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clock Created with Sketch. 15/08/21
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Originally posted by squidgy:
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A drill and completion process for a new well is a many stepped process, and each well/play type has a different pathway.3 examples classic - coarse grain, well sorted sand - drill and the mudlog tells you have a winner - order the casing, rent the tanks and book the wireline unit for perforation before the logs are run. Also start the government paperwork for perforation, flow control and tie in right away. The time between TD and commercial flow will be short - the Initial Production rate (IP) will be solid and there are no risks announcing to market as the reservoir will perform as expected - happy days.vuggy dolomite ala 21-6 - dolomite (secondary alteration of limestone enhancing poro/perm) - mudlog shows vugs/oil show - optimism but need wireline/petrophysics and commercialitity needs a flow test. So report mudlog results but the well needs time/analysis. Run wireline - petrophysics - announce casing (which is delayed in ordering and cementation (many options)). Announce casing and even perfs but the well flow/pressure and therefore commerciality is still uncertain (very strongly derisked but there is still a possibility of a raw egg to the face). Custom cement, perf, acidize, swab - depending on the reservoir response the well flows oil and preferential water/acid - days pass and the well produces more oil and less water (cleans up) - monitor the pressure (is it a big pod or a minnow) - monitor the water % and salinity (are all the perfs access oil or oil/water) - wait for steady state flow. Likely put a pump on the well. Realistically you are ~20 days from TD before you think you know how the well will do and maybe longer until you are sure you know.tighter sandstones ala 17-5 - clastics in some ways are easier since they are laid down by water action and are generally more consistent from well to well. But with tighter sandstones, the poro/perm and lateral variability is anything but classic. So the mudlog has some sand which has an oil show - this tells you 'hey I have a chance' - derisked but the casing/perm decision is still in the air, nevermind is it commercial. Wireline - petrophysics - casing decision - tentative press release. If the zone is promising - case - and now formulate frac design. Engineer and geo bash it around and a plan is made (easy to not find the 'goldylocks' and do nothing or frac a wet zone into the perfs and of course bigger fracs cost a lot more as you scale up). Design down - it takes a lot of time/planning to get the right equipment and water on site. perf/frac/clean up takes at least a week. Swab - put a pump on - get a steady state and sigh - finally give the market a number you can stand behind.
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@squidgy , you're spot on. I got a bit carried away with the large oil column in 2106 - but yes a lot of water under the bridge before you can say we nailed it.
(20min delay)