Experimental study on the in-situ foam performance stabilized by microbial polysaccharide and its diverting characteristics at high temperature

•A novel microbial polysaccharide diutan gum is proved to be an outstanding foam stabilizer.•Self-generated gas system is analyzed in terms of gas production volume and production efficiency.•The in-situ foam stabilized by diutan gum shows brilliant automatic foaming properties and temperature resistance even at 90℃.•Parallel core flooding experiments prove the distinguished plugging ability and diverting characteristics of the in-situ foam at 150℃.•The in-situ foam has great potential as diverting agent in heterogeneous reservoir stimulation at high temperature.