Methane and water jet after 25m

Methane gaz and water jet after 25m borehole during geotechnical investigation work.
The area under investigation consisted of grey silty clay of high plasticity (CH - OH) with peat layers at various depth.
After 25m, a layer of more permeable silty sand (SM) give rise of gaz jet at the beginning, and after about 30min, silty sand together with water come out for at least 3 hours.