The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 05, 1977
Filed:
Nov. 20, 1975
Thomas C Mondshine, Houston, TX (US);
NL Industries, Inc., New York, NY (US);
Abstract
The invention provides water base drilling fluids containing lime and potassium compounds which have the following advantages as compared to prior art lime muds and potassium muds: (a) provide better borehole stability than lime muds; (b) easier to control than lime muds and potassium muds; (c) drilled solids have much less effect on the rheological properties of these drilling fluids as compared to lime muds and potassium muds; (d) the thermal gelation of these drilling fluids after contamination with shale is much less severe than that of shale contaminated lime muds or potassium muds; and (e) bit balling and cuttings agglomeration when drilling mud making shales is much less than when using lime muds or potassium muds. These drilling fluids comprise a suspension of clay, lime and 10-30 ppb of a lignitic material in an aqueous phase, the drilling fluid having a Pm in the range from 1 to 40 and a pH in the range from 12.4 to 13.5, the aqueous phase being saturated with lime having a Pf in the range from 1 to 8 and a K.sup.+ concentration of at least 8000 ppm, wherein Pm > Pf. The invention also provides a method of preparing muds containing lime and potassium whereby the increase in viscosity and gel strength which normally accompanies the addition of lime to aqueous clay-containing muds is minimized which consists of adding to a suspension of clay and a lignitic material: KOH, KCl, and lime, in that order.