http://www.thebakken.com/articles/711/the-slickwater-story
...Slickwater fracks were used before gels and high viscosity fluids became the industry norm for conventional and unconventional fracking designs, but the simple design of a slickwater frack has proven to produce a more complex fracture network in the middle Bakken formation.
...The basics of the method involve water combined with a polyacrylamide friction reducer. The slickening agents reduce the friction of the water in the pipe and the viscosity of the fluid. Because the fluid is less viscous and the water is lighter, more volume is needed to carry the same amount of proppant to effectively prop open the fracture networks responsible for draining the reservoir. Higher rates of pressure are also required to move the water. Pumping rates of 100 barrels per minute are common—a much higher rate than other unconventional fracturing pumping method requirements. The high pressure needed to perform a slickwater frack also helps to stimulate more rock and create more fractures. The absence of gel also allows for a quicker and easier placement of proppant into the fractures allowing the hydrocarbons to flow back quicker.
Of all the concerns about slickwater treatments, the greatest is the water volume required. Because the Williston Basin is situated in a geographic region with an abundant water supply, operators are able to deploy the method without incurring high water costs. The amount of water needed to perform a slickwater frack job typically exceeds 4 to 8 million gallons. In some cases, the quantity of pumping trucks used to inject the pressurized water into the wellbore needs to be doubled. Because the fluid treatment doesn’t rely on additives, slickwater fracks are more conducive for produce and flowback water recycling efforts, the authors also wrote....
Fracturing Fluids 101
http://www.hexionfracline.com/fracturing-fluids-101
There are primarily three types of fracturing fluids currently used. These are water frac or slick water, linear gel, and crosslinked gel. All three of these frac fluids have different properties and applications.
Water frac is water containing a friction reducer and possibly a biocide, surfactant, breaker or clay control additive. This fluid has a low viscosity of 2 – 3 cP, which requires a high pump rate to transport proppant. Small proppant size like 40/70 is common with this fluid due to its low viscosity. Water frac is the least damaging to the proppant pack of the three frac fluid types and it is commonly used in gas wells.
Linear gel is water containing a gelling agent like guar, HPG, CMHPG, or xanthan. Other possible additives are buffers, biocide, surfactant, breaker, and clay control. This fluid has a medium viscosity of 10 – 30 cP, which results in improved proppant transport and wider frac compared to water frac fluid. Medium proppant size like 30/50 is common with this fluid. Linear gel is more damaging to the proppant pack than water frac and it is commonly used in both gas and oil wells.
Crosslinked gel is water containing any of the gelling agents used in linear gel and a crosslinker like boron (B), zirconium (Zr), titanium (Ti) or aluminum (Al). Other possible additives are buffers, biocide, surfactant, breaker, and clay control. This fluid has a high viscosity of 100 – 1000 cP, which results in better proppant transport and wider fracs compared to linear gel frac fluid. Large proppant sizes like 20/40 and 16/30 are common with this fluid. Crosslinked gel is more damaging to the proppant pack than linear gel and it is commonly used in oil and high liquid wells.
Other less common frac fluids include gelled oil, gelled acid, foamed oil with nitrogen, foamed water with nitrogen or carbon dioxide, and gelled LPG.
you placed some comprehensive explanation of frac fluids and frac techniques here that is likely to befuddle a layman. but if repeated enough it might stick.
BTW, reason Continental is saying it will only take 800mbo wells rather than 600mbo wells is not just where they are drilled but also how they are completed.
One can get higher recoveries if one completes the well differently.
A number of those so-called marginal areas of Eagleford and Bakken are really just not as prolific as the core. Doesn’t mean they too cannot produce enough to be commercial if one fracs the wells differently.
1. more stages
2. more fluids
3. longer laterals
4. Slickwater fluids
In time, multi-laterals(more than one lateral in a well) will rule the day too