Clay thermal expansion characteristics research on heavy oil reservoirs with strong water sensitivity

The clay content in Sha-1 member heavy oil reservoirs of Jinjia oilfield is high and has the swelling characteristic,which leads to the reservoir of strong water sensitivity,and restrict thermal recovery of the reservoir development.Therefore the research on the clay swelling under different temperature conditions has been carried out.Test results show that the main clay minerals content types are calcium montmorillonite.Under the condition of low temperature,namely formation temperature(45 ℃)test,the average inflation rate is 26.3%,and the reservoir is of strong water sensitivity.After poor heat and thermogravimetric(tg),high temperature autoclave experiment sample wafer spacing test results show that under the condition of the high temperature of 100℃above,the montmorillonite is dehydrated,the crystal spacing decreases,the dilatability is abate,and the water sensitivity is weak.When the temperature reached300 ℃,the montmorillonite crystal spacing is similar to standard crystal spacing,and the swelling disappeared basically.