EOR (Enhanced Oil Recovery)


The EOR is production recovery techniques which seek to produce oil which would not be recovered using the primary and secondary recovery methods where the oil has stopped flowing or where the water content of the oil reservoir has increased. EOR is widely applied today, as it can increase oil production without exploration risks.

EOR is a technique that was established during the 1970s mainly in the United States. Since the 1980s, TOYO has engaged in oil field development in which this EOR technique is applied. Most of the remaining crude oil lies in oil reservoir shows low mobility, and fluid that reduces the viscosity is injected into the oil reservoir in many cases in order to recover the remaining crude oil.
The fluid used is either heat, gas, chemical (surfactants) or polymer, and analyses of the reservoir dynamic behavior and operation data are needed when selecting the fluid to be injected and the recovery method. As such, the experience in developing planning in the similar projects as well as knowledge of properties and the underground behavior of the fluid to be injected are necessary to establish development planning using EOR techniques.

Guideline for Changing Oil Recovery System

EOR techniques and applicable oil fields

There are three major EOR techniques, namely thermal, gas and chemical flooding. Of these, chemical flooding is considered the technique that will be used in the future. All three methods recover remaining crude oil by lowering its viscosity or using displacing fluids, but thorough studies are needed when selecting a method taking into consideration the properties of fluid to be injected, the reservoir dynamic behavior and the quantity of remaining crude oil. Since oil fields are located in remote areas or under the sea, the purchasing costs for the fluid to be injected also need to be taken into consideration when selecting the EOR techniques. TOYO has also engaged in planning for the EOR project.

Typical Block Flow of Steam Injection System

Reservoir driving method in focus

The flooding method that has gathered greatest attention is the gas cap drive using CO2 for crude oil which involves the injection of carbon dioxide gas. To help prevent global warming, carbon dioxide produced and recovered on the ground is injected underground reservoir to recover the crude oil. If the method is applied improperly, however, a large volume of carbon dioxide gas might be produced again along with the crude oil. When applying the CO2 drive, a proper planning needs to be prepared after studying the production mode in deep knowledge of the reservoir dynamic behavior, surface facility planning, and the properties of the fluid to be injected as well as the EOR techniques.

TOYO has experience in project implementation related to carbon dioxide injection and studies on the CO2 drive methods. TOYO provides engineering services which offers the optimum plans for recovering crude oil using CO2 drive methods, with extensive experience and knowledge backed up by TOYO’s own urea synthesis process technology, knowledge on the behavior (physical properties) of carbon dioxide gas under high pressure, as well as the full experience of CO2 drive widely applied around the world.


Flow Schime for CO2 Miscible Flooding System(WAG System)

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