Ingénierie inversée

Often, drilling contractors operating with older designs of drilling rigs are faced with incomplete documentation and lack of traceability or lack of engineering evidence of the rig's rating. Clients face difficulties to retreive critical information such as hook load capacity, setback capacity or environmental data (max wind, heave, etc.). For such cases, INERTIA's developped internal procedures for the reverse engineering of existing structures and assemblies.

Inertia in-house engineering department assists you in confirming operational and environment ratings for any of your drilling structures:

  • Drilling Masts
  • Well Servicing Structures
  • Offshore Derricks
  • Substructure

All calculation are performed in line with the requirements of API Spec 4F, while the edition (2nd, 3rd or 4th) is selected depending on the year of manufacture of the drilling structure in question, or in line with client's requirements.

The scope of work includes a a full 3D Modelling of the primary structure in accordance with original OEM drawings when available. For cases where information are not available, a dimensional survey of the primary structure is performed to confirm the overall geometry of the structure as well as section properties of each of the load carrying member.


The process covers the compliance of each member of the primary structure as well as the integrity of welded, bolted and pinned connections used thougthout the structure.

Designs using hydraulics systems for raising or scoping are also verified to confirm the rating of the hydraulic rams with the calculated required strengths.

Simulations includes all required load cases dictated by the API Spec 4F as a minimum and specific client load cases when applicable. These includes operating, expected and unexpected storms, transit modes, pitch, roll and heave acceleration factors, etc.

On completion of the simulation, comprehensive, well documented, detailed and illustrated reports are provided with the necessary evidence of the structure’s capacities. A calculation report and package is normally provided for each of the phase 1 and phase 2 works when required due to the resolution of structural failures.

Should the structural simulation points out that some of the members suffers from overutilization, our engineering team will define the most effective way of reinforcing the structure by mean of member change, redirection of load path philosophy, strengthening of existing members, etc. Due to the cost involved as well as the impact on operations such reinforcement has, the selection of the reinforcement philosophy is a process in which the end user is closely involved for a smooth site implementation.

For more information, please send us a message via the contact page and our team will reach out to you at the earliest.