dilution with lighter oil, preheating with subsequent heating in the line, preheating and insulating, and injection of water to form a water ring. McAuliffe describes oil-in-water emulsions. We also have received patents in this area. The production of heavy, viscous crude at Cat Canyon field near Santa Maria, CA, requires the use of a viscosity reducer that allows the crude to be pumped from the wellbore to storage. Kerosene distillate (KD) has been used for this purpose at Cat Canyon for some time. However, cost and availability of KD at Cat Canyon caused some concern, so we began a research program to find an alternate to the KD mode of production. Our goal was to reduce viscosity of the heavy crude by some way other than dilution with a hydrocarbon solvent. By producing an oil-in-water emulsion, we succeeded in reducing the viscosity of the heavy crude oil from ~3,000 cp at 170 to 200°F to only 50 to 100 cp at these temperatures. We produced the oil-in-water emulsions by mixing the oil with water that contained an emulsifier. Another part of our objective was to produce a reversible oil-in-water emulsion that, after being prepared at the well, would have just enough stability to reach the heater-treater before separating into an oil layer and a water layer. In other words, we wanted to produce an emulsion that was not too stable; otherwise, it could cause problems at the heater-treater. The initial laboratory phase consisted of screening 44 commercial oilfield emulsifier-type chemicals to find a product that would form a low-viscosity. oil-in-water emulsion when used with the viscous Cat Canyon crude. Commercial Surfactant A. which gave the best results in the laboratory, also gave the best results in field tests conducted at Cat Canyon. The commercial product was more economical than KD alone, but we wanted the least expensive product. Therefore, it appeared more economically attractive for us to develop our own emulsifier packages. The work covered in the first part of this paper was conducted in wells at Cat Canyon field, first with commercial oilfield emulsifying-type chemicals and second with emulsifier packages developed in our laboratory.
- Energy > Oil & Gas > Upstream (1.00)
- Water & Waste Management > Water Management > Lifecycle > Treatment (0.34)
- Well Drilling > Drilling Fluids and Materials > Drilling fluid selection and formulation (chemistry, properties) (1.00)
- Production and Well Operations > Production Chemistry, Metallurgy and Biology > Downhole chemical treatments and fluid compatibility (1.00)
- Facilities Design, Construction and Operation > Processing Systems and Design > Separation and treating (1.00)
- Facilities Design, Construction and Operation > Processing Systems and Design > Heavy oil upgrading (1.00)
The common features In the process of oil recovery by steam injection in Shanjiasi of heavy oil reservoir are such as bed and inter-bed Oilfield, main problems are as following: (1) steam override or heterogeneity or vertical variation and the existence of steam break due to gravity segregation and heterogeneity; (2) intercalation with poor physical properties have restricted the low recovery percent of reserves after several cycles and large developing effect of thermal oil recovery and exacerbate the recovering discrepancy in vertical; (3) active edge and bottom developing difficulty. Especially due to the limitation of water as well as serious water invasion in producing wells; (4) perforation position, reservoirs have not been produced uneven steam injection profile and low steam sweep efficiency.
- Asia > China > Shandong > Shanjiasi Field (0.99)
- Asia > China > Shandong > North China Basin > Shengli Field (0.99)