In this drilling campaign, out of 6 development wells, MPD/C were utilized in 4 wells. 1 well utilized both MPD for drilling and MPC for 7" casing installation (Well A) and the other 3 wells (Well B, C, D) were drilled conventionally and conducted MPC for 7" casing installation upon confirmed to have a narrow operating drilling window due to the depleted sands which verified by several MPD dynamic leak off tests (DLOT) during drilling resulted satisfied for conducting MPC for 7" 23ppf casing. In both conventional drilling or MPD wells, the job is guided by the drilling window which consist of the pore pressure/collapse pressure serves as the lower limits and fracture pressure serves as the upper bound of the window.

The ability to control the well pressure profile with MPD system led to the Managed Pressure Cementing (MPC) as the alternative method implemented in this narrow pressure margin wells. MPC was planned in detailed by using the advanced MPD hydraulic modeling to model the surge effect of running in hole casing to setting depth and calculate the surface back pressure required to control the annular ECD/ESD during the different stages of cementing operation. Based on the surface back pressure target, the cementing parameters were designed and modelled accordingly to suit the cementing requirements.

This paper presents the engineering design considerations, execution methods and results of four development wells with MPC operations conducted by closing the annular BOP to create the closed loop system to cement 7" 23ppf production casing strings successfully without losses events.

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