MATHEMATICAL MODELING ON FRACTURE PROPAGATION CONTROL

The paper presents a one-dimensional transient mathematical model of compressible thermal two-phase flows of multi-component gas mixture and water in pipes. The set of mass, momentum and enthalpy conservation equations is solved for the gas and water phases. Thermo-physical properties of multi-component, gas mixture are calculated by solving the Equation of State (EOS) model. The Soave-Redlich-Kwong (SRK-EOS) model is chosen. Gas mixture viscosity is calculated on the basis of the Lee-Gonzales-Eakin (LGE) correlation. The proposed mathematical model is successfully validated on the experimental measurements of rapid decompression in conventional dry natural gas mixtures at low temperature and shows very good agreement with the experimental data at high and low pressure. The influence of temperature and water on rapid gas decompression process is investigated numerically. The HLP crack velocity model is used together with the proposed mathematical model in order to determine the minimum fracture arrest toughness in piping systems containing a natural gas mixture.