Formation Pressure While Drilling Technology Applied in Arctic Environment: Yamal Region Case Study

Abstract

Formation Pressure While Drilling tools were introduced to the industry several years ago (Pop, 2005). They have had widespread application and success especially in difficult offshore environemnts (Mishra, 2007) and very long horizontal sections (Larsen, 2008) but until recently they have been limited to high cost, deepwater environments. In many land environments Wireline Formation Tester (WFT) tools have often made more economic sense. In Russia FPWD tools have been run in the North Caspian and offshore Sakhalin both for drilling optimization (James, 2012) and for formation pressure guided well placement (Gupta, 2013) but had not ever been run on Land. In 2014, however a unique opportunity presented itself with very high angle wells drilled by Novatek in the field under Taz Bay. The wells being drilled had over 7000 m of vertical departure with deviation over 70 degrees. Additionally, since the field had been on production for some time, the wells were expected to encounter highly depleted sand layers. This implied highly unstable hole conditions and a significant risk of differential sticking. However, understanding the current reservoir pressure and therefore the amount of depletion was critical for managing the drilling hazards for this and future wells and for an accurate update of the hydrodynamic model. Given the risks associated with the hole instability a pipe-conveyed WFT was judged to be too risky and the FPWD tool was proposed.In this paper we will divide our presentation of this operation into three areas: conveyance and operational considerations, pretest design and execution and data analysis and integration