Steam Injection Temperature Research Articles

Influence of loading on the heat transfer rate and specific water consumption of detached loosed fresh palm fruits during vertical mini-batch sterilization

This study presents the effect of loading on the heat transfer rate and specific water consumption of detached loosed fresh palm fruits during sterilization. Sterilization is an integral process of palm oil extraction that consumes a lot of water. However, most industrial research in the past focused on fresh fruit bunch (FFB) sterilization dynamics. At the same time, the medium- and small-scale industries sterilize already detached loosed fresh palm fruits (LFPF) that have been removed from the spikelet as purchased from aggregators. Therefore, the process data generated from the sterilization of FFB might not be optimal for sterilizing LFPF. This study, therefore, investigates the transient response of variation in LFPF loading of the sterilization chamber to steam injection during steam sterilization of LFPF at 3 ± 0.5 bars using a vertical, single-peak LFPF sterilizer that combines the boiler and sterilizer in a single unit. The LFPF were loaded at mass intervals of 0.2 kg ranging from 0.2 kg to 2 kg. The vapour temperature dynamics, heat transfer rate, steam energy utilization efficiency and specific water consumption parameters were studied. The average vapour temperature varied from 100 °C to 130 °C for the LFPF mass range of 0.2 to 2 kg at steam injection temperature of 140 °C and pressure of 3 ± 0.5 bars. This temperature range matched the saturated vapour temperature of pure water at 1.0––2.8 bars absolute pressure but slightly lower than the saturated vapour temperature of 133.54 °C for pure steam at 3 bars. The percentage of steam energy utilization effectiveness is inversely related to the steam mass flow rate. While energy effectiveness increased with loading mass, the steam mass flow rate decreased with increased LFPF mass. The value of the heat transfer rate ranged between 1.7––55.4 W, while the specific heat transfer rate ranged between 8.5–––41.8 W/kg. The average specific water consumption ranged from 0.014 to 0.09 kg-water/kg-LFPF, with an average value of 0.031 kg-water/kg-LFPF. This value is lower than 0.112–––0.5 kg-water/kg-FFB, with an average value of 0.256 kg-water/kg-FFB for conventional FFB steam sterilization. This represents an 87.9 % reduction in water consumption in conventional FFB steam sterilization. An empirical model deduced for specific heat transfer rate and water consumption for steam sterilization of LFPF at 3 ± 0.5 bars and vapour temperature range of 100––130 °C showed a high coefficient of determination above 99 %.

A Numerical Simulation Approach for Superheated Steam Flow during Multipoint Steam Injection in Horizontal Well

Superheated steam flow during multipoint steam injection technology has a good effect on improving the steam absorption profile of heavy oil thermal recovery wells, enhancing the production degree of horizontal section of thermal recovery wells, and enhancing oil recovery. Based on the structure of multipoint steam injection horizontal string, considering the characteristics of variable mass flow, pressure drop of steam-liquid two-phase flow, and throttling pressure difference of steam injection valve in the process of steam injection, this paper establishes the calculation model of various parameters of multipoint steam injection horizontal wellbore and calculates the distribution of steam injection rate, temperature, pressure gradient, and dryness along the section of multipoint steam injection in horizontal wellbore. The results show that the temperature and pressure decrease gradually from heel to toe, and the steam dryness decreases gradually. Considering the influence of throttle pressure difference of steam injection valve and pressure drop of gas-liquid two-phase flow in the wellbore, the traditional calculation model of steam injection thermodynamic parameters is optimized, and the optimization of wellbore structure and steam injection parameters is an effective method to achieve uniform steam injection in horizontal wells. The steam injection uniformity of horizontal wells can be effectively improved by adjusting the steam injection valve spacing and steam injection parameters. When the steam injection volume is 200 m3/d and the steam injection valve spacing is 20 m, a more stable steam injection effect can be obtained. The findings of this study can help for better understanding of improving the uniformity of steam injection and enhancing the recovery factor.

Numerical Simulation Analysis of Wellbore Integrity and Casing Damage in High-Temperature Injection and Production of Shale Oil

Shale oil represents a relatively new form of unconventional oil and gas resource, and the extensive exploration and development of shale oil resources carry significant implications for China’s oil and gas supply and demand dynamics. At present, within the realm of low-maturity shale oil extraction technologies, the reservoir must be subjected to elevated temperatures ranging between 400 to 60 °C. Prolonged exposure of wellbores to such high temperatures can result in a substantial decrease in cement strength, the formation of microcracks due to cement cracking, and damage stemming from thermal stresses on the casing. Casing damage stands out as a prominent factor contributing to wellbore integrity failures and well shutdowns within the context of shale oil development. Given the limited natural energy reservoirs of shale oil formations, it becomes necessary to supplement the reservoir’s energy during the development process. Furthermore, shale oil exhibits high viscosity and poor flowability, and conventional water injection methods yield limited efficacy. This situation can induce significant shifts in the stress field and rock mechanical parameters, potentially activating specific formations and complicating the load dynamics on the casing. Consequently, the risk of failure increases. In light of these considerations, this study uses numerical simulations to study the integrity of high-temperature injection and production wellbores in shale oil and aims to encompass a comprehensive evaluation and analysis of the principal factors that influence casing damage, the fluctuations in thermal stress, and the yield strength of various steel grades of casings exposed to alternating stress conditions. Subsequently, this paper developed a model for simulating the temperature and pressure within shale oil and steam injection wellbores to support engineering design analysis. The research results indicate that the application of pre-stress results in a significant increase in stress at the casing pipe head while causing a noticeable decrease in stress within the pipe wall. When N80 casing is used, the entire casing experiences thermal stresses surpassing the casing’s yield limit. Stress concentration may arise at both ends of the external seal, potentially leading to casing contraction, shear failure, and, under non-uniform stress conditions, casing bending deformation. The temperature of steam injection significantly influences the temperature field of the casing wall, with stress values experiencing a marked reduction when the steam injection temperature decreases from 350 °C to 200 °C, underscoring the substantial impact of temperature on casing thermal stress. As the steam injection process advances along with injection-production cycles, shear stresses at the interface can exceed the bond strength, resulting in relative slippage between the cement and the casing. The bonding force between the wellbore and the cement primarily depends on the interface’s friction, particularly in the context of friction during wellhead lifting. This study endeavors to determine rational injection and production parameters under varying conditions, optimize completion methods, reduce casing damage, and extend the casing’s operational life; it aims to offer critical technical support for the safe and efficient development of shale oil resources.

Performance of high temperature steam injection in horizontal wells of heavy oil reservoirs

Steam huff and puff and steam flooding are important development methods for heavy oil reservoirs. At present, there are certain deficiencies in the research on the timing and methods of steam stimulation, steam flooding, and subsequent steam flooding. In addition, the research on the mass and heat transfer characteristics of high temperature steam injection in heavy oil reservoirs is still in the initiation stage. This article first studies the high temperature steam flow model in the horizontal wellbore of the SAGD process. On this basis, a horizontal well pattern model was established through numerical simulation software to analyze the heat and mass transfer characteristics of high temperature steam huff and puff and high temperature steam flooding. Results show that: (a) for heavy oil reservoirs with high temperature steam injection huff and puff, the first cycle of steam injection ends (day 22): the temperature near the well pattern of the horizontal well pattern is higher. In the area between the horizontal well patterns, the temperature rise is not obvious; (b) when the high temperature steam injection huff and puff phase of the heavy oil reservoir ends (900 days), most of the heat energy is recovered, and the formation residual heat is less; (c) After the huff and puff transfer, the thermal connectivity between the horizontal well patterns is better.

Study on the whole life cycle integrity of cement interface in heavy oil thermal recovery well under circulating high temperature condition

Cement seal failure is common in heavy oil thermal recovery wells, but the effects of steam stimulation on wellbore interface seal performance is unclear. The finite element model of plastic zone formation of cement sheath during high temperature circulating is established. The damage variable of the cement sheath is proposed to define the elastic-plastic transformation process of cementing interface, the interfacial debonding and micro-annulus size caused by thermal stress cycling are quantified, and the effects of key parameters such as steam injection temperature, cycle times, mechanical properties of cement sheath on the change of interface integrity are clarified. The results show that the tensile failure of cement sheath and the micro-annulus always formed on the inner wall of cement sheath, and outer wall remains intact. Excessive steam injection temperature (360 °C–420 °C) will cause an 8–45 μm micro-annual, excessive elastic modulus of cement sheath (>10 GPa) will cause a 20–62 μm micro-annular, the cement sheath with heat shrinkage property will form a 47–54 μm micro-annulus. Based on the sensitivity analysis, the matching relationship between the thermal cycle construction parameters and the performance index of cement sheath is established. The results can provide a reference for the design of cement parameters and engineering parameters under the thermal stress cycles.

Parallel particle swarm optimization for optimal SAGD operating scenario and well placement in a high dimensional search space

Steam-assisted gravity drainage (SAGD) has been commercially tested successfully in many oilfields with different characteristics. The operational parameters and wells’ location substantially affect the performance of SAGD, and designing a scenario optimization to find the optimum values of these parameters would enhance the efficiency of the process. Although most previous studies worked on optimizing some of the mentioned parameters separately, barely any optimized them simultaneously using a full 3D model since optimizing such a high-dimensional problem is time-consuming. In this study, whole-time scenario optimization is designed to simultaneously optimize the operational (steam injection rate, temperature, and production bottom hole pressure of all intervals) and well placement parameters of an 8-year SAGD. Parallel particle swarm optimization (PSO) is developed to determine the desired number of simulations concurrently to reduce computational costs. Also, the SAGD time is divided into four time intervals, and the effect of uniform and non-uniform time intervals on the net present value (NPV) and oil production is investigated. The outcomes showed that conducting parallel PSO would reduce the optimization time by 79.8%. Also, by applying the non-uniform intervals, the highest NPV is achieved, and the SAGD time declines to 6 years.

Thermodynamic Analysis of In-Cylinder Steam Assist Technology within an Internal Combustion Engine

For the requirements of rigorous CO2 and emissions regulations, steam assist technology is an effective method for thermal efficiency enhancement. However, few studies apply steam assist technology in modern internal combustion engines. Stimulated by its application prospects, the present study proposes a thermodynamic analysis on the in-cylinder steam assist technology. An ideal engine thermodynamic model combined with a heat exchanger model is established. Some critical parameters, such as steam injection temperature, injection pressure and intake pressure, are calculated under different steam injection masses. The thermal efficiency boundaries are also analyzed at different compression ratios to investigate the maximum potential thermal efficiency of the technology. The analysis shows that the in-cylinder steam-assisted cycle has the potential to increase engine efficiency considerably. Both steam injection temperature and injection mass improve thermal efficiency. Considering the energy trade-off relationship between steam and exhaust gas, the maximum gain in thermal efficiency achieved with the cycle is 14.5% at a compression ratio of 10. The optimum thermal efficiency can be increased from 54.0% to 59.71% by increasing the compression ratio from 10 to 16. The mechanism lies in the specific heat ratio enhancement from a thermodynamic perspective, which improves the thermal-heat conversion efficiency. The results provide considerable guidance for the future experimental and numerical studies of in-cylinder steam assist technology into modern engines.

Whole-time scenario optimization of steam-assisted gravity drainage (SAGD) with temperature, pressure, and rate control using an efficient hybrid optimization technique

Whole-time (simultaneous) scenario optimization of oil recovery over a long time necessitates control of many parameters which is very time-consuming. Usually, to reduce the decision variables, scenarios are optimized in separate intervals. As a new work, a whole-time scenario optimization of the steam-assisted gravity drainage (SAGD) process with several decision parameters (steam injection rate, temperature, and pressure of all intervals) is performed in a 3D reservoir defining an 8-year scenario. Two relatively fast optimization algorithms, i.e. particle swarm optimization (PSO) and pattern search (PS), are utilized to maximize the net present value (NPV). First, through different optimizations, appropriate population size is selected for PSO. Next, the performance of four different scenarios is investigated, and the excellence of whole-time scenario optimization is proved. It is concluded that a higher NPV is obtained by increasing the number of time-intervals. Furthermore, conducting the whole-time optimization with 8 time-intervals can reduce the SAGD process by 1 year. Finally, a new hybrid PSO-PS algorithm is proposed that uses the advantages of both PSO and PS algorithms and reduces the number of function calls. The hybrid algorithm could result in the same results as PSO, while remarkably improved the convergence speed (about 84%).

Experimental study on the mechanism and development effect of multi-gas assisted steam huff and puff process in the offshore heavy oil reservoirs

Multi-gas assisted steam huff and puff process is a relatively new thermal recovery technology for offshore heavy oil reservoirs. Some blocks of Bohai oilfield have implemented multi-gas assisted steam huff and puff process. However, the development mechanism still requires further study. In this paper, high-temperature high-pressure (HTHP) PVT experiments and different huff and puff experiments of sand pack were carried out to reveal the enhanced production mechanism and evaluate the development effect of multi-gas assisted steam huff and puff process. The results indicated that viscosity reduction and thermal expansion still were the main development mechanism of multi-gas assisted steam huff and puff process. Specifically, CO2 easily dissolved in the heavy oil that made it mainly play the role of reducing oil viscosity, N2 was characteristics of small solubility and good expansibility, and it could improve formation pressure, increase steam sweep volume and even reduce the heat loss. Meanwhile, injecting multi-gas and steam could break the balance of heavy oil component that made the content of resin reduce and the content of saturates, aromatics and asphaltene increase so as to further reduce the viscosity of heavy oil. Compared with steam huff and puff process, multi-gas assisted steam huff and puff process increased the recovery by 2–5%. The optimal water–gas ratio and steam injection temperature were 4:6 and 300℃, respectively. The results suggested that multi-gas assisted steam huff and puff process would have wide application prospect for offshore heavy oil reservoirs.

Transient measurement and modeling of integrated capillary viscometer for live oils at high temperatures with volumetric constraints

The viscosity of oils at reservoir conditions whether under natural depletion conditions or under induced conditions (i.e. EOR/IOR) is one of the key parameters for the dynamics of flow in porous media, and it has direct impact on the economically recoverable volumes as well as transportation problems where the fluids can get exposed to potentially wide range of temperatures. It becomes even more essential measurement for thermal based EOR techniques including high temperature steam injection or in-situ upgrading techniques due to strong (exponential) dependency of viscosity to temperature. Unfortunately, viscosity measurements for such applications suffer with the two key challenges. First, most commercial and research labs could measure viscosities up to 200 °C (while the application considered may induce temperatures as high as 300 °C beyond which most naturally occurring hydrocarbons starts decomposing). And second, these measurements are based on steady-state conditions, requiring significant volumes of oil samples. However, the available volume of oil samples for such applications may be very small for various reasons, including emulsions leading to very low useful volumes, cost of sampling, or inheritance of candidate samples from other laboratory processes, such as but not limited to core-flooding or reactive transport experiments.Therefore, in this work, we present a novel but simple technique to overcome these challenges by using simple capillary device that could be integrated to any system that requires charging and/or charging the candidate fluids such as PVT-cells, pressurized vessels that could be operated up to 300 °C or higher. Such integration utilizes the charging of fluids to the cell for viscosity measurements, leading to the following advantages:(i) it requires no additional volume of oil for viscosity measurements, and also saves the operational time and cost(ii) it could produce viscosity data at higher temperatures that are desired for in-situ upgrading or thermal EOR, even small amounts of particulates evolve in the bulk phase(iii) it ensures that the viscosity and PVT measurements are performed on the same sample eliminating the potential sample to sample variations.(iv) the proposed approach along with the developed methodology paves the way for a the implementation of unsteady in-line measurement of viscosities for pressurized systems. This includes not only lab processes, but also the downhole sampling where the method could be implemented in sampling devices.The technique proposed here is based on transient measurements and modeling of capillary viscometer, where pressure at the end points and flow rate through the capillary tube may vary with time (which is the most realistic conditions for variable back pressure systems or systems with frictional pistons). In addition to the experimental process, necessary mathematical model and interpretative analysis tools to quality check, assessment of the experimental data (and the establishment of the range of validity and limitations) are derived from first principals (bottom-up approach) using Navier-Stokes equations.

On the optimum operating temperature for steam floods

The technical, environmental and economic performances of a steam flood are partly influenced by the operating temperature (pressure). However, the definition and procedure for determining the optimum operating temperature are still debatable. Employing a combination of analytic modelling and numerical simulations, this paper investigates the existence (or otherwise) of an optimum injection temperature Topt for saturated-steam floods. Considering the maximization of productivity and thermal efficiency as objective, an analytic procedure, which explores the effects of temperature on injectivity, total steam enthalpy, oil viscosity and relative permeabilities, shows that the operating temperature (pressure) of a steam flood should not exceed 515 K (3.5 MPa). A simple closed-form expression is proposed for Topt as a function of basic rock and fluid properties. For an example three-dimensional reservoir model comprising an 8-m oil shale unit sandwiched between two sandy units each 15 m thick, numerical simulations show sensitivity to temperature (and viscosity effect) in the range 350–450 K, but becomes increasingly insensitive in the band 500–650 K. It is established that ~500–550 K is the optimum band when the optimization objective is to maximize both discounted oil recovery and cumulative oil-steam ratio. These results agree with an optimum injection temperature of ~501 K estimated from the proposed analytical model in this case. Therefore, based on the results of the analytical model, thermal simulations and other considerations, it is concluded that the optimum steam-injection temperature is project and system specific. The insights gained should find relevance in the design and management of steam floods, as well as other steam-based recovery processes.

Analyzing the effect of steam quality and injection temperature on the performance of steam flooding

The heavy oil reservoirs are currently mainly targeted by thermal enhanced oil recovery technologies, particularly, steam flooding. Steam flooding is carried out by introducing heat into the reservoir to unlock the recovery of heavy oil by reducing oil viscosity. Several investigations were carried out to improve oil recovery by steam flooding. Most recently, high steam flooding is reported as an effective approach to improve recovery in high pressure heavy oil reservoirs. The oil recovery from steam flooding is substantially affected by the steam quality and injection temperature. In this study, an attempt was made to look into the integration of parameters, i.e. steam quality and injection temperature upon steam flooding on oil recovery by using a simulation approach via ECLIPSE. The results obtained indicated that high temperature along with the moderate value of steam quality gives the best result regarding oil recovery for steam flooding in an economical way.

Research on influencing factors of injection capacity in cycle steam stimulation process with horizontal well in Bohai oilfield

Since the beginning of the 21st century, the proportion of heavy oil production has been increasing. Cycle steam stimulation (CSS in short) is the prevailing technology for the development of heavy oil reservoirs and has made a great contribution to the development of heavy oil. However, the current research on the factors affecting the steam injection capacity of CSS heavy oil reservoirs and the degree of influence of each factor is insufficient. Oil recovery and heat utilization efficiency are poor, especially in the oil fields with poor reservoir conditions and severe heterogeneity. In this paper, the reservoir geological model of the Bohai oilfield was established, and the CSS development was predicted. The problems in the development process of CSS in Bohai oilfield were pointed out. Then, laboratory experiments were carried out to study the steam absorption law of CSS heavy oil reservoirs in consideration of reservoir permeability, steam injection rate, steam injection temperature and crude oil viscosity. The result showed that higher formation permeability and steam injection temperature could improve oil displacement efficiency; higher steam injection rate would reduce oil displacement efficiency. Finally, the influence rules of different injection-production parameters were clarified to shed some lights on the efficient exploitation of heavy oil reservoirs.

Feasibility study and numerical simulation to design the steam flooding pilot test patterns

Steam flooding is a method of injecting steam to heat the oil and decrease its viscosity so that it will be easy to flow from injector to producer. Fula North East oil field is a massive edge and bottom water reservoir with good properties and high viscosity of crude oil. As of March 2018, the oil field has been fully commissioned in steam stimulation for 3 years and the water cut rises rapidly and the oil rate declines seriously. In this paper, through comprehensive analysis of the geological properties of reservoir, production dynamics of single well and cement quality of wellbore, the steam flooding pilot test area under different well groups is screened out. Advanced thermal enhanced oil recovery simulator has been used to build the model of 279, 888 cells to design and optimize steam flooding pilot area for this field. The best well space and development program are optimized; this paper supplies a theoretical foundation for the next step of steam flooding in the whole field. The results show that the optimum steam flooding parameters for this area are steam injection temperature of 270 °C, with 5–7 MPa injection pressure, steam injection quality of more than 0.6 and steam injection rate of 1.6 m3/day/ha/m, and the final recovery ratio will reach 32.3%.

Analytical modeling on the geo-stress and casing damage prevention with the thermo-hydro-mechanical (THM) coupling of multi-field physics

Understanding the rule of squeezing force on casing changing with the working parameters of wells, such as steam injection pressure, steam injection temperature and bottom hole pressure, is very important to prevent casing damage in the complex thermal recovery process involving the interaction of temperature, stress and seepage field. According to the theory of heat transferring, seepage mechanics and elastic–plastic mechanics, the mathematical model considering seepage-stress-heat transferring coupling of thermal recovery was established. The numerical model of the thermal recovery for a block in GuTong oil field was built, and the stress sensitivity of the rock was tested. The research work indicates that the permeability is more sensible to the stress when the maximum stress is less than 35 MPa. The calculation results of the temperature, pressure and vertical displacement fit well with the monitoring data, and the error is less than 20%. The stress and displacement of well wall achieve peak value in the 7th–9th cycles. In the ninth cycle, the maximum horizontal displacement of the well wall occurs and reaches about 13 cm, and the casing damage is most likely to happen in the 7th–9th production cycles. The equivalent element method was used to calculate the extrusion force on the casing pipe. The pressure on casing under different steam injection rate, temperature of steam and bottom hole pressure was obtained and used for prevention of casing damage during the thermal recovery of heavy oil.

Optimal scenario design of steam-assisted gravity drainage to enhance oil recovery with temperature and rate control

Steam-assisted gravity drainage (SAGD) is a commonly used thermal enhanced oil recovery (EOR) method in heavy oil reservoirs. Scenario optimizations are conducted with different optimization techniques to determine the optimal steam injection rate and temperature strategies. The performance of standard artificial bee colony (SABC), directed ABC (DABC), generalized pattern search (GPS) and mesh-adaptive direct search (MADS) algorithms were investigated. Also, the effect of initial guess and polling type on the performance of GPS and MADS were analyzed. DABC approaches the global optimum better than other employed algorithms, with a huge number of function evaluations. While, GPS is the fastest algorithm, likely to be trapped in local extrema. To eliminate this issue, the novel multi-region pattern search (MRPS) algorithm is proposed, in which the search space is divided into smaller subregions, each one is searched independently. Hence, search space is more efficiently explored and initial guess dependency is reduced. MRPS algorithm provided similar results to the DABC algorithm while lowering the computational costs up to 93%. MRPS algorithm is successfully applied for a 5-year SAGD scenario optimization. Furthermore, by scenario optimization, SAGD operation could be reduced for 1-year, providing the same NPV as that of the reference case operating for 4-years.

Investigation of In-Cylinder Steam Injection in a Turbocharged Diesel Engine for Waste Heat Recovery and NOx Emission Control

In this study, an in-cylinder steam injection method is introduced and applied to a turbocharged diesel engine for waste heat recovery and NOx emission reduction. In the method, cool water was first heated into superheated steam by exhaust. Then the superheated steam was directly injected into the cylinder during the compression stroke. The potential for fuel savings and NOx emission reduction obtained by this method was investigated. First, a two-zone combustion model for the baseline engine was established and calibrated with the experimental data. Based on the model, the effects of steam injection mass, temperature, and timing on engine performance and NOx emission were investigated. The results demonstrate that in-cylinder steam injection can improve engine performance and reduce NOx emissions significantly at all engine speeds. Optimal steam injection mass is obtained under full load at engine speed from 1000 rpm to 1900 rpm when the steam injection timing and temperature are −30° and 550 K, respectively. Under those conditions, engine torque is increased by 9.5–10.9%, brake-specific fuel consumption (BSFC) is reduced by 8.6–9.9%, and NOx emission is decreased by 83.4–91.8%. Steam injection mass and injection timing are the main parameters that significantly affect engine performance and NOx emission.

Effect of Processing Methods on the Quality of Tomato Products

Tomatoes are one of the most important specialty crops in United States and tomato products constitute a significant part of the food industry. The quality of tomato paste and juice is evaluated through their viscosity, color, flavor and nutritional value. Four processing methods were selected for this study, in-cluding conventional hot break, waring blender with steam, steam injection, and high temperature with shear (HTS) in a twin-screw continuous processor. The HTS method applies high temperature with shear mixer during hot-break tomato processing that improves the efficiency of the extraction process and the resultant tomato products possessed higher consistency, viscosity, and ly-copene content. Lycopene is an excellent antioxidant with cancer-preventing properties. This work showed that HTS method, utilizing whole tomatoes, produced a superior tomato product with a better color, higher viscosity, and improved bioactive properties.

Numerical simulation and optimization of steam-assisted gravity drainage with temperature, rate, and well distance control using an efficient hybrid optimization technique

ABSTRACTSteam-assisted gravity drainage (SAGD) is a thermal enhanced oil recovery technique through drilling of two horizontal wells. Effects of steam injection temperature, well rates, and their distance on oil recovery were analyzed and optimized. Steam temperature and well distances remarkably affect SAGD performance. Four metaheuristic algorithms (particle swarm optimization (PSO), imperialist competitive algorithm, cultural algorithm, and Bees algorithm) and pattern search optimization algorithm (PSA) are used for optimization. PSO performs better than other metaheuristics and PSA is the fastest one, while it is probable to be trapped in local optimums. Hybrid PSO-PS is proposed that starts with PSO and proceeds with PSA, and tested in an SAGD project and showed excellence over other techniques.

What Vacuum-Insulated Tubings and Casings Bring to Thermal Wells

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 182515, “What Vacuum-Insulated Tubings (or Vacuum-Insulated Casings) Bring to Thermal Wells,” by J. Damour and D. Johannson, Majus, prepared for the 2016 SPE Thermal Well Integrity and Design Symposium, Banff, Canada, 29 November–1 December. The paper has not been peer reviewed. This paper describes both design and economic considerations that lead to the selection of vacuum-insulated tubing (VIT) or vacuum-insulated casing (VIC) for the completion of thermal wells. The results shared in this paper are some of the parameters considered during thermal-well design: temperature on the casing and the tubing, and heat loss. Knowing these parameters, well integrity can be studied and the overall efficiency of the process estimated. Introduction The most common thermal enhanced-recovery methods are cyclic steam stimulation, steamflooding, and steam-assisted gravity drainage, which is widely used in Canada. The role of these thermal-recovery methods is to convey heat into the reservoir, mainly by convection. The temperature of the oil increases and its viscosity decreases significantly in the reservoir. These methods can substantially increase the oil production of a field, increase the recovery factor, or unlock some heavy-oil assets. Typical steam-injection temperature is between 250 and 310°C; in a few cases, it could be greater than 310°C. This high-temperature application requires adapting the design of the injector wells to avoid any mechanical failure of the well or to mitigate heat loss through the well. VIT or VIC are solutions to some of these issues. VIT technologies have evolved significantly since their first application. Different materials are used as insulation material, and several designs are proposed by the industry to achieve the best thermal-performance-vs.-cost equation. A model was developed to assess the temperature of the different components of a well—tubing, casing, cementation, and ground—and to provide the heat loss occurring during the steam injection. The results show that the wide range of VIT thermal performance provides a range of casing temperatures. Thus, the casing thermal expansion or thermal loads resulting from this temperature increase range significantly.