Synthesis and characterization of cation-exchanged laponite nanohybrids for use as drilling fluid viscosifier
T.X. Phuoc, Y. Soong, M.K. Chyu
National Energy Technology Lab, US
Keywords: laser ablation, nanohybrids
Abstract:In this paper we report our new approach to synthesize cation-exchanged Laponite nanohybrids for use as gel-forming, viscosity and weighting material stabilizing additives for drilling fluid application. To synthesize the nanohybrids, we use laser ablation in liquid technique to ablate a metal target submerged in deionized water containning one weight percent laponite and found that the technique can be used to successfully produce cation-exchanged Laponite crystals. General observations of the prepared samples indicated that an aqueous solution of 1 weight percent Laponite remained free flowing even after several weeks of aging. When bivalent metals Cu, Co, Zn, or Ni were ablated into it, the mixture underwent a transition to a stable gel very quickly. Although the weight percent of the nanohybrids was negligibly small compared to that of Laponite, aqueous suspensions of these cation-exchanged Laponite crystals were highly viscous with excellent shear thinning and thixotropic behavior. The fluid gelled quickly when it was at rest nevertheless its structure was broken easily and it transformed into a low viscosity fluid quickly on shearing. It was also found that, suspensions of these cation-exchanged laponite nanohybrids had the yield strength, (2.2 N/m2, 3.2 N/m2, and 1.7 N/m2 were measured for Ni, Co, and Cu-cation Laponite suspensions, respectively), that is sufficiently high for suspending weighting materials such as barite which requires the gel strength of about 0.5 N/m2.