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--- wellsite_geostop [20/03/2023 16:04] – mike_gss
+++ wellsite_geostop [20/03/2023 16:14] (current) – mike_gss
@@ Line 25: / Line 25: @@
 A solution was found by examining closely-spaced samples from nearby wells and producing a high-resolution biozonation scheme which utilised a pragmatic set of fossil events, specific to the Gorm Field and the surrounding areas, and to use a wellsite biostratigrapher to monitor closely-spaced samples taken on the approach to the reservoir section. It can be seen (see below) that these fossil events accurately define the target horizon which is the “transitional marls” immediately above the reservoir. More importantly, it also shows a series of closely-spaced subzones defined by separate fossil events which can be used to “flag” the approach of the target horizon. These subzones – because they are an expression of the local geology – may even be used to estimate rock thickness and provide estimates in actual distances to be drilled between marker events.
-The technique was used on the subsequent 12 production wells drilled with no “lost holes” thereby estimating a saving of $24 million by not losing any redrilling time or drilling equipment.
+{{:wellsite04.jpg?nolink|}}
+//Chart showing closely-spaced biostratigraphic events to warn of the impending arrival of the drill string in the target zone (green unit) just above the underpressured reservoir (blue unit). When the markers for higher zones like TM7 to TM4 were observed in the samples, the ROP could be controlled to allow closely-spaced samples to be taken to look for markers TM3 d, c, b, a and ax. When markers for TM2 were seen drilling could be stopped quickly without risk of penetrating the reservoir (TM1).//
+The technique was used on the subsequent 12 production wells drilled with no “lost holes” thereby estimating a saving of $24 million by not losing any redrilling time or drilling equipment. The estimated life span of the field was also increased because of the increased confidence in future safe drilling.