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Abstract
Fossil fueled power generation is the largest source of carbon dioxide (CO2), which could be captured and stored. Carbon capture and storage (CCS) is one of the most important emission reduction technologies available for large stationary CO2 sources. Depleted oil and gas fields and major CO2 sources nearby are ideal areas for large scale geological storage. Injection of CO2 into a depleted reservoir can enhance the recovery of hydrocarbons. The circumstances, in fact, dictate the CO2 enhanced oil recovery (EOR) industry and a power generation sector eager to magnify the mutually beneficial link between CO2-EOR and new industrial sources of CO2.

In 1986, the TPAO (Turkish Petroleum Corporation) started the first large scale immiscible CO2 injection project in southeastern Turkey. Around one million tons per year of naturally occurring CO2 has been injected into the Garzan carbonates in the Bati Raman Field. A substantial increase in the production rate and ultimate recovery has been experienced and more is expected. The Bati Raman immiscible CO2 injection project has been acknowledged as one of the most unique and successful enhanced oil recovery (EOR) applications in the history of heavy oil in fractured limestone reservoirs.

There are nearly 50 oilfields in Turkey, and a significant proportion of them would be potentially suitable for EOR. If sufficient volumes of CO2 were economically available, many of these could produce incremental oil for an extended period. It is a fact that sedimentary basins in the Middle East are typically carbonates and this limits the selection of EOR processes significantly. Having observed CO2 injection as an excellent choice for carbonates through the Bati Raman experience, one may extend the CO2 network idea to the whole region. This will not only activate the enormous EOR potential in the mature fields of the Middle East but also the permanent storage of CO2 through a common effort.

The utilization of captured CO2 for EOR will become feasible if CO2 recovery plants with a higher CO2 content give an attractive CO2 delivery cost and emission rights can be traded in the carbon market which was introduced by the Kyoto Protocol. The major challenge would be how to formulate a working and acceptable model between petroleum and power sectors and, to establish a market mechanism to ensure that this system becomes economically feasible.

Introduction
In order to stabilize the atmospheric concentration of greenhouse gasses, many countries have committed themselves to reduce their greenhouse gas emissions. Turkey ratified the Kyoto protocol, the U.N. - led pact to combat global warming, in 2009. Because Turkey is a developing country with tremendous economic growth, its energy demand is in an increasing trend. Hence, Turkey struggles with the twin challenges of enhancing domestic oil recovery and reducing emissions of greenhouse gases, mainly released from coal burning power plants. Considering both challenges, CO2 based EOR has been receiving increased attention.
Turkey’s light, medium and heavy crude oil fields have been under exploitation for more than four decades using primary methods. The expected –maximum- recovery factors for light/medium-light oil reservoirs are around 45% of the OOIP. In most of the fields, however, this figure is extremely low due to low API gravity of oil and unfavorable reservoir characteristics. Given the maturity of these resources, EOR projects were required but are challenging due to the heterogeneous nature of carbonate reservoirs and the heavy nature of oil. Average reservoir depths in most of the fields are marginal for a successful thermal application (Babadagli et al., 2008).

Waterflooding and chemical injection applications have their own inherent restrictions for heavy-oil containing heterogeneous carbonate reservoirs. Gas injection has appeared as a suitable option for this kind of reservoirs. CO2 injection into depleted oil reservoirs has been widely accepted as an effective technique for EOR and has been applied by TPAO for 24 years in the Bati Raman field. Heavy oil in Turkey is particularly synonymous with the Bati Raman field.