Optimizing hematite filter cake treatment using reducing agents

Area of Science:

• Petroleum Engineering
• Materials Science
• Corrosion Engineering

Background:

• Filter cake formation is vital for wellbore stability during drilling.
• Efficient filter cake removal is critical for restoring reservoir productivity post-drilling.
• Hematite-based filter cakes present unique solubility and removal challenges.

Purpose of the Study:

• To investigate factors affecting hematite filter cake solubility and removal.
• To identify optimal reducing agents and conditions for filter cake dissolution.
• To evaluate the impact of the treatment on core porosity and permeability.

Main Methods:

• Systematic examination of reducing agent types and concentrations.
• Assessment of temperature, particle size, and treatment duration effects.
• Utilizing Nuclear Magnetic Resonance (NMR) for porosity analysis.

Main Results:

• Ferrous chloride identified as the optimal reducing agent for hematite solubility.
• A composite solution (10 wt.% ferrous chloride, 6 wt.% hydrochloric acid) achieved ~99% removal efficiency.
• NMR confirmed restoration of core porosity and significant permeability enhancement.
• The composite solution demonstrated a lower corrosion rate compared to concentrated hydrochloric acid.

Conclusions:

• The developed composite solution offers an efficient and environmentally conscious method for hematite filter cake removal.
• This approach balances operational efficiency with reduced corrosion and environmental impact.
• Findings provide valuable insights for optimizing post-drilling operations and enhancing well productivity in the oil and gas industry.