Squaring Temperature Effects in HPHT Drilling &Well Integrity

This study focuses on developing robust High-Pressure High-Temperature (HPHT) drilling temperature models to characterize Well conditions, assess integrity risks, and evaluate annular pressure buildup (APB) driven by thermal variations. Particular attention is given to the failure mechanisms of gas-associated Wells subjected to cyclic thermal fatigue. When production tubing is exposed to hot formation fluids in contact with colder trapped annular fluids, differential heating occurs, resulting in fluid expansion and subsequent APB. This thermally induced pressurization, distinct from conventional heat transfer in formation Wells, poses a significant risk to long-term Well integrity. Well integrity is largely dependent on the casing cement interface and its ability to maintain an effective hydraulic seal throughout the operational life of the Well. Temperature-dependent drilling fluid volume changes commonly referred to as wellbore ballooning which further complicate the thermodynamic response of the hydraulic system. This system often behaves as a counter-current heat exchanger, amplifying non-linear thermal-hydraulic interactions. Accordingly, this work models annular pressure buildup in HPHT Wells, considering dynamic variations in temperature and pressure. Operability risks associated with APB are analyzed, and potential mitigation strategies are outlined to safeguard Well integrity under extreme downhole conditions.