During drilling and completion, the near-wellbore region suffers inevitable damage. Drilling mud filtrate and solids, cement filtrate, and displaced clays invade the formation, reducing permeability around the wellbore — sometimes by orders of magnitude. This skin damage restricts flow from the reservoir to the wellbore and can significantly reduce well deliverability below its natural potential.

In producing wells, ongoing damage accumulates from scale deposition (carbonate, sulphate, and barite), paraffin and asphaltene precipitation, bacterial growth, iron precipitation, fines migration, and clay swelling. Each mechanism further restricts productivity over the life of the well.

Matrix acidizing injects acid below the formation fracture gradient to dissolve carbonate minerals, remove scale, disperse mud filtercake, and create wormhole channels — restoring or exceeding original formation permeability without creating hydraulic fractures.

Acid fracturing injects acid above fracture pressure in carbonate formations. The acid differentially etches fracture faces, creating a conductive flow channel that remains open after pressure release — bypassing the damaged zone and connecting the wellbore to undamaged reservoir rock.

Wellbore cleanout targets scale, wax, asphaltene, corrosion products, and completion debris in the wellbore and perforations — restoring well flow efficiency without disturbing the formation.

A well-designed stimulation programme selects the right acid for the formation mineralogy and temperature, incorporates the correct additive package to prevent secondary damage, and applies diversion to ensure even coverage across all productive intervals.

Mud filtercake, clay swelling, fines invasion, and cement contamination reducing near-wellbore permeability.

Calcium carbonate, calcium sulphate, iron sulphide, and barite scale restricting tubulars and perforations.

Paraffin wax and asphaltene precipitation blocking tubulars, perforations, and near-wellbore pore throats.

Iron precipitation, bacterial plugging, clay migration, and emulsion blocks reducing productivity over time.

Multifunctional Stimulation Fluid

A specialty single-stage treatment combining HCl with a tailored organic solvent — simultaneously addressing mineral scale and organic deposits in one pump stage. Eliminates the need for a separate pre-flush solvent, reducing cost and pump time.

• ►Dissolves carbonate scale, cement, and formation carbonate minerals
• ►Simultaneously dissolves and disperses paraffin wax and asphaltene deposits
• ►Water-wets the formation surface, improving flowback efficiency
• ►Reduces surface tension and capillary pressure, improving acid penetration

Alcohol-Acid System

The Athlon Alcohol-Acid System for gas wells is specifically formulated for matrix acidizing and wellbore cleanup in gas and gas-condensate producers where water retention is a critical production impairment risk. The addition of alcohol to the acid system provides a unique set of benefits that are particularly important in low-pressure, water-sensitive, or tight gas reservoirs.

• ►Dramatically reduces the surface tension of the spent acid fluid
• ►Minimises capillary pressure in tight gas pore throats — the primary cause of water block
• ►Accelerates and improves completeness of spent acid flowback from the gas zone
• ►Reduces water block damage — a critical risk in low-pressure gas reservoirs
• ►Dissolves carbonate scale and removes near-wellbore mineral damage simultaneously

In gas wells, any retained water in the near-wellbore pore system creates a capillary barrier that significantly impedes gas flow. Standard acid systems leave aqueous spent acid in the pore space, which — in tight or low-pressure gas reservoirs — may not be produced back effectively under reservoir pressure alone. The alcohol component reduces the liquid-gas interfacial tension, allowing the gas phase to displace the spent acid more readily and fully, restoring gas deliverability post-treatment.

This system is equally effective in gas-condensate wells where condensate banking near the wellbore compounds the water block risk, and in coalbed methane (CBM) and tight gas formations where matrix permeability is inherently low.

Forms a protective film on steel tubulars, casing, and wellhead equipment — dramatically reducing the acid corrosion rate at treatment concentration and temperature. Calibrated to acid strength, temperature, and contact time. High-temperature grades available for BHT above 200°F.

Keeps dissolved iron (Fe²⁺ and Fe³⁺) in solution throughout the treatment and flowback cycle. Without iron control, ferric iron precipitates as iron hydroxide gel at pH above 2 — forming a gelatinous plug more damaging than the original scale. Essential in wells with iron-bearing formations or iron sulphide and carbonate scale.

Prevents stable acid-crude emulsions when acid contacts formation oil. Acid-crude emulsions are highly viscous and can be more damaging than the original formation damage. Modifies interfacial tension between acid and crude, ensuring clean phase separation and unrestricted post-treatment flowback of both fluids.

Prevents asphaltic sludge when acid contacts asphaltene-rich crude oils. Certain crudes precipitate as a rigid, tar-like sludge on acid contact — causing permanent, irreversible formation damage. Stabilises asphaltenes in suspension, preventing aggregation and precipitation during acid contact.

Soluble in both water and oil. Water-wets the formation surface, improves acid-rock contact, and reduces adsorption of surfactants and inhibitors onto the formation. Significantly improves post-treatment flowback by reducing capillary forces trapping water in pore throats — critical in tight, water-sensitive, or oil-wet formations.

Reduces interfacial tension between the acid and reservoir fluids, improving wetting, acid penetration into tight pore throats, and fluid recovery during flowback. Non-ionic and cationic formulations available based on formation wettability. Also used as a cleanup aid during spent acid displacement and overflush stages.

Prevents clay swelling and fines migration during and after the treatment — particularly critical in sandstone acidizing where acid-altered pore water triggers swelling of clay minerals or release of formation fines. Applied in the main acid stage and overflush for maximum protection.

Prevents secondary scale precipitation as spent acid neutralises and mixes with produced fluids. Rising pH during flowback can cause dissolved calcium, barium, and sulphate to re-precipitate — re-damaging the zone just treated. Added to the acid stage and/or squeezed into the formation for extended protection.

Pre-flush solvent used ahead of the acid to dissolve and displace paraffin wax and asphaltene deposits from the wellbore, perforations, and near-wellbore matrix. Ensures acid contacts mineral rock rather than an organic coating — which dramatically reduces acid effectiveness. PAS-3250 is Athlon's specialty organic solvent for combined asphaltene and paraffin removal.

In sour wells, acid treatments liberate H₂S from iron sulphide scale dissolution and the formation itself. The scavenger neutralises and binds H₂S as it is generated, preventing toxic gas release to surface. Essential for personnel safety and regulatory compliance in all sour service well treatments.

Added to the treatment fluid or overflush to reduce the viscosity of residual crude in the near-wellbore zone for heavy and extra-heavy crude oil formations. Allows spent acid and crude to flow back freely, reducing the risk of high-viscosity crude restricting perforations or tubing and improving the post-treatment productivity response.

Ensures even acid distribution across multiple productive intervals by temporarily blocking high-permeability zones — forcing acid into lower-permeability, damaged intervals that need treatment most. Available as a viscoelastic fluid system (ATH-ADD-DIV-L) that degrades with temperature for clean flowback, or a particulate/ball sealer system (ATH-ADD-DIV-P) for mechanical perforation diversion. Critical in long or heterogeneous intervals for uniform stimulation response.

Contact our technical team for acid system selection, additive package design, and treatment volume calculations tailored to your well.