RE: Formation damage - causes, solutions & prevention.9 Aug 2025 17:29
An AI response:
Predator Oil & Gas – Investor Fact Sheet (Aug 2025)
A consolidated, fact-based view of the Guercif (Morocco) and Trinidad projects
1️⃣ Historical & Geological Context
• Oil flowed to surface in Guercif licence over 100 years ago; early drills often:
- Hit gas instead of oil (ignored at the time due to low demand).
- Were off-structure or too shallow to intersect deeper targets.
• Surface seepage studies confirm subsurface gas, oil, and condensate.
• Scotforth RSDD-H satellite data (privately held by GRH) is reported positive for Guercif and has been used successfully in other regions to predict drilling outcomes.
2️⃣ Well Data & Reservoir Quality
• Three wells (MOU-1, MOU-3, MOU-4) contain substantial net pay zones of overpressured biogenic gas.
• Outstanding porosity & permeability verified by Nu-Tech — positive for production potential.
• Formation damage identified in all drilled wells; restricting flow.
3️⃣ Formation Damage – Cause, Solution, Prevention
Cause:
• Guercif gas pressure is higher than expected for given depths → precautionary overbalanced drilling used heavier drilling mud to prevent blowouts.
• Heavier mud infiltrated high-permeability sands, blocking pore space and impeding gas flow.
• Additional damage from explosive perforation — heat and pressure can compact/plasticise reservoir material.
Solution:
• Perforate beyond the 'skin' of damaged rock into undamaged reservoir.
• MOU-3 A-sands required larger perforating guns to penetrate two casing layers and reach reservoir.
• Nitrogen lift recovered undamaged sand, proving perforations reached target — but perforation tunnels still partly obstructed.
• Possible next steps if pressure build-up fails to clear debris: acid stimulation or other cleaning methods.
• Larger guns will easily penetrate single casing in other MOU-3 horizons and other wells.
Prevention (MOU-6):
• Drill at balanced pressure now that pressures, mineralogy, and depths are known — prevents mud invasion.
• Consider alternative completions (pre-slotted casing, sand filters, gravel packing) to avoid explosive perforation entirely and potentially accelerate drilling.
4️⃣ Latest RNS Highlights (1 Aug 2025)
• MOU-3 'A' Sand successfully perforated with larger guns.
• Gas present, but no commercial flow yet due to residual damage.
• Well shut-in for possible slow pressure build-up.
• MOU-6 well design underway — aims to prevent formation damage.
• Drilling to start at earliest opportunity this year, likely from existing MOU-3 pad.
• Testing programme delivered
Contd..