By Peter M. Duncan, PhD
Founder & Co-Chairman, MicroSeismic, Inc.
I ended my December Blog with the admonition that when we pass by a gas pump it should trigger a prayer for a little price stability so we can get back to work. As I sit writing this, oil is flirting with a $30/bbl price against a surging US dollar, the Dow is off 1,200 points since the end of the year and the majors are announcing more layoffs. Ouch!! No prayers being answered here I am afraid.
Mentioning “pray” takes me back 10 years to the early days of MicroSeismic when we were performing our first frac monitoring jobs. Back in those “ancient” times, frac jobs were often pumped into the entire 3,000 foot lateral, which might be an open hole or a cased hole with 3 to 5 zones of perforation. Operators referred to this method of stimulation as “pump and pray”. The industry soon learned that such an approach was not very effective. Natural zones of weakness soaked up all the treatment and left most of the wellbore unstimulated. Microseismic data was fundamental to revealing what was happening at the reservoir. We could see that the events were concentrated in just a few spots along the wellbore.
Since that time the industry has learned to treat the well a small portion at a time, using different techniques to isolate a few hundred feet of wellbore into a single treatment interval or stage. Modern laterals are often divided into 20, 30, 40 or even more stages so that the well is stimulated more completely along its entire length with the expectation that it will then more likely drain the reservoir over its entire length. Older wells that were treated with fewer stages offer an opportunity for re-frac’ing with the intention of filling in between the zones that were frac’ed originally. Diverting the re-frac into new rock is a challenge that has not been completely solved and many re-frac’s have been attempted with what can only be called a return to “pump and pray”. Microseismic data has shown that such open-hole re-stimulations, even when some diverters are used, are only reaching the heel-ward third of the well. Once again microseismic data is revealing what is really happening in the subsurface, tearing down the old models so that we can move forward where innovation is required.
Inevitably we come back to the importance of innovation in the face of any challenge, be it technical or economic. As it is often said, “necessity is the mother of invention”. So this month, I would like to encourage you, every time you see a gas pump, to “pray” for inspiration to solve the challenges we face …. and maybe just a little more patience.