Once upon a time I was posted to a department in an oil company which dealt with the early-stage designs of new installations, much of which was geared towards providing enough information for a cost estimate to be carried out. To a rough order of magnitude, the cost of a new offshore installation (either floating or fixed to the seabed) can be estimated from its weight. Keeping things simple, the weight of an offshore facility comprises Equipment Weight, Piping Weight, Structural Weight, and Others.\u00a0If you have enough data, it is theoretically possible to work out the total weight of a new offshore installation by taking just the Equipment Weight and applying various ratios from similar, existing facilities. Most large engineering companies do this in order to obtain order-of-magnitude weights and cost estimates, but it is very much a finger-in-the-air approach which, at the early stages of a project, is fine.<\/p>\n
The problem with my new department was they did the equivalent of dividing 11.3 by 3.4 and writing the answer as 3.32352941. Any GCSE science or maths teacher will tell you the answer to any calculation cannot be more accurate than the initial input data. But when we did estimates using data with an accuracy of \u00b1 30%, we’d make comparisons of estimates that were within 10% of each other and propose weight savings of 5%. If you think it’s just journalists who are innumerate, be aware there are engineers with the same affliction working in large oil companies.<\/p>\n
Then things got a whole lot worse. Weight ratios apply to offshore facilities because they are designed as a single unit relatively<\/em> unaffected by their location (I’m talking topsides<\/a> or floaters here, not the jackets<\/a> or other support structures). I’m simplifying massively, but the point is that the weights of floating and other offshore facilities are not primarily driven by where they are installed. By contrast, the cost and complexity of onshore installations is enormously impacted by topography and geotechnical conditions under the soil. As you can imagine, building a facility on flat, firm ground is a bit easier than doing so on the side of a granite mountain or in a marsh. Civil engineering accounts for approximately 30-40% of the cost of constructing an onshore oil and gas installation, mainly grading the site, bringing in aggregate and compacting, and building the vast underground networks of pipes and cables needed to run the thing. This is why the first things you do when you’re thinking about building an onshore plant is the topographical and geotechnical survey; it’s sort of hard to do anything without it.<\/p>\n But I worked with very clever people, and they came up with a way of estimating the costs of an onshore facility regardless of where it was located. Insofar as topography went we could just assume it was flat, and soil conditions could be ignored or data from a project on another continent used instead. That soil conditions can vary dramatically across a hundred metres didn’t seem to matter. Furthermore, we could use ratios to work out the weights like we did offshore. Now I spied a problem with this. Offshore, on a global basis, there is probably a relationship between Total Equipment Weight and Total Structural Weight; all equipment on such facilities is supported by structural steel, after all. But onshore equipment is generally placed on a concrete plinth sunk into the ground, the size of which is driven by the soil conditions and equipment weight. The structural steel supports some equipment and a lot of piping and cables, but it does a very different job to that on offshore facilities. In many instances, the structural steel around a piece of onshore equipment is negligible. In short, on an onshore plant there is no ratio from other facilities\u00a0which can be used to estimate structural weight using equipment weight. But here were were, applying the same methodology as if it could.<\/p>\n Having some experience on onshore sites, I began to use my noggin a little. In one estimate, I ascertained that a vessel had no structural steel at all: it rested on its own legs and there was no maintainable valve on top which would need an access platform. But two managers queried this: they asked how the structural steel weight could be zero. I said it was because there is no structure associated with this vessel. They said this must be wrong, and I should apply a ratio of 30% vessel weight. So I asked them what structure they thought I was missing. They couldn’t say, but they told me to add the weight in, which came to several tonnes.<\/p>\n A little later, they got an intern with no post-graduate engineering experience to create a formal procedure for estimating the weights of onshore facilities, convinced that from such data the costs could be derived. They then passed it around all the engineers for comments. I noticed that it did not consider many components of the underground networks, which as I said comprises a huge portion of the costs. The most glaring omission was the firewater ring main, which is big, expensive, and common to all onshore oil and gas facilities. The reason this wasn’t included was because it would be designed “later”, which I found actually meant “nobody here knows anything about firewater ring mains so it’s best to pretend they don’t exist”.<\/p>\n I’d only been in the department a few weeks and I naively thought I’d be being helpful by pointing out, as I have done above, why this new methodology drawn up by the intern was fatally flawed. I drafted a comprehensive email with examples and explanations and sent it to my boss and the head of department, whose brainchild this new methodology was. A few days later I was called into an office where both of them were waiting and told to close the door. Their talk with me can be summarised as follows:<\/p>\n “We have read your email, but the decision has been made to adopt this methodology going forward. Your job is to follow it without asking questions.”<\/em><\/p>\n This was probably the first time it dawned on me that in many corporate departments results are meaningless, and all that matters is people obediently follow the process. I fought it for about a year, then just got with the program and pumped out absolute garbage which got wrapped up in more garbage and presented to senior management right up to the CEO. It didn’t take me long to work out whatever rubbish we were generating was not the basis on which decisions were getting made – the company wouldn’t be in business if that were the case – and the entire process, which cost millions of dollars, was merely to keep people employed. I once remarked in the wake of the oil price crash that if the company wanted to cut costs they could get rid of our entire department and employ a child to roll dice every time senior management wanted figures. That went down about as well as my critique of the estimation methodology.<\/p>\n The experience left me wondering how much of this sort of thing goes on in major corporations with names you’ve heard of. Quite a bit, would be my guess.<\/p>\n","protected":false},"excerpt":{"rendered":" Once upon a time I was posted to a department in an oil company which dealt with the early-stage designs of new installations, much of which was geared towards providing enough information for a cost estimate to be carried out. … Continue reading