The invention relates to a casing head, in particular to a casing head for
thermal recovery of thick oil. The casing head comprises a hollow casing, a telescoping
pipe, and a hollow hanger, wherein bevels which can be matched each other are arranged on the inner wall of the casing and the outer wall of the hanger; the hanger is hung in the casing through the matching of the bevels, and a
flange is fixedly connected to the top end surface of the casing and compacts the hanger downwards; an inwards-constrcted raised edge is arranged at an the opening in the lower end of the hanger, and an outwards-extended raised side is arranged at an the opening in the upper end of the telescoping
pipe; the raised side can be matched in the hanger in a manner of moving up and down, and sealing rings are arranged between the raised edge and the hanger; a spring is positioned in the hanger, and the upper end and the lower end of the spring respectively support the lower end surface of the
flange and the upper end surface of the telescoping
pipe, so that the raised side and the raised edge are in tight contact. According to the casing head disclosed by the invention, the spring is additionally mounted between the
flange and the telescoping pipe, and the spring is used for absorbing energy generated when the telescoping pipe is heated to be and expanded, so that during conventional
welding, the influence of the heated telescoping pipe on weld joints is avoided, and potential safety hazards are eliminated.