Redefining Technical Limit – Managed Pressure Directional Drilling Solution in Mexico Homol Field
Authors: Lopez Mata J. L. , Perez S.. , Vizcarra H. H. , Ngan Alex , Garcia Gil E. A. , Liewald J. Basto 
Published: March 2021

This paper will discuss the Managed Pressure Directional Drilling fit-for-purpose solution deployed to meet drilling challenges in Mexico's offshore Homol field. This innovative solution integrates a new state-of-the-art Rotary Steerable System (RSS) with Managed Pressure Drilling (MPD) technology. Drilling hazards such as the ballooning effect due to drilling plastic formations, losses, wellbore instability, and stuck pipe were effectively mitigated, and improved drilling performance with reduced NPT was delivered compared to other directional drilling systems.

The solution requires the integration of two highly technical disciplines, MPD and Directional Drilling. Hence, a Joint Operating & Reporting Procedure (JORP) and a defined communication protocol proved crucial for effective execution. The solution is based on a rigorous Drilling Engineering process, including detailed offset well analysis to deliver a comprehensive risk assessment and mitigation plan jointly with the Operator to tackle drilling hazards such as ballooning without compromising the directional drilling requirements. In addition, flow processes and procedures were developed for contingency events, including but not limited to losses, stuck pipe, wellbore instability, and well control.

After successfully deploying the new RSS tool in Mexico offshore, the Operator came across a challenging directional well with a history of ballooning effect, losses, stuck pipe, and wellbore instability. Combining the RSS tool with MPD Constant Bottom Hole Pressure (CBHP) technique to mitigating the ballooning effect while maintaining constant surface back pressure (SBP), the well was drilled while minimizing the downhole pressure fluctuation to mitigate against wellbore instability until reaching the lower paleocene formation, taking care to maintain an equivalent circulating density (ECD) of 2.04g/cc while drilling, and 1.99g/cc during connections, in order to reduce the ballooning effect observed in offset wells. As a result of careful planning, the RSS and downhole-surface communication continued to work well, while the MPD CBHP variant successfully mitigated against ballooning and well control hazards. The paper will also discuss the effective communication protocol between directional drilling, MPD services, and rig contractors to ensure safe operational alignment.

Rotary steerable systems (RSS) for directional drilling must drill in increasingly hostile environments and with different challenges inherent to formations; examples of this are formations with plastic behavior that cause ballooning effect. This phenomenon can confuse drilling crew cause its behavior is very similar to kicks from wells. Homol is an oilfield with marked ballooning characteristics, causing significant Non-Productive Time (NPT). Drilling challenges in the Homol field require the utilization of both Directional Drilling technology and MPD techniques to improve drilling performance and reduce NPT at the same time. However, the technologies need to be optimized for one another.

Also, directional services had to ensure reliability and accurately position wells, while the MPD technology to discern ballooning from actual influx and managing wellbore stability. This article describes the teamwork carried out by the directional team and MPD to avoid/minimize the ballooning effect while drilling directional jobs, improving operational time. The paper also includes a planning and operational blueprint to reduce NPT related to, while increasing drilling performance in terms of rate of penetration (ROP) and wellbore quality to allow the liner to be run to section TD in the Lower Paleocene formation.