Showing papers on "Steam injection published in 2002"

The effect of steam treating waste cooking oil on the yield of methyl ester

Abstract: The effect of steam injection and sedimentation treatment of waste cooking oil on the quality of TG, to be used as a raw material for the production of biodiesel, was investigated. The effect of steam treatment was evaluated in terms of a number of physical and chemical characteristics. Significant decreases in the moisture, FFA, and PV, as well as increased energy value, were observed. GC analysis of the treated materials demonstrated little change in either the overall composition of the oils or the iodine value. The decreases in moisture from 1.4 to 0.4% and in FFA from 6.27 to 4.28% were found to correlate strongly with an increase in yield of ester from 67.5 to 83.5%.

Liquid addition to steam for enhancing recovery of cyclic steam stimulation or laser-CSS

Abstract: LASER-CSS provides a method to improve cyclic steam-based thermal recovery methods for heavy oils and bitumen. A key improvement over prior art consists of mixing liquid hydrocarbons into the injected steam instead of injecting such hydrocarbon as a separate slug in front of a steam stimulation cycle. The objective of the invention is to enhance field applications of Cyclic Steam Stimulation (CSS) by contacting and mobilizing more of the bitumen with the same amount of steam. This is to help increase the recovery efficiency and ultimate recovery normally achieved with conventional CSS-type process operations. The proposed LASER-CSS method utilizes existing CSS wells at some intermediate stage of reservoir depletion. Liquid hydrocarbons are directly mixed and flashed into the injected steam lines, injected into the CSS wellbores and further transported as vapors to contact heavy oil or bitumen surrounding steamed areas between adjacent wells. For the most part injected hydrocarbons are reproduced dissolved within the produced bitumen phase. The optimum loading of hydrocarbons injected with steam will be chosen to maximize pressure drawdown and fluid removal of the reservoir using conventional CSS artificial lift equipment already in place.

The Effect of Hydrogen Donor Additive on the Viscosity of Heavy Oil during Steam Stimulation

Abstract: The effect of the hydrogen donor additive on the viscosity of the heavy oils in the process of steam stimulation was studied. The results indicate that the heavy oil obtained from the Liaohe oilfields in China can undergo aquathermolysis at 240 °C for 24 h. After aquathermolysis, the viscosity of the oil sample decreased by 80%, and the SARA compositions changed. However, when there is no hydrogen donor additive in the reaction system, the viscosity of the reacted oil measured at different times after reaction will regress rapidly. With 0.8% tetralin, one of the most popular hydrogen donor additives, the viscosity did not regress again. The results are very useful for the popularization and application of the new technology for the in situ upgrading of heavy oil by aquathermolysis.

Flue Gas Injection into a Mature SAGD Steam Chamber at the Dover Project (formerly UTF)

Abstract: The Dover Project (formerly the Underground Test Facility) is the world's first field pilot of the Steam Assisted Gravity Drainage (SAGD) process using dual horizontal well pairs to recover bitumen. There have been four phases of SAGD piloting at the Dover site thus far. The Phase B pilot, which consists of three 500 m long horizontal well pairs spaced 70 m laterally apart, has been in continuous operation since early 1993. Phase B reached the peak production rate of 300 m 3 /d or 100 m 3 /d per well pair on average in the middle of 1994. After sustaining the peak rate for about two years, the production has been in decline with a steady increase in steam-oil ratio. Research carried out in the past few years suggested that the addition of a suitable amount of non-condensable gases (NCG) would be an effective method to wind-down the steam chamber. It provides an economic means to continue bitumen production by utilizing the large amount of heat stored in the SAGD chamber. Beginning in April 1998, a small amount of natural gas was added continuously to the steam injection. The concentration of NCG has increased steadily in the past 3.5 years. The resulting performance has been better than initially expected. Based on the success of this NCG-steam wind-down strategy, a four-month flue gas injection test was conducted in 2001 to investigate the possibility of using the more cost-effective flue gas, rather than natural gas as an injectant. This paper summarizes the rationale for selecting the NCG-steam wind-down strategy, the field implementation of the flue gas injection test, and the resulting pilot performance. The successful implementation of this technology will have a profound impact on the overall process economics.

Field Foam Applications in Enhanced Oil Recovery Projects: Screening and Design Aspects

Abstract: An in-depth analysis was conducted for over forty foam applications in Enhanced Oil Recovery (EOR) projects, and numerous production well treatment operations involving the use of foam in cyclic steam operations and in gas miscible floods, to derive insights on screening and design aspects in such applications. Foam can be used to solve conformance problems caused by either a thief zone or gravity override; The proper identification of the cause, as well as of the production well(s) affected is basic to the definition of the problem. Either blocking/diverting foams or in-depth mobility control foams can be placed through the injection wells. On the other hand, foam treatment in production wells is done mainly to mitigate an override problem. The most important factors in foam assisted EOR projects were determined to be: (a) manner of foam placement in the reservoir (injection of pre-formed foam, co-injection foam and SAG or surfactant alternating gas foam), (b) reservoir pressure and c) permeability. While pre-formed foam are effective mainly in the treatment of the production wells, the co-injection foam and SAG can be employed for solving specific sweep efficiency problems in EOR projects. It is concluded that for designing a steam-foam project (which is essentially a low pressure foam application) a foam quality in the range 45% to 80% should be considered. In this kind of application, a co-injection foam is to be employed and the additives (surfactant and non-condensable gas) are to be injected intermittently (on and off), superimposed on a continuous steam injection. Injection cycles as short as 7 days (2 days-on and 5 days-off) should be considered. Under suitable conditions, an oil rate increase of 1.5 to 5 times, a decrease in water cut by 20 %, and an incremental oil recovery of 6%-12% OOIP can be achieved with such an implementation. At high pressure, such as in gas miscible flooding (CO 2 and hydrocarbon gas ), foam application can result in excessive mobility reduction factors, and injectivity reduction. Due to this reason, alternate injection of surfactant solution and gas (SAG foam) is favoured over a co-injection mode of placement. Recommendations for laboratory tests in support of a proper design of the field pilot are presented.

Microbial activity in soils following steam treatment.

Abstract: Steam enhanced extraction (SEE) is an aquifer remediation technique that can be effective at removing the bulk of non-aqueous phase liquid (NAPL) contamination from the subsurface, particularly highly volatile contaminants. However, low volatility compounds such as polynuclear aromatic hydrocarbons (PAHs) are less efficiently removed by this process. This research evaluated the effects of steam injection on soil microbial activity, community structure, and the potential for biodegradation of contaminants following steam treatment. Three different soils were evaluated: a laboratory-prepared microbially-enriched soil, soil from a creosote contaminated field site, and soil from a chlorinated solvent and waste oil contaminated field site. Results from field-scale steaming are also presented. Microbial activity before and after steam treatment was evaluated using direct epifluorescent microscopy (DEM) using the respiratory activity dye 5-cyano-2,3, ditolyl tetrazolium chloride (CTC) in conjunction with the fluorochrome 5-(4,6-dichlorotriazinyl) aminofluorescein (DTAF) to yield a quantitative assessment of active and total microbial numbers. DEM results indicate that steamed soils that were analyzed while still hot exhibited microbial activity levels that were below detection. However, soil samples that were slowly cooled, more closely reflecting the conditions of applied SEE, exhibited microbial activity levels that were comparable to presteamed soils. Samples from a field-site where steam was applied continuously for 6 weeks also showed high levels of microbial activity following cooling. The metabolic capabilities of the steamed communities were investigated by measuring cell growth in enrichment cultures on various substrates. These studies provided evidence that organisms capable of biodegradation were among the mesophilic populations that survived steam treatment. Fluorescent in situ hybridization (FISH) analysis of the soils with domain-level rRNA probes suggest that both Archaea and Bacteria survived steam exposure.

Geomechanical and Thermal Reservoir Simulation Demonstrates SAGD Enhancement Due to Shear Dilation

Abstract: A novel numerical analysis is described, in which the steamassisted gravity drainage (SAGD) recovery process in bituminous oil sand is studied. A geome chanical/reservoir simulator was modified to incorporate the absolute permeability increases resulting from the progressive shear dilation of oil sands. The objective was to obtain a realistic prediction of shear dilation, as the oil sands approached failure and beyond, and the concomitant increases in permeability. Changes in the in situ stresses that caused this dilation were due to the combined effects of reduced effective stress with high-pressure steam injection, and increased deviatoric stress with thermal expansion under lateral confinement. The resultant volumetric strains were used to modify the absolute permeability characteristics of the oil sands as the SAGD process progressed. The spatial and temporal growth of enhanced permeability zones resulted in an accelerated steam chamber growth. The relationship between volumetric strains and absolute permeability changes was obtained from existing laboratory data on quality specimens of non -bituminous Athabasca oil sands. The source sample was obtained from an outcropping of the McMurray Formation, thus avoiding most of the sample disturbance associated with unconsolidated core obtained conventionally. Under triaxial loading, the resultant volumetric strains increased absolute permeabilities by a factor of 4 to 6. The analysis is innovative in that the model used an effective stress approach, and used the volumetric strains to modify absolute permeabilities. Thus, the encroaching SAGD steam chamber was found to modify the stress regime, which in turn modified the permeabilities within the reservoir. Geomechanical enhancement of the SAGD process was found to be a significant beneficial effect, and would be increased by operating the SAGD process at higher injection pressures.

The Behaviour of Non-Condensible Gas in SAGD-A Rationalization

Abstract: The development of the SAGD process has been facilitated by the ability to predict performance from theory. Analytical and numerical methods have given results similar to those obtained in the field and in laboratory-scaled models. It was realized before any field projects were undertaken that horizontal wells would be required and that production rates of hundreds, or even a thousand or more, barrels per day of bitumen production were possible. There was also success in predicting the quantities of steam required. In early analyses, the permeability of the reservoir was assumed constant and non-condensible gas was ignored. The effect of reservoir layering are discussed and it is proposed that, in layered reservoirs, with permeability ratios less than about 2, the height average permeability should be used in the Lindrain equation. Several authors have pointed out that when dissolved gas is included in their numerical simulation models, it tends to accumulate in the steam chamber, particularly towards the top, and inhibit the process by lowering the clew point of the steam. In some cases, this appears to choke the process and severely limit production and recovery. On the other hand, it has been appreciated that the accumulation of gas, and even its intentional addition to the steam, can be desirable because the lowering of the temperature of the steam chamber at the top reduces the heat, and hence the steam, requirement. The SOR is improved. The role of gas is discussed and it is shown that gas can move relatively easily, in small fingers, through the reservoir beyond the steam chamber. This allows the purging of gas from the chamber and also the pressure support of the chamber by gas flowing from the exterior. The intrusion of gas into the region above a rising chamber raises the pressure and tends to push oil downwards-the Steam and Gas Push. Varying the steam injection rate can control pressure and allow the optimization of the gas content of the chamber, Results from a new computer program, HOTSTEAM, are discussed. Unlike its predecessor, HOTWELL, the new program allows the injection rate of the steam to be scheduled and it also provides for the support of the chamber pressure by gas-either from the reservoir or from injection. The program includes a continuing analysis of the production well hydraulics and predicts the WHP as a function of time for natural lift. The development of the SAGD process has been facilitated by the ability to predict performance from theory. Analytical and numerical methods have given results similar to those obtained in the field and in laboratory-scaled models. It was realized before any field projects were undertaken that horizontal wells would be required and that production rates of hundreds, or even a thousand or more, barrels per day of bitumen production were possible. There was also success in predicting the quantities of steam required. In early analyses, the permeability of the reservoir was assumed constant and non-condensible gas was ignored. The effects of reservoir layering are discussed and it is proposed that, in layered reservoirs, with permeability ratios less than about 2, the height average permeability should be used in the Lindrain equation.

Multiphase flow in homogeneous porous media with phase change. Part I: Numerical modeling

Abstract: A model for the description of multicomponent and multiphase flows with phase change in porous media is presented. This type of flow occurs in steam injection operations for an effective heating of porous media or the extraction of fluid phases from porous structures. These processes are common applications in the field of chemical engineering. The heat exchange between solid and fluid phases is, in contrast to traditional steam injection processes as the tertiary oil recovery or the remediation of soils, the dominant mechanism for these technical applications. Furthermore, high spatial and transient temperature gradients appear and complicate the modeling of the heat transfer. This results in special requirements for the generalized modeling of these processes and is analyzed at first. Then a thorough presentation of the modeling and the numerical implementation is given. Finally, numerical results are presented and a short validation with own experimental data is done.

The Effect of Operating Pressure on the Growth of the Steam Chamber Detected at the Hangingstone SAGD Project

Abstract: At the Hangingstone reservoir of the Athabasca oil sands, Japan Canada Oil Sands (JACOS) started initial steam circulation of the SAGD Phase I project in April 1999, and the regular operation in July. The expected performance was achieved in the early period. The operation pressures were gradually raised from 4,800 kPa in mid-November 1999 to 5,300 kPa in mid-December. In early 2000, initial circulation of the Phase II wells, which consist of three SAGD pairs of 750 m wells, were started. Steam produced at the Phase I steam generator was supplied to warm up these wells. Because of this dual use of steam, the injection pressure of the Phase I wells had to be reduced to 4,600 kPa. A significant change in the growth rate of the steam chamber was detected at some of the observation wells. This was reflected as a suspension of vertical growth of the steam chamber. A new generator to supply steam for Phase II wells was completed in July 2000. Accordingly, the steam injection pressures for Phase I wells were increased in August and the vertical growth of the steam chamber was resumed. The measured temperature changes in the observation wells, the results of numerical simulation study, and conceivable mechanism of the growth of steam chamber are presented in the paper.

Evaluation of steam and water injection effects on gas turbine operation using explicit analytical relations

Abstract: The changes in performance of a gas turbine resulting from the injection of steam or water into the combustion chamber are evaluated using explicit analytic relations. From the values of pe...

Bulk decontamination and degermination of materials in a sub-atmospheric saturated steam environment

Abstract: A method and apparatus for significantly reducing the biological load on consumer products such as food products, spices, produce, botanicals, cosmetic ingredients, barrels, pallets, crates, birdseed and medical products. The method involves applying a continuous stream of saturated steam to a material in a sealed biological burden reduction chamber (2). The continuous stream of saturated steam is created in the chamber (2) by correlating a desired temperature to pressure based on the use of Saturated Steam Tables. The apparatus includes a bioburden reduction chamber (2), a temperature controller (10), an air injection system (5), a steam injection system (6), and an evacuation system (7).

Production Acceleration and Injectivity Enhancement Using Steam-Propane Injection for Hamaca Extra-Heavy Oil

Abstract: The largest known hydrocarbon deposit in the world, the Orinoco Belt in Venezuela, contains oil with a gravity ranging from 9 to 14° API. The Hamaca project encompasses more than 400 square miles of the Orinoco Belt and is believed to contain more than 30 billion barrels of extra-heavy oil (9° API). Production of the project started in November 2001 and the target is to produce some 30,000 m 3 (190,000 barrels) a day over a life span of more than 35 years. This study found that using propane as a steam additive can accelerate oil production and improve the effect of steam injectivity in the Hamaca field. In our laboratory study, steam-propane injection accelerated the start of oil production by 21% compared to that with pure steam injection. In the field, this could translate into significant gains in discounted revenues and a reduction in steam injection costs. Second, steam injectivity with propane as an additive was up to three times higher than that for pure steam injection. Third, accelerated oil production and increased injectivity were practically the same for all of the runs using propane as a steam additive (irrespective of the propane-steam mass ratios). Propane appears to be a viable steam additive at propane-steam mass ratios as low as 2.5:100.

The Effect of Heat Transfer Between Nearby Layers on the Volume of the Steam Zones

Abstract: The work of Mandl and Volek is extended analytically to include the effect on the volume of the steam zone in one layer owing to heat transfer from a second layer undergoing steam injection. The contribution of the heat transfer delays the onset of heat convection across the advancing condensation front (the critical time) and significantly increases the volume of the steam zone even where 30 or more feet separate the layers. The increase in the heat content of the steam zone (or volume) increases with increasing ratio of the sensible to latent heat of the injected steam, and is larger than the increase in the total heat content. The interpretation for this behavior is that heat transfer delays the rate of condensation of the steam vapor, this being more important at poor steam qualities. Results of the simple approach presented here have been confirmed qualitatively through numerical simulation.

Commercial kitchen steam cooker has a sensing system to monitor the build-up of scale on the steam injection nozzle

Abstract: The cooking chamber (2) has a fan (5) and heater (7) blowing steam from a nozzle (8), a pump (9) and steamer (10). The reduction in input of steam is monitored by temperature (14) and humidity (15) sensors, electronic control unit (16) and indicator unit (17).

Washing device for indoor machine of air-conditioner for home use

Abstract: PROBLEM TO BE SOLVED: To save a curing work before a washing work, to form a washing device is a compact manner, to suppress consumption of washing liquid, to enable the execution of delicate washing, and to eliminate a need for a particular drying work. SOLUTION: A washing device comprises a washing device body provided with a steam injection device and a vacuum suction device; a steam injection nozzle to inject steam fed from the steam injection device; a cleaning head having a polluted water suction nozzle to suck polluted water, generated through injection of steam, to a vacuum suction device; and a hose to couple the washing device body to the cleaning head. The washing device body integrally juxtaposes the steam injection device and the vacuum suction device. The steam injection nozzle and the polluted water suction nozzle are vertically disposed at the tip part of the cleaning head. A grasping part and a control part to control steam injection and vacuum suction are disposed. Steam injection and vacuum suction are executed simultaneously and in parallel with each other.

Piston engine with sequential steam injection has thermal insulation lining on combustion chamber wall, piston base, and cylinder wall, and regulated steam injection volume and injection timing

Abstract: Combustion chamber wall, piston base, and cylinder wall of the engine are coated with a thermally insulating material. A steam injection nozzle in the cylinder head is arranged, so that injected steam volume and injection timing can be regulated. The thermal insulation coating heats up after a few engine cycles, and this is followed by several cycles with steam injection, so that the insulation cools down again. The injected steam takes-up heat from the hot combustion chamber wall, to increase working pressure and efficiency of the steam power process.

Water Recovery Systems for Steam-Injected Gas Turbines: Size Optimization and Life Cycle Savings

Abstract: Steam injection in gas turbines has been used for many years to increase the power output as well as the efficiency of the system and, more recently, to reduce the formation of NOx during the combustion. The major drawback in steam-injection technology is the need of large amounts of fresh water that is eventually lost into the atmosphere along with the exhaust gas. This loss not only increases the operating costs of the system, but also creates other “external” costs in terms of environmental impacts. In order to take advantage of the steam-injection technology and reduce both operating costs and potential environmental impacts, water recovery systems to recuperate the injected steam from the exhaust gas can be implemented. This paper briefly describes the computer models developed at the University of Massachusetts Amherst to optimize water recovery systems. As an example, the optimum size, power requirement and capital cost for two different systems applied to the GE LM2500 gas turbine are shown. Finally, a comparative economic analysis between the costs of installing and operating a water recovery system and the costs of buying and treating water on a regular basis during the lifetime of the project is presented. The results support the economic feasibility of water recovery for mid-size steam-injected gas turbines before having introduced the external costs associated with the use of water resources.Copyright © 2002 by ASME

Steam Conformance Along Horizontal Wells at Cold Lake

Abstract: This paper describes Imperial Oil's success in identifying and remediating poor steam conformance in a horizontal well used in Cyclic stearn Stirmutation operations. Imperial Oil si conducting Horizontal Wel Cyclic Stean Stimulation (HWCSS) at nine horizontal wells located at two pads in Cold Lake. Steam conformance along horizontal wells is a significant. issue in these types of thermal aplications. The horizontal wellls are completed with Limited Entry Perforations (LEP) to improve distribution of steam along the liner. One of the HWCSS pads, D36, has been the subject of both 4D seismic and injectivity analyses to chaaracterize stem conformance along the horizontal section over the first three cycles. These analysis techniques showed that four out of the five wells on the pad had excellent steam distribution along the horizontal liners. However. one of the wells, D36-H1, showed little or no steam conformance along the last half of the liner. This lock of horizontal steam conformance put the recovery expectations of this well at risk. A workover conducted on D36-H1 successfully removed sand that had been obstructing the liner Steam injection subsequent to the clean-out showed steam distributed across the majority of the liner (most of the LEPs accepting steam).

Heavy and thermal oil recovery production mechanisms

Abstract: The Stanford University Petroleum Research Institute (SUPRI-A) studies oil recovery mechanisms relevant to thermal and heavy-oil production. The scope of work is relevant across near-, mid-, and long-term time frames. In August of 2000 we received funding from the U. S. DOE under Award No. DE-FC26-00BC15311 that completed December 1, 2003. The project was cost shared with industry. Heavy oil (10 to 20{sup o} API) is an underutilized energy resource of tremendous potential. Heavy oils are much more viscous than conventional oils. As a result, they are difficult to produce with conventional recovery methods. Heating reduces oil viscosity dramatically. Hence, thermal recovery is especially important because adding heat, usually via steam injection generally improves displacement efficiency. The objectives of this work were to improve our understanding of the production mechanisms of heavy oil under both primary and enhanced modes of operation. The research described spanned a spectrum of topics related to heavy and thermal oil recovery and is categorized into: (1) multiphase flow and rock properties, (2) hot fluid injection, (3) improved primary heavy-oil recovery, (4) in-situ combustion, and (5) reservoir definition. Technology transfer efforts and industrial outreach were also important to project effort. The research tools and techniques used were quite varied. In the area of experiments, we developed a novel apparatus that improved imaging with X-ray computed tomography (CT) and high-pressure micromodels etched with realistic sandstone roughness and pore networks that improved visualization of oil-recovery mechanisms. The CT-compatible apparatus was invaluable for investigating primary heavy-oil production, multiphase flow in fractured and unfractured media, as well as imbibition. Imbibition and the flow of condensed steam are important parts of the thermal recovery process. The high-pressure micromodels were used to develop a conceptual and mechanistic picture of primary heavy-oil production by solution gas drive. They allowed for direct visualization of gas bubble formation, bubble growth, and oil displacement. Companion experiments in representative sands and sandstones were also conducted to understand the mechanisms of cold production. The evolution of in-situ gas and oil saturation was monitored with CT scanning and pressure drop data. These experiments highlighted the importance of depletion rate, overburden pressure, and oil-phase chemistry on the cold production process. From the information provided by the experiments, a conceptual and numerical model was formulated and validated for the heavy-oil solution gas drive recovery process. Also in the area of mechanisms, steamdrive for fractured, low permeability porous media was studied. Field tests have shown that heat injected in the form of steam is effective at unlocking oil from such reservoir media. The research reported here elucidated how the basic mechanisms differ from conventional steamdrive and how these differences are used to an advantage. Using simulations of single and multiple matrix blocks that account for details of heat transfer, capillarity, and fluid exchange between matrix and fracture, the importance of factors such as permeability contrast between matrix and fracture and oil composition were quantified. Experimentally, we examined the speed and extent to which steam injection alters the permeability and wettability of low permeability, siliceous rocks during thermal recovery. Rock dissolution tends to increase permeability moderately aiding in heat delivery, whereas downstream the cooled fluid deposits silica reducing permeability. Permeability reduction is not catastrophic. With respect to wettability, heat shifts rock wettability toward more water wet conditions. This effect is beneficial for the production of heavy and medium gravity oils as it improves displacement efficiency. A combination of analytical and numerical studies was used to examine the efficiency of reservoir heating using nonconventional wells such as horizontal and multilateral wells. These types of wells contact much more reservoir volume than conventional vertical wells and provide great opportunity for improved distribution of heat. Through simulation and analytical modeling of the early-time response of a reservoir to heating with a horizontal well showed that cyclic steam injection is an effective technique to heat a reservoir prior to continuous injection during a gravity drainage process.