Application Guide for Formate-Based Products Specially Formulated for Shale Gas Well Completion Fluids

Solid and liquid potassium formate and sodium formate may be used as salt based foundation materials for shale gas completion fluids and potassium acetate can be used as an additional component in certain formulations. The target density, shale compatibility, corrosivity, and compatibility with future fracturing fluids should be the basis for selection.

I. Solid Potassium Formate (Industrial Grade ≥97%)

Application: It is used as the formulation of completion fluid of shale gas horizontal well. It may suppress salinity and potassium ion.

Ingredient characteristics: Potassium ions for shale inhibition; Solids free system to reduce particles incursion into the reservoir. Verification requires shale swelling testing and core damage testing.

Recommendations for application: Determine the dose based on the design density and the active substance of the product. Assess the rheological characteristics, compatibility and system performance after complete dissolution or thorough mixing of the system after temperature change.

Precautions: Highly hygroscopic; keep in a sealed, dry atmosphere. For high concentration systems, compatibility should be tightly controlled to prevent conflicts with cationic treatment agents.

II. Liquid Potassium Formate (Industrial Grade ≥75%)

Application: Used to prepare formate completion fluids on site without the requirement to dissolve the solid raw ingredients.

Raw material characteristic: Being a liquid product, no on-site dissolving is required. The active content has to be checked and evaluated for compatibility with flowback aids, corrosion inhibitors and subsequent fracturing fluids.

Usage recommendations: Dose is calculated based on design density and active product content. Check the rheological characteristics, compatibility and performance of the system during temperature changes. during complete dissolution or uniform mixing.

Precautions: Viscosity rises at low temperatures, thus provide sufficient insulation of storage tanks during winter. Store in a sealed container to avoid crystallisation due to evaporation of moisture for long-term storage.

III. Solid Sodium Formate (Industrial Grade ≥98%)

Application: Component of formate based finishing fluids, may be used with potassium formate.

Raw material characteristics: Sodium formate may be mixed with potassium formate to modify density and cost. Inhibition performance, corrosivity and reservoir compatibility must be checked.

Usage recommendations: The dose may be calculated based on the design density and the active substance of the product. Test rheological qualities, compatibility and system performance during temperature changes after complete dissolution or thorough mixing.

Its inhibitory performance is lower than potassium formate, thus it is not suited for high-pressure and deep shale gas wells. It has to be used with a stabiliser at high temperature to avoid performance deterioration.

IV. Industrial-grade Potassium Acetate (Solid/Liquid)

Application: Can be used as a pH-adjusting component in finishing fluids; compatibility with other additives should be tested.

Ingredient characteristics: The pH of the system may be adjusted using potassium acetate. The corrosion inhibition performance and its effect on the stability of the finishing fluid must be validated in the target formulation.

How to use: Calculate the dose by the design density and the active content of the product. Evaluate the Rheological characteristics, Compatibility and System performance after temperature change to completely dissolve or mix thoroughly.

Note: The solid is very hygroscopic, keep in sealed container; overdosing influences the density of the system, so the dose should be managed.

 Applicable Scenarios for Raw Materials

Formate-based raw materials can be used to formulate shale gas completion fluids. Solid forms are suitable for on-demand dissolution and mixing, while liquid forms allow for direct metering and dosing; however, the completion fluid's density, reservoir compatibility, and compatibility with fracturing fluids still require verification under the specific conditions of the target well.