Deformation of ductile cuttings from sandstone in the mechanical compaction process was designed through the“experimental system of triaxial rock deformation” ��and the influence on porosity was studied by looking into the deformation characteristics of ductile cuttings�� The design indexes are as follows: simulated depth 0 ��4 000 m��interval depth 500 m��and pressure range 0 ��120 MPa at interval of 1�� 5 MPa�� The experi- mental results show that the porosity decreases as buried depth increases��indicating a negative relationship be- tween them�� The amount of compression was mainly obtained by porosity reduction and cutting deformation�� De- formation of ductile cuttings is mainly ductile deformation; and deformation of crystal fragments is mainly ex- pressed as brittle fracture�� resulting in decrease of particle size�� The research is of certain value for the explora- tion and development of oil and gas��