Research on properties of hollow glass microspheres/epoxy resin composites applied in deep rock in-situ temperature-preserved coring

Abstract

Deep petroleum resources are in a high-temperature environment. However, the traditional deep rock coring method has no temperature preserved measures and ignores the effect of temperature on rock porosity and permeability, which will lead to the distortion of the petroleum resources reserves assessment. Therefore, the hollow glass microspheres/epoxy resin (HGM/EP) composites were innovatively proposed as temperature preserved materials for in-situ temperature-preserved coring (ITP-Coring), and the physical, mechanical, and temperature preserved properties were evaluated. The results indicated that: As the HGM content increased, the density and mechanical properties of the composites gradually decreased, while the water absorption was deficient without hydrostatic pressure. For composites with 50 vol% HGM, when the hydrostatic pressure reached 60 MPa, the water absorption was above 30.19%, and the physical and mechanical properties of composites were weakened. When the hydrostatic pressure was lower than 40 MPa, the mechanical properties and thermal conductivity of composites were almost unchanged. Therefore, the composites with 50 vol% HGM can be used for ITP-Coring operations in deep environments with the highest hydrostatic pressure of 40 MPa. Finally, to further understand the temperature preserved performance of composites in practical applications, the temperature preserved properties were measured. An unsteady-state heat transfer model was established based on the test results, then the theoretical change of the core temperature during the coring process was obtained. The above tests results can provide a research basis for deep rock in-situ temperature preserved corer and support accurate assessment of deep petroleum reserves.