SUPRI heavy oil research program. Annual report, February 8, 1995--February 7, 1996

The goal of the Stanford University Petroleum Research Institute (SUPRI) is to conduct research directed toward increasing the recovery of heavy oils. Presently SUPRI is working in five main directions: (1) flow properties studies to assess the influence of different reservoir conditions (temperature and pressure) on the absolute and relative permeability to oil and water and on capillary pressure; (2) in-situ combustion to evaluate the effect of different reservoir parameters on the in-situ combustion process; (3) steam with additives to develop and understand the mechanisms of the process using commercially available surfactants for reduction of gravity override and channeling of steam; (4) formation evaluation to develop and improve techniques of formation evaluation such as tracer tests and pressure transient tests; and (5) field support services to provide technical support for design and monitoring of DOE sponsored or industry initiated field projects. This report consists of abstracts of reports and copies of technical papers presented or published

Characterization of surfactants in the presence of oil for steam foam application

The steam foam process has been applied in the oil fields since the late 1970's. The mechanism of the process, however, is not known fully; particularly the detrimental effects of oil on foam, while known, are still unexplained. Understanding the mechanisms of foam generation, stability, and mobility of foam to improve the development of field level projects has been the focus of the attention of many workers of the oil industry. Extensive laboratory studies have been carried out, mostly without oil but some with oil. This study falls in the later category. A one dimensional sandpack (6 ft X 2.15 in) model is used to investigate the behavior of four anionic sulfonate surfactants of varying chemical structure with steam. The study is performed with an crude oil at residual oil saturation of about 12 percent of the pore volume. The observed pressure drops across the various sections of the pack are used to study the behavior of the surfactant. The tested surfactants vary in chain length, aromatic structure and number of ionic charges. A linear toluene sulfonate produced the highest strength foam in presence of the oil at residual saturations, as compared to the alpha olefin sulfonates. This is in contrast to the behavior of the surfactants in the absence of oil, where the alpha olefin sulfonates perform better. The reason for this change in behavior is the relative propagation rate of the foams produced by the surfactants. This conclusion is based on the observation that increase in propagation rate decreases the detrimental effect of oil; while the propagation rate is of little significance without oil. The disulfonate performed better in the presence of oil. The improvement in the performance is embedded in the propagation rate of these surfactants as the rate of propagation in this case is also high. But the true mechanism of improvement in the strength of the foam instead of deterioration needs further study

Steam foam studies in the presence of residual oil

The lack of understanding regarding foam flow in porous media necessitates further research. This paper reports on going work at Stanford University aimed at increasing our understanding in the particular area of steam foams. The behavior of steam foam is investigated with a one dimensional (6 ft. {times} 2.15 in.) sandpack under residual oil conditions of approximately 12 percent. The strength of the in-situ generated foam, indicated by pressure drops, is significantly affected by injection procedure, slug size, and steam quality. The surfactant concentration effect is minor in the range studied. In the presence of residual oil the simultaneous injection of steam and surfactant fails to generate foam in the model even though the same procedure generates a strong foam in the absence of oil. Nevertheless when surfactant is injected as a slug ahead of the steam using a surfactant alternating (SAG) procedure, foam is generated. The suggested reason for the success of SAG is the increased phase mixing that results from steam continually having to reestablish a path through a slug of surfactant solution

SUPRI heavy oil research program

This report summarizes the progress of the research performed by the Stanford University Petroleum Research Institute (SUPRI) during the past three years. Some of SUPRI's past results are discussed briefly for the following five projects: flow properties studies;in-situ combustion; additives to improve mobility control; reservoir definition; and support services. Abstracts of technical reports published from 1990--1993 are also included

SUPRI Heavy Oil Research Program, SUPRI TR 85

This report concerns progress made during the 1990--1991 fiscal year. Information is given an the following projects: (1) A Study of End Effects in Displacement Experiments; (2) Kinetics of In-Situ Combustion; (3) In-Situ Combustion with Metallic Additives; (4) Steam-Foam Studies in the Presence of Residual Oil; (5) Characterization of Surfactants in the Presence of Oil for Steam-Foam Applications; (6) CT Imaging of Steam and Steam Foam Laboratory Experiments; (7) Microvisualization of Foam Flow in Porous Media; (8) Transient Foam Flow in Porous Media with Cat Scanner; (9) Study of Matrix/Fracture Transfer During Steam Injections; (10) Transient Behavior of Gravity Drainage Wells; (11) Multivariate Optimization of Production Systems; (12) Ultrasonic Flowmeter. (VC

SUPRI heavy oil research program

The 14th Annual Report of the SUPRI Heavy Oil Research Program includes discussion of the following topics: (1) A Study of End Effects in Displacement Experiments; (2) Cat Scan Status Report; (3) Modifying In-situ Combustion with Metallic Additives; (4) Kinetics of Combustion; (5) Study of Residual Oil Saturation for Steam Injection and Fuel Concentration for In-Situ Combustion; (6) Analysis of Transient Foam Flow in 1-D Porous Media with Computed Tomography; (7) Steam-Foam Studies in the Presence of Residual Oil; (8) Microvisualization of Foam Flow in a Porous Medium; (9) Three- Dimensional Laboratory Steam Injection Model; (10) Saturation Evaluation Following Water Flooding; (11) Numerical Simulation of Well-to-Well Tracer Flow Test with Nonunity Mobility Ratio