A Mlcroscoplc Study Of The Effect Of Variable Wettability Conditions On Immiscible Fluid Displacement

Abstract

Publication Rights Reserved This paper is to be presented at the 38th Annual Fall Meeting of the Society of Petroleum Engineers of AIME in New Orleans, La., on October 6–9, 1963, and is considered the property of the Society of Petroleum Engineers. Permission to publish is hereby restricted to an abstract of not more than 300 words, with no illustrations, unless the paper is specifically released to the press by the Editor of the JOURNAL OF PETROLEUM TECHNOLOGY or the Executive Secretary. Such abstract should contain conspicuous acknowledgment of where and by whom the paper is presented. Publication elsewhere after publication in the JOURNAL OF PETROLEUM TECHNOLOGY or SOCIETY OF PETROLEUM ENGINEERS JOURNAL is granted on request, providing proper credit is given that publication and the original presentation of the paper. Discussion of this paper is invited. Three copies of any discussion should be sent to the Society of Petroleum Engineers office. Such discussion may be presented at the above meeting and considered for publication in one of the two SPE magazines with the paper. Abstract This paper presents the results of a microscopic investigation of immiscible fluid behavior under variable wettability conditions. Seventeen waterfloods were conducted in a monolayer glass-bead flow cell under water-wet neutral-wettability, oil-wet, and wettability-reversal conditions. Quantitative production data were obtained for each flood. Also, a 16 mm film recording utilizing an arriflex camera was made during each flood test. Photographs taken from 16 mm film recordings are herein presented as being representative of the microscopic and macroscopic behavior for the fluid systems studied. Residual oil structures were visually defined as being noncontinuous under water-wet conditions. Oil-wet conditions yielded both continuous and noncontinuous type structures. The idea of residual oil continuity under oil-wet conditions is proposed as being responsible for increased oil production when going from an oil-wet to a water-wet condition. In all cases during these experiments where additional oil was recovered during a reversal flood, there was essentially continuity of the residual oil saturation following the conventional waterflood under oil-wet conditions. It has been shown that, where residual oil continuity existed, oil mobility may be established from a transient change in contact angle. An attempt has been made to define the mechanism responsible for this phenomena. Introduction The recovery of additional oil from a reservoir following primary depletion can be achieved only by the application of energy from external sources such as the introduction of heat and/or kinetic energy of other fluids. A process which supplies this additional energy is called a secondary recovery process. Unfortunately, present secondary recovery methods, which are economical, still leave up to 40 per cent of the reservoir's original oil content trapped by capillary and hydrodynamic forces.