21.1 Designing the wellpath

The well planner has to consider all of the following criteria when designing the original wellpath;

1. Is the design drillable in the formations it encounters?
2. Are the doglegs practical from a Torque and Drag standpoint, drillpipe fatigue, casing wear, formation damage, the potential for positioning ESPS or other dogleg dependent completion equipment?
3. Does the design hit the target with confidence?
4. Does the design avoid other wells safely and avoid geo hazards?

Once the well plan has been created the first time, it will only be a geometrical solution which may need reviewed in the light of experience.

The following shows some of the feedback from the field and some possible remedies that will ensure that the well plan is improved for the next iteration:

Problems

1. Shallow formation can’t take the build rate.
2. Rotating the tangent drops 0.5 per 100.
3. Formation at 6700 to 6800 TVD is too soft.
4. Can’t get RSS to go above 5.2 degs/100.
5. Formation tops are always early.
   

*Remedie*s

1. Build at 1 then 1.5 then 2 in shorter sections.
2. Design the tangent as a 0.5 per 100 drop.
3. Either pass through at low inc or design a drop.
4. Use the RSS actual DLS value in the design.
5. Compensate to observed depths.