Crisman Annual Report 2009 - Harold Vance Department of ...

Experimental Investigation of Caustic Steam Injection for Heavy Oils
Introduction
Heavy oil is a part of the unconventional petroleum
reserve. Heavy oil does not flow very easily and
is classified as heavy because of its high specific
gravity. With increasing demand for oil and with
depleting light oil resources, it is essential to explore
the unconventional petroleum reserve of which
heavy oil constitutes a major part, about 15% of the
world’s remaining oil reserves.
Objectives
An experimental study was conducted to compare
the effect of steam injection and caustic steam
injection in improving the recovery of San Ardo and
Duri heavy oils.
Approach
A 67 cm long x 7.4 cm O.D (outer diameter),
steel injection cell was used in the study. Six
thermocouples were placed at specific distances
in the injection cell to record temperature profiles
and thus the steam front velocity. The injection cell
was filled with a mixture of oil, water and sand.
Steam was injected at superheated conditions of
238°C with the cell outlet pressure set at 200 psig,
the cell pressure similar to that found in San Ardo
field. The pressure in the separators was kept at 50
psig. The separator liquid was sampled at regular
intervals. The liquid was centrifuged to determine
the oil and water volumes, and oil viscosity, density
and recovery. Acid number measurements were
made by the titration method using a pH meter and
measuring the EMF values. The interfacial tensions
of the oil for different concentrations of NaOH were
also measured using a tensionometer.
Accomplishments
Experimental results show that for Duri oil, the
addition of caustic results in an increase in recovery
of oil from 52% (steam injection) to 59% (caustic
steam injection). However, caustic has little effect
on San Ardo oil where oil recovery is 75% (steam
injection) and 76 % (caustic steam injection).
Significance
Oil production acceleration is seen with steam-caustic
injection. With steam caustic injection there is also a
decrease in the produced oil viscosity and density for
both oils. Sodium hydroxide concentration of 1 wt%
is observed to give the lowest oil-caustic interfacial
Crisman Annual Report 2009
tension. The acid numbers for San Ardo and Duri oil
are measured as 6.2 and 3.57 respectively.
Future Work
The following are the main recommendations for
future research:
» To study further the effect of sodium hydroxide
on different kinds of oils and to understand the
effect of the acids present in the oil in reducing
interfacial tension.
» To conduct the experiments on previously
waterflooded sandpacks for very heavy oils like
San Ardo.
» Core flooding would also be helpful in understanding
the process of alkaline steam flooding with both
heavy and lighter oils.
» To test the combination of sodium hydroxide
with additives which form the basis for alkaline
surfactant process–as in Alkaline Surfactant
Polymer (ASP) injection-in improving the recovery
of oil.
» To test non-thermal means of caustic flooding for
heavy oils.
Project Information
1.3.12 Experimental and Simulation Studies of Heavy Oil
Recovery using Steam and Steam Additives
Related Publications
Madhaven, R.: 2009. Experimental Investigation of Caustic
Steam Injection for Heavy Oils. MS thesis. Texas A&M U.,
College Station, Texas.
Contacts
Daulat Mamora
979.845.2962
daulat.mamora@pe.tamu.edu
Rajiv Madhaven
CRISMAN INSTITUTE
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