Tuesday, June 15, 2010

There's mud and then there's mud

kw: observations, efficiency

There was a news article today about drilling practices. Though it was focused on drilling for natural gas, it applies equally well to all petroleum drilling. A bit of debate was presented about the health risks of living near an active drill rig, and not just because of the hydrocarbons that are the target of the drilling. No, this was about drilling mud. Drilling companies have declined to tell what components and additives are used in their drilling mud, and people with health problems are frustrated because they can't find out what they are being exposed to.

What is drilling mud? It is primarily the lubricant for a drill bit. It is pumped down the drill string (the pipe that supports and drives the drill bit) to the drill bit, which has holes, where it is forced out and returns up the drilled shaft outside the drill string. At the top, it is recycled: rock chips are filtered out, possibly additives are put in, and down it goes again. It consists mostly of water and a clay such as Bentonite.

There are two kinds of additives. One kind is various petroleum products that increase its lubricating qualities. These are the target of all the secrecy. Each drilling company uses proprietary formulas that they hope give them a competitive advantage so they can drill the most feet for the dollars spent. The other main additive is a density additive, the most common being Barite, because it is best to keep pressure in the hole to avoid blowouts. If the target is known to be under great pressure, a lot of Barite is used. Without any Barite, the drilling mud is only about 70-80% as dense as the rock it is drilling through. All that rock pressure may be focused in the gas or oil reservoir, so it is necessary to hold it back and control its rise once the drill bit breaks through into the producing layer.

This latter point produces little controversy. The secrecy surrounding the first issue, the lubricant additives, is the point of contention. In my opinion this secrecy must be breached. This is not just a matter of keeping trade secrets. Obviously, there are differences in optimum formulas for best drilling efficiency, which differ from rock type to rock type. Each drilling company thinks it has the best formulas. Even more obviously, only one of them is right in any particular instance! ALL the others are less efficient.

It would make better sense to get those formulas out in the open, and compare them in real-life situations. Let a set of best practices for each rock type be codified, and all the drilling companies will benefit. So will the people who could then find out just what it is that they are breathing or otherwise being exposed to as drilling proceeds, perhaps right in their neighborhood.

To those who would protest that a lot of drilling research has been published, the key formulas have been published only in quite general form, and all the article of which I am aware are rather old. This needs to be brought up to date and made completely explicit. This is an area for which trade secrets cause more harm than good.

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