Environmental Effects of Drilling Fluid Additives

Environmental Impact of the Offshore Oil and Gas Industry by Stanislav Patin - a unique summary of world-wide studies on the environmental issues associated with offshore oil and gas exploration and development

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Muddied Waters

A Survey of Offshore Oilfield Drilling Wastes and Disposal Techniques to Reduce the Ecological Impact of Sea Dumping

by Jonathan Wills, M.A., Ph.D., M.Inst.Pet., for Ekologicheskaya Vahkta Sakhalina (Sakhalin Environment Watch); 25th May 2000

Environmental Effects of Drilling Waste Discharges (continued)

Go to Previous Page: "Non-Water Quality Environmental Impacts";
The Effects of Discharges of Drilling Fluid Additives

The Effects of Discharges of Drilling Fluid Additives (continued)

In the US the Environment Protection Agency, like OSPAR, publishes generic and chemical names, usually without trade name equivalents. The following table shows the latest (April 2000) generic list of additives in use with SBM in US waters. Some are also used with WBM.

Table 8: Synthetic Based Fluid (SBF) Typical Composition

Source: US Environmental Protection Agency, Washington D.C. office. pers. comm.April 2000

Function	Generic Name	Concentration
Continuous phase (base fluid)	LAO IO Paraffin Ester	55-70 vol.%
Emulsified phase	CaCl2 or NaCl brine	20-35 vol.%
Emulsifier	Amine or fatty acid	8-20 lb/bbl (of whole mud)
Oil wetting agent	Amine or fatty acid	8-10 lb/bbl
Weight material	Barite Calcium carbonate	50-350 lb/bbl (depends on final mud density needed)
Filtration control	Amine Clay Amine Lignite	2-15 lb/bbl
Viscosifier	Amine Clay Dimer/trimer fatty acid	0.5-7 lb/bbl
Alkalinity control	Lime	1-6 lb/bbl
Activity (shale) control	Calcium chloride (preferred) or sodium chloride	20-35 wt.% in the water phase only

An old but still useful source of public domain information on drilling mud additives is a document produced a quarter of a century ago by the Industrial Marketing Research Association (Industrial Marketing Research Association (IMRA). 1975. Chemicals in Oil Exploration and Recovery. London. See Appendix 1). It lists the main ingredients of drilling mud in 1975 as follows:

Table 9: IMRA Table of Drilling Fluid Components

Name of chemical	Function	"Examples of quantities used" per annum per rig
Barytes	Weighting material	4,500 tons
Bentonite	Weighting material	400 tons
Attapulgite	Weighting material	150 tons
Sodium tetraphosphate	Dispersant/thinner	3 tons
Sodium pyrophosphate	Dispersant/thinner	2 tons
Causticised metal lignite	Dispersant/thinner	10 tons
Ferrochrome lignosulphate	Dispersant/thinner	100 tons
Pre-gelatinised starch	Filtrate reducer	2 tons
Polysaccharide	Filtrate reducer	100 tons
Carboxy-methyl cellulose ("CMC")	Filtrate reducer	120 tons
Soluble polyacrylate	Filtrate reducer	25 tons
"Temperature resistant product"	Filtrate reducer	2 tons
Polymeric fluid loss reagent	Filtrate reducer	65 tons
Aluminium stearate	Defoamer	2 tons
Alcohol defoamer	Defoamer	30 drums
Mica	Lost circulation material	10 tons
Walnut shell	Lost circulation material	10 tons
Asbestos	Lost circulation material	10 tons
"Mixture"	Lost circulation material	10 tons
Potassium chloride	Inhibition/shale shakers	1,000 tons
Encapsulating polymer	Inhibition/shale shakers	45 tons
Biopolymer	Viscosifier	2 - 50 tons
Potassium hydroxide	pH control	1 - 10 tons
Caustic soda	pH control	125 - 150 tons
Salt	Sodium source	1 ton
Gypsum	Calcium source	<220 tons
Calcium chloride	Calcium source	4 tons
Lime	Calcium source	20 - 150 tons
Sodium carbonate	Hardness/cement remover	26 tons
Sodium bicarbonate	Hardness/cement remover	10 - 12 tons
Chlorinated phenols	Bactericides	1 ton
Unidentified	Emulsifier	2 drums
Unidentified	Surfactant	2 - 10 drums
Unidentified	Lubricant	10 drums