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The Lisama field located in the middle Magdalena basin is well known as oneof the high pressure areas drilled in Colombia by
ECOPETROL (NOC). Densities up to 21.0 ppg are often reached and side tracks due to hole instability are common in the area,
sometimes as many asthree (3) per well, making plans in days and costs difficult to control.
The use of real time tools such as Pressure While Drilling (PWD) on the Lisama No 167 well demonstrated that only
monitoringthe fluid density at surface is not enough to keep the hole open and stable. Monitoring with PWD demonstrates that
real annulus pressure involves all kind of parameters affecting the mud densityincluding temperature, solids content and
compressibility, so that the real pressure and the Equivalent Mud Weight (EMW) can be determined at any point of the wellbore.
In this directional well, thechallenge for the service company is to use an MWD system that works with high-density fluid
conditions. Conventional systems have an operational limit of 18.0 ppg, so an electromagnetic telemetry...