PATHPLANNER 3D
WELL PLANNING MODULE

Simplified 3D Well Planning

The planning of a directional well path has never been simpler. PathPlanner is now available for the planning of complex well paths in three dimensions. If you can dream it, PathPlanner can plan it.

Segmented Analysis

PathPlanner plans your well in segments. You define ending points for segments based on attitude (inclination and azimuth)or coordinates (north, south, TVD). The segment options available include:

Straight Line Segment Options
• Ending Measured Depth
• Ending True Vertical Depth
• Ending North Coordinate
• Ending East Coordinate
• Ending Displacement
  
  Two Dimensional Segment Options
• Ending TVD and DogLeg
• Ending Measured Depth and DogLeg
• Ending Inclination and DogLeg
• Ending Inclination and TVD
• Build and Hold
  
  Three Dimensional Segment Options
• Ending Coordinates
• Minimum Energy
• Build and Hold
• Ending Direction and DogLeg
• Ending Attitude and DogLeg
• Ending Coordinates (S-Curve)
• Double Arc

Special Features

• multiple wells on a single plan
• auto sidetracking feature
• 3D visualization
• Kick-Off Point and Curve calculators
• Unlimited targets

Minimum Energy 3D Well Planning Segment

Minimum energy is a new algorithym for PathPlanner that attempts to provide a realistic approach to wellbore curvature. This unique segment is explained below:

Minimum Energy builds a complex wellplan based on a model of the drillstem. Probably the best way to understand what's happening here is with a 'hands on' description. Find a thin straight flexible steel rod. Grab the rod with both hands, one hand at each end. Now apply some pressure to the rod so that it flexes. Don't apply so much pressure that the rod holds a bend, it should return to it's original straight form when released. We now have a flexed rod constrained at it's endpoints. Note that the rod always forms a nice looking natural curve. Note that these curves look very much the same if one interchanges the steel rod with a different rod that has a different diameter or is made of some other steel. These natural curves are known as the minimum energy curves of the rod. They are called minimum energy curves because these are the curves which require the rod to retain the minimum amount of elastic energy in order to meet the imposed constraints. This property is what makes these same curves ideal for directional drilling. Minimizing the retained elastic energy minimizes the friction due to forces upon the walls of the drillstem. The astute observer might note that using endpoint constraints would appear to concentrate the forces at the endpoints. It does. Concentrating forces elsewhere would lead to excessive friction along the segment and poor communication of power between the endpoints.

Here's how to use the minimum energy algorithm. If a course length of 0 is entered for a minimum energy curve then PathPlanner will propose a course length. To find the best curve the course length should be varied and the results examined until a 'suitable' curve with a low maximum dogleg is found (the maximum dogleg is just the highest dogleg on the proposed section). What precise course length should be used will be left to the operators discretion. This is MUCH easier to do in 'Update data dynamically' mode (see the Options Dialog to change this mode). It's definitely recommended that you play with this a bit to get a look at the different curves produced.

Get a temporary segment displayed that has a different attitude at the target and at least 10 segments or so. Try lowering the course length until you start getting error messages, then raise it back up a little until you get a curve again. You should be getting a curve with fairly exteme dogleg near the endpoints, a flat midsection, and a short courselength. As one raises the courselength you should notice the extreme doglegs near the endpoints come down until you reach a point where the maximum dogleg's are no longer at the endpoints, but within the midsection of the segment. The initial region will likely be most useful where one can afford the higher dogleg and will accept that in favor of 'excessive' course length. Typically this situation would arise in situations where the wellplan is long in relation to the flexability of the drillstem and the change in attitude is not excessive. As one continues to raise the courselength the value of the maximum doglegs will continue to come down and the position of the maximum doglegs will move towards the center of the segment. This region is likely to be more useful where the courselength of the segment is short in relation to the flexability of the drillstem and there is significant change in attitude. As one continues to raise the course length the drops in maximum dogleg will become less significant, the maximum doglegs will merge, and the proposed path may adopt loops in order to accomodate the excessive course length. Increasing the dogleg beyond the point where the maximum dogleg's have merged is likely to be of little use unless truly radical changes in attitude need to occur with a target position that is very close, but that would not be a very efficient plan.

A quick start for minimum energy. The best way to start is likely to find the course length for which the position of the maximum dogleg's has just begun to creep in from the endpoints. If this path looks good then keep it, retained elastic energy should be should reasonably low without excessive courselength. If the doglegs look good but you think you could use less pipe then lower the course length until you are satisfied (more pipe = more weight for significantly horizontal sections). If the doglegs look high then raise the courselength until you are satisfied. One can also match the dogleg at the entry point of the new curve with the dogleg at the tie-in and modest energy reductions will be achieved but these will largely be 'outweighed' by the principal consideration of course length vs. dogleg through the segment.