Publications

In deepwater wells, annular pressure buildup (APB) caused by thermal expansion of fluid could jeopardize the intergrity of the well, thus an accurate prediction of the APB phenomenon is critically needed. It is expected that using this model could give better accuracy of the APB phenomenon, thus the integrity of the well could be maintained for the service life of the well. In this study, an improved model of APB with thermally changed expansivity and compressibility in deepwater wells is presented This improved model utilises three required types of data - casing specification, fluid specification, and temperature change. Then, the model is simulated by calculating casing thermal expansion, force acting to casing, fluid thermal expansion, and compression of the fluid. The improved model then integrates those four calculations and results the cummulative pressure buildup in the annulus. Moreover, this model also shows the relation between the generated pressure buildup with temperature change to analyze the behavior of the fluid in various increases in temperature. The results shows that there is a significant difference between the improved model that utilizes the dynamic value of expansivity and compressibility coefficient and the current model that is using isothermal expansivity and compressibility coefficient. The pressure difference due to APB varies with the type of fluid that is contained in the annulus. Therefore, thermodynamic behavior of certain fluid in typical range of temperature should be known to precisely determine the APB. By knowing the exact thermodynamic behavior of the trapped fluid, the APB could be precisely predicted. Thus the well could withstand until its service life is completed. Keywords: APB, improved model, deepwater well