Mud Retort - Audit

NOTICE: Our Mathcad database got attacked and infected with a virus. Unfortunately, we've had to shut it down until further notice.

You can safely browse the pages, as the Mathcad server was separate to this main website, and was only accessible here. (We used something called an iFrame, which is like a window into a different website).

UPDATE 28th of January 2020: the virus happened just over a week ago. We've temporarily cut and pasted the text parts of the Mathcad pages rather than having blank pages there.

UPDATE 3rd of February 2020: We've been unable to recover the Mathcad worksheets and offer them in a format that provided total security to users. They were published a decade ago, and our IT people say that they would need a complete re-creation with the latest code and security fixes.

APPEAL: These 44 pages were created, and offered as a free resource for over a decade. We know from our website analytics that more than 1000 users visited each month. If only half of these regular visitors donated $20, we would have enough to create an even better solution. As you know, time is money, have these Mathcad pages saved you $20 in time over the years? We expect that they have, not to mention the learning opportunities provided to new engineers entering the industry.

Please, donate at least $20 as a one-off payment, to bring back the drillers Mathcad back as an always free to use resource!

YES! I've gotten value from the drillers Mathcad in the past, and a $20 is a very affordable way of saying thanks. I also want to preserve this tool for future engineers.

NO! I can't or won't donate to the restoration fund. I'm happy to spend a few minutes to offer a testimonial to help encourage the effort. These worksheets do have value. Offer Feedback.

Mud retort analysis, release 3a, issued 1 July 2008. AUDIT version.

The current release of this worksheet exists in three different versions. They are identical apart from the way they are formatted. The Work version displays the intermediate calculations. The Audit version shows all intermediate calculations. The PDA version removes all text and formats the input and output fields for optimum viewing on a mobile, small-screen device.

User input



Enter empty retort chamber weight. Frt1 =



Enter full retort chamber weight. Frt2 =



Enter final retort chamber weight after retorting. Frt3 =



Volume of mud sample in chamber. Vrt =




Volume of distillate after the test. Vdl =



Volume of water after the test. Vw =


Click here when any values are modified to update the result.


Note that the first 3 entries are entered in units of grams Force, not Mass. This allows pressure gradients to be calculated first, then divided by g (gravitational acceleration) to find mudweights.

Calculate the pressure gradient of the mud.

Calculate the mud weight of the mud (note; g = acceleration due to gravity converts force based units to mass based units).

Calculate the VOL percentage of oil in the mud.

Calculate the VOL percentage of water in the mud.

Calculate the VOL percentage solids in the mud

Calculate the MASS percentage solids in the mud.

For the oil/water ratio, calculate the volume percentage of oil and water in the fluid part of the mud only.


Pressure gradient of the mud under test.

Mud weight of the mud under test

Mass percentage of solids in the mud.

Volume percentage of solids in the mud.

Volume percentage of oil in the mud.

Oil – water ratio.

Worksheet references

Original formulae from MI Drilling Fluids Handbook, ref MI-0020 6/97.

Version 1 of this worksheet was issued on 27 June 2008.

Malcare WordPress Security