Managing the High Temperature Risk in a Horizontal HPHT Deepwater Well

Abstract

Objectives/Scope The bottom hole circulating temperature of horizontal wells can be higher than those of vertical wells. That risk is compounded in HPHT slim-hole applications where static geothermal temp can reach 320°-350° F. The combination of horizontal wellbore geometry, HPHT conditions, and slim-hole design results in significant challenges to achieving the primary objectives of drilling and data acquisition. This paper describes a technical workflow established through collaboration between the operator and service providers to manage high temperature risks to ALARP (As Low As Reasonably Possible) with effective design optimizations. Methods, Procedures, Process The workflow consists of risk assessment, offset data analysis, HT (high temperature) model calibration, model-based sensitivity analysis, and design optimization on BHA, hole size, and parameters. Multiple modelling software are used to support this physics-based design approach. Results, Observations, Conclusions The established workflow identified a set of effective risk mitigations through bottom hole assembly (BHA) redesign, hole size change, drilling parameter adjustment, and a decision-based TD criterion. The previously identified HT risks are reduced to ALARP and can be managed during execution. Novel/Additive Information The target well will be the first horizontal HPHT deepwater well to be drilled in GOM deepwater. The workflow described in this paper can help reinforce the physics-based design optimizations, and avoid HT related damages to critical downhole tools with limited supply and long replacement lead times due to current market constraints.