Wet cutting coming over shale shakers can be used to determine cutting bulk density. This post demonstrates you how to find bulk density (specific gravity) in specific gravity of cutting using mud balance so please read and understand procedure to determine resulting weith with cutting plus water (RW) and then use RW to determine specific gravity of cutting bulk density.
Procedure to obtain resulting weight with cuttings plus water (RW):
1. Cuttings must be washed free of mud. In oil base mud, diesel oil can be used instead of water.
2. Set mud balance at 8.33 ppg.
3. Fill the mud balance with cuttings until a balance is obtained with the lid in place.
4. Remove lid, fill cup with water (cuttings included), replace lid and dry outside of mud balance.
5. Move counterweight to obtain new balance. This value is “Rw” = resulting weight with cuttings plus water in ppg.
The specific gravity of cutting is calculated as follows:
SG = 1 ÷ (2 – (0.12 x Rw))
SG = specific gravity of cuttings – bulk density
Rw = resulting weight with cuttings plus water in ppg
Determine the bulk density of cuttings:
Rw = 14.0 ppg
SG= 1 ÷ (2 – (0.12 x 14.0))
SG = 3.13
Moreover, if you can to convert specific gravity to mud weight (ppg and lb/ft3) and pressure gradient (psi/ft). Learn more about how to Convert specific gravity to mud weight (ppg and lb/ft3) and pressure gradient (psi/ft)
Please the Excel sheet used to calculate Bulk Density of Cuttings Using Mud Balance
Ref books: Lapeyrouse, N.J., 2002. Formulas and calculations for drilling, production and workover, Boston: Gulf Professional publishing.
Bourgoyne, A.J.T., Chenevert , M.E. & Millheim, K.K., 1986. SPE Textbook Series, Volume 2: Applied Drilling Engineering, Society of Petroleum Engineers.
Mitchell, R.F., Miska, S. & Aadny, B.S., 2011. Fundamentals of drilling engineering, Richardson, TX: Society of Petroleum Engineers.