Experimental investigation on inorganic scaling induced by the shale reaction with oxidation solution

Abstract

Inorganic scale produced from shale reservoir oxidation during hydraulic fracturing will block pores and fractures, thus hindering the multi-scale transportation of shale gas. The results show that the cations produced after soaking in distilled water mainly consisted of Ca²⁺, Mg²⁺, Na⁺, K⁺ and Fe²⁺. Pyrite and chlorite contain reduced Fe, and the oxidized solution dissolves the reduced iron in shale, further increasing the ion concentration in shale, especially the Fe²⁺. The shale produced precipitation and solid particles after soaking in solutions containing dissolved oxygen and different oxidation solutions. The oxidation solution affects the concentration of ions and the type of solid particles produced in the soaking process.