Propagation characteristics and application effects of measurement-while-drilling pressure wave for early gas-kick detection

Abstract

An important technical measure to ensure drilling safety is to use advanced well-control technology to detect the early gas-kick. This research proposed an early gas-kick detection method based on the propagation characteristics of measurement-while-drilling (MWD) pressure wave, which was completely different from the conventional detection method, to timely detect gas-kick. In this work, we simulated the propagation characteristics of the pressure wave in the annulus gas-liquid two-phase flow by establishing an unsteady mathematical model for the first time, breaking through the limitations of testing the propagation characteristics of the pressure wave through physical experiments and revealing the law of propagation and attenuation of the pressure wave under arbitrary variable values. Second, we conducted field tests on the application effects of this technology based on the time difference of the pressure wave propagation in the gas-liquid two-phase flow and liquid single-phase flow, which confirmed the feasibility and advancement of this technology. Research results showed that gas volume fraction, system pressure, angular frequency, virtual mass force, drag force, and shear stress would affect the propagation and attenuation of the pressure wave in the annulus gas-liquid two-phase flow to varying degrees. Moreover, the application effects showed that using this technology to detect the occurrence of early gas-kick could be approximately 7–9 min earlier than the conventional detection method.