What is waterflooding in reservoir engineering?
1 Waterflooding. Waterflooding is a form of oil recovery wherein the energy required to move the oil from the reservoir rock into a producing well is supplied from the surface by means of water injection and the induced pressure from the presence of additional water.
What is the purpose of waterflooding?
Waterflooding is a process used to inject water into an oil-bearing reservoir for pressure maintenance as well as for displacing and producing incremental oil after (or sometimes before) the economic production limit has been reached. This is done through the displacement of oil and free gas by water.
What is a waterflood in oil field?
1. n. [Well Completions, Enhanced Oil Recovery] A method of secondary recovery in which water is injected into the reservoir formation to displace residual oil. The water from injection wells physically sweeps the displaced oil to adjacent production wells.
What are the different types of patterns used for waterflooding?
‘” The patterns include the direct line-drive square pattern, the five-spot pattern and the seven-spot network. Note that, for well spacings near 330 ft, the injectivities are of the order of 5.0, 5.4 and 7.0 for the case of the line-drive, five-spot and seven- spot networks, respectively.
Why is water injected in oil wells?
Water injection is used in the production of oil where high pressure water is injected into the oil reservoir to increase pressure to increase oil recovery from an existing reservoir. Water injection wells can be found both on- and offshore.
What is Vrr in oil and gas?
Voidage replacement ratio (VRR), which is defined as the ratio between the volume of injected fluid and the volume of produced fluid, measures the rate of change in reservoir energy. Conventionally, operators try to maintain a VRR close to one during the whole field life.
What is water injection in oil and gas?
What is a 5 spot pattern?
1. n. [Enhanced Oil Recovery, Heavy Oil] An injection pattern in which four input or injection wells are located at the corners of a square and the production well sits in the center.
What is flooding pattern?
1. n. [Enhanced Oil Recovery] Also known as injection pattern, the particular arrangement of production and injection wells.
What is sweep efficiency in oil reservoir?
Vertical sweep efficiency is the fraction of vertical cross-sectional area of the reservoir between injection and production wells that is swept by water at a given time. It can be used to estimate and predict the unswept fraction of the reservoir by water injection and the additional oil recovery potential.
What is surfactant flooding?
Surfactant flooding is an important technique used in enhanced oil recovery to reduce the amount of oil in pore space of matrix rock. Surfactants are injected to mobilize residual oil by lowering the interfacial tension between oil and water and/or by the wettability alteration from oil-wet to water-wet.
What is Vrr in reservoir?
Voidage Replacement Ratio (VRR) can be defined as the ratio between the total fluid injection in reservoir barrels and the total fluid production in reservoir barrels.
What is mobility ratio?
The mobility ratio is a single term that describes the rate and efficiency of oil displacement by other immiscible fluids. Diminishing values of M(less than one) are generally considered as favorable values, and increasing values (greater than one) are considered as unfavorable values.
What is displacement efficiency?
Displacement efficiency is a measure of the amount of mobile fluid in the system. In addition to displacement efficiency, recovery efficiency for oil depends on the amount of oil contacted by injected fluids. Areal and vertical sweep efficiencies measure the degree of contact between in situ and injected fluids.
What is IFT in surfactant?
Surfactants are known as interfacial tension (IFT) reducer additives in enhanced oil recovery (EOR) process. The use of chemical surfactants has always been a challenge due to the high cost of materials and sometimes non-compliance with the environment.
What are the types of oil reservoir?
Typically, there are five main types of reservoir fluids: black oil, volatile oil, condensate (retrograde gas), wet gas, and dry gas.
What is the purpose of water flooding an oil reservoir?
The principal reason for waterflooding an oil reservoir is to increase the oil-production rate and, ultimately, the oil recovery. This is accomplished by “voidage replacement”—injection of water to increase the reservoir pressure to its initial level and maintain it near that pressure.
When did waterflooding become used to recover oil fields?
By the 1970s, most onshore oil fields in the US, USSR, and China, for which waterflooding was the logical recovery process, were being produced by use of this technology in various well-pattern arrangements.
What are the key oil properties of a waterflood?
Oil properties are important to technical and economic success of a waterflood. The key oil properties are viscosity and density at reservoir conditions.
How much oil is in the Ekofisk reservoir?
Discovered in 1969, Ekofisk had produced over 1.7 billion barrels of oil as of 2002, out of an estimated 6.7 billion barrels originally in place. The Ekofisk reservoir has exceptional production characteristics. The discovery well had an IP of over 10,000 barrels of oil per day ( Feazel et al., 1985 ).