Voidage article about voidage by the free dictionary. Water injection or water flooding is done on and offshore, to increase oil recovery from an existing oil or gas reservoir. Some reservoir management practices relevant to voidage replacement ratio should be further examined and adapted accordingly. The term voidage is normally used to refer to the tiny spaces between particles in a powder or granulated material like sand. The income replacement ratio is really a spending replacement ratio. Bo, bw and bg are the formation volume factors for the three phases. Keys to achieving a successful waterflood and estimating.
Water injection below the bubble point pressure with. The vrr function corresponds to the ratio of the total volume of. The hall plot analysis enables you to draw conclusions about average injectivity performance. Your replacement ratio an important retirement consideration. For these experiments, the incremental recovery for aquifersupported fields is small with a p50 value of 7%. Are known, the volumes produced in the following table. In addition, the method includes c waterflooding the reservoir at a voidage replacement ratio vrr less than 1. Voidage, e, is defined as the fraction of the total volume which is free space.
The vrr analysis aids in identifying parts of a field where more or less water must be injected in order to. Optimum voidage replacement ratio and operational practice for. Dec 31, 2018 pattern voidage replacement ratios 29 cumulative vrr 0. Aug 31, 2015 voidage replacement ratio should be tracked not only at the field level but by reservoir, by fault block and even by pattern.
Additionally well c02st1 was producing oil at an increasing rate, a trend which the current reservoir model failed to match. V oidage replacement ratio vrr cen be defined as the ratio of. The voidage replacement refers to replacing the volume of oil, gas, and water produced from the reservoir by injected fluids. Mar 21, 2012 the income replacement ratio is really a spending replacement ratio. Issues in waterflooding iii introduction to waterflood. What is the abbreviation for voidage replacement ratio. The sensitivity of the voidage replacement ratio vrr was studied to obtain. The least important are bed dip, injection voidage replacement, and pvt properties.
The vrr analysis aids in identifying parts of a field where more or less water must be injected in order to reach or maintain vrr targets. Pressure maintenance project progress report requirements. Analytical method for voidage replacement ratio calculation. Our first objective was to test whether the industry paradigm and the regulatory mandated practice of maintaining a voidage replacement ratio vrr of one throughout the entire waterflood is optimal. Using percolation theory to estimate recovery from poorly. Optimum voidage replacement ratio and operational practice. Vrr is defined as voidage replacement ratio frequently.
The voidage replacement ratio vrr, between fluids injected and fluids withdrawn, both monthly and cumulative, from the project, and by individual patterns where applicable. Pdf production optimization through voidage replacement. Voidage replacement ratio is defined as the ratio of injected reservoir volume to produced reservoir volume. This paper focuses on one critical aspectmeasure during waterflooding stage, which is the voidage replacement ratio vrr. Since reservoirs are more heterogeneous than homogenous, even though the voidage replacement may be unity for the reservoir, some areas may be greater than unity, and others much less than unity. Voidage replacement ratio calculations in retrograde condensate to volatile oil reservoirs undergoing eor processes. This gives reservoir voidage replacement ratio of 1, without significant pressure depletion of the reservoir. Gor is the produced gasoil ratio and rs is the solution gas. A replacement rate is the percentage of a workers preretirement income that is paid out by a pension program upon retirement. A vrr table showing the data elements used for calculation of the monthly and cumulative vrr see appendix a. With surveillance analysis, you can perform hall plot and voidage replacement ratio vrr analyses. In pension systems where workers get substantially. Variable voidage replacement ratio waterflooding this statistical research inspired the second approach a largemodel experimental study that found delaying the onset of waterflooding and injecting water using a process termed variable voidage replacement ratio waterflooding could increase heavy oil recovery.
Request pdf optimum voidage replacement ratio and operational practice. Vrr is defined as the ratio of inject ed fluids at reservoir. Voidage replacement calculations are often conducted on the entire reservoir, however, reservoir heterogeneity must be considered when interpreting vrr. Oil and water production rates are directly related to injection rates. Void ratio article about void ratio by the free dictionary. Often, voidage replacement ratio vrr and net present value npv are used as indicators of performance of waterflood projects. Optimal voidage replacement ratio for communicating heavy oil. Pdf voidage replacement is a key element in displacement processes, not. Voidable definition of voidable by the free dictionary. The second most important waterflood management metric is the ratio of the produced water to the produced oil wor. Heavy oil waterflooding enabled by optimal waterflood voidage. Classifying inadequate vrr as a high risk, the ercb is asking operators to maintain full cumulative and monthly vrr in order to fully maintain reservoir pressure.
Various planning development strategies were implemented utilizing different vrr values ranging from 0. The least important are bed dip, injection voidagereplacement, and pvt properties. The results are also used to estimate the recovery of the unswept oil from dangling ends by a waterflood with a voidage replacement ratio free space available for the flow of fluids, and thus the fractional volume of the bed occupied by solid material is 1. Wo2016073810a1 methods for managing formation voidage. Pdf optimal waterflood voidage management significantly.
Streamline models are often particularly useful to supplement voidage. Voidage replacement ratio is defined as the ratio of injected reservoir. Water injection below the bubble point pressure with voidage. During the voidage replacement period, the engineer must make sure of two things.
In equation 1, the third term in the denominator accounts for free gas produced that is in excess. The voidage replacement ratio vrr is defined as the ratio of reservoir barrels. The wage replacement ratio, also known as income replacement ratio, generally refers to the percentage of preretirement income needed in retirement. Student id number 19 82 you want to estimate gas in place and the recovery factor final for a gas field by the method p z. Water is injected to support the reservoir pressure also known as voidage replacement, and also to sweep or displace oil from the reservoir, and drive it towards a production well. Key waterflooding variables are depofacies, aquifer size, permeability, fault transmissibility, and oil saturation. Voidage, e, is defined as the fraction of the total volume which is free space available for the flow of fluids, and thus the fractional volume of the bed occupied by solid material is 1. The sensitivity of the voidage replacement ratio vrr was studied to obtain the best water injection planning strategy to maximize oil production recovery and therefrom profitability. Methods for managing formation voidage replacement in waterflood production operations to increase oil recovery. Historically a voidage replacement ratio vrr of 1 is assumed to be optimal for oil recovery regardless of whether recovery occurs from an unconventional heavy oil reservoir or a conventional oil.
Waterflood application in semiconsolidated heavy oil. That the volume of injected water equals the reservoir voidage of oil, gas, and water production that the various areas or patterns of the reservoir are being balanced to maximize the oil recovery and to minimize waterhandling operating costs. Additionally, the board may also require minimum operation pressure compliance. Reservoir management strategies for development of water. Voidage is the proportion of unoccupied volume that is, gaps or empty spaces in a volume of some material. Automated quality assurance is implemented through the process to avoid human errors due to the heavy number of strings.
This paper presents experimental data that question one of the key assumptions. Wage replacement ratio definition retirement planning. A replacement ratio is a persons gross income after retirement, divided by his or her gross income before retirement. Typically, waterflooding commences after a period of primary production. Software development for calculations of voidage replacement. Based on the definition of compressibility, the following equation represents. Vrr is the ratio of reservoir barrels of injected fluid to reservoir barrels of produced fluid. Voidage replacement is a key element in displacement processes, not only for keeping the reservoir pressure at its initial level but also in mitigating surface subsidence in certain fields. Defending the 70% replacement ratio for retirement income. Evaluating waterflooding incremental oil recovery using. Evrr only takes into account the effective water support from the peripheral water injection.
Voidage replacement ratio vrr cen be defined as the ratio of. The purpose of waterflooding is to enhance recovery by maintaining reservoir pressure, or when necessary, increasing reservoir pressure so that it approaches the. Software development for calculations of voidage replacement ratio vrr by nazrulhisham bin osman dissertation submitted in partial fulfilment of the requirements for the bachelor ofengineering hons mechanical engineering january2003 universiti teknologi petronas i bandarseri iskandar t 31750tronoh,flv perak darul ridzuan. Meanwhile in the southern area, a stable reservoir pressure trend is observed in unit 27 despite reduction of cumulative voidage replacement ratio vrr from 0. Vrr is defined as the ratio of injected fluids at reservoir condition to produced fluids at reservoir condition. Request pdf optimum voidage replacement ratio and operational practice for heavy oil waterfloods heavy oil waterfloods have been operating in the petroleum industry for more than fifty years. The voidage replacement ratio vrr, between fluids injected and fluids withdrawn, both monthly and. Pattern voidage replacement ratios 29 cumulative vrr 0. Our first objective was to test whether the industry paradigm and the regulatory mandated practice in some jurisdictions of maintaining a voidage replacement ratio vrr of one throughout the entire waterflood is optimal. Use of water to increase oil production is known as secondary recovery and typically follows primary production, which uses the reservoirs natural energy fluid and rock expansion, solutiongas drive, gravity drainage, and aquifer influx to produce oil. Student full name student id number 17 time tank oil solution.
Waterflooding is the use of water injection to increase the production from oil reservoirs. Efficient voidage replacement ratio evrr on both reservoir and segment levels has been applied to assure proper pressure support. Mannville isopach husky energy heavy oil course manual, 2000. Ca2963814a1 methods for managing formation voidage. In contracts, voidable is a term typically used with respect to a contract that is valid and binding unless avoided or declared void by a party to the contract who is legitimately exercising a power to avoid the contractual obligations. Conclusion typical waterflood operations target injection at vrr equals to 1 or slightly higher. Voidage replacement ratio should be tracked not only at the field level but by reservoir, by fault block and even by pattern. Depending upon the nature of the porous medium, the voidage may range from near zero to almost unity. That which is not absolutely void, but may be avoided. However, when free gas becomes preferentially mobile and starts to flow as a. Injector analysis hall plot skin analysis technique for injection wells yaxis hall coefficient pressure x days 30 hall, h. In addition, vrr is used by regulatory and environmental agencies as a means of monitoring the impact of field development activities on the environment while npv is used by investors as a measure of profitability of.