Asset management is a science that requires balance. The art of running an asset at its full capacity, with minimum downtime, but in a safe manner is probably one of the biggest challenges in the oil and gas industry nowadays.
Several techniques are used in assessing the reliability of an asset’s production performance. A range of techniques are also used to assess the safety of and risks posed by an asset too. Often these reliability and risk analysis methodologies are used in isolation and may give contradicting answers. Due to the diversity of and specific focus of these methodologies, it is sometimes often difficult to measure the impact of decisions whilst considering both risk and reliability.
Let us consider a simple example – a company is designing a gas export compression system.
Design expert: Welcome to our meeting. We have finished the conceptual design of our gas export system and I would like to know the outputs of your QRA and RAM analyses.
Risk expert: Hey, we’ve got some really nice isorisk curves from the conceptual design! Everything is acceptable so you can move forward with the project as it is.
Reliability expert: Hold on! The production efficiency of the system, as it is designed with one compressor, is not acceptable! We need to add another compressor as a redundant path of production. We have performed cost benefit analysis of this investment in equipment and ongoing costs and see a very positive return. The parallel redundancy provided by the additional compressor will increase the production efficiency considerably ensuring we meet our contractual requirements for gas delivery.
Risk expert: If we introduce a parallel compressor, running as a hot parallel for increased productivity this will double the failure frequency of loss of containment scenarios. If I run this quickly through my QRA I can see that the project exceeds tolerable risk criteria. What are our options if we must have a redundant system Mr Design expert?
Design expert: Well, if we must have two compressors, there are basically two configurations for the second one: active or passive (standby mode).
Reliability expert: Good thinking! We would have to add some possible failure on demand for the second compressor but this will definitely increase the overall production efficiency.
Risk expert: Yes and, as the second pump will be off most of the time, I could assume that it is only functional when the first one is in a failed state which basically means it will not double the number of potential accidental scenarios.
Design expert: So it has been decided! An additional compressor running in standby-mode.
LCC expert: Another pump?! What is the cost of that?
This story is very simple and has happy ending but I believe it helps to illustrate how difficult it is to find a balance between risks and productivity factors.
For almost 150 years, DNV has focused its activities on managing risks to life, property and environment. We are looking forward to the new challenges the oil and gas industry is bringing on board (or deep, perhaps ultra –deep, down on the sea bed).
Author: Victor Borges