Wettability control agents play a vital role across key stages of oil and gas field development, including drilling, completion, acidizing, fracturing, production, and gathering. While their application focus and technical requirements vary by scenario, the core objective remains consistent: optimizing recovery and improving operational efficiency through tailored wettability management.
(1) Drilling & Completion: Minimizing Formation Damage from the Start
Invasion of drilling and completion fluids into the reservoir can alter wettability and cause formation damage. Adding wettability control agents helps mitigate this issue.
During Drilling: Agents (added at 0.5%-2%) in drilling fluid form a protective film on rock surfaces. This helps prevent adsorption of organic additives and solid particles, maintaining water-wet conditions and reducing oil-based contamination. For instance, in a sandstone field, using a fatty alcohol polyoxyethylene ether-based agent reduced reservoir wettability alteration from 75% to 20% and permeability impairment from 65% to 18%.
During Completion: Agents for completion fluids (0.3%-1%) require low damage potential and high compatibility to avoid negatively impacting subsequent production. For example, in horizontal well completions, using amphoteric ionic agents with completion fluid helped prevent wettability alteration from fluid retention while maintaining fluid mobility and wellbore cleanliness, contributing to a 25%-30% increase in initial well production.
(2) Acidizing Operations: Improving Efficiency & Flowback
Acidizing generates residues, and spent acid can remain trapped in pores, potentially altering wettability and causing blockages. Wettability agents here serve two main purposes: modifying wettability to improve rock dissolution efficiency, and lowering surface tension to promote faster spent acid flowback. These acid-compatible agents (typically 1%-5%) must work well with other additives like corrosion inhibitors. In a low-permeability carbonate field using alkyl betaine in mud acid treatment, rock dissolution efficiency improved by 30%, spent acid flowback increased from 70% to 90%, and post-treatment permeability recovery reached 88%, aiding in well production increase.
(3) Fracturing Treatments: Supporting Fracture Conductivity & Cleanup
Fracturing is crucial for stimulating low-permeability and unconventional reservoirs, but injected fluids can alter wettability and reduce fracture conductivity. Wettability agents (0.5%-2%) used here need temperature/salt tolerance, compatibility with various frac fluids, and the ability to lower interfacial tension. For example, in shale gas water-based fracturing, non-ionic agents can help shift shale surfaces from oil-wet to intermediate-wet, lower interfacial tension, and improve fluid recovery. Their use can also help reduce oil adsorption on fracture faces. In one shale gas field, using a nano-silica modified agent increased flowback recovery from 55% to 85%, enhanced fracture conductivity, and supported increases in average daily gas production.
(4) Production Operations: Aiding Recovery & Sustaining Output
From primary to enhanced recovery methods, wettability agents help by modifying wettability to reduce hydrocarbon flow resistance.
Waterflooding: Adding agents (50-200 mg/L) to injection water can help shift oil-wet or mixed-wet rock toward water-wet or intermediate-wet states, potentially reducing oil adhesion and improving water sweep efficiency. In a mature field, continuous injection of petroleum sulfonate-based agents contributed to maintained production rates and a reduction in water cut.
Enhanced Oil Recovery (EOR): These agents are a component in chemical EOR formulations (e.g., polymer, alkali, or combination drives). Working with other chemicals, they can help modify wettability, emulsify/disperse oil, and lower interfacial tension to improve recovery. In a high-water-cut field, a combination drive system incorporating a betaine-based agent helped increase recovery beyond waterflooding.
Heavy Oil Production: For viscous heavy oil, agents can help emulsify and disperse the oil while altering rock wettability to reduce adhesion. In a steam soak operation for heavy oil, using an alkyl phosphate ester-based agent was associated with reduced oil viscosity and improved well production.
(5) Gathering & Wellbore Cleaning: Managing Flow Assurance
In surface flowlines, deposition of asphaltenes or resins can restrict flow. Similarly, scale or wax in the wellbore can hinder production. Wettability agents can assist in addressing these issues.
Gathering Lines: Adding agents (100-300 mg/L) to flowlines can help emulsify deposits and alter pipe surface wettability to inhibit adhesion, supporting flow efficiency. In one case, where line restrictions increased pressure by 30%, using a fatty alcohol polyoxyethylene ether-based agent helped restore normal pressure levels.
Wellbore Cleaning: Circulating or soaking with higher-concentration agent solutions (5%-10%) can help disperse organic deposits. For a well experiencing declined production due to wax blockage, a treatment using a dodecyl dimethyl benzyl ammonium chloride-based agent helped restore near-original production rates.
Post time: Dec-12-2025