Degradable fiber for use in well treatment fluid, method for manufacturing same, and well treatment method

A method for manufacturing a degradable fiber for use in well treatment fluid in which the fiber is formed from a resin that degrades in treatment fluid for hydrocarbon resource recovery, an oligomer component content of a resin forming an outer surface of the fiber is not greater than 1 mass %, and a birefringence of the fiber is not less than 0.02, comprising a spinning step and a drawing step, the oligomer component content of a resin that forms an outer surface of an undrawn yarn obtained in the spinning step being not greater than 1 mass %, and a birefringence of a drawn yarn before heat treatment in the drawing step being not less than 0.02.

A well treatment method using a well treatment fluid containing a degradable fiber for use in well treatment fluid and a proppant, the fiber being formed from a resin that degrades in treatment fluid for hydrocarbon resource recovery, an oligomer component content of a resin forming an outer surface of the fiber being not greater than 1 mass %, and a birefringence of the fiber being not less than 0.02.