Historymatching of coreflood experimental data through numerical modeling is a powerful tool to get insight into the relevant physical parameters and mechanisms that control fluid flow in enhanced oil recovery processes. An experimental and numerical study of chemically enhanced. Furthermore, a smaller wag slug size of co 2wag injection led to a higher oil rf and the optimum wag slug ratio was approximately 1. Water alternating gas wag water alternating gas involves gas injection followed by water injection gas injection increases displacement efficiency water injection increases sweep efficiency. Water alternating gas wag water alternating gas involves gas injection followed by water injection gas injection increases displacement efficiency water injection increases sweep efficiency 5. The surfactant phase behavior, for the aid of foamassisted chemical. Builder tool was used to make physical model and winprop for. The main gas injection methods include co 2 flooding, nitrogen flooding and flue gas flooding chen and reynolds. Also, availability of hydrocarbon or co2 gases in the field makes it attractive for gasbased enhanced oil recovery eor methods such as. Optimization of the water alternating gas injection.
This process is used mostly in co 2 floods to improve hydrocarbon contact time. Scenarios of water injection and gas injection were simulated separately and their results were compared with each other and with intermittent water and gas injection. Simulation of water and gas injection in an oil reservoir. Thesubscriptso,wand grefer to oil, water and gas and the superscripts injand prodrepresent injection and production.
Optimum wateralternatinggas co2wag injection in the. Comparison of oil removal in surfactant alternating gas. A design of experiment was used to create oil rim models from a wider range of reservoir, operational and reservoir architecture parameters. Evaluation of oil recovery by water alternating gas wag. Srivastava, laxminarayan mahli, irs, ongc summary it is an established fact that substantial amount of oil usually remains in a reservoir after primary and secondary processes. The environmental risks and oversight of enhanced oil. Investigation on the wateralternating gas oil recovery. Recovery factors of sag, wag, water flooding and gas flooding are about 87%, 70%, 66% and 59%, respectively.
Recovered oil in the case of alternating injection of surfactant and nitrogen is more in comparison to water flooding, gas injection and water alternating gas. While water injection is known to be effective in piston engines, using aviationgas, to prevent detonation and enhance power output. Enhanced oil recovery, heavy oil an enhanced oil recovery process whereby water injection and gas injection are carried out alternately for periods of time to provide better sweep efficiency and reduce gas channeling from injector to producer. Enhanced oil recovery by water alternating gas wag injection. The environmental risks and oversight of enhanced oil recovery in the united states an overview of class ii well trends and regulations in epas underground injection control program august 2017 prepared for prepared for clean water actionclean water fund by. Water alternating gas wag injection process is a proven enhanced oil recovery eor technology with many successful field applications around the world. Wateralternatinggas wag injection, the most common form of co 2eor, in which either fresh water or produced water oil field wastewater is injected in intervals between co 2 injections.
An experimental study of alternative hot water alternating. The wag scheme is a combination of two traditional techniques of improved hydrocarbon recovery. Pdf ensemblebased optimization of the wateralternating. However, there is still an incomplete understanding of these processes and the need for comparative work is inevitable. The most important criterion for miscibility determination is the minimum miscibility pressure mmp. The immiscible displacement method with co 2 injection, although not mentioned in the above. Eor can extract 30% to 60% or more of a reservoirs oil, compared to 20% to 40% using primary and secondary recovery.
Outputs were predicted after 5, 15, 25 and 35 cycles of injection in each network following changes. Gas injection is an attractive process to implement the shortcomings of water flooding, which can maintain reservoirs pressure and reduce stratum damage jia, 2006. Fundamentals of carbon dioxideenhanced oil recovery co 2. A twophase water alternating gas injection experiment alternating pure co 2 and pure water injection. According to the us department of energy, there are three primary techniques for eor. To avoid injectivity problems and other operational limitations related to the simultaneous. A brief presentation on what water alternating gas type of enhanced oil recovery is all about. The application of neural network models on the estimation. Ensemblebased optimization of the wateralternatinggasinjection process. Wag pilot projects demonstrate that wag incremental recovery factor typically ranges from 5 to 10% of original oil in place, though up to 20% has been observed in some fields.
Water alternating gas injection wag also referred to as combined water and gas injection cgw is an enhanced oil recovery eor method where water and gas injection are carried out alternately in a reservoir for a. The use of wateralternatinggas injection can potentially lead to improved oil recovery from the fields. The water alternating gas methodology is a combination of two oil recovery. Wag followed by gas, in which a cheaper gas such as nitrogen is injected following the co 2 injection cycle. Optimization of a water alternating gas injection compositional fluid flow simulation with simultaneous water alternating gas injection optimization on the upscaled synthetic reservoir cerenai the main objective of this work is to devise a production strategy, on a brazilian presalt. Wateralternatinggas wag injection is a relatively mature oil recovery technique in hydrocarbon reservoirs that has long attracted the interest of the oil and gas industry due to its successful performance. Over 60% of the light crude oil was produced in the first two cycles of the miscible co 2wag injection. It is known that using the wateralternatinggas wag injection some of that oil can be produced. Ensemblebased optimization of the wateralternatinggas. To increase the extent of the reservoir contacted by the injected gas, the gas is generally injected intermittently with. Miscible displacement methods, which include injection of hydrocarbon gas, co 2, or inert gas under high pressure. Alternative injection of gas as slugs with water slugs, or alternative water gas injection, is the conventional technique for improving the recovery factor due to its high potential for mobilizing the residual oil in place in the reservoirs and to control gas mobility. Simulation optimization of wateralternatinggas process. Although co 2 injection increases microscopic displacement efficiency, unless complete miscibility is achieved, suboptimal sweep efficiency may be obtained because of gravity segregation and the channeling of co 2 through highpermeability zones or by.
Alternating water injection with co 2 injection results in better mobility control and increases. Abstract water alternating gas injection wag is normally employed to improve the volumetric sweep efficiency of miscible flooding processes. Co2wateralternating in jection can e ectively enlarge swept volume and oil displacement e ciency. We conducted a mechanistic numerical simulation study aiming at modeling previously performed wateralternatinggas and foamassisted chemical flooding coreflood. A parametric investigations of swag injection technique.
The application of this technology remains limited due to the complexity of the wag injection process which requires timeconsuming indepth. The wag injection process aims to squeeze more oil out of the reservoirs. Enhanced oil recovery abbreviated eor, also called tertiary recovery, is the extraction of crude oil from an oil field that cannot be extracted otherwise. Changing injection rate and duration of injection, while keeping the same wag ratio, does affect the performance of wateralternatinggas technique. In this paper, simulation of water and gas injection was examined in an oil reservoir intermittently. The objectives for this study were to increase the oil recovery while reducing the gas production and the parameters selected for optimization in this study were the bottomhole pressure, the well position, the injection rate and wag ratio. Wellbore stability model based on iterative coupling. Matthew geraci syed jehangeer ali courtney romolt regina rossmann. Mechanistic modeling of wateralternatinggas injection.
Wagwater alternatinggas eor processes mobility oil and gas. Wateralternatinggas wag injection a novel eor technique for mature light oil fields a laboratory investigation for gs5c sand of gandhar field. It was originally proposed as a method to improve the sweep efficiency of gas by using water to control the mobility ratio and to stabilize the front caudle and dyes, 1958. Enhancement of co2 trapping efficiency in heterogeneous. Chemically enhanced water alternating gas cewag is a novel eor technology after wag injection process. Engineering, has presented a thesis titled, optimum wateralternatinggas co 2wag injection in the bakken formation, in an oral examination held on december 10, 2014. Mechanism of cewag injection varies with injected chemicals viz. Wateralternatinggas wag injection is a relatively mature oil recovery technique in hydrocarbon reservoirs that has long attracted the interest of the oil and. Also in development are emulsified fuelwater blends that reduce no x emissions by 15 to and particulate matter by 12 to 23. The results show that in both the waterwet and mixedwet cores, the performance of wag injection is better than water injection and gas injection alone. The following committee members have found the thesis acceptable in form and content, and that the candidate demonstrated satisfactory knowledge of the subject material. Co2wateralternating injection has greater popularity nowadays 11,12.
The production rates in gs5c reservoir have been declining for the past two to three years with significant increase in water cut. Alternatingco2 injection in the secondary and tertiary recovery. Critical parameters affecting water alternating gas wag. Mechanism of injectivity loss during wateralternatinggas. Co 2wateralternatinggas co 2wag flooding generally leads to higher recovery than ither continuous co 2 flooding or waterflooding. Published on december 21, 2015 december 21, 2015 257 likes 22 comments.
Fundamentals of carbon dioxideenhanced oil recovery eor. Water alternating gas injection wag is normally employed to improve the volumetric sweep efficiency of miscible flooding processes. Estimation of the oil recovery factor for the albertine. We thus studied the efficiency of each injection option and predicted the associated storage capacities and co 2. Despite its proven success, wag application growth has been.
Enhanced oil recovery by water alternating gas wag. The performance of wag process is measured by its incremental recovery factor over secondary recovery. Gasbased eor co 2 injection air injection hc injection nitrogen injection flue gas injection wag water alternating gas fawag foam assisted wag waterbased eor surfactants polymer alkaline polymer gels meor microbial eor low salinity waterflood thermal methods. Wateralternatinggas wag injection is a relatively mature oil recovery technique in hydrocarbon reservoirs that has long attracted the interest of the oil and gas industry due to its successful. Literature search indicated a number of numerical studies investigated the effect of flooding rate, gravity forces, slug size, and heterogeneity on. A response surface model was generated based on a concurrent oil and gas production and a pareto analysis was. Natural water influx hydrocarbon gas injection ch 4 immiscible and miscible and others compaction drive nonhydrocarbon gas injection n 2, co 2 combination drive water alternating gas wag, surfactant alternating gas sag, nano alternating gas nag and others 2. If a reservoir pressure reaches mmp, co2 ooding is miscible. Novel approach for predicting water alternating gas.
Optimization of hydrocarbon water alternating gas in the. In total, 223 samples were collected from simulations for training the networks. Cmg software was used in this article for reservoir simulation. Water alternating gas wag injection process is a proven eor technology that has been successfully deployed in many fields around the globe. Gas injection is the second largest enhanced oil recovery process, next only to thermal processes used in heavy oil fields. Multiphase flow and hysteresis phenomena in oil recovery. The results show that in mixedwet core, oil recovery by the wag test which had started with water injection. Experimental and numerical investigation of wormholing. Water alternating gas wag injection are improved oil recovery methods that involve threephase fluid flow. Literature search indicated a number of numerical studies investigated the effect of flooding rate, gravity forces, slug size, and heterogeneity on wag processes performance.
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