IT DOESN’T take an oil minister to tell us that we need more oil and that it is “understood by Government at the highest level”. Any teenager old enough to fill up the family car knows that. Consumers pay good money for petrol to make sure oil companies also know that. That has been the real incentive to tackle fields previously viewed as too old, too deep, too hot, and develop the technology to make it happen.
Every oilfield has two geo-pressures that dictate pretty much everything that drilling can do. These pressures set the limits for the maximum and minimum loads it can sustain without breaking down or blowing out.
One of drilling’s jobs is to balance the pressure load in a well below the maximum limit and above the minimum. So it’s no surprise they want a nice fat difference between the two limits. The bigger it is the easier it is to manage.
It should also come as no surprise that, like people, oilfields sag and shrink with age. In an oilfield, pressure limits sag and differences shrink, leaving little room for drilling to get through without breaking or losing something. Already, in some of the world’s largest and oldest fields, drillers are struggling to reach and recover the still profitable oil.
It’s not just old oilfields that are exceeding the limits of modern drilling technology. Deep wells and deep water in young fields can have stubbornly defiant narrow pressure limits which can be complicated even further by high temperature.
Drilling is a discipline known to be equally defiant as nature, but we should be happy it is, otherwise oil would have peaked a generation ago. In its search for a solution, drilling has turned to an emerging technology known as Managed Pressure Drilling, or MPD, that enables drilling through narrow pressure barriers.
Managed Pressure Drilling is a new method that gives drilling automated control of the pressure load in a well and the ability to manage it within specific limits. In fact, with MPD, wells that not long ago were impossible to finish are being drilled into oil that was impossible to reach. Automated MPD was adopted early in the North Sea to reach oil stranded below layers of unstable rock and in between horizontal wells. It is still in use today to help mitigate the risks of drilling deep wells with high temperature and high pressure.
It has also been adopted early in several deepwater Gulf of Mexico fields where, in some cases, drilling went from less than a 30% success rate to 100%. However, in these fields, automated MPD is not viewed as the last resort – it’s the only one.
The oilfield is known to adopt new technology more slowly than other industries. However, one clear sign that automated MPD is rising in acceptance is its use to reduce drilling pressure to levels lower than ever before and drill through pressure differences smaller than ever attempted.
As unconventional as MPD may appear to be, if its current success is anything to go by, this technology will be in use in every oilfield very soon. Having successfully tackled some of the world’s most un-drillable wells, MPD has proved it’s already up to the challenge. As oil reserves crash to lower levels, the shift towards MPD will only accelerate.