Ann: VPE: Coring Results for Snatcher 2 - 12/08/2, page-25

re: Ann: VPE: Coring Results for Snatcher 2 -... The press release is obviously good news but the operator is prudent to wait on logs and testing (I assume they will do at least MDT which is a simple pressure, small sample technique) to decide the signifance of the well and whether to case the well (although core is usually a pretty good indicator it is only one piece of the puzzle). As mentioned in a previous post when a well is cased you can be more assured a commercial win has been made but until casing is announced, the results should be considered as hightly encouraging.

Channel Systems
Think of a modern river like the Swan - take the water out and cover the whole thing in shale (a sudden (<10,000 years) sea level rise of say 40m - yes even before Al Gore this happened repeatedly). Now drill wells and if you hit a sand bar you win but if you miss the sands bars you lose (sort of like yayhting in reverse). Complicate this (since Mother Earth is a Harsh Mistress) by overprinting the river system 5 or 6 times over top of the old system so the channels are sometimes stacked but sometimes carve into each other and sometimes are absent.
Your 3D might be able to tell you where the overall river went (called a channel belt) and you might have some idea where in the belt to drill to maximize your chances to hit sand but until you drill the well and analysed the data you would not be sure.
And of course you have to summize what is between wells. Do the sands look the same (there are litterally 10s of ways of judging this - colouration, grain size, impurities, dip etc.)? But even if the sands look the same and have the same oil/water contact they may not be connected and part of the same field.
Core and logs go a long way to answering this but it is pressure information that is used to connect and separate sands. When the well is pressure tested (sometimes with one well flow while the other measures) it will be established whether the two wells are in communication. Since Charo 3 is not public is may be hard to judge whether it is separate or not to the Snatcher wells.

In short when you map channels in a belt, you drill them on a disconnected assumption (selecting the best spot on 3D) and then let the data, most importantly pressure, tell you if they are connected. All this information is used to determine the size of the field and how and where to drill development wells.