© Christopher S. Miller | Alaska Stock

“In that stage, there was a lot of core testing to determine the PMP [porosity and permeability] of the material,” Homestead says, noting that before fracking was commonplace the PMP of the substrate around an oil or gas site determined its potential for development. “There was a lot of testing to identify how we could move fluids and gasses through the formation to get them to wells.”

Another test that the industry relied on—and continues to rely on—is the American Petroleum Institute (API) gravity test. This lab test measures how light or heavy the petroleum is compared to water.

“We would do the initial testing on those crude oils for identifying how low the viscosity was and how high API gravity was,” Homestead says. “So they could start modeling how much they can extract out of the formations, and that’s what maybe would determine if they would put another well and in that area.”

The composition of the crude oil is also tested at early stages of development to determine its British Thermal Unit (BTU) value, which allows companies to determine how valuable the oil is, Homestead explains.

At the early stages of some wells, lighter oil can easily be pumped out. However, as a site matures, it becomes more and more difficult to extract oil, requiring additional steps—and more lab work.

Often, after a site has been pumped, it’s flushed with gas deposits to push the oil into the wells.

“Even further into production, they’ll start pumping water down there to push new oil. Using water, that involves a lot more chemistry,” Homestead says. “Once you start taking water from a different source and pumping it down into the well around it and start mixing it in there, you can have chemical reactions that can start to happen.”

It’s essential that the water being pumped into the site is tested along with moisture native to the site to ensure that when they mix they won’t create precipitates that can plug the formation.

“There was some testing that had to be there to make sure that they weren’t going to create a problem for themselves and close off production,” Homestead says. “There is a lot of very interesting chemistry that happens with the oil field waters, and it’s all pressure-related and temperature-related and what anions and cations are present in the fluids.”

Some of the testing being done by SGS—and companies offering similar services—must be done onsite.

“We used to go on to these drill rigs to do onsite testing because some of these parameters are fleeting. You take them out of the well and depressurize the samples and the chemistry starts changing—you do not know the chemistry as it is in the formation.”

Though labs play an essential role in understanding the potential of a site, as well as the best ways to tap into it, the roles they play in the industry are much broader.

PND Engineers Senior Structural Engineer Corey Roche focuses on a different type of material testing for the oil and gas industry.

“In my world, it’s still materials testing, but it’s just in a structural sense,” Roche says. “So, it’s steel materials, concrete materials—especially testing to do with the Arctic, such as fracture initiation due to cold temperatures on steel. And there’s some fancy testing that can be done in the lab to verify material that is meant to be used on the North Slope can perform well in the conditions.”

The extreme Arctic cold puts additional stress on building materials used for vertical structures, roads, and everything in between.

An example of structural lab testing done on steel is a Charpy v-notch test. This measures the amount of energy absorbed across a fracture. Essentially, it’s measuring a material’s resistance to tensile cracking, Roche explains.

“It’s a physical destructive test. So you have to cut samples from the material and send it to a lab, and they do a destructive test,” Roche says, noting that the failure-point depends on the type of steel, temperature, load application, and various other attributes of the material and situation being tested. Not only does the steel being used on the North Slope need to be tested, but the welding materials and welding procedures also need to be lab-tested to ensure that they won’t fail in the field.

For concrete, which is a relatively brittle matrix even outside of Arctic conditions, the PND Engineers team tests for the air content of the general mix design.

“If you have some control-level air inside the actual concrete structure, it performs a little bit better in terms of cyclic loading in terms of temperatures,” Roche says. “It’s just a little bit more durable in the freeze-thaw cycles.”

Roche notes that there are several ways to test concrete for air content inclusion, including in freshly mixed concrete and hardened concrete. Another option is to test the material’s performance and resistance to the freeze-thaw cycle.

“What you’re doing with the lab test is you’re truthing out the procedure and materials that they’re using. You’re making sure that the procedures that they plan to use will actually work,” Roche says. “You match the lab test procedure to the field procedure, so it’s a verification that means and methods are going to perform.”

Despite the rigorous material testing done in the labs, there are still failures out in the field. This is often caused by anomalies in the materials, Roche explains.

Labs will only test a certain percentage of all materials, “you’re not going to find everything prior to going out to the field.

Torsten Mayrberger, principal and geotechnical engineer at PND Engineers, also conducts lab testing to support the oil and gas industry. However, much of the focus of his work is soil testing.

“We do a lot of soil testing—we have a lab here for that—a lot of that has to do with the identification of materials that we use for roads and pads,” Mayrberger says.

Part of this work is discovering gravel sources. Once a source has been identified, the team will test and characterize the gravel to see if it’s usable.

“We’ll check for fines [silts and soils] content because we don’t want to have a lot of fines,” Mayrberger explains, noting that the team attempts to identify sites close to where the road or pad is being constructed for economic reasons.

The mineral makeup of the rock is examined and identified as part of the testing process. However, Mayrberger points out that with few gravel options on the North Slope, they often don’t have the luxury of options.

“Beggars can’t be choosers, so to speak,” Mayrberger says. “We also do strength testing on soils, including frozen soils.”

Soils, which arrive at the lab as cylinder core samples, are strength tested to establish their load-bearing abilities, which are impacted by the type of materials they are comprised of, including ice.

“We test them for first strength in their frozen state. And then, we also test how much settlement we’ll get from a certain type of soil,” Mayrberger says.

Understanding the settlement properties of soils are especially important in the Arctic due to the freeze-thaw cycle. The amount of settlement due to ice in the soil has significant impacts on road-building efforts.

For non-frozen soil, density is strongly correlated to strength, but that’s not necessarily the case with frozen soils, Mayrberger notes. When it comes to frozen soils, factors impacting soil strength include how cold the ice in the soil matrix is and the salinity level.

“Soils in the Arctic may have salinity within the soil matrix and the salinity actually weakens the soil mass,” Mayrberger says. “So we do test for salinity, and then we have to change our design parameters to account for that.”

One of the biggest challenges facing Mayrberger and others examining frozen soils is the lack of significant empirical data when compared to the sort of data sets available to geoengineers in the Lower 48.

Specifically, very little research has been done in the West on salinity and the effects of salinity on strength, Mayrberger says.

“A lot of that work that we’ve done for projects where we’re in the saline soils is based on our experience and our own research and development,” Mayrberger says.

It can also be challenging to keep samples frozen while being transported to a lab that can test the materials while they are still frozen, Mayrberger adds.

While significant amounts of lab testing must be done ahead of construction for oil and gas industry infrastructure, there is also a plethora of environmental testing that must take place on materials after oil has been extracted from a site.

“When you step away from the production side—the upstream side—there is the environmental testing itself,” Homestead explains.

Among the various environmental tests done, one set examines exploration byproducts, such as drilling fluids and drilling cuttings. These materials need to be well-characterized so companies know how to dispose of them safely.

“These materials are tested for heavy metals, as well as oils,” Homestead says. “Depending on those results, the materials have to be handled differently. Whether the oil has to be separated out or if it has to be encapsulated because of the heavy metals depends on these results.”

Homestead says the logistics of operating in Alaska present difficulties that similar companies don’t face in the Lower 48. Mayrberger concurs.

“It’s very expensive to do exploration up on the Slope because we’ve got to do it in the winter. The remoteness makes it very difficult—just getting personnel out to the drill site and then back to camp every day,” Mayrberger says. “And then, you know, once we get it back to the lab, things have to remain frozen.”

Despite the additional difficulties of operating in the Last Frontier, the need for the raw data derived from lab tests is crucial for engineers working for oil and gas companies to determine the best approach to continue to extract resources from Alaska and keep the state’s economic engine running.