Ultrahigh-pressure/high temperature (UHP/HT) wells are very challenging because of the narrow drilling margins, which can cause either losses or an influx. In a field in Malaysia, the pore pressure and fracture gradient were too close to allow conventional drilling, so the managed pressure drilling (MPD) technique was used to drill these wells.

Cementing under MPD is a new technique in this area. A technical assessment revealed that there is limitation in the currently used cementing placement simulator in that it cannot simulate the real-time MPD cementing placement. The current hydraulic simulator does not account for automated real-time annulus choking to apply the backpressure and safely place the cement in the annulus. In addition, it does not take into account the downhole viscosity change due to pressure and temperature effects and which is not imposed by the testing protocols from API. To check the effect of the downhole conditions on the fluid viscosities, which will have an effect on the friction pressure in the annulus during the placement, and to reduce the risk during the cementing job, two in-house hydraulic simulators were identified and used to benchmark the currently used simulator results; the design workflow was changed to account for the additional simulations, and the new technique was implemented successfully to cement under MPD conditions.