Researchers present new observations in oil saturation

A paper appeared in Processes.

Senior Research Associate Alexander Bolotov mentions that the paper is a continuation of a longstanding search for optimal reagents for evaluating oil saturation.

One of the the techniques used for such evaluations is single-well chemical tracer test (SWCTT). Tracers are used in oil production for monitoring and are useful in finding out the potential of enhanced oil recovery.

“When we use enhanced oil recovery, for instance, surfactants or polymers, we need to measure the differential in oil saturation before and after the action. This research is dedicated to the monitoring process,” says he.

The technique can be used for feasibility studies of tracers suitable for a wide range of temperatures – from 20 to 120 C. The tracer is a liquid injected into a well for a certain time.

“There are several hundreds of well treatments performed worldwide using the single-well test technology, but nowhere are the criteria for selecting a tracer described or formulated, and no rationale for its further behavior in reservoir conditions is given. Also, there are no recommendations and methods for evaluating how to calculate the reactivity of the tracer, taking into account the competing process of extraction from the aqueous to the oil phase. These two processes are usually tested separately in laboratories to determine the process parameters for tracer injection and soaking. We showed the relationship of these processes and their influence on the selection of a tracer for the given reservoir conditions – this is temperature, reservoir salinity, and residual oil saturation. We showed an algorithm that allows you to understand which chemical tracer is optimally injected, as well as determine the conditions for holding and developing a well to interpret the results of tracer inflow profiles. Tracer injection is a technological process that is influenced by a combination of factors, therefore, the success depends on the methods that allow calculation and forecasting,” continues Bolotov.

The academic community and the oil industry are interested in such algorithms. As part of the research, a PhD thesis will be prepared.