Well Design Optimization
15 April 2017
Need your opinion on the optimization of a well.
1300 m Depth
Surface Casing - 9-5/8" = 450 m [Spud Mud is used]
Production Casing -7" = 1200m [ PHPA Mud]
Production Liner - 5" = 1300 m [ KCL Polymer- Drilled Blind in case of severe losses]
Now, the surface section is drilled to the first known gas zone, and it is drilled without a diverter, and drilled with spud mud within a day or two. The second section is drilled within 4-5 days which has two shale zones that need to be cased off as soon as possible.
The third section is drilled within a day in the payzone,which is a highly depleted limestone formation [ ~ 800 psi], hence the additional hole section.
Now, there was an option of combining the last two section and then cementing using stage cementing, but it has its own drilling risks, in case of losses, the whole section above it would loose the hydrostatic.
The well takes around 12-14 days at an average, and we need to reduce it more, the flat times have been optimized at max. Bit designs have been as aggresive as they can be and we control the ROP at times.
Need to know if anyone of you has any suggestions for further optimizing the well design.