Individual Treatment Fluid Application

(Matrix acid, Scale Inhibitor, Biocide, Corrosion, Drag Reducers dissolvers etc.)

1. Acid Stimulation
2. Scaling and Scale Inhibition
3. Diverters
4. Drag Reducers/Biocide/Corrosion

To clearly identify favourable non-damaging fluid candidates, remedial treatments and / or incorporate mechanisms or design operations to improve results for field use the permeability results, cryogenic SEM analysis and dry SEM analysis are required. If the above treatment fluid applications are considered based solely on permeability results then this may carry an associated risk because of fines migration and / or other flow reducing barriers. If drilling and/ or completion options are considered for any one sample type based on performing only single SEM analysis then this may carry an associated risk. However, if both dry and cryogenic SEM analysis is performed there would be less associated risk. Engineers would be able to customise the design of the fluid(s) and / or design mechanisms for successful field deployment based on knowing the full scope of damage mechanisms (nature and distribution). Therefore, Corex (UK) Ltd recommends both dry and cryogenic SEM to provide a complete evaluation of all possible fluid and solid damaging mechanisms.

In essence, to clearly identify favourable non-damaging fluid candidates, remedial treatments and / or incorporate mechanisms or design operations to improve results for field use the permeability results, cryogenic SEM analysis, dry SEM analysis, thin section analysis and XRD are required.

The below movie illustrates an example with expandable clays which could swell during water injection, thus effecting the integrity of the rock.

Click here to view the clip Windows Media Player

Acid Stimulation

Corex can perform various acid stimulation sequences tailored to individual requirements. The laboratory has staff trained specifically in the use of chemicals such as, hydrofluoric acid (HF) as well as hydrogen chloride acid (HCl).

The image below illustrates and outline of Dissolved Dolomite Rhomb.

Enlarged pore and dissolved Potassium feldspar, with an amorphous silica deposit left behind after acid application.

Scaling and Scale Inhibition

Untreated sample

This view shows the untreated plug which has undergone to prior flood test analysis to determine the natural cements and clays present. The only cement type is quartz, and no clays were observed.

Treated sample formation brine flood test

This view shows the plug after formation brine has been flooded through it at reservoir conditions. A scale composed of calcium carbonate (aragonite) has precipitated due to a brine/rock incompatibility.

Scale inhibitor plus formation brine

This view shows the plug after an inhibitor squeeze program followed by formation brine. No aragonite scale has formed and only an inhibitor scale is visible. The inhibitor has effectively prevented scale formation.

If you would like additional information on this subject please read through this Corex publication which may be of further interest, "Scale Management through Laboratory Analysis and Wellbore Monitoring Surveys".

Diverters

Fluids tend to flow along the path of least resistance; this can mean that some areas of low permeability in the formation are subject to less treatment fluid than others. A diverter enables fluids to target the areas that need it the most.

Corex design tests to assess chemical diverters' capabilities in the production intervals to restrict or improve fluid flow.

Drag Reducers/Biocide/Corrosion

Corex run coreflood tests that examine drag reducers, biocide and corrosion fluids to access if these chemicals will cause an adverse effect on the permeability.