INTECSEA - Precision at a Price

Precision at a price

26th September 2016

By: Dave Baker

My discipline is in Chemical Engineering and although I am no longer practicing the “dark arts” I do remember being taught that it was OK to be a bit vague on occasion. Despite the huge amount of detail provided on compositional analyses, it was always deemed difficult to determine the exact nature of fluids in pipes or other vessels. Prediction of fluid behavior has moved on considerably since my graduation in 1978, but I am told it’s still a relatively imprecise science by some of the top practitioners.

Some of my colleagues are structural engineers who pride themselves on being able to more accurately determine stresses and strains on materials because it is easier to visualize on a more practical level. We’ve all bent a paper clip or plastic ruler to failure after all! But I also remember an amusing quotation I came across in my early days in the oil and gas industry, which is “engineering is the art of modelling materials we do not wholly understand, into shapes we cannot precisely analyze so as to withstand forces we cannot properly assess, in such a way that the public has no reason to suspect the extent of our ignorance” (D. L. Dykes 1917-1997). There may still be some truth behind that statement, but we should not kid ourselves that we understand and can predict with 100% certainty the nature of all materials.

Of course, there are several industries that need precision to be at the highest level possible. Nobody would want to undertake laser eye surgery if the ophthalmologist tries to convince you that his/her measurements were “pretty good” but only to an accuracy of +/-50%. Similarly, if you’re on your way to Mars you want the NASA scientists to adopt extraordinarily low tolerances to get you there (and back?) in one piece. And if I phone my bank for a balance I want to know precisely what’s in my account and not just a rough estimate.

Does the oil and gas industry really need the level of precision that seems so appealing to engineers? Especially when, after hours and hours of analysis, we tend to slap on safety factors “just to be sure” or round numbers up to the next whole integer. Let’s be clear, I am in NO WAY advocating that we calculate things on the back of a napkin and hope for the best. Whatever we do must not deter us from ensuring our industry is as safe as humanly possible, both to our people and the environment. But what if, instead, we divert some of those precious hours in achieving a precision to five decimal places into adding real value to a project in the Concept/Front End phase. In other words, let’s strive to get things on the right track first before firing up our computers for overnight runs on a multitude of cases because “that’s what we’ve always done.”

To add real value would be to spend time in justifying the locations of the field architecture and to confirm that going from A to D is a far better solution than going from B to E. Have, for example, the flowline system options considered the production profile throughout the full field life (a compromise) or just in the first few years of operation (an ideal)? Has an Integrated Asset Modelling tool been used that simulates life of field analysis together with reservoir information and production chemistry? What cost estimating tools are best suited? Where is the raw data coming from and what is the quality and auditability of our decision making? I’m sure there are many other issues out there worth considering.

Challenging the early stages of a project and getting things right up front would seem a sensible use of engineering hours within what currently is all too often a limited budget. Regrettably, but understandably, in the present market environment, not all oil and gas clients have the inclination to remunerate companies for this cerebral input; but at what cost at the end of the day? We will still need to do the number crunching and not all computer output will be resigned to the waste bin, but maybe we should begin to re-boot our thinking in the future. Think of it as being a bit like doing a Ctrl Alt Delete on our PCs!