Marrying horizontal drilling with fracking is a new development
Horizontal drilling isn’t new. Such wells have been drilled for the better part of a century. But combining it with hydraulic fracturing to produce gas and oil from shale is a far more recent development, and improving technologies have continued to improve drilling methods and well productivity.
“The most recent generation of (drilling) equipment can allow for a 90-degree turn in just a few feet,” the Colorado Geological Survey said in a 2011 report.
Thom Kerr of the Colorado Oil and Gas Conservation Commission said the development of multi-stage fracking, which allows for hydraulic fracturing individual segments of a bore to ensure the entire length is adequately fractured, is important to horizontal drilling. The long lateral reaches of such wells can require a lot of frack stages — more than 30, compared to maybe seven or eight for typical Piceance Basin wells, said Matt Abell of Encana USA. That’s one of the reasons for horizontal drilling’s added cost.
He said improvements such as better electronic surveying equipment and improved drilling fluids help extend how far a well can be drilled, and the degree to which it accurately reaches its target.
Challenges remain. Between the depths of some of the wells that may be drilled — locally, potentially 14,000 feet or deeper — and their reach, the total wellbore length might reach 20,000 feet. Drilling pipe lying on its side in the lateral segment creates added friction, Abell said.
Also, higher bottom-hole temperatures sometimes reaching 300 degrees Fahrenheit can create problems for sophisticated downhole electronic equipment, and the industry is trying to respond through means such as the use of ceramics, he said.