Flow assessment and integrity support

Recently our global client came to us with a problem. They were looking to improve oil recovery from one of the biggest field developments in the North Sea in recent years.

The background

Apollo has supported some of the biggest names in the oilfield services market for 10 years with a blend of high-end technical problem solving and emphasis on customer service.

To improve oil recovery, our client was looking to inject gas into the formation via the production wells. The client was previously injecting through the gas lift orifice but the flow rate was restricted due to its size. To increase the injection flow rate and reduce the well downtime, it was proposed to inject through the crossover loop which would increase flow rate and allow for faster gas injection.

The client needed to know what the safe maximum flow rate was for injection.

The process

From the start, it was clear this needed to happen quickly. Initially, we were given 3 weeks to deliver from start to finish. This was a strict deadline as set by their operator client and financial and reputational outcomes were on the line.

We met with the client as soon as they were available and defined what was required from an integrity perspective and then wrote the basis of design for approval.

The deliverables

Apollo determined the maximum flow rate that the client could safely inject into the well in order to prevent erosion from liquids, solids and to ensure the integrity of the Christmas tree is maintained.

Apollo used Ansys software to determine the erosion rate and fatigue life at every location of the component as well as using OLGA to accurately model the fluid phase changes. Fatigue analysis is often completed using complex hand calculations and systems such as Excel, however, after guidance from one of our principal engineers and the initiative and creativity of one of our young engineers, Ansys was used and the calculations were verified using hand calculations.

And for all you engineers who just want the facts:

The Problem

• The end client wanted to improve oil recovery  to prolong the life of the well to keep production going beyond expected life of the well by injecting gas through the crossover loop and not the gas lift orifice

The Solution

• Using ANSYS for fatigue analysis, Apollo gave the client the confidence that their system would exceed the fatigue life they require and would allow for increased production with no safety risk
• Using OLGA to accurately model how the fluids change phase through the choke
• Using ANSYS Fluent to calculate the erosion from liquid and solids through the system.  At the end providing a simple metric, the client could use to understand how much they could inject
• Providing the client with a visual deliverable allowed them to quickly understand where failure could arise once fatigue life has been reached

The Outcome

• Apollo delivered flow assessment and integrity report confirming the safe maximum flow rate and that the fatigue life would not be affected
• This allows for the client to confidently operate the xmas tree in a new configuration, increasing production and extending the life of the well