Aggie, following is the second half of my answers to your questions:
<3. You haven't mentioned the depths involved, or whether there have been any problems with wellbore stability. Typically with fractured carbonates (limestones and dolomites), if this has been any kind of problem while drilling vertically, then it stands a good chance of becoming a serious problem if drilling directionally or horizontally. Columbia is a region which is known to manifest problems with wellbore stability due to tectonic stress. I wonder if that is a factor here.>
<I would doubt that they would choose to try to produce simultaneously from a horizontal drainhole and a vertical well - I might be misreading your comment about 11 producers, did they already have 6 wells before the 5 dry holes?. Typically a casing window is milled (if necessary), then the hole is plugged back with a sidetrack plug. The well is then sidetracked to horizontal. It has become a fairly common practice to drill dual horizontal drainholes and complete them separately. The fractures I spoke of usually have a regional context, so the idea would be to have 2 drainholes 180 degrees apart (one headed north, one south, for example), again, to intersect the maximum number of fractures.>
The depths range from about 6,000 feet (most are in th 6,000 foot range) to 8,700 feet. Sorry about the confusion my note caused on how many wells. They have drilled a total of 10 wells – but the last 5 wells were “botched.” A Yahoo poster defined “botched” as “SEV introduced cement to an underbalanced reservoir. “ Neither SEV or the Yahoo posters ever mentioned a problem with wellbore stability. I'll ask in a Yahoo post and let you know.
<5. Why are ARCO acidizing - Is it an acid-frac? Acid jobs are typically done in carbonates to remove near-wellbore damage resulting from drilling operations. Acid-frac's are designed to extend the existing natural fractures.>
I'm not a technical person and cannot answer why the acidization. There is mention in SEV news releases and Yahoo posts of stimulation, perforation and fracturing. Following is what one poster and SEV said which may help explain the reason.
“RESULTS NOT BAD IMHO <test on TP 1W lateral was to test pressure communication from this well to the other well ie ES 6E was shut in to observe pressure response from the test well, and of course to get a production rate, however the rate was limited by the pump size ie 1500 b/d approximately, after the well is acidized to remove skin damage a bigger pump capable of much higher rates will be installed ie 10000 to 15000 b/d, however the ability to store and truck the oil will limit the higher rate tests to short periods, maybe a day or so, the ES 6E was apparently damaged too much to repair ie the water from a shallower formation was not shut off due to a bad cement job that couldn't be repaired, the geologic results still appear to be favorable with the high probability of good oil production if redrilled, the TP 3E will be tested later in the Villeta by fracturing and then the shallower Cimmarona, this may require a redrill however via a lateral well, imho lateral drilling with slotted liner or open hole completions may solve well problems of the last four wells. “
SEV news release said: “Seven Seas also announced that although the Tres Pasos 4-E well encountered 303 feet of Cimarrona formation with oil and gas shows and no water contact, the well bore did not appear to intersect the larger fracture system due to a rotation in fracture system orientation at the Tres Pasos 4-E location. Consequently, the well may not be commercially productive without a successful fracture treatment or the drilling of a lateral extension. The Company is continuing evaluation and analysis to determine whether to fracture
treat the reservoir in this well bore.”
Thank you very much, Aggie, for your help on this!!! I've actually backed up the truck and SEV is now a major portion of my portfolio. It appears to be way undervalued based on the reserve estimates and a new, capable management team.
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