Okay, give me a chance to show my ignorance in all of this plugging stuff.
As I understand it, a well is drilled and steel casing is inserted into the well shaft to potentially contain tremendously high pressures of the oil and/ or gas when it is encountered. After the casing is placed down to the desired depth, the casing is somehow perforated at the different stratum where evidence of oil-laden materials were encountered during the drilling operation. After the casing is perforated, the well is "fracked", meaning fluid materials are pumped down the well casing at tremendous pressure to create fractures in the oil bearing strata, thereby creating paths for all that wonderful black stuff to enter the well casing and come to the surface. A good well will have enough pressure to produce free flowing oil and gas and usually some nasty salt water to the surface where it is gleefully collected. A lesser quality well will require a "pump-jack" to pump the oil and salt water to the surface. (That's one of those see-saw looking contraptions.) When all the oil is pumped up, the well is usually plugged and abandoned.
Well, what I imagine that we have here is a well casing with perforations at some depth or various depths to 7500 +/-feet, and additional "perfs" at depths greater than 7500 +/- feet. I believe the perfs below 7500 feet happen to be in a stratum that happens to be connected to other neighboring wells. I believe in our situation the plug is being set at 7500 +/- feet to block the stratum that would contaminate other wells. The water bearing sands are usually a lot closer to the surface (or at least in Texas), so I don't think the plug has anything to do with that.
Sorry about the long post, but I guess there is not much else to read on this thread. Oh! I want to thank KZAP, TraderGreg, and a few of the regulars for giving me something to read when I check in here.
I may be way off base, but this is what I think is going on here.
K Joseph |
