PRODUCING ULTRALOW INTERFACIAL TENSION AT THE OIL/WATER INTERFACE

In view of the world-wide shortage of petroleum and the fact that a large amount of residual oil will remain in the reservoir after the primary recovery and water flooding stages, the use of Enhanced Oil Recovery (EOR) methods to recover as much as possible of this residual oil has become increasingly important worldwide. The predominant and most promising EOR technique is the micellar-polymer flooding process which uses a surface active agent (a surfactant) to decrease interfacial tension and hence allows oil to freely move from its original location through the porous media. The purpose of this paper is to present an experimental study of the factors affecting the equilibrium interfacial tension (IFT) at the oil/water interface. A large number of experiments was conducted to study the variations of IFT as a function of many parameters including reservoir temperature, pressure

STUDYING THE INTERACTIONS BETWEEN AN ARABIAN HEAVY CRUDE OIL AND ALKALINE SOLUTIONS

An experimental study to examine the effectiveness of alkaline flooding for the recovery of an Arabian heavy crude oil is presented. The interfacial tension (IFT) behavior of crude oil/alkali systems over a wide range of parameters (pressure, temperature, alkali concentration and time) was studied. These alkaline reagents react with the acidic species in crude oil to form surface-active soaps in-situ. This leads to a lowering of interfacial tension (IFT) and subsequently the mobilization of residual oil. The equilibrium IFTs obtained through alkaline flooding are compared with the IFTs when a synthetic surfactant (dodecyl benzene sulfonic acid sodium salt) is used in EOR recovery. A mathematical model representing the complete chemistry of the transient process is also presented. The model consists of a set of differential equations describing reactions, diffusion, and adsorption at the oil/alkaline solution interface. The kinetic parameters i

DOI: 10.1080/00986440390171107 EXPERIMENTAL INVESTIGATION OF CRUDE OIL DESALTING AND DEHYDRATION

Oil produced in most oil fields is accompanied by water in the form of an emulsion that must be treated. In addition, this water normally contains dissolved salts, principally chlorides of sodium, calcium, and magnesium. If crude oil is left untreated, when it is processed in a refinery the salt can cause various operating problems. This paper investigates experimentally the effect of five factors (gravity settling, chemical treatment, freshwater injection, heating, and mixing) on the efficiency of the dehydration=desalting process for a Kuwaiti crude oil and a commercial demulsifier (Servo CC 3408). These factors are systematically varied and efficiency is analyzed. Two efficiencies are defined: a Salt Removal (S=R) efficiency and a Water Cut (W=C) dehydration efficiency. The investigation was carried out through changes made to a single factor at a time as well as multiple variations of factors. Plots, based on experimental data, showing the variation of the two efficiencies as a function of the various factors are given. Two main conclusions are drawn for the system studied. First, excessive amounts of a demulsifying agent ha

The Influence of Temperature, Pressure, Salinity, and Surfactant Concentration on the Interfacial Tension of the N-Octane-Water System

An elaborate experimental study was conducted for the determination of the interfacial tension (IFT) values for a n-octane=water system for a wide range of experimental conditions of temperatures, pressures, and salt concentrations that exist in a natural oil reservoir. Three different surfactants were used in the analysis: dodecyl benzene sulfonic acid sodium salt, sodium dioctyl sulfosuccinate, and hexadecyl trimethyl ammonium bromide. The measured IFT values were correlated linearly to pressure (P), temperature (T), and salt concentration (CB) in the aqueous phase. There was an almost 20-fold reduction noticed in the IFT values with the addition of surfactants. This behavior was best related by an exponential expression in terms of the surfactan