Drilling Mud Cleanup
Drilling muds can often contaminate geological samples, and appropriate cleaning strategies have to be used to clean samples before testing to ensure the generation of meaningful data.
Weatherford Laboratories has developed multiple strategies for the successful removal of drilling mud contamination for geological samples.
Oil based muds (OBMs)
Cuttings collected while drilling with OBM need extra attention, since the oil used in the formulation of the mud will significantly interfere with the analysis of indigenous organic matter (oil, gas, kerogen, etc.) in the samples. For example, falsely high oil yields might be predicted if the OBM is not accounted for or removed. Other mud additives such as various lost circulation materials (LCM) also require special attention.
Cleaning strategies may include:
- Water washing (no detergent)
- Water washing with detergent
- Solvent washing (different solvents available)
- Solvent extraction (soxhlet or ultrasonic)
- Sieving – Removal of contaminants based on particle size
- Magnetic cleanup – Metal shards/fragments removed by magnet
- Floatation for LCM – LCM often have low density and will float in water or solvent
- Picking of LCM particles from sample
- Combinations of above procedures often required