An Improved Model for Predicting the Trapped Annular Pressure in the Deepwater’s Annulus Containing Foam Material

Abstract

An improved model for calculating the trapped annular pressure in deepwater was created in order to precisely estimate the trapped annular pressure using foam materials. the model fits the pressure-volume experimental data using the constitutive equation of foam material put forward by Goga V. A temperature influence factor is calculated to explain the effect of temperature. During calculation, the annulus is divided into segments for the calculation, the variable temperature is loaded in increments, and the pressure is calculated using the method of bisection. Through an example, the effect of foam volume on the results of annular pressure is analyzed, and the improved model is compared to the prior model. The results show that the actual annular pressure does not increase monotonically with the wellbore temperature due to the decrease of foam material’s crushing pressure caused by the temperature increase, but there will be a small decrease. And foam material has good applicability and strong effect in the mitigation of trapped annular pressure in deepwater.