Prediction of Wellbore Temperatures During Mud Circulation and Cementing Operations

Abstract

An improved method predicts mud circulation temperatures and accounts for heat evolution in cementing operations more accurately than presently used API correlations or other numerical techniques. This method is based on an existing mathematical model of the wellbore and the formation near the wellbore. This model has been improved by using heat transfer coefficients and formation thermal conductivities determined by simultaneously fitting 28 unsteady-state circulating temperature measurements made on nine wells. Data used in this analysis were obtained from wells ranging in depth from 9225 ft to 22,725 ft, with static bottom-hole temperatures ranging from 230 to 410 deg F. The effect of heat evolution on cement pumping time is compensated for by a modified cement testing procedure. This procedure is based on experiments to determine the timing of heat evolution during the cement hydration. The experimental procedure used to simultaneously measure cement consistency and quantity of heat evolution is described.