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Technical Paper: HP/HT Exploration Well in Offshore Malaysia Pushed Automated MPD System to Maximum Utilization, Identifying Safest Drilling Operating Window

Society: SPE
Paper Number: 167930
Presentation Date: 2014
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Abstract


TTD-1 has been identified as the deepest HPHT well ever drilled by PCSB in Malaysia. Managed Pressure Drilling (MPD) enabled the Operator to drill and explore new sands and confirm new hydrocarbon reservoirs at 325 degrees F with an undisturbed bottom hole pore pressure of nearly 15,000 psi. The MPD technique in conjunction with the best HPHT practices was able to overcome challenges while drilling this exploration well. Challenges included

  1. Abnormal pressure ramp-up (greater than 17 psi/ft)
  2. High pore pressure steps in new sands
  3. Identifying and controlling wellbore breathing
  4. Controlling losses on the HPHT tight window zone

Technology and practices, including well control, HPHT drilling practices, pore pressure prediction and MPD, were integrated by the Operator during the planning and execution stages. The focus was to integrate MPD and HPHT procedures as well as optimize the available tools to maximize daily drilling footage and maintain the integrity of the well at all times. Annular friction losses (greater than 800 psi) were offset by Surface Back Pressure (SBP) to maintain constant bottomhole pressure (BHP) at all times, except instances when the annular backpressure was reduced for short periods to perform dynamic flow checks. Dynamic flow checks were performed every 45 feet measured depth to map the pore pressure. One of the dynamic flow checks identified one pressure step increase (greater than 1.0 ppg) and a 0.5 bbls gain on the trip tank at the same time. The dynamic formation integrity test (FIT) was successfully implemented to identify the upper limit of the operating window.

Proper application of these MPD procedures identified the minimum operating window as 1.0 ppg and guided the Operator to call for TD of the well. The well was drilled to a depth of 4,830 m, and thus penetrated vast gas bearing reservoirs. This technical paper aims to share a case study of HPHT drilling practices combined with Automated MPD successfully adopted to explore new sands with minimal offset geological and petrophysics information.

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