Physical and chemical advanced oil recovery methods at last stage field development

Since water flooding is the main recovery method, primal goal is the increasing its efficiency. That is possible by chemical methods, which is allows to increase the oil recovery, but one problem takes place. The result is not longterm-stable and it keeps degrade although the treating still coming. Its connected with deterioration of the structure of recoverable reserves and with a limited range of technologies used in certain geological conditions. This suggests the need to find new EOR-technologies. One of the methods that could significantly increase oil recovery in the late stages of field development is polymer flooding.
Results
1. The positive result on polymer flooding can be achieved in next conditions:
• an objective selection of the pilot area
• adaptation of the technology of polymer flooding to the real conditions of the oilfield
• design and adaptation of hydrodynamicmodels of area flooding
• the right choice of technological solutions
• a professional approach to the work performance.
2. The opportunity of utilizing waste water must be provided during the process of implementation of the project, due to reduced volumes of injection into injection wells, followed by an increase of oil recovery with an accompanying increase in the volume of produced water.
3. Analysis of infill drilling of production wells or sidetrack drilling on the old wells and coring to determine the residual oil saturation after exposure will be informative to evaluate the effectiveness of polymer flooding at the impact area.
Сonclusions
1. It’s strongly recommended to periodically alternate polymer injection with water, as well as necessary to provide a special wellhead equipment for the preparation and injection of polymer to reduce mechanical destruction during long-term process of polymer flooding,.
2. It’s necessary to create fresh water slug before injection of more stable polymer in structure in special geological condition to reduce chemical destruction.
3. It’s necessary to select laboratory thermostable polymers, as well as to look for when selecting an impact object on its current reservoir temperature to reduce the thermal destruction.
4. Analysis of polymer flooding shows that additional oil production is 1300 t per 1 t of reagent, the average reagent flow is 400 t per impact object.