Showing papers on "Steam injection published in 2009"

The effect of air preheating in a biomass CFB gasifier using ASPEN Plus simulation

Abstract: In the context of climate change, efficiency and energy security, biomass gasification is likely to play an important role. Circulating fluidised bed (CFB) technology was selected for the current study. The objective of this research is to develop a computer model of a CFB biomass gasifier that can predict gasifier performance under various operating conditions. An original model was developed using ASPEN Plus. The model is based on Gibbs free energy minimisation. The restricted equilibrium method was used to calibrate it against experimental data. This was achieved by specifying the temperature approach for the gasification reactions. The model predicts syn-gas composition, conversion efficiency and heating values in good agreement with experimental data. Operating parameters were varied over a wide range. Parameters such as equivalence ratio (ER), temperature, air preheating, biomass moisture and steam injection were found to influence syn-gas composition, heating value, and conversion efficiency. The results indicate an ER and temperature range over which hydrogen (H 2 ) and carbon monoxide (CO) are maximised, which in turn ensures a high heating value and cold gas efficiency (CGE). Gas heating value was found to decrease with ER. Air preheating increases H 2 and CO production, which increases gas heating value and CGE. Air preheating is more effective at low ERs. A critical air temperature exists after which additional preheating has little influence. Steam has better reactivity than fuel bound moisture. Increasing moisture degrades performance therefore the input fuel should be pre-dried. Steam injection should be employed if a H 2 rich syn-gas is desired.

Heterogeneity Impact on SAGD Process Performance in Mobile Heavy Oil Reservoirs

Abstract: The increasing oil demand and the significant amount of heavy oil/bitumen reserves will motivate a huge effort on the development of heavy oil reservoirs in the next decades. Within this framework, Steam Assisted Gravity Drainage (SAGD) is a very promising technique to produce heavy oil from thick and high permeability reservoirs. The small scale field tests conducted up to now highlighted the influence of heterogeneities on the development of the steam chamber involved in SAGD. This work presents a numerical investigation of the effects of heterogeneity on SAGD performance when applied to produce mobile heavy oil. A set of reservoir models is randomly generated with 0, 10, 15 and 20% of shale and a statistical analysis is performed to quantify the impact of shale distribution on oil production and SAGD efficiency. It is shown that the influence of shale baffles depends on their locations relatively to well pairs, the most detrimental ones being located between the injector and producer. In addition, we observe that 1/2, 1/3 and 1/4 only of the cumulative oil volume produced for the homogeneous model after 3 years of SAGD process are recovered when shale proportions are 10, 15 and 20% and that CSOR evolves from 2 for the homogeneous model to 3 for the models with 20% of shale.

Well blowout rates and consequences in California Oil and Gas District 4 from 1991 to 2005: implications for geological storage of carbon dioxide

Abstract: Well blowout rates in oil fields undergoing thermally enhanced recovery (via steam injection) in California Oil and Gas District 4 from 1991 to 2005 were on the order of 1 per 1,000 well construction operations, 1 per 10,000 active wells per year, and 1 per 100,000 shut-in/idle and plugged/abandoned wells per year. This allows some initial inferences about leakage of CO2 via wells, which is considered perhaps the greatest leakage risk for geological storage of CO2. During the study period, 9% of the oil produced in the United States was from District 4, and 59% of this production was via thermally enhanced recovery. There was only one possible blowout from an unknown or poorly located well, despite over a century of well drilling and production activities in the district. The blowout rate declined dramatically during the study period, most likely as a result of increasing experience, improved technology, and/or changes in safety culture. If so, this decline indicates the blowout rate in CO2-storage fields can be significantly minimized both initially and with increasing experience over time. Comparable studies should be conducted in other areas. These studies would be particularly valuable in regions with CO2-enhanced oil recovery (EOR) and natural gas storage.

Microwave-Assisted Heavy Oil Production: An Experimental Approach

Abstract: Conventional enhanced oil recovery (EOR) methods, such as steam injection, are usually not cost-effective for deep wells and wells produced from thin pay zones, because of excessive heat loss to the overburden. For such wells, minimizing heat losses can be achieved using microwave heating. In this study, the feasibility of this method was investigated. Heavy oil samples from conceptual reservoirs (Bati Raman, 9.5° API; Garzan, 12° API; and Camurlu, 18° API) in southeast Turkey were used. Using a novel graphite core holder packed with crushed limestone premixed with crude oil and water, effects of operational parameters, such as heating time and waiting period, as well as rock and fluid properties, such as porosity, permeability, wettability, salinity, and initial water saturation, were studied. It was found that high-salinity water promotes oil production during microwave-assisted production. High water saturations lead to higher oil productions regardless of the viscosity of the oil. It was finally concl...

Oil pool development simulation system, oil pool model body and its data processing method

Abstract: The invention relates to an oil deposition steam injection thermal recover multi-mode linkage three-dimensional simulation system. The system comprises a steam injecting system, an oil deposit model body, a burden pressure system, and a data acquiring and graph processing system, wherein the oil deposit model body is used for simulating an actual oil deposit; and the oil deposit model body comprises a shell of an oil deposit model, a heat insulating layer, a simulative oil deposit, a simulative straight well, a simulative horizontal well, a pressure guiding pipe, and a thermocouple and an interface of the thermocouple. The technical proposal realizes the simulation of steam thruput elastic energy, and the design of high-temperature and high-pressure oil deposit model body meets the requirements of well networks and well types for various assemblies.

Pore-level Investigation of Heavy Oil Recovery using Steam Assisted Gravity Drainage (SAGD)

Abstract: Successful application of gravity drainage process, facilitated with steam injection, using horizontal wells in various field tests, especially within Canada, indicates that high recovery factor and also economical steam to oil ratios are achievable. Steam Assisted Gravity Drainage recovery scheme was theoretically developed, pilot tested, and commercialized in Canada; however, there are still several technical challenges to be solved in this process. The pore-scale events of heavy oil recovery in SAGD process are not yet well understood to the extent of incorporating pore-level physics of the process into mathematical models. Investigation of the physics of fluid distribution and flow behavior in porous media for SAGD process at the pore-scale is expected to result in significant improvement in understanding the macroscopic phenomena observed in either laboratory or field scale. The main objective of this paper is to visually investigate and to document the pore-scale events of the SAGD process using glass micromodel type of porous media. SAGD experiments were carried out in micromodels of capillary networks etched on glass plates which were initially saturated with heavy oil. Experiments were conducted in a vacuum chamber in order to reduce the excessive heat loss to the surrounding environment. Initial results indicate that when the heavy oil-steam interface is established, gravity drainage process takes place through a layer of pores, with a thickness of 1-6 pores, in the direction perpendicular to the interface. The interplay between gravity and capillarity forces results in the drainage of mobilized oil. The visualization results demonstrate the phenomenon of water in oil emulsification at the interface due to the local steam condensation. The extent of emulsification depends directly to the temperature gradient between the steam phase and cold bitumen. Other pore-scale phenomena such as film-flow drainage type of mobilized oil, localized entrapment of steam due to the capillarity followed by condensation, steam condensation at the interface due to temperature gradient, and snap-off of liquid films are also illustrated using glass micromodels in pore-level visualization experiments.

Steam Injection Pressure and the SAGD Ramp-Up Process

Abstract: Most SAGD projects require about one to two years for ramp-up. Over this period of time, oil rate will be below peak oil rate and SOR will be higher than long-term steady-state SOR. This paper discusses the effect of steam injection pressure on SAGD ramp-up time, the associated geomechanical effects and optimization of the ramp-up phase of SAGD. Different steam injection pressures induce different reservoir geomechanical behaviour in oil sands. Higher steam injection pressure is capable of inducing more favourable reservoir geomechanical effects (such as shear dilation and isotropic unloading), improving the reservoir permeability, and subsequently, benefiting the long-term SAGD operation. This paper indicates that the ramp-up time can be reduced due to the favourable geomechanical effects. A coupled reservoir geomechanical simulation technique was applied for this investigation. In addition, cap rock integrity concerns when applying high injection pressure are also addressed. It is recommended that during or following the ramp-up phase, the injection pressure be lowered to a safe operating pressure to ensure cap rock integrity. The effects of low and high steam chamber pressures on SAGD oil rate are also discussed.

Subsurface nuclear measurement systems, methods and apparatus

Abstract: Methods and related systems are described for use for making subterranean nuclear measurements. The system can include a plurality of elongated scintillator members each generating optical signals in response to ionizing radiation. Optical detector units can be optically coupled to at least one end of each elongated scintillator member so as to detect optical signals from each elongated scintillator member. The system can be suitable for permanent or semi-permanent deployment downhole. For example, the system can operate for more than six months in a subterranean deployment measuring cosmic radiation. The system can be suited to monitor density changes in subterranean regions of interest, for example, density changes brought about by steam injection as part of a steam assisted gravity drainage operation.

A New Process Combining Cyclic Steam Stimulation and Steam-Assisted Gravity Drainage: Hybrid SAGD

Abstract: A new thermal recovery scheme is proposed that utilizes Steam-Assisted Gravity Drainage (SAGD) well pairs as well as Cyclic Steam Stimulation (CSS) wells placed in between the SAGD well pairs. The wells are operated in CSS mode until the steam chambers are in contact with each other and then switched to SAGD operation. It is shown that the new process recovers greater amounts of bitumen with lower injected steam in shorter operation time than is achieved with SAGD, Fast-SAGD and CSS.

Simulation of steam distillation process using neural networks

Abstract: Steam distillation process improves oil recovery processes involving steam injection up to 50%. Due to its immense effect on oil recovery, several attempts have been made to simulate this process experimentally and theoretically. Since detailed crude oil data is rarely available, a model should be presented to predict the distillate rate with minimum entry parameters. For this purpose, a Multi-Layer Perceptron (MLP) network is used in this research as a new and effective method to simulate the distillate recoveries of 16 sets of crude oil data obtained from literature. API, viscosity, characterization factor and steam distillation factor are input parameters of the network while distillate yield is the result of the model. Thirteen sets of data were used for training the network and three remaining sets were used to test the model. Comparison between the developed MLP model, Equation of State (EOS)-based method and Holland–Welch correlations indicates that the errors of the MLP model for training and test data sets are significantly lower than that of those methods. Also, the MLP network does not require oil characterization, which is a necessary and rigorous step in EOS and Holland–Welch methods.

A two-stage high-temperature preheated steam gasifier

Abstract: A gasifier is disclosed combing two reactors using externally generated preheated high temperature steam injection into the first reactor, where the heating demand for gasification is supplied by the sensible energy from the steam. The gasifier can produce a medium and higher LCV syngas. The first reactor is a fixed bed gasification section where the coarse feedstock is gasified, and the second reactor is an entrained-bed gasification section where the liquid and fine feedstock is gasified. Solid coarse feedstock is devolatilized in the first fixed bed reactor of the gasifier by means of high-temperature steam, and subsequently, in the second reactor subjected to a higher temperature sufficient to crack and destroy tars and oils. Activated carbon may be formed as co-product. The gasifier may be used with various solid and liquid feedstocks. The gasifier is capable of gasifying such different feedstocks simultaneously.

In situ thermal process for recovering oil from oil sands

Abstract: A method of recovering oil from an oil sands reservoir comprises first applying cyclic steam stimulation (CSS) to a series of generally horizontally extending wells in the reservoir; then applying steam assisted gravity drainage (SAGD) to at least one vertically-spaced well pair in which one well in each well pair is part of the series of wells to which CSS was applied, while producing oil from at least one single well in the series of wells. In this case, each single well is adjacent to and offset from at least one of the well pairs. The method can then further comprise applying a SAGD blowdown to an injector well of each well pair and producing oil from a producer well of each well pair and from the single well to economic limit.

Methods for generation of subsurface heat for treatment of a hydrocarbon containing formation

Abstract: Methods of generating subsurface heat for treatment of a hydrocarbon containing formation are described herein. Steam is provided to at least a portion of a hydrocarbon containing formation from a plurality of substantially horizontal steam injection wells. A mixture comprising hydrogen sulfide and an oxidant is combusted in one or more flameless distributed combustors positioned in one or more substantially vertical wellbores to generate heat. At least one of the substantially vertical wellbores is within ten meters of an end of at least one of the substantially horizontal steam injection wells, and at least a portion of the generated heat is transferred to a portion of the hydrocarbon containing formation located between at least one of the substantially horizontal steam injection wells and at least one of the substantially vertical heater wells to mobilize formation fluids for recovery.

Simulation Study of Steam Assisted Gravity Drainage (SAGD) in Fractured Systems

Abstract: The Steam Assisted Gravity Drainage (SAGD) process, a developed Enhanced Oil Recovery (EOR) process to recover oil and bitumen, has been studied theoretically and experimentally in conventional reservoirs and models and is found a promising EOR method for certain heavy oil reservoirs. In this work simulation studies of the SAGD process were made on different fractured models consisting of fractures in both Near Well Region (NWR) and Above Well Region (AWR) and even in the presence of networked fractures. At early stage of the SAGD process in fractured system, steam moves through the fractures first and then the matrix blocks are heated primarily by conduction and possibly some steam invasion. The steam-oil interface forms and develops from all sides of the matrix and oil chamber rather than a steam chamber forms and shrinks in the center of each block. SAGD process recovery enhanced in the presence of vertical fractures but horizontal fractures were harmful on the recovery. Fracture spacing was not a very important parameter in the performance of steam processes in fractured models. High fracture frequency improved SAGD performance since it reduced the time period necessary for heating the matrix block and enhanced heating process by conduction. Horizontal fractures between injector-producer wells had an insignificant effect on the process since SAGD production mechanism is based on steam chamber development in AWR rather than NWR. Horizontal fractures extension increase reduced ultimate oil recovery attainable by SAGD. In the networked fracture model the presence of vertical fractures improved the recovery achieved in the case of horizontal fractures alone.

Dispersed Systems in Heavy Crude Oils

Abstract: Due to very large reserves, heavy crude oils represent an important challenge for the oil industry. Their production has to handle very viscous hydrocarbons and involves the use of advanced methods such as cold production or steam injection. Cold production is faced with the foamy oil phenomenon: while extracted, a heavy crude oil is submitted to a depletion that can induce the formation of dispersed gas bubbles and makes it appear as a foam. With steam injection, water is invariably produced and emulsions may be formed. These two situations show how heavy crude oils are concerned with dispersed systems. The aim of the article is to evaluate the impact of this dispersed phase, either bubbles or droplets, on the flow properties of heavy crude oils. To do so, measurements have been carried out with a controlled stress rheometer under pressure and temperature. Live samples were obtained by recombining a stock tank oil with methane inside the pressure cell of the rheometer. The first part of the article is dedicated to the foamy oil phenomenon. It demonstrates that contrary to spherical bubbles, deformed bubbles can give rise to significant viscosity reduction, which is governed by the capillary number. The second part deals with water-in-oil emulsions. Again, experimental results show that dispersed droplets increase viscosity unless they get sufficiently elongated by the applied shear rate. The last part of the article is particularly original as it studies some rheological experiments of heavy crude oils in presence of both gas bubbles and water droplets. It investigates to what extent the presence of water influences the bubbly characteristics of live heavy crude oils. The experimental work suggests that for optimum design and operations, it is essential to determine oilfield viscosities i.e. under pressure and temperature on live and changing dispersed systems.

System and method for treating oil-bearing media

Abstract: A process and system for oil-contaminated soil remediation and oil recovery from oil-bearing media such as oil-contaminated soil, different types of oil-bearing sludge's from oil producers, upgraders and refineries, oil shale, oil sands, and coal oil shale, oil sands and coal includes (1) a portable or fixed twin thermal desorption unit with two rotating trundles in one stationary house, and (2) multiple co-combustion burners burning coal, scrap tires, used oils, sludge's containing high oil content, propane and natural gas to supply heat for the twin desorption unit, and (3) a suction fan to create a slightly vacuum environment, receive vapors and send them to (4) a cooling line with a heavy component condenser to condense heavy oils, a set of air cooling pipe to condense light oils and steam and a three-phase (gas/oil/water) separation tank to separate oil from water, and (5) a feeding line with a blender to break wet lumps and a crasher to break rocks presence in the raw material being processed.

Conformance Control of CSS and Steam Drive Process With a Carbamide Surfactant

Abstract: Based on physical modelling, this paper discusses the feasibility of injecting additives to control the conformance of the cyclic steam stimulation (CSS) and steam drive processes in the Biquan 10 Block of the Henan Oil Field. The lab test results show that waterflooding with the addition of a carbamide surfactant can decrease residual oil saturation by 4.7% and that steam drive with the addition of this same surfactant can improve the sweep volume and increase the oil recovery factor by 17.5%. Also, field application results confirmed that injecting this surfactant in the CSS and steam drive processes can increase oil production, lower steam-oil ratio (SOR) and improve the economic benefits significantly.

Technical Advancements in SAGD Evaporative Produced Water Treatment

Abstract: There has been a shift away from the use of warm lime softening (WLS) and weak acid cation (WAC) ion exchange for produced water treatment to the use of mechanical vapour compression (MVC) evaporation followed by high pressure drum-type boilers. Approximately 18 steam assisted gravity drainage (SAGD) produced water evaporators are operating or are in various stages of construction in Alberta and overseas. Since the commissioning of the first such evaporators in 2002, many technical advancements have occurred which have resulted in reduced operating costs, improved reliability, reduced scaling and fouling potential, improved distillate quality and improved boiler feed quality for steam generation. This paper provides details of the technical advancements in evaporative produced water treatment based on full-scale operating data and lessons learned. It also presents improved evaporator configurations, discusses improvements in contaminant reduction and scale prevention systems, demonstrates how capital and operating costs can be drastically reduced as compared to earlier evaporator system designs, and provides recent advancements in modularization, evaporator disposal treatment, deoiling, membrane preconcentration, and zero discharge solids drying techniques.

Chemical cleaning method and system with steam injection

Abstract: Disclosed are methods and apparatus for cleaning heat exchangers and similar vessels by introducing chemical cleaning solutions and/or solvents while maintaining a target temperature range by direct steam injection into the cleaning solution. The steam may be injected directly into the heat exchanger or into a temporary side stream loop for recirculating the cleaning solution or admixed with fluids being injected to the heat exchanger. The disclosed methods are suitable for removing metallic oxides from a heat exchanger under chemically reducing conditions or metallic species such as copper under chemically oxidizing conditions. In order to further enhance the heat transfer efficiency of heating cleaning solvents by direct steam injection, mixing on the secondary side of the heat exchanger can be enhanced by gas sparging or by transferring liquid between heat exchangers when more than one heat exchanger is being cleaned at the same time.

Analysis and Simulation of Steam Distillation Mechanism during the Steam Injection Process

Abstract: Steam distillation could improve the oil recovery efficiency during the steam injection enhanced oil recovery process. Because of its immense effects on oil recovery, it is important to investigate the main parameters of steam distillation as well as the effects of oil and reservoir properties during this thermal process. In this work, the simulation of batch steam distillation is performed on 18 sets of crude oil found in the literature. The developed model is highly compatible with respect to the input oil properties that can also characterize the oil with minimum entry. The calculated distillates were compared to the experimental data, and the results show an average relative error of 13.74% for 15 sets of crude oil data, each calculated at 20 different points. According to this study, the superheat conditions of steam and the amount of light oil fractions have the greatest effect on the distillation yields, while the steam saturation conditions have less considerable effects. It was also found that th...

Steam-injection boiler used for producing high-dryness superheated steam

Abstract: The invention relates to a steam-injection boiler used for producing high-dryness superheated steam, which comprises a heat interchanger, a radiant section, a convection section, a chimney, an external steam-water separator, an overheater, a boiler body, a water pipeline, a burner, an electric heater, an oil heater and a flash tank. The front part inside the boiler body is provided with a burner, the middle part thereof is provided with the radiant section, the rear part thereof is provided with the convection section; the burner is respectively connected with the electric heater and the oil heater through a lead and a pipeline; the outside of the radiant section is provided with the heat interchanger; an exit is provided with an external steam-water separator; the heat interchanger is connected with a water-feeding pump through the water-feeding pipeline; the steam-water separator is respectively connected with the overheater and the flash tank through the pipeline; the lower part of the convection section is provided with the overheater, the upper part thereof is provided with the chimney; and the radiant section and the convection section are respectively connected with the heat interchanger through the pipeline. The boiler is novel in structure, reasonable in design, and reliable in working, and can produce high-dryness superheated steam, thereby improving the effect of thick oil thermal recovery technology in SAGD.