The invention relates to a source block with a downhole seismic source for use in seismic acquisition during production, comprising:

a device for locking the block in a first position spaced from the well casing,

a device for releasing the locking device,

a device for urging the source block against the casing.

The source block is characterized by comprising, a fluid circuit for controlling the operation of the locking and releasing devices, this fluid circuit comprising a rupture disc.