IWC 13‐37D

Prepared Discussion of: 

Recovering Valuable Byproducts from Oil 

and Gas Wastes

Discusser: JOHN SCHUBERT, P.E, 

 HDR 

 Sarasota, Florida 

The authors of this paper are to be 

congratulated for presenting a paper on an 

area which has heretofore not received a 

great deal of attention. That is the handling 

and disposition of drilling fluids from oil and 

gas well installation. The information 

presented provides a picture of how these 

materials are handled, which is quite 

informative to those of us who do not work 

with drilling fluids every day. Thank you 

authors for presenting this paper. 

That said, there were some areas where 

additional information, or more complete or 

supporting information would be valuable in 

helping the reader understand the 

operations that are described. A list of 

some of the questions that occurred to me 

while reviewing the paper include the 

following: 

1. The typical Marcellus Shale well 

might use 4,000,000 to 5,000,000 

gallons (95,000 to 120,000 bbl) 

water in hydrofracturing with 

flowback of maybe 20% of that. In 

comparison, what rate is mud 

circulated in a drilling operation, and 

what rate is typically wasted, both on 

an ongoing basis and as a total 

volume during the drilling event ? 

2. In WBM, how much of the clay 

present is added as bentonite or 

other purchased clays versus the 

amount picked up in drilling typically 

? For muds that have a high amount 

of clay from the formations being 

drilled, can that material be reused ? 

(I.e. does it have similar fluid 

properties and shape to the 

purchased bentonite.?) 

3. In describing the benefits of oil 

based muds (OBM ?), the authors 

state one benefit is enhanced shale 

inhibition. What does this term 

mean ? 

4. In the section titled “Well Head 

Drilling Fluid Treatment” the authors 

indicate that due to the volume of 

drilling fluid required it is most 

economical to reuse drilling fluids to 

the greatest extent possible. Can 

the authors provide some indication 

of the cost to prepare drilling fluid, 

and the usage rates as outlined in 

question 1, so that the reader can 

appreciate the economic incentive 

for reuse. 

5. What is the downside of reuse ? 

Does the use of virgin drilling mud 

provide any benefit in terms of 

energy utilization, bit life, or drilling 

speed ? 
IWC 13‐37D

6. In the section on Well Head Drilling 

Fluid Treatment, several comments 

are made relative to the 

concentration of solids after 

screening, the content of oil, and the 

dewatering of solids to form a cake. 

Some typical numbers to support 

these positions would help the 

reader more fully understand the 

drivers for the handling processes 

selected. Particularly useful would 

be the solids concentrations before 

and after screening, the typical 

flowrate through a screening station, 

and the solids concentration in the 

cake. The concentration of 

hydrocarbons in the various streams 

would also be of interest. The screen 

sizes typically used would also 

provide insight into the nature of the 

solids at various points in the 

system.. 

7. The fluid passing through the 

screens is noted as containing large 

amounts of solids. Is there a typical 

range of values that might be 

expected for this ? 

8. In Table 1, the solids content of the 

mud entering the system is indicated 

as 6%, with a concentration of solids 

in the mud returning from the system 

of 4%. This would seem 

counterintuitive if the mud is 

increasing in solids in the drilling 

process, by collecting cuttings. 

9. Is the weight of sludge wasting 

controlled only by the particle size 

distribution, or are there any other 

factors that govern the wasting rate 

? 

10. The paper indicates that screenings 

from OBM can be blended with coal 

and burnt for energy, or subjected to 

thermal desorption. What types of 

operations can use coal blended 

with drill cuttings as a fuel source ? 

Is the hydrocarbon content of the 

screened cuttings sufficient to 

prevent disposal of the material 

directly ?. Can the material be 

washed with a detergent or 

extractant to remove the oil prior to 

disposal ? 

11. Would clays from wasted mud be 

handled in the same fashion as 

cuttings (i.e. thermal desorption)? 

One would think that drilling mud 

solids, being relatively fine, would 

retain some hydrocarbons on the 

substantial surface area they 

provide. 

12. Did Holo-Scru pay for product 

placement in this paper ? 

13. What are carbonate based 

coagulants ? 

14. At the example treatment facility, are 

drilling mud wastes handled 

separately or together with flowback 

and produced water ? 

15. The product water from the 

treatment system is noted as being 

sold, but would have a high sodium 

chloride content. It is not stated but 

implied that it is sold for 

hydrofracturing use. Are there any 

other uses for which this water is 

sold ? 

16. How much of the 1 MGD capacity at 

the example treatment facility is 

dedicated to handling drilling muds ? 

Can the facility accept oil based 

muds as well as water based muds 

? 

A larger overall question relates to the title 

of the paper. The issue is that the paper is 

identified as being focused on recovering 

valuable byproducts. Yet there is little 
IWC 13‐37D

mention in the paper of the value of any of 

the byproducts. While it is reasonable to 

assume that the oil has a value, and that the 

cuttings have little value, there is little in the 

presented information to convince anyone 

the byproducts actually have a value. The 

key driver appears to be disposal cost 

minimization, and not byproduct value. In 

that respect, the disposition of mud solids 

(clays) is probably key to the discussion. 

The paper implies that attrition of solids in 

drilling limits the amount of mud that can be 

recycled and dictates the wasting rate. 

However, the final page of the paper 

indicates that the mud solids can be 

recycled. Some explanation of how the 

finer solids generated through initial use in 

drilling are reused, and the value of the 

material, should be provided. 

Again, the authors are to be congratulated 

for bringing this subject to the attention of 

the attendees. This is a subject that is 

rarely discussed, and presents unique 

handling/treatment 

Requirements.