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Unconventional oil and gas – how crucial is western technology?
The development of unconventional resources in the US is creating a shift in the energy industry. A report by the International Energy Agency (IEA) last year estimated that the country’s oil output will overtake that of Saudi Arabia by 2017, making the country practically self-sufficient and on its way to becoming a net exporter.
"The United States, which currently imports around 20 per cent of its total energy needs, becomes all but self-sufficient in net terms – a dramatic reversal of the trend seen in most other energy importing countries… Energy developments in the United States are profound and their effect will be felt well beyond North America – and the energy sector," it said.
The report also added: "The recent rebound in US oil and gas production, driven by upstream technologies that are unlocking light tight oil and shale gas resources, is spurring economic activity – with less expensive gas and electricity prices giving industry a competitive edge."
The IEA said it expected a continued drop in US oil imports, with the country becoming a net oil exporter by around 2030 and reaching near self-sufficiency in energy by 2035. Natural gas has also sparked a gold rush in the US, with shale now accounting for a third of the country’s gas supplies and expected to account for half by 2035.
As highlighted by the IEA, new technologies are driving this oil and natural gas boom in the US, helping to unlock the nation’s vast unconventional resources. These include reservoir analysis tools, drilling technologies and equipment which reduces the environmental impact of the latter.
As the energy industry continues to push the boundaries of unconventional oil and gas exploration, increasing reliance is placed on the information acquired through reservoir analysis – getting it right the first time is key.
To that effect, global oil and gas technology provider Schlumberger has released MicroScope 475, a new high-resolution resistivity and imaging-while-drilling technology which enhances reserves calculation, horizontal well placement and completion design. The tool is designed to address challenges in unconventional shale plays, as well as carbonate and clastic reservoirs.
The MicroScope tool provides laterolog resistivity measurements and images with azimuthal sensitivity which are then used for reserve estimates and horizontal well placement. The 4 3/4-inches (in) Microscope 475 tool can be used in hole sizes ranging from 5 7/8 to 6 1/2 in, according to the firm.
“Optimal placement of the borehole in the reservoir, accurate evaluation of formation properties and identification of geological features that impact producibility are key elements of a successful well,” said Andy Hendricks, president, Drilling & Measurements, Schlumberger.
MicroScope technology has already been deployed in Asia and North America. According to the firm, the technology enhanced formation evaluation in a tight gas reservoir in Asia.
“The application of MicroScope in this challenging thin tight gas reservoir has helped us make accurate real-time decisions while drilling,” said Peng Hai Run, chief geologist, PetroChina SWOGC. “The success of this well has opened more opportunities to our company in developing the thin target reservoirs.”
In Wyoming, US, the technology was used in the Niobrara formation in the Denver-Julesburg basin.
“Keeping the wellbore within the highly fractured layer required accurate real-time information to guide steering decisions. MicroScope images facilitated well placement and fracture analysis to optimize hydraulic fracturing stage designs,” Schlumberger said.
Drilling the way
Horizontal drilling and hydraulic fracturing – also known as “fracking” – are the key technologies which first made shale gas recovery in the US a viable economic exploit. As these technologies improve, there is a need to keep up with the pace in order to strike gold in the exploration of unconventional resources such as shale oil and gas.
Oilfield services firm Baker Hughes this year unveiled a new shale technology, the FracPoint MP sleeve, which enhances hydraulic fracturing and reduces overall pumping time. Building on the FracPoint completion technique, the technology provides increased contact with the reservoir, offering more controlled hydraulic fracture initiation points and improving connectivity to the pay zone.
The new shale equipment allows operators to fracture through five sleeves per stage with as many as 17 stages per well, Baker Hughes claims, in addition to connecting with the reservoir through as many as 85 sleeves and 680 ports. The system uses openhole packers to isolate multiple stages and ball-activated sleeves to divert the fracturing treatment into the formation. With the new FracPoint MP sleeve, a single ball is used to open five sleeves per stage. Each sleeve includes eight DirectConnect ports placed 45 degrees apart over the extension of the sleeve.
“At each stage, a ball is dropped, the sleeves are opened and hydraulic pressure pushes the telescoping DirectConnect ports into the formation at high velocity. The ports act like chisels to initiate fractures at controlled points along the wellbore. This results in accurate placement of the fracture treatment and better connectivity to the reservoir,” the oilfield service firm says.
While crucial to unlock shale gas riches, hydraulic fracturing poses several environmental risks. There are concerns that the process can lead to the contamination of groundwater as a result of spills and faulty well construction. The wastewater associated with shale gas extraction, for instance, can also contain fracturing fluid additives, metals, and radioactive materials. One of the key questions is precisely how to manage this wastewater, as current water treatment plants are not designed to remove some of these contaminants.
A research team from the University of Minnesota is developing innovative biotechnology to purify fracking wastewater. The project could reduce the environmental and health risks associated with the controversial hydraulic process. The team is using naturally-occurring bacteria embedded in porous silica materials to decontaminate the fracking wastewater, a technology initially developed to remove agricultural pesticides from soil and water. Fracking relies on pressurised fluids to create fractures deep in the earth, through which natural gas and oil will escape. Wastewater returns to the surface where, through the biotechnology developed, it is treated and released into surface water, injected back into the earth, or recycled for use for fracking other wells.
The National Science Foundation’s Partnerships for Innovation (NSF-PFI) program is funding the research through a USD 600,000 grant. If the project is successful, the team will be eligible for additional NSF funding. The team will also work with Tundra Companies of Minnesota on silica encapsulation technologies, and with Luca Technologies of Boulder, Colorado on using encapsulated microbes to recover natural gas from depleted coal beds.