As the development of directional drilling technology, more and more development wells in South China sea are drilled with high inclination which can reduce the rig mobilization cost, maximize the trajectory footprint in reservoir and improve the project CAPEX. At the same time, the formation pressure measurement plays an important role in the reservoir description and completion design. Because the formation pressure acquisition takes stationary time, the conventional cable-conveyed technology cannot fully meet the operation requirement. Therefore FPWD (Formation Pressure While Drilling) technology is developed to fit for the needs from high inclination wells.
FPWD technology essentially takes probe, setting piston, precise pressure gauge built into a collar which can be compatible with all other LWD (logging while drilling) tool. When taking the pressure measurement, the setting piston pushes the whole tool to contact the borehole wall and creates a fully sealing volume between tool and formation pores. Then the probe draws the fluid to create the pressure re-equilibrium which will be recorded by the pressure gauges. Formation pressure is then derived from the recorded pressure profile. In order to minimize the stationary time and reduce risk, the optimization approach within tool is also developed to automatically choose acquisition parameters within preset time limit (Julian et. al, 2005).
With the enabling of formation pressure measurement from FPWD technology, various applications have been tried in high inclination development wells in South China sea. It includes reservoir energy depletion profile determination, fault sealing determination and artesian gas injection optimization etc. FPWD provides the critical information for the reservoir description and production enhancement in South China sea (Shusheng et. al, 2011).