ENHANCED HYDROCARBON RECOVERY BY GAS INJECTION PROCESSES
Main researcher
: GORIČNIK, BOGDAN (72195) Assistants
SEČEN, JOSIP (3003)
DERNIKOVIĆ, BORIS (9364)
SARAPA, MARIJAN (7182)
CSISKO-IVIĆ, MARGIT (88836)
BAUK, ANTUN (134824)
JUTTNER, IVANKA (16283)
Type of research: developmental Duration from: 04/30/91. to 04/30/94. Papers on project (total): 14
Institution name: Rudarsko geološko naftni fakultet, Zagreb (195) Department/Institute: Reservoir Engineenring Department Address: 41000 ZAGREB, Pierottijeva 6
Communication
Summary: The following methods of oil recovery (EOR) by gas
injection were studied: (1) Mechanism and efficiency of carbon dioxide
(CO2) process, which included (1a) examination of miscibility zone
formation (external or in situ) and its influence on oil recovery; (1b)
mathematical modeling of oil-CO2 mixture phase behavior by Peng-Robinson
EOS regression to experimental PVT-data; (1c) examination of injection CO2
mobility control in relation to fluid flow characteristics and oil
recovery. An apparatus for CO2 foam generation, mobility and oil recovery
measurements was constructed. Basic relations between foam quality,
mobility and produced oil were determined; (1d) Corrosion process in
CO2-environment was investigated. Corrosion rates of oilwell materials were
measured and predominant corrosion mechanism at different p,T-conditions as
well as water chemical composition were determined.Degree of protection of
the materials by corrosion inhibitors was determined. The nature of the
corrosion process of austenitic steel welds was also examined. (2) Process
of gas (natural gas/methane,carbon dioxide,nitrogen) injection into gas
condensate field was investigated. PVT-relations of condensate-injection
gas mixtures were measured and degree of retrograde vaporization
determined. Phase diagrams and corresponding mathematical models (PR EOS)
were made. Simulation of the retrograde vaporization dynamic process was
performed in order to obtain process parameters. (3) Methane gas injection
into partially depleted oil reservoir was investigated. Based on
experimental reservoir oil PVT-data, fluid phase behavior model was made.
Extensive simulations of cyclic process of gas injection were made.
Produced gas injection composition was determined for different schemes of
maximum gas pressure. Process of oil production during pressure maintenance
was also examined. Comparative analysis of the results favors gas
storage/cycling scheme.
Research goals: (1) Development of improved and/or new methods of
experimental oil displacement simulation tests, (2) Measurement of
PVT-behavior of oil/condensate-injection gas mixtures in conjunction with
enhanced oil recovery predictions, (3) Mathematical modelling of
hydrocarbon fluid-injection gas mixtures, based on contemporary
equations-of-state, with subsequent use of the models in fieldwide
simulators, (4) Determination of corrosion mechanism of oilwell materials
in CO2 environment, based on corrosion rate measurements under realistic
p,T-conditions. In addition to more fundamental contributions in
understanding the nature of phase transitions and thermodynamics of complex
natural hydrocarbon mixtures, the results of the research project are
expected to furnish important data needed for feasibility study of the EOR
processes investigated. Other information about the project.