A seawater deaerator is essential in recovering every last bit of oil from the seabed, so as to maximise the returns of investment.
Edwards’ solution consists of a tower to treat the retrieved mixture of seawater, gas and oil; and a specialised Liquid Ring Pump and its backup. This is used during the secondary recovery of oil.
Here’s a rundown of how oil is retrieved from the seabed during the primary and secondary recovery.
Primary Recovery of Oil
The reservoir has formed in a layer of porous rock that has impermeable rock above and below it. These impermeable rock layers have trapped the fluids in place and prevented them from dispersing and being lost.
The fluids in the reservoir comprise natural gas, crude oil, and water.
Fluids can be produced from a reservoir without any stimulation or pumping because of the natural energy available within the hydrocarbon reservoir itself, being at a high pressure and temperature. The pressure in the reservoir is considerably higher than that in the wellbore (bottomhole pressure) so this high differential pressure will drive hydrocarbons towards the well and up to the surface. This method of recovering hydrocarbons is referred to as “primary recovery”.
However, over time as hydrocarbon production continues, the pressure in the reservoir declines and so does the differential pressure. The rate of hydrocarbon production therefore declines.
To enhance hydrocarbon production, operators often employ artificial lift systems. These systems help reduce bottomhole pressure or increase differential pressure. Common artificial lift methods include rod pumps, electrical submersible pumps, and gas-lift installations. Despite advancements in secondary recovery techniques, artificial lift remains a primary method for optimizing production from unconventional wells.
It should be noted that whilst a production well may be described as an “oil well”, the fluid produced from it will always comprise a mixture of crude oil, produced water and gas. An initial stage of the oil production process will separate these three components into individual streams for treating as necessary.
Secondary Recovery using Water Injection
Primary recovery reaches its limit when either the reservoir pressure is too low, resulting in uneconomical oil production rates, or when the proportions of gas and/or water in the production stream make effective and economical separation challenging. Typically, during primary recovery, only around 30% of the initial hydrocarbons in place can be produced from oil reservoirs.
The “secondary recovery” stage of hydrocarbon production employs an external fluid such as water (usually treated seawater) or gas which is injected through injection wells located in rock that has fluid communication due to porosity and/or fractures, to maintain reservoir pressure and particularly in the case of water injection, to displace oil towards the production wells and sweep it from the reservoir.
In recent times it has become common for installations to employ secondary recovery as a “pressure maintenance programme” during the primary recovery production phase to improve production for economic reasons.
Water injection is a widely used “secondary recovery” technique for increasing the rate of oil production from an oil field and the total amount of oil in the oil reservoir that can be extracted for use, to increase revenue and profitability of the associated oil production facility.
Water injection uses a series of individual process packages installed on an oil production facility, together referred to as the “water injection system” or “water injection package”, to treat a flow of water, usually seawater, to enable it to be injected into the rock formation of the oil reservoir through specially drilled injection wells to maintain the pressure within the reservoir and to drive the crude oil held in the reservoir towards the production wells. Through which the oil flows to the production facility for transporting to a refinery.
In the secondary recovery stage of oil production, limitations arise when the injected fluid (either water or gas) is significantly produced from the production wells, rendering further production economically unviable.
The combined utilization of primary recovery and secondary recovery methods in an oil reservoir typically results in extracting approximately 70% of the original oil in place.
Why choose Edwards’ as your vacuum deaerator supply specialist?
Edwards water injection water deaerators, or as they often referred to, seawater deaerators (sometimes referred to as de-oxygenation towers), form a key part of treating water to make it suitable for injection into the reservoir by the water injection system.
This method of secondary recovery using treated water is referred to as “water injection” or “waterflooding”.
Edwards water injection water deaerators, or as they often referred to, seawater deaerators (sometimes referred to as de-oxygenation towers), form a key part of treating water to make it suitable for injection into the reservoir by the water injection system.
This method of secondary recovery using treated water is referred to as “water injection” or “waterflooding”.
Edwards - Hick Hargreaves Seawater Deaerators – expertise that you can count on
Edwards acquired Hick Hargreaves in 2001, which specialises in the application of mass transfer, heat transfer and vacuum technology for main contractors and end users in oil and gas production, petrochemicals, power generation, pharmaceutical production, nuclear waste processing, foodstuffs manufacture and other process related industries.
Edwards - Hick Hargreaves has supplied vacuum deaerators since 1930, when applications were largely for boilers and process water systems.
Since that time the company also developed the unique spray technology, which has been enhanced and applied to water injection applications for oilfield development since the mid 1970’s.
Edwards Hick Hargreaves has developed a substantial installation reference list, including a significant number of demanding floating offshore installations, with clients which include most of the major operators and contractors worldwide.
Edwards provide the expertise to design the tower, to supply the tower (if required) and to supply the specific Liquid Ring Pumps that are required for your purpose. You can depend on our long-proven track record to achieve your requirements.
You can choose between:
Spray/pack deaerators
Packed column deaerators
Trace gas stripping deaerators
As Edwards designs and manufactures both deaerators and vacuum pumps, this gives you a single point of contact for a seamless, quick, and hassle-free experience. This also ensures we can optimise the overall design for the best efficiency, with minimal design iterations.
