New Chemistry for Chromium-Free Bentonite Drilling Fluids Stable at High Temperatures (1995)

New Chemistry for Chromium-Free Bentonite Drilling Fluids Stable at High Temperatures Burrafato Giovanni; Burrafato Giovanni Agip S.p.A. Search for other works by this author on: This Site Google Scholar Miano Fausto; Miano Fausto Enichem Augusta Industriale Search for other works by this author on: This Site Google Scholar Carminati Stefano; Carminati Stefano Eniricerche SpA Search for other works by this author on: This Site Google Scholar T.P. Lockhart T.P. Lockhart Eniricerche SpA Search for other works by this author on: This Site Google Scholar Paper presented at the SPE International Symposium on Oilfield Chemistry, San Antonio, Texas, February 1995. Paper Number: SPE-28962-MS https://doi.org/10.2118/28962-MS Published: February 14 1995 Cite View This Citation Add to Citation Manager Share Icon Share Twitter LinkedIn Get Permissions Search Site Citation Giovanni, Burrafato, Fausto, Miano, Stefano, Carminati, and T.P. Lockhart. "New Chemistry for Chromium-Free Bentonite Drilling Fluids Stable at High Temperatures." Paper presented at the SPE International Symposium on Oilfield Chemistry, San Antonio, Texas, February 1995. doi: https://doi.org/10.2118/28962-MS Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentAll ProceedingsSociety of Petroleum Engineers (SPE)SPE International Conference on Oilfield Chemistry Search Advanced Search ABSTRACTThe broad substitution of aqueous drilling fluids for oil-based muds will require that the performance limitations of current aqueous muds be overcome. The research described in this paper is focused on the most commonly-used aqueous drilling fluids, lignosulfonate (LSO3-dispersed bentonite muds, and addresses two important issues that restrict their wider use: their limited stability at elevated temperature, and their reliance on chromium-containing additives (Cr-LSO3 and Cr-lignite) for control of their rheological properties.In this paper, new hypotheses regarding the mode of action of Cr(VI) and Cr(III) in Cr-LSO3/bentonite muds are formulated on the basis of new and published experimental observations. Of primary importance are the ideas that (1) LSO3-bound Cr(III) is the form which enhances the thinning power of LSO3 and (2) Cr(VI) stabilizes LSO3/bentonite muds primarily by acting as a latent source of Cr(III). Acting on these hypotheses, it has been found that Cr(III) complexes of appropriate kinetic stability can duplicate the theology-stabilizing function of Cr(VI). Further pursuit of this coordination chemical approach has led to the identification of a family of Zr(IV) complexes with which chromium-free drilling fluids of outstanding rheological stability can be prepared. The general chemical factors influencing the theology-stabilizing activity of metal ion complexes are examined. Finally, the unexpected and remarkable thinning power of the Zr(IV) citrate complex is described and its implications for the formulation of novel drilling fluids are briefly discussed.INTRODUCTIONThe need to reduce the environmental impact of drilling operations has led to a renewal of interest in aqueous drilling fluids.1–4 Compared with oil-based muds, however, the aqueous drilling fluids currently available do not offer equivalent performance in two important areas: rheological stability at high temperature and shale stabilization, Further, some of the additives employed in aqueous drilling fluids are themselves increasingly subject to environmental regulation.Where shale instability and formation temperatures are not critical issues, the most commonly used aqueous drilling fluids are dispersed or high solids muds formulated with bentonite clay. Bentonite is employed at a concentration from 2-6% by weight in these drilling muds in order to impart Bingham-type theology to the fluid. It also helps to control fluid loss by participating in filtercake formation.5 In most drilling situations, a thinner must also be added in order to control the tendency of aqueous bentonite dispersions to thicken or gel upon prolonged exposure to elevated temperature.Chromium-containing lignosulfonates (Cr-LSO3) are the thinners most widely employed in dispersed bentonite mud formulations. Another chromium-containing additive, Cr-lignite, is widely used in these muds for fluid loss control, and has a secondary function as a theology control agent at elevated temperature. These chromium-containing additives, however, are increasingly subject to environmental regulation. Keywords: rheological stability, drilling fluid selection and formulation, bentonite mud, upstream oil & gas, drilling fluids and materials, new chemistry, concentration, drilling fluid formulation, chromium-free bentonite drilling fluid stable, drilling fluid property Subjects: Drilling Fluids and Materials, Drilling fluid selection and formulation (chemistry, properties) This content is only available via PDF. 1995. Society of Petroleum Engineers You can access this article if you purchase or spend a download.