Thin sands24 Jul 2024 01:48
@Oladopo. You should not be concerned about thin sands. The reason they are not commonly recognised as gas-producing horizons is because standard logging methodology has poor resolution, so cannot detect potential gas-bearing strata less than 1m thick. NuTech log analysis has much greater resolution, so can detect far more potential reservoirs that might otherwise be missed. Some of the horizons in the current Sandjet evaluation are these thin sands, but there are plenty of much thicker strata being tested as well.
Thin does not necessarily mean small - there are plenty of examples of thin sand beds that have enormous lateral continuity. About a year ago, Caterham7 provided a reference regarding such thin sands, from which I quote:
"Beds from the Madeira basin plain are known to be continuous over 100-700 km, with sand correlated over 100-200 km (Stevenson et al., 2013), although only 2 out of 20 described turbidites have a maximum thickness greater than 0.3 m. On the Cascadia margin (Adams, 1990; Nelson et al., 2000), thirteen (30-60 cm thick) seismic-triggered turbidite beds are continuous for more than 500 km downstream in the Cascadia channel, whilst one 20 cm thick turbidite is continuous for ‘only’ 150 km in the Astoria channel. In the Mediterranean, a megaturbidite connected to the tsunami triggered by the Crete earthquake (Polonia et al., 2016) can be correlated for more than 100 km; however, most of that deposit (up to 24 m) is composed of mud, while the maximum reported sand thickness is 1.3 m (Hieke and Werner, 2000). The maximum sand thickness of the Sumatran margin 2004 event is 1 m, but it is continuous for more than 200 km (Patton et al., 2015).
https://eprints.whiterose.ac.uk/131925/7/1-s2.0-S0264817218302551-main.pdf