Around a borehole, the removed rock has to be supported by the mud. If mud weight is too low, the hoop stress exceeds rock strength and the hole fails in shear, producing breakouts and cavings; if it is too high, the rock fails in tension and the hole takes losses. Between those two is the safe mud weight window, and in many formations it is narrow.

Trajectory changes the window. In a normal fault stress regime, a vertical well is usually the most stable; in a strike-slip or reverse regime, the preferred direction may be quite different. For horizontal wells, drilling parallel to the minimum horizontal stress direction is usually the most stable choice. These are design decisions with large operational consequences.

Shale adds time and chemistry. Water-based mud exchanges water with shale, changing near-wellbore pore pressure and strength, and failure that does not appear immediately can develop over hours or days. That is why a section can drill cleanly and then pack off on the trip, and why mud chemistry is part of stability management rather than a separate subject.

By the end of this training, participants will be able to:

• Determine in-situ stress magnitudes and orientations from available data.
• Measure and estimate rock mechanical properties from cores and logs.
• Explain shear and tensile failure mechanisms around a borehole.
• Build wellbore stability models and safe mud weight windows.
• Assess the effect of trajectory on stability and optimise well direction.
• Assess shale chemical and time-dependent instability.
• Analyse stability in depleted, faulted and naturally fractured formations.
• Monitor stability in real time using drilling, caliper and cavings data.
• Select mitigation through mud weight, chemistry and drilling practice.
• Apply wellbore strengthening and loss prevention methods.

The course is instructor-led. Stability analysis is developed with calculations and applied to real wells, with participants building mud weight windows from log and stress data and comparing them with the problems the wells actually had. Cavings descriptions, caliper logs and drilling data are used for real-time diagnosis exercises. Participants are encouraged to bring their own problem wells for discussion.

Organisations sending participants to this training will:

• Reduce instability-related non-productive time and sidetracks.
• Design trajectories and mud weights that keep holes stable.
• Improve hole quality for casing running and cementing.
• Drill depleted and faulted formations more reliably.
• Recognise instability early and respond correctly.

Participants will:

• Understand the mechanics of wellbore instability.
• Be able to build a safe mud weight window.
• Be able to assess trajectory effects on stability.
• Be able to diagnose instability from drilling data and cavings.
• Be able to select effective mitigation measures.

• Drilling and well engineers
• Geomechanics specialists
• Wellsite and operations geologists
• Drilling fluids engineers
• Rig site supervisors
• Well planners and technical authorities

Upon successful completion of this training course, delegates will be awarded an official Certificate of Completion issued by the Petroleum Engineers Association (PEA), an ISO 9001:2015 certified training organization. The certificate carries 10 Credits and formally records the total learning hours completed.

Each certificate is signed by the Course Facilitator and the CEO of the Petroleum Engineers Association, and serves as verifiable proof of professional training that delegates can present to employers and professional bodies worldwide.