INPUT   DATA

Title

Mud weight		ppg
Chlorides		ppm
CEC of mud		lb/bbl
CEC of shale		lb/bbl
Retort Analysis: Water		% by volume
Retort Analysis: Oil		% by volume
Retort Analysis: Solids		% by volume

---

---

OUTPUT   VARIABLES

Salt water	% by volume
Suspended solids	% by volume
Spec. gravity of saltwater
Spec. gravity of solids
Low gravity solids	% by volume
Barite	% by volume
Barite	lb/bbl
Bentonite	% by volume
Bentonite	lb/bbl
Drilled Solids	% by volume
Drilled Solids	lb/bbl

Recommended Maximum	% by volume
Solids fractions
Low gravity solids

Basic Solids Analysis

Step 1:  Percent by volume saltwater (SW)

where   Salt_ppm = Chlorides content in parts per million

Step 2: Percent by volume suspended solids (SS)

Step 3: Average specific gravity of saltwater (ASG_SW)

Step 4: Average specific gravity of solids (ASG)

where   MW_ppg = Mud weight in pounds per gallon

Step 5: Average specific gravity of solids (ASG)

Step 6: Percent by volume of low gravity solids (LGS)

Step 7: Percent by volume barite

Step 8: Pounds per barrel barite

Step 9: Bentonite Determination

    If cation exchange capacity (CEC)/methylene blue test (MBT) of SHALE and MUD are KNOWN:

    a) Bentonite,lb/bbl:

    where S = CEC of shale
             M = CEC of mud

    b) Bentonite, % by volume = [Bentonite, lb/bbl] / 9.1 .

    Else If cation exchange capacity (CEC)/methylene blue test (MBT) of SHALE is UNKNOWN:

    a)Bentonite, % by volume:

    b) Bentonite, lb/bbl = [Bentonite, % by volume] x 9.1 .

Step 10: Drilled solids, % by volume

         = LGS_%byVolume – Bentonite_%byVolume

Step 11: Drilled solids, lb/bbl

        = DrilledSolids_%byVolume x 9.1 .

Recommended Maximum Solids Content

The maximum recommended Solids Fractions (SF^*), and

the maximum recommended Low Gravity Solids (LGS^*) are expressed by:

where   MW = Mud weight in pounds per gallon.

BIBLIOGRAPHY

• Lapeyrouse N.J.; Formulae And Calculations For Drilling And Workover; Gulf Publ. Co., Houston, 1992, chap. 3.
• Mian M.A.; Petroleum Engineering Handbook For the Practicing Engineer; Pennwell Publ Co, Tulsa, 1992, vol II, chap. 8.