Technology of Enhanced Oil Recovery (EOR)
EOR technology is associated with the ever-increasing demand for energy. Undoubtedly, nowadays the most environmentally friendly technologies are the use of solar and wind energy, the use of tidal energy and hydroelectric power plants work cab follow them in the rank of descending order of "the environmental safety".
The technology of enhanced oil recovery can be designated as the third stage of exploitation, preceded with the use of natural energy of the reservoir (due to the presence of stocks of energy: elastic, gas cap, dissolved edge waters, as well as the corresponding gravity potential) and maintaining the pressure in the reservoir with water or gas injection.
It is possible to classify the enhanced oil recovery technologies according to the types of working agents.
Types of applied working employed agents:
- Thermal, representing measures to influence of heat from the steam on the reservoir, as a result of inner combustion, the oil is pushed either by hot water or by cyclic steam well treatment.
- Gas, increasing the completeness of oil extraction in the result either of air pumping or of stimulation by hydrocarbon gas, carbon dioxide, nitrogen, flue gases and other gases.
- Chemical, water solutions of surface-active substances displace oil, including foam systems, polymers, either acids or alkalis or a wide variety of chemical compositions of the compounds. These include a variety of methods of microbiological substances influence on the oily layers.
- Hydrodynamic, this class with certain assumptions can combine different technologies that are involved in the exploitation non-drained reserves, flooding barrier of gas and/or oil deposits, carrying out manipulation of cyclically repeated flooding, operation of forced fluid withdrawal and step-thermal flooding.
- The group of combined methods most close to everyday practice: basically, there is a need in combining impact of the above-mentioned methods to enhance the work efficiency of the third phase of wells operations.
Physical enhancement of oil recovery should be separated, because this term combines situation of oil displacement by agents in the result of the capacity formed by the use of its own reservoir energy, in contrast to the methods of enhanced oil recovery, characterized by a high potential of displacing agent. In addition, physical methods, usually lead only to a short-term increase in production, and do not necessarily increase the total resulting oil recovery (i.e. the entire period of operation of the wells).
The most popular physical technologies of EOR are the following:
- hydraulic fracturing;
- the use of electromagnetic effects;
- the use of horizontal wells;
- wave impact on the reservoir;
- a combination of the above-mentioned technologies, as well as the use of other methods and techniques that are similar to the nature of the action.
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