Was wonder if anyone was familiar with the engineering side of part of the fracking process? Once the horizontal boring is complete, say 1/2 to 1 mile in length, after fracking takes place how far do the fracking fissures travel.....4-5 feet...200 feet???? I can't get a straight answer out of anybody I talk to. Thanks, Gary Stinnett
Dear Mr. Stinnett,
Knowbody really knows that answer. There are documented reports of fracs travelling vertically over 1500 feet and likewise in horizontal direction the same distance. So much depends on the formation itself, not only the engineering of the frac job itself. I have read that even ambient temperature can change the density of the slick water used for fracs, thus changing its properties in use.
Buddy CottenActually, through a technique known as micro-seismic, fractures can be mapped with decent accuracy. It is expensive so most operators will do it on a random sampling of wells, to help them fine-tune their procedures. Typical fracture extensions initiated in horizontal wellbores are on the order of a few hundred feet. It's these studies that help the Operator determine the optimum spacing between wells. Ideally you want the fractures from adjacent wells to overlap, but not reach all the way to the other wellbore. The fact that many plays are downspacing to as many as 16 wells per Section can be traced to the fact that the fracture mapping is indicating 300-400' of extension.
There are some very interesting videos on You Tube relative to drilling and fracturing. Give it a look.
Mr. Durrett is correct, and here is some additional information to go with it.
"The design projects the length of the fractures from the well measured three ways: the hydraulic length, which is the distance the fracing fluid will travel, sometimes as far as 3,000 feet from the well; the propped length, which is the slightly shorter distance the proppant will reach; and the effective length, the still shorter distance within which the fracing operation will actually improve production." - See more at: http://caselaw.findlaw.com/tx-supreme-court/1102236.html
Not being able to keep the fractures on the lease in question led to a lawsuit that ended up being decided as the 2008 landmark Texas Supreme Court Case, COASTAL OIL & GAS CORP. and Coastal Oil & Gas USA, L.P., Petitioners, v. GARZA ENERGY TRUST et al., Respondents.
Microseismic hydraulic fracture images (along with passive microseismic monitoring) are a great aid in completion design, but the unknown aspect is the reason that adjoining producing horizontal wells are often shut in during fracing operations, so that producing wells are not killed with encroaching fracwater. Completion design will use the fracture direction and dimensions, as well as the volume created by stimulation during the completion phase as datapoints in future design.
Best
Buddy CottenGreat information...Thanks to everyone!!!!! Gary Stinnett
Thanks, Buddy & Steve. Great information to know.