MudSim Achieves Milestone in Calculations for AkerBP
Recently, our team faced an important challenge from AkerBP: to evaluate MudSim’s accuracy by simulating and calculating key drilling parameters. The goal was simple yet critical—compare our results with AkerBP’s established data, focusing on Equivalent Circulating Density (ECD), Equivalent Static Density (ESD), and standpipe pressure.
Project Overview: Gekko North Well – 25/4-B-1 AY1H
AkerBP’s well, located in the Gekko North field and drilled using the DeepSea Nordkapp rig, provided a robust dataset for this evaluation. This well, with a total depth (TD) of 2729 meters, had already undergone extensive calculations by AkerBP. Our task was to replicate these calculations using MudSim to verify the tool’s accuracy and pinpoint areas for further development.
Key Drilling Parameters and Input Data
The following key drilling parameters were provided by AkerBP:
- Section Length: From the 13 3/8’’ shoe to TD at 2729 meters.
- Flow Rate: 3850 liters per minute (lpm).
- Rotary Speed: 150 revolutions per minute (rpm).
- Boost: 1000 lpm.
In addition to these parameters, we utilized a comprehensive set of inputs. This included the well schematic, end-of-well report, pore pressure plot, lithological description, wellpath, and drilling fluid data.
Simulation of Equivalent Circulating Density (ECD)
We used MudSim to simulate the ECD based on the provided data. The simulation employed the Herschel-Bulkley fluid model, which used parameters derived from a data-fitted procedure utilizing Fann data at 20°C. This model also included calculations for wall shear stress, friction factor, and an interpolation between laminar and turbulent flow regimes, guided by Reynolds number and effective viscosity.
Results: The simulation results closely matched AkerBP’s original calculations. This alignment demonstrates MudSim’s potential accuracy in replicating real-world drilling scenarios.
Adjusting for Pressure and Temperature: Equivalent Static Density (ESD)
Next, we turned our attention to ESD, which accounts for changes in drilling fluid density due to pressure and temperature variations. Our model incorporated factors such as thermal expansion and compressibility of the drilling mud.
Findings: The simulation revealed that while thermal expansion has a minor effect on the pressure profile, it remains a critical factor, especially in pressure-sensitive formations. The results were consistent with AkerBP’s data, reinforcing MudSim’s reliability in this context.
Standpipe Pressure Calculation
To calculate standpipe pressure, we simulated the pressure drop from the pump to the drill bit and back to the surface. This included pressure losses in the drill pipe, drill bit, and annulus.
Simulation Result: The standpipe pressure was calculated to be 132.05 bar. This calculation mirrored AkerBP’s results, further validating MudSim’s accuracy.
A Milestone in MudSim’s Development
MudSim’s outputs for the Gekko North well were within expected limits. However, this evaluation highlighted some areas for improvement. Specifically, enhancing the ESD model by incorporating fluid flow energy transport could improve accuracy. This enhancement would be particularly valuable in challenging drilling environments, where even minor improvements can significantly impact safety and efficiency.
The successful replication of AkerBP’s drilling parameter calculations marks a significant milestone in MudSim’s development. These positive results confirm MudSim’s potential to become a reliable tool for optimizing drilling operations. As we continue to refine the software, we aim to further enhance its capabilities to meet the complex demands of modern drilling operations.
