Estimation of gas blowout volume in wells with uncontrolled blowout and laboratory studies

Abstract

Gas blowout occurred during drilling may cause catastrophic environmental hazards and economic losses. It is thus one of the important tasks to accurately determine the gas blowout volume so that an effective rescue plan can be worked out in case of gas blowout. In this paper, a numerical method for estimating the gas blowout volume was presented based on the Bernoulli Equation and the corresponding software was programmed. In the process of numerical estimation, the velocity distribution of the blowout flame characterized by the axisymmetric laminar flow was investigated through an analysis of the dynamic flowing features of the gas gusher, and the relationship between the gas production of a well and the height of the blowout flame was then analyzed with the Bernoulli Equation to obtain the numerical results of the gas blowout volume. The results were then compared with those laboratory measurements, and the software was revised based on the comparisons. Some conclusions were drawn. First, when the spout shape of a gusher is constant, the gas production is proportional to the height of the blowout flame, and inversely proportional to the gas kinematic viscosity, the stoichiometric ratio factor and the oxygen concentration. Second, the errors between the results estimated using the revised software and the laboratory measurements are within the allowable range, and the software can automatically generate a report. In a word, the method and software presented in this paper can be an effective technique for preparing a sound and safe rescue plan in case of gas blowout, and is of great significance in relieving the hazards of a well with uncontrolled blowout. Keywords: Gas well, Well with uncontrolled blowout, Estimation of gas blowout volume, Gas production, Axisymmetric, Laminar flow, Gas gusher, Flame height, Software