The Characteristics of Suspended Solids in Sandstone Reservoir Injection

Abstract

Neogene unconsolidated sandstone reservoir is widely utilized for district heating in North China. Decrease of recovery rate due to clogging problem significantly influences the sustainable development of geothermal resources. Guantao formation in Laoling field, Shandong Province is chosen as the typical sandstone reservoir. In order to understand the clogging processes and establish efficient tail water treatment system, porosity, mineralogical and granularity characteristics of reservoir rocks and suspended solids are analyzed. The porosity and permeability of Guantao formation is up to 30% and 133-397mD respectively. With abundant primary intergranular pores and corrosion pores, this reservoir has good-medium performance of storage. Sharing the similar features of mineral components and major elements with formation, suspended solids in geothermal water are mainly derived from reservoir rocks. 95% of the total suspended solids volume in geothermal water has a particle size greater than 3μm. The existing filtration system is effective in removing particles larger than 100μm and the finer filtration needs to be improved.