The influence of core holder output port on core internal fluid flow

Abstract

ABSTRACTCore holder is a common experimental device in the field of petroleum exploration. Each kind of core holder has an output port. The objective of this paper is to determine whether the output port will affect the fluid flow in the core. The function of the output port is to collect and derive the fluid. A compression ring with a thickness of 5 mm and a diameter of 25 mm was fabricated by using 3D printing technology. We add the ring between the rock sample and the output port. The ring does not affect the function of the output port but avoids direct contact between the output port and the core end face. We find that permeability test results obtained by adding a ring are larger than that obtained by the core holder without a ring. A numerical simulation model is established according to the size of the output port. The influence of the output port on the velocity and pressure distribution in the rock sample is analyzed by using the coupling of Stokes and Darcy flow numerical simulation method. It is pointed out that the output port affects the fluid flow within 5 mm near the end face of the rock sample. The fluid velocity is unstable in the range of 5 mm near the end face of the rock sample. In order to reduce the influence of the output port on fluid flow in the core, five new types of output port grooves are designed in this paper. Comparing the numerical simulation results of different grooves schemes, it is considered that adding a 5 mm cylindrical cavity between the output port and the rock sample can reduce the influence. It is suggested that the output port should not be in direct contact with the core, and the output port and the end face of the core should be separated by 5 mm.