Use Of Water Injection Research Articles

Effects of water injection on reaction temperature and hydrogen production in horizontal co-axial underground coal gasification

Underground coal gasification (UCG) is process of directly recovering energy as combustible gases such as hydrogen and carbon monoxide by combusting unmined coal resources in situ. During UCG process, the temperature in the gasification zone can exceed 1,300 °C, raising concerns about the potential melting of the steel pipe for oxidant injection. To control the temperature in the gasification zone, the use of water injection as an injection agent can be an option. Injecting water during UCG process serves two purposes: it decreases the temperature in the reaction zone by the endothermic effect of water, and it enhances the production of H2 by the reduction reaction of water. However, injecting excessive amounts of water may lead to a significant decrease in the temperature in the reaction zone, consequently cannot maintain the temperature range required for the UCG reaction. This study discusses the effects of water injection on the temperature of the gasification zone and the product gas by developing a chemical reaction model of UCG using COMSOL Multiphysics® software. The model was developed based on the temperature and produced gas results obtained from laboratory-scale artificial coal seam UCG experiments. Our findings reveal that water injection significantly influences the gasification process, controlling temperature in the reaction zone and promoting H2 production through steam gasification and water-gas shift reactions. Moreover, under the experiment and analysis conditions of this study, it is revealed that water injection up to an H2O/O2 molar ratio of 3.9 can effectively control the temperature of the gasification zone with enhancing H2 production.

Exploring the benefits of hydrogen-water injection technology in internal combustion engines: A rigorous experimental study

Previous hydrogen researchers have demonstrated the great potential of hydrogen as a zero-carbon fuel and its wider operational ability to directly replace the existing fossil-fuelled internal combustion engines (ICE). Hydrogen direct-injection technology can operate at stoichiometric combustion conditions, fully eliminating the intake backfire phenomena, which has the benefit of low airflow requirements and is a suitable solution for naturally aspirated ICE platforms. However, significant challenges must be addressed when operating an H2 ICE at or near stoichiometric. These include rapid pressure rise rate, high in-cylinder gas pressure and temperature and the consequential higher engine-out NOx emissions. This study provides a comprehensive experimental analysis of the effect of water injection on a light-duty H2 engine’s performance, efficiency, burn durations and NOx emission. The engine was modified to operate with hydrogen via a centrally-mounted direct H2 injector and an intake port-mounted water injection system. The study included water vapour measurements, NOx concentrations and other exhaust gases. The practical implications of these findings are significant. The results demonstrated that the NOx emissions were reduced by 79% when the water was injected at a rate of 5 kg/h at 10 bar IMEP and 2000 rpm. This reduction in emissions, coupled with the observed decrease in cylinder pressure and the rate of pressure rise, could substantially improve engine performance and efficiency. At higher load regions, the water injection extended the maximum engine load to 24 bar IMEP and increased the engine torque output by 10%. The maximum Indicated Thermal Efficiency (ITE) increased from 41% at 16.5 bar IMEP to 42.5% at 18 bar IMEP at a lower lambda, with a corresponding reduction in the intake-air-boost pressure requirement. Of particular note, the use of water injection decreased the engine-out NOx emissions under high-load conditions by more than 55%, even at richer AFR compared to pure hydrogen operation.

Evaluating silicosis risk: Assessing dust constitution and influence of water as a primary prevention measure in cutting and polishing of silica agglomerates, granite and marble

An increasing number of silicosis cases have been reported related to the use of silica agglomerates. Many studies agree on the severity of this disease, which often presents with severe clinical forms in young workers and after a short latency period.Are there differences in the composition of dust generated by cutting and polishing with silica agglomerates versus granite and marble? Does the use of water injection reduce the risk associated with the use of these materials?We carried out a comparative observational-analytical study, measuring the concentration of dust generated during different machining operations on three different materials: granite, marble, and silica agglomerates. The effect of water injection on dust generation was evaluated.Personal sampling pumps were used, connected to a cyclone with polyvinyl chloride filters. The flow rate of the pumps was adjusted using a piston flowmeter. Measurements with a cascade impactor were made to assess the size distribution of respirable crystalline silica particles within the respirable fraction. In addition, environmental measurements with a spectrometer were made.10 tests were carried out on granite and silica agglomerates for each procedure. In the case of marble, with very low silica content, only 2 tests of each type were carried out. Duration of each measurement was between 6 and 25 min. Cleaning times were set for each of the operations.The amount of dust collected in the respirable fraction was 70.85, 32.50 and 35.78 mg/m3 for dry cutting; 6.50, 3.75 and 3.95 mg/m3 for wet cutting; and 21.35, 13.68 and 17.50 mg/m3 for dry polishing, for granite, marble, and silica agglomerates respectively.Dry procedures in marble, silica agglomerates and granite showed higher dust concentration of particles smaller than 0.5 μm. Silica agglomerates showed higher concentrations of respirable crystalline silica particles than granite and marble, mainly with dry procedures. The greater production of small particles in dry and wet procedures with silica agglomerates shows that water injection is an insufficient preventive measure.

A comprehensive evaluation of water injection in the diesel engine

Due to increasing climate awareness and the introduction of much stricter exhaust emission legislation the internal combustion engine technology faces major challenges. Although the development and state of technology of internal combustion engines generally reached a very high level over the last years those need to be improved even more. Combining water injection with a diesel engine, therefore, seems to be the next logical step in developing a highly efficient drive train for future mobility. To investigate these potentials, a comprehensive evaluation of water injection on the diesel engine was carried out. This study covers >560 individual operating points on the test bench. The tests were carried out on a single-cylinder derived from a Euro 6d four-cylinder passenger car with the port water injection. Furthermore, a detailed pressure trace analysis (PTA) was performed to evaluate various aspects regarding combustion, emission, etc. The results show no significant effects of water injection on the combustion process, but great potential for NOx reduction. It has been shown that with the use of water injection at water-to-fuel rates of 25%, 50%, and 100%, NOx reduction without deterioration of soot levels can be achieved in 62%, 40%, and 20% of the experiments, respectively. Furthermore, water injection in combination with EGR offers additional reduction in NOx emissions.

Water Injection for Oil Recovery in Mishrif Formation for Amarah Oil Field

The water injection of the most important technologies to increase oil production from petroleum reservoirs. In this research, we developed a model for oil tank using the software RUBIS for reservoir simulation. This model was used to make comparison in the production of oil and the reservoir pressure for two case studies where the water was not injected in the first case study but adding new vertical wells while, later, it was injected in the second case study. It represents the results of this work that if the water is not injected, the reservoir model that has been upgraded can produce only 2.9% of the original oil in the tank. This case study also represents a drop in reservoir pressure, which was not enough to support oil production. Thus, the implementation of water injection in the second case study of the average reservoir pressure may support, which led to an increase in oil production by up to 5.5% of the original oil in the tank. so that, the use of water injection is a useful way to increase oil production. Therefore, many of the issues related to this subject valuable of study where the development of new ideas and techniques.

Potential use of real-time dissolved oxygen sensors for oxygen scavenging feedback control

The North Sea oil and gas sector has been operational since the 1970’s and the natural pressure in the reservoirs has been gradually decreasing, which has led to an increased use of water injection to facilitate the required pressure for oil and gas extraction. This involves high pressure and flow of sea water, which is transported through the offshore facilities and due to the corrosive environment, it introduces corrosion. One of the main culprits is dissolved oxygen, which the offshore operators actively remove with vacuum and chemical oxygen scavengers. The vacuum deaerators have a removal limit, after which the dissolved oxygen concentration is decreased using chemical oxygen scavengers most often sodium sulfite, but this adds a cost. The main expense is not the chemical itself, but the side product of the chemical reaction, which leaves sulfates, that feed sulfate reducing bacteria, leading to a production of Hydrogen sulfide which leads to sour corrosion. One solution to reduction in dissolved oxygen and oxygen scavenger is proper control of the facilities. This work investigates the potential for feedback control of the facilities using an online dissolved oxygen instrument, where an experimental study of three commercial dissolved oxygen instruments has been performed, with good results.

Water-Injection Techniques Increase Recovery in Conventional Gas Reservoirs

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 191206, “Exploiting Water-Injection Techniques for Increasing Gas Recovery in Conventional Gas Reservoirs,” by Keval Darvesh Rambaran, SPE, Sarah Tammie Chin Chee Fat, SPE, and Lugard Evans Layne, SPE, University of Trinidad and Tobago, prepared for the 2018 SPE Trinidad and Tobago Section Energy Resources Conference, Port of Spain, Trinidad and Tobago, 25–26 June The paper has not been peer reviewed. Primary gas recovery for a volumetric reservoir ends when the reservoir pressure declines below the value required to flow gas to the surface at the sales-line pressure. Secondary gas-recovery techniques can then be used to increase the recovery. The most common of these techniques is gas compression, but another feasible technique that is rarely explored is water injection. This paper evaluates the incremental benefit of water injection in a conventional gas reservoir when compared with gas compression. Introduction An operator hopes to increase the recovery in Reservoir TM-20 in the Sorrel Field offshore Trinidad and Tobago by use of water injection once the technique is deemed more economical than gas compression. The wells in the reservoir are drilled from the Tamarind Platform, which also acts as a hub for the separation of fluids from fields in the immediate vicinity. Gases and liquids are piped through separate lines, with the liquids heading to the onshore liquid-processing facility. However, the company can modify the platform separators to operate in three phases and use the produced water for injection. Company records show that the average water-production rate from the platform is approximately 5,000 BWPD. If the shut-in wells were to be opened, roughly 10,000 BWPD of produced water and 15 MMscf/D of gas would be added for each well until liquid loading, thus increasing gas output significantly. Field History The Sorrel Field is a retrograde gas-condensate field located in the Columbus Basin, which has been producing from the TM-20 reservoir since 1998. The reservoir is a faulted sandstone formation of good quality that is divided into two hydrocarbon-bearing segments and underlain by an active aquifer. Segments 1 and 2 have been producing from Wells X and Y and Wells A and B, respectively, as shown in Fig. 1. Unlike Segment 1, primary gas recovery in Segment 2 ended because of a decline in the reservoir pressure, thus making it a suitable choice for water injection. Segment 2 is a wedge-shaped structure bounded by two faults, with both faults being interpreted as sealing. Production in Segment 2 began in April 1999 with a reservoir pressure of 4,732 psig. It ended in January 2014 because of an inability to flow at the sales-line pressure of 950 psig.

Real-time management of the waterflooding process using proxy reservoir modeling and data fusion theory

Waterflooding is the use of water injection to enhance the oil recovery in mature oil reservoirs. In this paper an adaptive algorithm has been introduced for waterflooding management in oil reservoirs based on proxy modeling technique. The presented approach is capable to handle the time-varying nature and the inherent nonlinearity of the complex process. In addition, any variation either in market prices or in operational costs is compensated by the designed adaptive controller to fix the obtained profit (here, the net present value: npv) at a desired achievable value. The observed outcomes on 10th SPE-Model#2 benchmark case study have shown that by using this algorithm, any feasible desired trajectory for the expected benefit can be satisfied during the waterflooding-based production. Since the suggested controller has adaptive structure, it can be re-adjusted continuously in each time-step, using available operational data, to take into account the reservoir dynamical variations as well as the external disturbances to present an acceptable performance. By including a monitoring module in the algorithm structure based on data fusion technique, the updated profitability/productivity status of the reservoir is estimated. By using this information the npv setpoint induced to the closed-loop system can be automatically re-adjusted such that it always remains in an acceptable and reasonable range. In conclusion, the proposed methodology is an applicable solution for fairly profit-sharing in different kinds of contracts. In other words, the gained profit can be appropriately allocated to the shareholders according to the contractual obligations or a defined npv trajectory while considering the current condition of the reservoir. This strategy helps to prevent from ultra-production in a specific period of time by the clients or contractors which may lead to an unexpected reduction in the share of other parties in the reservoir life-cycle.

The Effect of Water Injection on the Control of In-Cylinder Pressure and Enhanced Power Output in a Four-Stroke Spark-Ignition Engine

This paper presents the results for liquid water injection (WI) into a cylinder during the compression and expansion strokes of an internal combustion engine (ICE), with the aim of achieving an optimal in-cylinder pressure and improving power output using CFD simulation. Employing WI during the compression stroke at 80° of crank angle (CA) before top dead centre (bTDC) resulted in the reduction of compression work due to a reduction in peak compression pressure by a margin of about 2%. The decreased peak compression pressure also yielded the benefit of a decrease in NOx emission by a margin of 34% as well as the prevention of detonation. Using WI during the expansion stroke (after top dead centre–aTDC) revealed two stages of the in-cylinder pressure: the first stage involved a decrease in pressure by heat absorption, and the second stage involved an increase in the pressure as a result of an increase in the steam volume via expansion. For the case of water addition (WA 3.0%) and a water temperature of 100 °C, the percentage decrease of in-cylinder pressure was 2.7% during the first stage and a 2.5% pressure increase during the second stage. Water injection helped in reducing the energy losses resulting from the transfer of heat to the walls and exhaust gases. At 180° CA aTDC, the exhaust gas temperature decreased by 42 K, 89 K, and 136 K for WA 1.0, WA 2.0, and WA 3.0, respectively. Increasing the WI temperature to 200 °C resulted in a decrease of the in-cylinder pressure by 1.0% during the first stage, with an increase of approximately 4.0% in the second stage. The use of WI in both compression and expansion strokes resulted in a maximum increase of in-cylinder pressure of about 7%, demonstrating the potential of higher power output.

Hydrochloride Acid Effect on the pH Value of the Superabsorbent Polymer (SAP) Solutions

In mature oil fields, the use of water injection is common, but is limited by reservoir heterogeneity. Differences in permeability can increase water production and subsequently increase operating cost. Superabsorbent polymers can be used to control reservoir fluid flow. Understanding the kinetics of these polymers, such as AT-O3S and 2G-110, is the key to their proper use during the treatments. The polymers used are both a cross linked Sodium polyacrylic acid, these three factors determine the extent to which the polymers will absorb water, which induces swelling. Swelling is strongly dependent on salinity, pH, and temperature. This study investigated the influence of pH by using brines with different percent weight ratios of deionized water and Calcium Chloride. The polymer is destroyed and a white precipitate made of Calcium polyacrylate is formed, due to the presence of divalent cations in the solution. In order to decrease the effects of the reaction, the pH of the solution was modified. As pH drops, it is observed that the precipitation decreases substantially, especially in dilute solutions. It can be inferred that the precipitation effects can be mitigated through the appropriate use of acid washes, preflushes, and polymer concentration in many cases. However, high temperatures might cause further precipitation in brines containing divalent cations.

Experimental study on lift-off acoustic environments of launch vehicles by scaled cold jet

Mitsubishi Heavy Industries (MHI) have been operating the current Japanese flagship launch vehicle H-IIA and H-IIB, and developing the next flagship launch vehicle H-X. The concept of H-X is affordable, convenient, and comfortable for payloads including mitigation of acoustic environment during launch. Acoustic measurements were conducted using scaled GN2 cold jet and aperture plate to facilitate understanding of lift-off acoustic source and to take appropriate measures against it without use of water injection. It was seen that the level of vehicle acoustics in high frequency range depends on the amount of interference between the jet and the plate, and enlargement of the aperture is effective for acoustic mitigation.

Inhibition of Scale Formation Using Silica Nanoparticle

Because of the wide use of water injection for enhanced oil recovery in the oil fields in order to displace oil into the production well, many reservoirs experience scale deposition problems. Scale formation can cause the production path to be blocked and also cause significant reduction in productivity. One of the most common methods for preventing or lowering the amount of scale formation is applying the scale inhibitors. In this work, silica nanoparticles are used as a scale inhibitor. Conductivity is used as a property of the fluid to show the amount of ion in the solution, leading us to predict the amount of scale formed in the solution. An optimum amount of silica nanoparticles could reduce the rate of conductivity decreasing the solution and consequently lowering the scale deposition, which is the aim of this challenging subject in the oil industry.

High-pressure Water Jet Injury to the Abdomen: A Case Report and Literature Review

The rise in high-pressure water jet injuries over the last century corresponds to the increased usage of this technology in a number of industries. Some of the most common applications include the use of water injection to stimulate oil production in reservoirs, the use of hydroblasting in industrial cleaning, and the use of water jet cutting to engrave or slice materials like sheet metal, concrete, and glass. These devices generate pressures up to 55,000 pounds per square inch (psi) and can deliver liquid at flow rates up to 60 gallons per minute [1,2]. Depending on the surface area of the nozzle, fluid velocities can mimic those of military rifles in the range of thousands of feet per second.

Experimental Investigation on Aerodynamic Behavior of a Compressor Cascade in Droplet Laden Flow

The possibility to augment the power output of gas turbines by the use of water injection becomes more and more attractive in recent years as unsteadily available renewable energy sources become more present and the need of reserve power rises. Depending on the installed system, water injection may result in a two phase flow inside the compressor. The water droplet laden compressor flow promises benefits in efficiency and to some extent in performance and stability. A promising approach is the stabilizing influence on highly stressed airfoils as experimentally and numerically investigated by different research groups. Multiple numerical investigations have been undertaken by different research groups which found similar results. The ongoing experimental investigation presented in this paper focuses on the influence of a droplet laden flow on an axial compressors' aerodynamics over the range of relevant incidence flow angles. The result of the series of experiments is a comparison of a dry air compressor flow and a droplet laden air compressor flow at high velocity (Ma>0.85). The variables were water load and incidence angle. The discussion will investigate the effects of the presence of water droplet on the compressor cascade's discharge flow properties and their influence on the relevant performance parameters. For this a discussion of the loss coefficient the detailed discharge flow velocity and the axial velocity density ratio will take place.

Towards scalable production of polyamide 12/halloysite nanocomposites via water-assisted extrusion: mechanical modeling, thermal and fire properties

In this study, polyamide 12 (PA12)/untreated halloysite nanotubes (HNTs) nanocomposites are prepared in a semi-industrial scale extruder using a non-traditional “one step” water-assisted extrusion process. A morphological study is carried out using a combination of scanning electron microscopy and transmission electron microscopy analyses to evaluate the influence of water injection and filler content on the quality of clay dispersion. The use of water injection slightly improves the nanoscale dispersion at low HNTs content (<8 wt.%), while this effect is more pronounced at higher filler loading (16 wt.%). A mechanism explaining the physico-chemical action of water during extrusion is proposed. The materials are characterized with respect to their mechanical, thermo-mechanical, thermal and fire properties. A strong correlation is found between nanostructure and physical properties; the more uniform dispersion of the clay nanotubes, the higher mechanical reinforcement, thermal stability and fire retardancy of PA12 nanocomposites. Tensile tests results are interpreted in terms of three mechanical models: the Halpin–Tsai's model for stiffness and the interfacial strength model and the Pukanszky's equation for yield strength. Linear fits of the experimental data confirm that the superior reinforcement of nanocomposites prepared using water injection results from improved clay dispersion and better interfacial adhesion between PA12 and HNTs. In view of these promising results, the proposed direct melt compounding method could be easily scaled-up towards the production of PA12–HNTs nanocomposites at an industrial scale. Copyright © 2013 John Wiley & Sons, Ltd.

Water injection in directly injected turbocharged spark ignition engines

The paper explores the use of water injection in a turbocharged, direct injection, spark ignition engines fuelled with ethanol where port injection of water numerically prove to be effective in increasing the charge efficiency, reducing the tendency to knock, and controlling the temperature of gases to turbine. With injection of water in selected operating conditions, the engine may run higher compression ratios and boost pressures and closer to maximum brake torque spark advances for improved top power output and peak efficiency as well as better part load efficiencies. The paper suggests the introduction of this old technique now used in aftermarket kits possibly evolved to direct water injection in the design stage of novel turbocharged engines.

Model study on the kinetics of oil field formation damage due to salt precipitation from injection

Due to the extensive use of water injection for oil displacement and pressure maintenance in oilfields, many reservoirs experience the problem of scale deposition when injection water starts to break through. In most cases, the scaled-up wells are caused by the formation of sulfate and carbonate scales of calcium and strontium. Due to their relative hardness and low solubility, there are limited processes available for their removal and preventive measures such as the ‘squeeze’ inhibitor treatment have to be taken. It is therefore important to gain a proper understanding of the kinetics of scale formation and its detrimental effects on formation damage under both inhibited and uninhibited conditions. This paper presents the results of an experimental and theoretical study of permeability reduction of porous media caused by scaling. Two incompatible solutions of calcium and sulfate/carbonate ions were injected into the porous medium, where calcium sulfate or calcium carbonate was generated by chemical reaction. Mechanisms by which a precipitate reduces permeability include solids deposition on the pore walls due to attractive forces between the particles and the surfaces of the pores, individual particles blocking pore throats, and several particles bridging across a pore throat. The characteristics of the precipitate influence the extent of formation damage. Conditions such as large degree of supersaturation, presence of impurities, change in temperature, and rate of mixing control the quantity and morphology of the precipitating crystals.

Evaluation of Advanced Combustors for Dry NOx Suppression With Nitrogen Bearing Fuels in Utility and Industrial Gas Turbines

The work described in this paper is part of the DOE/LeRC Advanced Conversion-Technology Project (ACT). The program is a multiple contract effort with funding provided by the Department of Energy, and technical program management provided by NASA LeRC. Combustion tests are in progress to evaluate the potential of seven advanced combustor concepts for achieving low NOx emissions for utility gas turbine engines without the use of water injection. Emphasis was on the development of the required combustor aerothermodynamic features for burning high nitrogen fuels. Testing was conducted over a wide range of operating conditions for a 12:1 pressure ratio heavy-duty gas turbine. Combustors were evaluated with distillate fuel, SRC-II coal-derived fuel, residual fuel, and blends. Test results indicate that low levels of NOx and fuel-bound nitrogen conversion can be achieved with rich-lean combustors for fuels with high fuel-bound nitrogen. In addition, ultra-low levels of NOx can be achieved with lean-lean combustors for fuels with low fuel-bound nitrogen.

Advanced Technology Improves Recovery at Fairway

The most important decision made in the early stages of this miscible recovery project was to hang loose. The original plan of operation allowed for injecting all gas, all water, or any combination, depending upon what new information was gained as the project went along. Radioactive tracers, new logging techniques, numeric modeling, and sophisticated down-hole equipment provided that information. Introduction The Fairway (James Lime) field is about 30 miles south of Tyler, Tex. The discovery well was drilled in July, 1960. near the eastern edge of the field, which eventually proved up over 400 million bbl of oil in place under about 23,000 acres. The 10,000-ft James Lime reservoir is a reef development at Fairway, quite different from the regional character of the formation. Three major zones exist in the reservoir as a result of differing conditions of reef growth environment. From the start, this complex, highly stratified, variable-permeability, reservoir offered quite a challenge to the operators. The James Lime oil is an undersaturated 48 degrees API-gravity crude containing from 1,350 to 1,600 cu ft of solution gas per barrel. Saturation pressure varied with depth and ranged from 3,950 to 4,350 psia. The reservoir fluid was determined to be miscible, with lean hydrocarbon gas or flue gas at about 4,800 psia - about 400 psi below the initial reservoir pressure. Connate water saturation ranged from 10 to 30 percent, and the porosity averaged about 12.5 percent. Unitization studies showed that incremental economics favored an alternate gas-water high-pressure miscible recovery project over waterflooding or immiscible gas injection. The operators recognized that many miscible projects had experienced poor recovery and even lost projects had experienced poor recovery and even lost money. Alternating gas and water injection represented the "outer limits" of miscible recovery technology available at the time and involved a high degree of risk. The decision was made to go ahead with the alternating approach, but with a program designed to have a large degree of operational flexibility. In this manner, necessary changes and adjustments could be made along the way. Additional recovery from the alternating gas-water high-pressure miscible recovery technique in use at Fairway is significant. Production exceeded the estimated primary reserves of 65 million STB of oil in June, 1971 (see Fig. 1). Currently the Unit is producing the top allowable of 40,500 BOPD. producing the top allowable of 40,500 BOPD. Injection capacity determines the maximum production rate at Fairway. The average reservoir production rate at Fairway. The average reservoir pressure has been maintained essentially constant at pressure has been maintained essentially constant at 4,500 psi since early 1970. An expansion program to increase gas injection capacity from 70 to 100 MMcf/D and water injection from 60,000 to 90,000 BWPD is currently in progress. With the increased injection capabilities and 13 new wells, now drilling. the Unit will be capable of producing at 100-percent market demand factor, about 53,000 BOPD for about 2 years before it declines as a result of an increasing voidage of injected fluids. Mobility Control The use of water injection to restrict the mobility of the injected gas is the key factor in the improved recovery of the Fairway project. A reduction of viscous fingering of the gas and improved sweep efficiency through water injection is very important in the over-all control of the Fairway project. Many of the early indications of fingering were in the north end of the field (Fig. 2) where gas injection was concentrated initially. Fig. 3 illustrates the typical relationship between producing trends and injection cycles. producing trends and injection cycles. JPT P. 354

Mobility Ratio - Its Influence on Flood Patterns During Water Encroachment

Abstract The results of potentiometric model studies and numerical computations are described. The purpose of these studies was to determine the influence of the mobility ratio on flooding efficiencies during water encroachment in petroleum reservoirs, in systems of regular well geometry. The direct line drive well pattern having relative spacing distances of one and one-half to one was investigated for water to oil mobility ratios of 10, 1, and 0.1. The results of these studies indicate that the pattern sweep efficiency is very dependent upon the mobility ratio. Introduction The almost universal occurrence of water in the immediate neighborhood of oil-bearing sands lends considerable emphasis to the desirability of having a rational analysis of water encroachment into petroleum reservoirs. This problem has become increasingly important with the accelerated use of water injection for secondary recovery operations. The water encroachment problem has been studied from both the theoretical and experimental viewpoints by Muskat. He has formulated, in a precise manner, differential equations to express flow in a water encroachment system, and rigorous analytical solutions have been developed for the linear, radial, and spherical cases. However, it becomes exceedingly difficult to solve the encroachment problem rigorously for any general two-dimensional system in which the shape of the two-fluid interface is not immediately evident from the geometry of the system. The difficulty lies in the fact that a rigorous analytical solution requires that the shape of the two-fluid interface be known simultaneously with its instantaneous position and with the pressure distribution on both sides of the interface. Although this paper concerns the study of the two-fluid system of oil and water, the methods described in the paper are generally applicable to other systems of incompressible and immiscible fluids in which the displacing fluid sweeps the displaced fluid down to a residual value. In each region it is assumed there is only one mobile fluid and its mobility is constant throughout the region. The same procedure, with minor alterations, is applicable for gas injection systems provided the assumption can be made that both the displaced and displacing gases can be described by steady state formulas.