Seal and seal assembly for a fluid pressure pulse generating tool

A fluid pressure pulse generating tool comprising:

• (a) a fluid pressure pulse generator;
• (b) a pulser assembly comprising a pulser assembly housing that houses a motor and a driveshaft extending from the motor out of the pulser assembly housing and coupled with the fluid pressure pulse generator;
• (c) an annular seal surrounding a portion of the driveshaft and enclosed by the pulser assembly housing, the annular seal configured to be in sealing contact with the driveshaft or a sealing cylinder surrounding the driveshaft;
• and
• (d) a seal assembly comprising a seal assembly housing with a longitudinally extending bore therethrough that receives the driveshaft and a seal enclosed by the seal assembly housing, the seal comprising:
• (i) an annular seal section comprising an internal sealing surface in sealing contact with the driveshaft or a sealing cylinder surrounding the driveshaft and an external sealing surface in sealing contact with an internal surface of the seal assembly housing;
• and
• (ii) an annular heel section providing an interference fit with the driveshaft or with the internal surface of the seal assembly housing.

A driveshaft unit for a fluid pressure pulse generating tool comprising:

• (a) a longitudinally extending cylindrical driveshaft with a first end for coupling with a fluid pressure pulse generator of the tool and an opposed second end for coupling with a pulse generating motor of the tool;
• and
• (b) a seal assembly comprising a seal assembly housing with a longitudinally extending bore therethrough that receives the driveshaft and a seal enclosed by the seal assembly housing, the seal comprising:
• (i) an annular seal section comprising an internal sealing surface in sealing contact with the driveshaft or a sealing cylinder surrounding the driveshaft and an external sealing surface in sealing contact with an internal surface of the seal assembly housing;
• and
• (ii) an annular heel section providing an interference fit with the driveshaft or with the internal surface of the seal assembly housing.