Reducing the Risks and Costs of Highly Deviated and Extended Reach Drilling Through the Application of Formation Pressure While Drilling

Abstract

Extended reach and highly deviated wellbores enable operators to intersect multiple reservoir targets with a single wellbore, a capability that would not have been possible had the well been drilled vertically. The driver for drilling these kinds of wells is to reduce the total cost of developing a field. With advances in drilling motors and rotary steerable systems, drilling these types of wells has become common, but there are still challenges in acquiring sufficient formation evaluation data. Often these wells are drilled in already producing fields where depleted zones will be encountered. This, coupled with the high deviation makes wireline conveyed evaluation risky and expensive, in particular since these well types typically require pipe conveyed wireline operations. Logging while drilling (LWD) tools have been able to provide sufficient petrophysical data for the better part of two decades. It is only in recent years that it has become possible to acquire formation pressure data while drilling and thereby provide critical answers to operator asset teams with regards to fluid type, well-to-well connectivity, and depletion trends. In a drilling campaign in Southeast Asia two highly deviated wells and two extended reach wells were drilled and evaluated successfully using LWD technology both for petrophysics and also formation testing, with an ultimate economic advantage to the operator compared with wireline logging. A formation pressure while drilling (FPWD) service was used to measure formation pressure and record fluid gradients. This paper details the operator's objectives, perceived challenges, operations planning, and the ultimate execution and real time support that made this application of FPWD technology a success.

Numerical analysis of the effects of downhole dynamic conditions on formation testing while drilling

“…FTWD can not only carry out the function of WFT, such as fluid sampling, pressure and temperature testing, but also can be used for detecting annular pressure and original formation pressure in real time to optimize mud formulation and improve drilling safety. FTWD is suitable for the formation testing of extended reach wells and horizontal wells and hence can reduce the drilling time and cost over WFT (Hou et al, 2005;Lee et al, 2004;Finneran et al, 2005;Pop et al, 2005;Proett et al, 2003;Seifert et al, 2005;Fey et al, 2011;Masoud et al, 2009;Di et al, 2012a;2012b;2012c). So far only major international oil service companies have developed their own FTWD tools, such as StethoScope developed by Schlumberger, TesTrak developed by Baker Hughes and Geo-Tap developed by Halliburton.…”