Well-bore Stability

Isamgeo personnel has about 20 years of experience in delivering wellbore stability analysis for well design in different hydrocarbon production environments: onshore, offshore, high-pressure and high-temperature, chalk, depleted reservoirs, deep-water and ultra-deep-water domains and carbonate reservoirs.


Projects have been developed in North Africa (onshore), North Sea, Gulf of Mexico, Caspian Sea, West Africa and the Middle East (onshore). 


Isamgeo’s wellbore stability analysis aims to reduce the Geological Non-Productive Time of its customers’ drilling operations.

Reducing the Geological Non-Productive Time for Safe and Cost-Efficient Drilling Operations

The Geological Non-Productive Time is the unplanned rig time spent to remedy drilling hazards and events related to geological and subsurface features. Some of the drilling hazards are:


    • Mud losses and lost circulation;
    • Well kick;
    • Tight hole;
    • Stuck pipe;
    • Hole packing off.

Figure 1 shows two examples, where the Geological Non-Productive Time (GNPT) is a significant fraction of the total Non-Productive Time. GNPT may cause drilling significantly over budget and beyond the scheduled rig time, with spiraling costs for operators. These can be a heavy burden especially in the exploration phase.

Figure 1. Examples of Geological Non-Productive Time from the Gulf of Mexico and the North Sea (Bagala, 2019). 

Isamgeo’s wellbore stability analysis produces the mud weight window for the whole geological sequence. It contains the main drilling gradients:


  • Equivalent Circulating Density (from design or estimations);
  • Pore Pressure Gradient;
  • Collapse Gradient;
  • Losses Gradient;
  • Fracture Gradient.


The mud weight window can be regarded as a true drilling roadmap that accounts for potential drilling risks and their origin.

Figure 2. The mud weight window as a roadmap for drilling (Bagala et al, 2010).

Isamgeo can perform real-time geomechanical analysis, where the mud weight window is continuously updated. This is possible in cases that the pilot hole drilling for data acquisition is followed by more complex horizontal drilling, see Figure 3.

Figure 3. Workflow for Real-Time Geomechanics (Bagala 2019).

In this perspective, Isamgeo’s personnel is able to work with asset teams and drilling groups for the monitoring and assessment of real-time data for drilling optimization.