- •Physical foundations of oil fields development and enhanced oil recovery methods
- •Introduction
- •1.2 Pool-reservoir properties.
- •1.3. Heterogeneity and anisotropy of reservoirs
- •2.1. Rock pressure and effective pressure.
- •2.2. Reservoir energy types.
- •2.3. The main sources of reservoir energy.
- •2.4. Operation modes of oil deposits.
- •2.5. Elastic-water drive
- •2.6. Dissolved gas drive
- •2.7. Gas cap drive.
- •2.8. Gravity drive
- •3.1. Productive formation.
- •3.2. The reservoir recovery and oil recovery factor (orf).
- •3.3. The well patterns - development systems of production facilities on natural recovery modes.
- •3.4. Enhanced recovery systems
- •3.5. Field development systems
- •3.5.1. Simultaneous production facilities development
- •3.5.2. Successive development systems.
- •3.6. Oil fields development parameters
- •3.6.1. Technological development parameters
- •3.6.2. Borehole grid. Wells’ density.
- •3.6.3. Krylov’s parameters. Compensation factor. Water cut factor.
- •3.6.4. Oil fields development rates.
- •3.6.5. Development stages of the production facilities (oil fields)
- •3.7. Types of water flooding
- •3.7.1. Edge water flooding.
- •3.7.2. Boundary water flooding
- •3.8. Circle water flooding.
- •3.8.1. Direct line drive systems. Their varieties – block systems.
- •3.8.2. Grid water flooding systems.
- •3.8.3. Selective and Spot water flooding.
- •3.8.4. Barrier water flooding system.
- •4.1. Porous formation models.
- •4.1.1. Deterministic model
- •4.1.2. Stochastic-statistical model.
- •4.2.4. Pollard model.
- •4.2.5. Models use peculiarities of the reservoirs of complex structure.
- •4.3. Water saturation and watering.
- •4.4. Reciprocating and non-reciprocating oil displacement.
- •4.4.1. Reciprocating displacement.
- •4.5. Displacement characteristics.
- •5.2. Project documentation.
- •5.3. Field-geologic characteristic of the deposit.
- •5.4. Rational development system.
- •6.1. Geological peculiarities reservoir structure with high-viscosity oil.
- •6.2. The deposit Russkoye
- •6.3. Katangli deposit.
- •6.4. Canada high-viscosity oil deposits.
- •6.5. The main peculiarities of high-viscosity oil deposits development.
- •7.1. Enhanced oil recovery methods classification.
- •7.2. Production stimulation methods (psm)
- •7.3. Enhanced oil recovery methods (eorm)
- •7.4. The forms of residual oil condition.
- •7.5 The reasons of residual oil condition.
- •7.6. The conditions of effective enhanced oil recovery methods use.
- •7.7. Oil deposits management and enhanced oil recovery methods.
- •8.1. Oil displacement by water solutions of surface-active reagents (sar)
- •8.2. Sar adsorption
- •8.3. Sar (surface-active reagent) composition.
- •8.4. Polymer oil displacement.
- •8.5. Micellar-polymer flooding method.
- •8.6. Conformance change or control (straightening the injectivity profile) (cc)
- •8.7. The choice of the areas and wells for injectability profile enhancement technologies implementation.
- •9.1. Filtration flows’ direction changing.
- •9.2. Forced fluid withdrawal (ffw)
- •9.3. Cyclic water flooding.
- •9.4. Combined non-stationary water flooding.
- •10.1. Oil displacement by carbon dioxide (co2).
- •10.2. Oil displacement by hydrocarbon gas
- •10.3. Water-alternated-gas cyclic injection.
- •11.1. Physical processes, happening during oil displacement by heat-transfer agents.
- •11.2. Oil displacement by hot water and steam.
- •11.3. The method of heat margins.
- •11.4. Combined technologies of enhanced oil recovery of high-viscosity oil deposits.
- •11.5. Thermal-polymer reservoir treatment (tpt)
- •11.6. Cyclic steam treatment of producing wells
- •Disp-lace-ment front
- •Ther-mal front
- •Combustion front
- •Disp-lace-ment front
- •Ther-mal front
- •Injection temperature
- •11.8. Thermal-gas method of treatment.
- •12.1. Formation hydraulic fracturing (fhf)
- •12.2. Well operation with horizontal end.
- •12.3. Acoustic methods.
- •Conclusion.
- •The list of symbols and abbreviations.
- •Content
- •Introduction 3
- •4.1. Porous formation models………………………………………………..38
- •4.1.1. Deterministic model……………………………………………………38
7.4. The forms of residual oil condition.
During the development of the production facilities of the oil fields on the natural drives or with the formation stimulation, there are the zones in the reservoirs where there are the residual recoverable oil reserves. The recovery of such reserves from the developing formations is a necessary condition for oil recovery enhancement; it gives an opportunity to achieve development project indicators [20].
According to the expert estimation the residual oil reserves (100%) are quantitatively distributed as follows [1]:
1) oil, remaining in low-permeability formations (interlayers), and areas that are not water flooded- 27%;
2) oil in stagnant zones of homogeneous formations - 19%;
3) oil, remaining in the lenses and impermeable screens, not drilled by the wells - 24%;
4) capillary hold-up oil and film-type oil - 30%
Residual oil 1) -3), which are not covered by the process of flooding due to the high macroinhomogeneity of the developing formations and stagnant zones, formed by the flow of fluid in the reservoir is 70% of all the remaining reserves. It is the main reserve for enhanced oil recovery. To increase oil recovery with the help of residual oil is possible in the result of the current development systems and technologies improvement, as well as thanks to the use of hydrodynamic methods of enhanced oil recovery.
The remaining part 4) is left in flooded reservoirs due to their microinhomogeneity and can be recovered in the result of different physical and physical-chemical stimulation methods.
The compositon of residual oil condition.
Changing the properties of oil in the process of development can occur both in the direction of increase and decrease of the produced oil density. The weighting of oil is associated with the decrease of reservoir pressure in the process of development and loss of light fractions of oil during degassing and oil oxidation in the process of water injection, due to gravitational move deep into the deposits of heavy oils. Lighter oils can remain in the upper parts of the anticline folds. Oil properties may vary within small areas of the same productive formation.
The forces, holding the residual oil.
The presence of residual oil reserves, due to macroinhomogeneity of the formations, depends on the low speed of oil filtration in low-permeable zones, formations, interlayers and lenses, and it is caused largely by the pollution, clogging of the bottom-hole formation zones during the drilling process and water injection.
The forces operating in the reservoir, saturated by two or more mobile phases are divided into viscosity (viscous) force, surface, gravity, and elastic forces.
Surface or capillary forces create at the liquid phase boundary the pressure that is equal to 0.01 - 0.3 MPa. Surface forces are determined by the wettability of the rock and microinhomogeneity of porous medium and size of pore channels.
Viscosity forces (hydrodynamic resistance) are proportional to the oil viscosity. When the dynamic viscosity factors are high there can appear maximum pressure differential or initial pressure differential preventing oil filtering (Annex 3).
Gravitational forces create permanent pressure differential, that is numerically equal to the difference of oil, gas, water densities. The value of this differential may be 0.1 - 10 MPa/m. As a result there is an emersion of oil in water or gas in oil.
Elastic forces arise from changes in the stress-strain state of the reservoir due to decrease of reservoir pressure. They cause clogging of the pore channels, reduction of micro-fissures and, consequently, contribute to the appearance of the residual oil saturation.