NITROGEN GAS INJECTION

Ziel

The aim of the project is to study the possibility of miscible displacement in North Sea hydrocarbon reservoirs by nitrogen, and to study the recovery efficiency during nitrogen injection.
The advantages of nitrogen with respect to carbon dioxide are :
- Low production costs of the injection gas
- Availability
- Nitrogen is inert with respect to the wells and production facilities.
The advantage of nitrogen injection with respect to methane reinjection is that the methane is available for commercial exploitation.
Fluid phase equilibria of nitrogen and aromatic compounds have been measured and interpretated.
An introductionary economic evaluation has been performed.
A high pressure slim tube apparatus has been developped.
A two phase in situ sampling device has been designed and constructed. With this device the compositional path can be measured under reservoir conditions.
A fully compositional 1-D reservoir simulator has been modified and calibrated to describe slim tube experiments. With the help of this simulator the number of slim tube experiments, necessary to determine the minimum miscibility pressure can reduced.
The results of the simulation agree with the experiments.
Gravity drainage experiments pointed out that capillary forces are dependent on the interfacial tensions between all the phases present.
A high pressure pendent drop cell has successfully been designed and constructed. The measurements on a carbodioxide system indicate that the parachoor value can be seen as a correlation coefficient. Once determined, the interfacial tension can be estimated.
The project comprises the following items :
a. A theoretical study on gas injection in oil reservoirs. A literature study has been performed on Miscible gasinjection.
b. A theoretical study on N2-oil phase behaviour. A literature study on hydrocarbon systems with nitrogen has been performed. c. Development of a computer model. A fully 1-D compositional reservoir simulator has been modified and calibrated for the simulation of slim tube experiments.
d. Design and construction of experimental rigs. A high pressure (1000 bar) and temperature (120 C) slim tube apparatus, including a two phase sample facility has been designed and constructed. A high pressure (1000 bar) and temperature (120 C) vapor liquid equilibrium cell, including an in situ sample facility has been designed and constructed. A high pressure (1000 bar) and temperature (250 C) pendent drop cell, for interfacial tension measurements, has been designed and constructed.
e. Investigation of phase behaviour of oil/nitrogen. Numerous calculations have been carried out. Interaction coefficients have been experimentally determined.
f. Conducting displacement experiment. Numerous displacement experiments have been carried out:
- atmosferic: miscible, immiscible and partly miscible fluid-fluid displacements, gravity drainage experiments in the presence of three phases (oil, water and air);
- 50-100 bar, 50 deg.C: Slim tube experiments using carbon dioxide as injection gas and pentane, decane, butylbenzene or a mixture as the reservoir fluid;
- 320-420 bar, 100 deg.C: Slim tube experiments using nitrogen as injection gas and a simple synthetic oil, representing a Statfjord fluid, as reservoir fluid.
g. Field test proposaland economic evaluation. An introductionary economic evaluation has been performed on nitrogen injection vis-a- vis a depletion scenario for a North Sea field.

Programm/Programme

ENG-HYDROCARB 1C - Programme (EEC) of Community projects in the hydrocarbons sector, 1973-1985

Thema/Themen

1.5 - IMPROVED OIL RECOVERY

Aufforderung zur Vorschlagseinreichung

Data not available

Finanzierungsplan

DEM - Demonstration contracts

Koordinator

COLLEGE VAN BESTUUR DELFT UNIVERSITY OF TECHNOLO

EU-Beitrag

Keine Daten

Adresse

BUREAU HOGESCHOOL COLLEGE VAN BESTUUR P.O. BOX 5
2600 Delft
Niederlande

Gesamtkosten