Abstract Currently, well control events are almost exclusively detected by using surface measurements. Especially in deepwater, where the riser comprises a substantial section of the wellbore, early kick detection is paramount for limiting the severity of a wellbore influx and improves the ability to regain well control.
While downhole data is presently available from downhole tools nearby the bit, available data rates are sparse as wireless telemetry bandwidth is limited and wellbore measurements compete with transmission of other subsurface data. High-bandwidth downhole data transmission system, via a wired or networked drillstring system, has the unique capability to acquire real-time pressure measurement at a number of locations along the drillstring.
The paper describes the four processes to improve well control for deepwater operations through the use of downhole data independent from surface measurements. First, networked drillstring provide efficient kick detection and the identification of ballooning zones. Gas inside the riser is also detected and decision support is offered between using the mud-gas separator or diverter. Second, a methodology is proposed using direct measurement of downhole real-time pressure for maintaining constant bottomhole pressure during well kills in deepwater. Third, downhole surge and swab pressures are available through measurement while tripping system. Fourth, well control barriers are verified using downhole information, independently from surface data. All of these workflows allow for higher levels of automation, supporting wellsite personnel and improving the safety of operations. The paper presents examples of field data that illustrate these cases.