Welcome to A-V pipelining

Bob Eden
CAPCIS
Manchester, UK

Given the low price of oil, the cost of oil recovery is again under assault. Radical solutions are blue sky necessities for others to fund. Apart from drilling the hole, processing and transporting systems eat up the cash and any quick fix for newbuild ideas must be welcome.

One quick fix for transport has been around for over a hundred million years and, unless this magazine has fallen into creative young hands, you have a first-hand experience of the fix. What kind of fix has a pedigree as old as the oil we mine? Indeed - what kind of fix has personally assisted me in writing and yours in reading this missive? Answer: an exquisite low OPEX (and zero CAPEX) flow assured pipeline gathering and distribution system shifting the red stuff around inside us.

Natural strategy

Apart from a strange T-junctioned vein I can see on the back of my hand, the system is generally free of sharp bends. Arteries especially are smoothly branched and right-sized to minimize frictional losses and energy requirements of the pumping system. Keeping the heart beating for the next forty years or so is not helped when right-sizing is lost. Before the link between heart disease and arterial hardening was established, many a Victorian pathologist commented on the ex-patient having the heart of an ox, being unaware that the oversized pump was nature's high-OPEX final solution to a pipelining flow-assurance problem.

Understanding how nature solves engineering problems is the preserve of the biomimeticists. The blood system of any animal is simply a well-established low energy solution to fluids transport. Success in nature means getting your own way. The less energy-consuming baggage to handle, the better. Whatever is a "proven" (and hence successful) natural strategy always has an elegant engineering solution in tow - even without the benefit of a CAD package or a linear programming facility.

Nature seeks out low-energy solutions, and this should make it a bedfellow with the engineer. However, engineers like to take things apart and put them back together again, and so tend to eschew anything furry with a pulse for inspiration. But, given the push in the medical field to come up with designer heart repair solutions, there is now engineering software that models the heart and circulation system for low energy fixes. The engineering behind the medical fix is such that the pipeliner can use it without ever having to unzip a thorax.

Industry parallels

So what are the principles? Low energy pumping means a minimal pump size, so getting the low OPEX right means a short cut to the best CAPEX solution. For some distribution systems, the energy savings offered by nature over their rectilinear pipelining cousins are reckoned to be more than 40%. This means smaller pumps for the same job or shifting more produced fluids, given the old pump specification.

What's more, the angles at junctions and the ratio of diameters between the main line and the branches have peculiar low-energy minima that nature exploits and the pipeliners can copy. This kind of "arterio-venous" (A-V) pipelining can be readily adopted for the field using minor constructional modifications. But who would dare to copy an old idea.

Now, the job of squeezing a quart through a pipe made for a pint - drag reduction - is very old hat for nature and is becoming established in the pipelining industry for existing lines. Drag reducers are found in blood and, amongst other places, on the skin of a fish. After all, something moving through a fluid obeys the same frictional laws as fluid moving through a something.

Combining drag reduction with the A-V pipeline, the oil should be positively falling out of the well. Since drag reducers are surface active agents, combining their chemistry with a corrosion inhibitor means a multifunctional chemical for pipeline wall treatment that saves energy costs.

Voila! We have environmental benefits through saving chemicals and energy, and what's more, waxy fluids that spend less time inside a slippery pipe are less likely to precipitate because they stay warm over a longer distance in the same time. We could be getting positively biological here, but with low-cost A-V pipelining, and with nothing living in sight, even the accountant can smile.

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