by rockdoc123 » Thu 16 May 2013, 12:03:50
$this->bbcode_second_pass_quote('', 'A')nd while we’re on the subject let me fling the facts about the hot “new” Eagle Ford Shale play at everyone again. In the 1940’s alone there were numerous vertical wells completed in the EFS. Yes…a fair bit of activity in this “new” play over 60 years ago. Half of those leases drilled produced from 310k to 822k bo. And that lease that produced 822k bo since Sept 1947 is still producing today: made 134 bo during Feb 1013. That may not sound very impressive but that’s still almost $150k/yr gross income…I would be very happy to own that lease today. Of the 4,149 wells completed in the EFS during the boom since 2008 only 293 wells have produced from leases that have recovered more oil than that one developed in 1947. While it’s true that many of the wells are new and have much more oil to recover it’s also good to remember that many of these wells have already gone thru their high decline rate period and their better days are long behind them. Fortunately, thanks to high oil prices, we can use expensive modern tech to recover much more oil from this half century old proven trend then the earliest wells were capable of.
I've mentioned this before and you chose to ignore it, but the wells in the Eagleford pool you refer to prior to around 2007 were completed, yes in the Eagleford Formation, but in the sandstone unit at the top of Eagleford Formation. The Railroad Commission itself indicates the first true shale production was in 2008. The clay and carbonate rich zones below that are the areas that are currently being targeted with horizontal wells. Characterizing it as the same play is incorrect and extremely misleading for those here still trying to come to grasp with what shale production is. The two are not the same at all, one is conventional, the other unconventional. From what I've seen the sandstones which sit at the top of the Eagleford (sometimes referred to as sub-Clarkesville) have variable permeability ranging from 10's of md to 100's of md, not very unconventional. The small fracs that were utilized over this zone seem to more directed at dealing with well bore damage than actually opening up reservoir. In contrast the wells being drilled today are a kilometre or more in horizontal reach with anywhere from 7 to 15 stages of fraccing, usually slickwater in nature.They are all targeting the shales and the permeabilities in those zones are nano-darcies not micro-darcies. As a consequence you see the rapid declines in the first few years which is followed by a long flat production profile with very little in the way of decline. Hence the need to drill a lot of wells to have a relatively flat production rate of any significance. When these shale horizontals were drilled and completed the operators fully expected to see exactly what they got, they were not expecting typical standard decline rates associated with conventional pools, it is predictable.