Patent ID: 7326817

Claim:
A method for producing low sediment toxicity hydrocarbons suitable for use in a drilling fluid, the method comprising the steps of: dimerizing, trimerizing, or oligomerizing olefins using a zeolite type catalyst, whereby dimerized, trimerized, or oligomerized olefins are obtained; hydrogenating the dimerized, trimerized, or oligomerized olefins, whereby a hydrogenated composition is obtained; fractional distilling the hydrogenated composition; and collecting a fraction of hydrocarbons having a boiling point above about 280° C. and below about 320° C. and having a sediment toxicity towards Leptocheirus plumulosus with a median lethal concentration (LC 50 ), in accordance with ASTM Guideline E 1367, EPA 600/R-94/025, of more than about 500 mg/kg, wherein the fraction of hydrocarbons comprises low sediment toxicity hydrocarbons.