Abstract:The end−Permian mass extinction constituted a major event in the history of cri− noids. It led to the demise of the major Paleozoic crinoid groups including cladids, disparids, flexibles and camerates. It is widely accepted that a single lineage, derived from a late Paleo− zoic cladid ancestor (Ampelocrinidae), survived this mass extinction. Holocrinid crinoids (Holocrinus, Holocrinida) along with recently described genus Baudicrinus (Encrinida), the only crinoid groups known from the Early Triassic, are considered the stem groups for the post−Paleozoic monophyletic subclass Articulata. Here, we report preliminary data on unex− pectedly diverse crinoid faunas comprising at least four orders from the Lower Triassic (Induan and Olenekian) of Svalbard, extending their stratigraphic ranges deeper into the early Mesozoic. These findings strongly imply that the recovery of crinoids in the aftermath of the end−Permian extinction began much earlier at higher palaeolatitudes than in the central Tethys.

Fluid samples were acquired in an exploration well and subsequent pilot hole for an operator in deep water on the Norwegian continental shelf to identify the reservoir fluids and to check for potential connectivity between two reservoir targets. Several limiting factors meant that pipe-conveyed logging after drilling was not a viable option. Consequently, a logging while drilling (LWD) formation fluid sampling tool was run as a part of a LWD evaluation program to collect fluid samples while drilling and when pulling out of the hole after reaching TD (total depth) of the section. A team of global and local experts was established to plan the job. The team performed a risk analysis to identify risks and plan mitigating actions. Several challenges were identified, including the potential damage to equipment from vibration when drilling out the shoe track or from hitting stringers while drilling the formation. Other challenges identified involved potential tool movement from rig heave during sampling and required sampling time as a function of the duration of formation exposure to drilling mud before sampling. The team assessed the risks and established a plan to mitigate them, and the job was performed according to plan in February and March of 2014. A total of nine fluid samples were collected in two well sections, completing each section in one drilling run. This paper discusses the results of the third-party laboratory sample analysis. The formation evaluation logs were inconclusive as to whether or not the reservoir contained oil, condensate, or gas at some depths because of the laminated structure of the formation. The LWD fluid sampling technology confirmed that the reservoir contained gas. This paper also discusses the job planning, mitigating actions that were introduced, implementation and results of the job, and the benefits of fluid sampling while drilling.

Because wells are becoming increasingly longer and more complex in trajectory and construction, safe operating limits for running pipe are becoming increasingly smaller. Because of narrow buckling margins in small diameter drillpipe and tubing, an accurate measurement of pipe tension is critical to ensure success when running this pipe. Severe buckling could result in tubing damage or failure, generating potentially significant non-productive time (NPT) or loss of the wellbore. Unreliable surface measurements for hookload and the need to measure minor changes in weights have created a need for the means to measure them. A fully validated and applicable solution is available to overcome these challenges. When run in conjunction with a measurement-while-drilling (MWD) toolstring, including a pressure-while-drilling (PWD) sensor, directional sensor, a controller module and pulser, the tool containing strain gauges provides real-time updates and stores data in memory, with tension readings at the sensor depth, to represent the weight of the string below that point. This paper presents two cases in which this solution was successfully applied, using strain gauges to measure tension below a point of interest in a string of pipe or tubing in non-drilling applications. Accurate torque and drag modeling with tripping-in weights and buckling limits plotted against real-time updates from the strain gauge tool provided continuous updates on the load regime downhole. This enabled the tension to be maintained above the buckling limits. Where the tension fell below the limits, remedial actions were taken or operations were carefully continued with extra vigilance for any signs of a deteriorating situation or of string lockup. The benefits of using strain gauges have been found in yet another non-drilling application described in this paper. Technology to measure tension that has been traditionally used in the improvement of drilling performance can also be applied to improve the performance in activities that pose the challenges of overcoming low operational margins.