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Title: Evaluation of saponite and saponite/sepiolite fluids for geothermal drilling

Technical Report ·
DOI:https://doi.org/10.2172/5908401· OSTI ID:5908401
; ;  [1]
  1. Texas Tech Univ., Lubbock, TX (USA). Dept. of Geosciences

The rheology and other properties of drilling fluids containing saponite and a saponite-sepiolite mixture as the main vicosifier have been systematically evaluated in the temperature range of 300-600{degree}F under appropriate confining pressures up to 16,000 psi. Saponite represents the magnesium analog of the clay mineral montmorillonite, which is the main constituent in conventional bentonite-based fluids. The fluid with 6% saponite exhibits a prominent viscosity enhancement at temperatures above 250{degree}F. This viscosity enhancement is easily controlled by salts and hydroxides of Na and K. The addition of Na-polyacrylates (low- and high-molecular weight polymers) eliminates the viscosity anomaly of pure saponite fluids. These polymers also increase the filtration control of saponite. The anomalous viscosity enhancement of saponite is significantly reduced by the addition of sepiolite (a clay mineral with a fibrous morphology). 12 refs., 31 figs., 26 tabs.

Research Organization:
Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Texas Tech Univ., Lubbock, TX (USA). Dept. of Geosciences
Sponsoring Organization:
USDOE; USDOE, Washington, DC (USA)
DOE Contract Number:
AC04-76DP00789
OSTI ID:
5908401
Report Number(s):
SAND-88-7115; ON: DE91009854
Country of Publication:
United States
Language:
English