Prediction and Experimental Measurements of Water-in-Oil Emulsion Viscosities During Alkaline/Surfactant Injections
Oil production is generally a complicated multiphase flow inside pipelines, with possible water-in-oil (W/O) emulsions present with other usual phases such as free water and free oil. The W/O emulsions formed can present significant hurdles in production facilities for pumping fluids and during pipeline transport. It is well known that high shear rates provided by pumps, chokes, or valves result in stable emulsion behavior for a field in primary production. Several field tests are under way to test the potential of surfactant flooding as a tertiary-recovery mechanism. The effect of addition of surfactants on the emulsion rheology of production fluids, as in alkaline/surfactant/polymer (ASP) flooding, is not very well understood. This understanding of W/O-emulsion rheology in ASP-injection oil recovery is essential for design of pumps and pipelines as well as for handling flow-assurance issues.
In this paper, we report results from experiments as well as modeling of W/O-emulsion rheology that can form during ASP injections. We focus here only on the alkaline/surfactant (AS) part of these injections in order to clearly understand the impact of surfactants, removing the uncertainities that come with large rheology changes with polymer addition. The effect of surfactants on the rheology of W/O emulsions was studied by making two different types of emulsions: (1) native-brine W/O emulsions without surfactants to provide a baseline and (2) brine W/O emulsions with surfactants used in ASP injections. This way, the impact of ASP injections on emulsion rheology can easily be quantified. A new correlation is developed, based on in-house historical experimental data, to describe rheology of emulsions without surfactants. This correlation should assist in managing the uncertainties that come from extrapolating emulsion rheology measured in the laboratory to actual field conditions. Further, to understand the effect of ASP injections, new experimental measurements were made by adding surfactants to brine solutions. The addition of surfactants resulted in different rheology as compared with emulsions formed by brine solutions. These differences have been attributed to the W/O interfacial tension (IFT), and IFT was added to modify the original correlation. To our knowledge, this is the first study that explicitly relates emulsion rheology with IFT.
Subsea High-Boosting Multiphase Pumps Increase Oil Recovery in Aging Field (Includes presentation slides)
Production from an offshore Angola field has been decreasing because of subsea pressure declines amid water-cut increases and limited gas compressor capacity. The development process leading to the selection of high-boosting multiphase pumps is described.
Nanotechnology for Oilfield Applications: Challenges and Effects
This paper presents a critical review of the recent literature to determine the status of research and development and field application of nanotechnology in the oil field.
Case History of Dehydration-Technology Improvement for HCPF Production in the Daqing Oil Field
High-concentration polymer flooding can improve oil-displacement efficiency but separation of oil/water mixture becomes more difficult because of emulsification. In this work, a case history of dehydration technology for HCPF production and lab investigation of emulsion behaviors are reviewed.
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07 May 2018