Taking A Microscopic View Of The Shales

While operators often don’t have the luxury of studying their shale acreage up close and personal, reservoir characterization can help answer many of the questions that plague developers of these unconventional resources.

One of the key issues with shale is its mineralogical composition. Hydrocarbon molecules aren’t simply sitting in pore spaces in the shale. Often they’re actually connected to the organic content, such as kerogen, making them even more challenging to produce. Understanding these shales at the molecular and even nanometer scale could help operators determine better ways to release the oil and gas.

A company called McCrone Associates Inc. has the tools and technology to provide that analysis. According to Craig Schwandt, a geologist with McCrone, his company has access to tools that few oil companies possess.

“The new technology allows one to examine the nanometer-scale features of materials,” Schwandt said. “Most people don’t really know about it. It’s new within the last three years, and it really does open up avenues for investigation.”

He added that interest is growing in understanding the nanoporosity of shale plays. “The technology is available and could benefit companies that might not have those resources themselves,” he said.

Several new techniques have been introduced recently to study cuttings and cores at the well site, but McCrone handles samples in the lab. Schwandt explained that there’s a difference in the preparation of the samples that provides a more robust answer in the lab. “One of the features of electron microscopy is the ability to sample using ion polishing,” he said. “It’s important at the nanometer scale to determine whether something is a feature or an artifact. In the field you get a more coarse sample.” This “quick and dirty” sampling can provide information at the micrometer scale, but to make out mineralogy, a sample needs to be studied at a finer scale in the lab. McCrone does research for its clients and customizes its service offerings to suit their needs. “There’s a range, from determining the composition to determining the structure,” Schwandt said. “We can identify elemental materials as well as organic materials. We can do characterization using backscattered electron imaging, elemental analysis, and X-ray diffraction to define the phases and provide the data to oil company petrologists in a format for their geochemistry modeling.”

Currently, McCrone serves a host of industries, but it is just entering the oil and gas business. Schwandt said that it is a difficult foray since oil companies tend to be loath to share their data. Toward this end, McCrone provides the critical confidentiality required by clients. And the ultimate answer comes at a fraction of the cost to drill and complete a well.

“It’s a lot cheaper for them to experiment with sending us a few samples rather than buying the equipment themselves,” he said. “Each of these instruments costs about (US) $1 million. A couple thousand dollars isn’t anything by comparison.”