Iran, with a record of over one century of oil production, is currently one of the major oil producing countries of the world.
According to I.R .Iran oil ministry 20 years plan and overview plan, following targets must be achieved:
• Capacity building for 5.7 million bbl production per day in 2015
• Increasing in natural gas production to 900 million cubic meter per day in 2015
• Supply 100 million cubic meter per day natural gas for consumption in industrial Sector .
Several of the old fields have been depleted to an uneconomical level of production and 9-11% yearly reduction has reported in these fields which requires significant amount of natural gas for re-injection so that currently over 100 million cubic meters of natural gas is reinjected daily to maintain or enhance oil production to an economical level. It is estimated that in order to maintain oil production, over 200 million cubic meters of natural gas will be needed daily by 2015.
Some of these oil fields have experienced an annual depletion in productivity between 9 to 11 percent which can be enhanced by secondary or tertiary recovery. Considering that most of the reservoirs are of the carbonated fractured type containing heavy crude, the selection of the optimum secondary or tertiary recovery method is of great importance.
For example production rate of Aghajari oil filed decrease from 1,023,000 bbl per day in 1973 to 145000bbl per day in 2005.56 million cubic meter natural gas comes from South Pars must be injected into reservoir to raise 300000 bbl per day production.
Already ,there are some main projects for secondary recovery in Iran ,include water injection in several onshore and offshore fields like Salman (Sasan) oil field ,natural gas injection in Aghajari project and gas reinjection in Amak group fields and also there are some plan for water and WAG for Resalat ,Reshadat and Dorood.
Both carbonated and sandstone reservoirs could be suitable for CO2 flooding and there are several successful projects in sandstone reservoir and carbonated reservoir in the world. According to oil density, reservoir pressure ,oil in place ,oil saturation and reservoir material, several reservoirs in Iran could be suitable for CO2 miscible or immiscible flooding .
At this time, some few reservoirs were considered and nominated for CO2 EOR , both of southern and central National Iran Oil Company and also Offshore National Iranian Oil Company going to perform some pilot project and in next step expand develop it to large scale EOR .
Compared with the miscible case, in the immiscible case the amount of C7+, well depth, well pressure and temperature are of less importance. The immiscible ones are also more suitable for heavy oils whereas for oils with API gravity of more than 25, the miscible ones are advantageous. Reservoirs screening for CO2 injection could be perform with respect to the type of reservoir and the distance to major sources of CO2 emission. Other information such as the in-situ amount of oil, production capacity, reservoir’s porosity, thickness of the core, area of the reservoir, oil viscosity and density, reservoir pressure, saturation water, the amount of carbon dioxide and hydrogen sulfide and the heavy hydrocarbons were also must be investigated. The efficiency of oil displacement increases as the initial saturation of oil increases. It is therefore recommended that the saturation of oil should be more than 30% for CO2 EOR to be effective.
Rahbord Energies storage group was responsible about investigation , study and selection suitable sink for store emitted CO2 in 20 years from Ramin Power Plant.
For this purpose ,group gathered all general information about reservoir, crude and production . information were screened and updated to obtain valid data needed for reservoir screening.
In other hand, more than 70 reservoirs which had CO2 injection program, were studied and a qualitative criteria obtained for CO2 EOR instead of those one recognized in literatures. two methods practiced for screening :first all reservoirs data imported in screening software and best results noticed. In second one a qualitative method followed according to obtained criteria and also some existing one. More than 40 reservoirs were studied by Storage group ,and some of them selected for CO2 miscible injection. storage group simulated CO2 flooding in selected reservoir and forecasted incremental production in different scenario.Geological maps were studied to make sure about storing CO2 safe and with minimum possibility of leakage. Rahbord Energy also estimated storage capacity in Southern oil fields.Nitrogen Injection
Importance of achieving optimize oil recovery is assumed necessary and unavoidable because of highly dependence of global economy to limited hydrocarbon reservoirs.
Three decades ago, natural gas widely was used in EOR/IOR projects, but after 1960 because of costs increasing and natural gas sources limitation, the nitrogen and other inert gases or flue gases were injected in reservoir according to oil type and reservoir pressure in miscible and immiscible condition for oil displacement.
Investigation of nitrogen injection project in different oil reservoirs in the world, expects that nitrogen and inert gas injection can be more economical than natural gas injection instead of no asphaltene, minimum sediments and no corrosion. Nitrogen could be injected widely in oil reservoir in miscible and immiscible displacement, miscible bank followed by nitrogen, pressure maintenance, gas lifting and N2 WAG scenarios.Our Services on EOR
Rahbord Energy Alborz ltd provides a chain of perfect engineering and field services for up stream, EOR and CO2 injection projects with best quality .detail investigation of suitable reservoir selection and confirm newest worldwide experiences and then complete and perfect reservoir study on offshore reservoir as well as selected onshore field.
In addition, the company capable to perform conceptual design , basic engineering , detail engineering for surface facilities, injection facilities, production units , pipe lines and well engineering .we also offer our experiences in field engineering , drilling engineering , well engineering and supervisions. Some Rahbord Energy special services in CO2 injection and EOR projects are as follow however wont be limited by them :
Rahbord Energy Alborz offers following services to all clients
Screening of suitable reservoir
Investigation and study of reservoir history
Study of previous reservoir reports:
Petro physics ( investigation of previous petro physics
data and reports)
Geo physics and geology
Preliminary investigation of field geological data
U.G.C map prepare
2nd and 3 nd seismic ( or previous seismic data investigation)
Drilling- field data processing
Structural map processing and prepare
Study of underground layers interconnection
Fracture and fault and their distribution in reservoir study
Layers permeability study
Horizontal- vertical inter connection study
Preparing of 3d model of reservoir
Hydro dynamic investigation
Wet ability investigations
Investigation of temperature changes
Reservoir characteristics study
Reservoir Water study prediction
Volume oil in place
Fault direction and characteristics prediction and
investigation by core study and well tests
High salinity, GOR, and VFP calculation
Well efficiency analyses and lost profile study
Well completion study
In place Oil and gas calculation by mass balance
Production tests analyses and investigation and PLT
Dynamic and static pressure and temperature profiles
Reservoir production history analyses
History match and water gas , oil production study and
1-asphaltin and wax
2-PVT data study
1- 3-MMP test minimum miscibility pressure
2- 4-CCE test
5-DL test in pressure temperature
6-Bubble point tests
7-Viscosity test in reservoir condition and other pressure