New parameters for quality control of the flooding agent during the operation of the reservoir pressure maintenance system

For decades, oil fields in Western Siberia have been operated using a system of reservoir pressure maintenance. At the same time, produced water is often used as a flooding agent, as well as water from the Apt-Alb-Cenomanian aquifer complex. The quality of water flooding agent is regulated by documents OST 39-229-89 “Water for water flooding of oil reservoirs. Determination of compatibility of injected and formation water on calcite and gypsum by calculation method” and OST 39-225-88 “Water for oil reservoir flooding. Quality requirements”. It is substantiated that these regulations, developed more than 30 years ago, require expansion of controlled indicators. In particular, it concerns the content of microdoses of oilfield reagents, such as demulsifiers and corrosion inhibitors, in waterflooding agents. It has been established that the negative consequence of getting even microdoses of incorrectly selected reagents into waterflooding agents and then into the productive formation is under-extraction of oil. The paper proposes a method for rapid control of the ability of the flooding agent to wash oil from solid surfaces. Objectives. The work aims to study the ability of waterflooding agents with microdoses of reagents to wash out oil and justify the necessity of including this parameter in the list of its controlled parameters. Methods Applied. Washing effect of aqueous fluids in relation to oil films was investigated with the help of our patented installation, which allows to record the kinetics of oil films washing in automatic mode. Originality. For the first time the possibility of significant influence of microdoses of reagents on the flooding agent properties was substantiated. Result. A method for quantitative evaluation of the washing action of waterflooding agent is proposed. The evaluation of this parameter is recommended to be included in the list of waterflood agent quality indicators. Practical Relevance. The identified need to assess the impact of microdoses of oilfield reagents on the quality of waterflooding agent will allow more correct selection of these reagents, which in turn will ensure the reduction of their negative impact on oil production.

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