LAUSR

Abstract In the process of geothermal reservoir exploitation, the performance of cementing material in high temperature environment is the key to ensure the quality of cemented casing for wall protecting and leakage plugging or effective zonal isolation. Based on a systematic approach of theoretical analysis, experimental research and microscopic analysis, this paper presents a new Nano SiO2-basalt fiber composite cement (NSBF) for application in geothermal reservoir exploitation. The NSBF consists of a modification of Class G oil-well cement with optimized additions of fly ash, Nano SiO2, basalt fiber, early strength agent (ZQ), and a water reducing agent (GB). The physical properties of the NSBF (fluidity, pump-ability, setting time and compressive strength), obtained by carefully prepared lab tests, were shown to be suitable for high temperature application. Finally scanning electron microscopy (SEM) and X-ray diffraction (XRD) were used to analyze the micro characteristics for an interpreted hydration mechanism of NSBF at high temperature. Our study results may provide a new product for a quality cementing material or better zonal isolation material in the exploitation of geothermal reservoir.