Injectivity Determination

The objective is to determine the level of filtration that is required so that unacceptable injectivity losses do not occur. There is of course an economic trade off between capital and operating costs as a high degree of filtration requires more capital but fewer well work-overs.

The work should be done at site with the actual injection water as it is impossible to mimic the solids’ loading with synthetic water.

Prior to visiting site the cores must be selected and prepared so we can liaise with the client’s reservoir department. Core preparation can be done by the client or by Alcedo and involves cutting and cleaning the plugs, measuring porosity and permeability, XRD analysis to determine clay content and vacuum saturate in simulated formation water.

A custom-built filtration and core-flooding rig is sent to site and requires 2 full-time operators for a minimum of 9 days (including set-up and dismantling).

The test will reveal how permeability declines depending on the injection water quality and the blocking characteristics. SEM and XRD are used to examine the cores after flooding.

The injectivity study does not, by itself, provide the well injectivity decline (or well half life). Many other parameters need to be taken into account (e.g. fracturing, permeability distribution, well characteristics, etc.) but these are provided as part of the overall study.