MODULE 11-DIRECTIONAL DRILLING Flashcards
Define directional drilling?
Controlled deviation of a well bore along a planned course from a starting location to a target location.
Applications of directional drilling?
- reservoir optimization
- multiple exploration wells from one well bore
- to conform to environmental regulations
- relief wells
- Sidetracking
- Inaccessible locations
- Salt dome drilling
- Fault controlling
- Multiwell Drilling
- Horizontal wells
- Extended Reach drilling
- Multilateral wells
What are the 3 well profiles?
J-Type
S-Type
Horizontal
What 3 things must you know to determine the best diametric profile from surface to TD?
- surface position
- target position
- TVD
Define KOP
The depth below surface the well will be deviated in a given directions (start of buildup section).
Define Well Inclination
The angle that the well bore deviated from vertical Common angles (15-60 degrees)
Define EOB
The location where the well inclination has been reached.
Define hold angle
inclination is held constant (AKA Sail angle)
Define tangent angle
The section drilled with at the hold angle (AKA hold section or locked in section).
Define start of drop
where the well bore starts to drop inclination
Define End of drop
where the well bore finishes dropping inclination
Define target displacement
the lateral distance from the surface location to the target (D3)
Define target location
a defined point in space with geographical coordinates and a given true vertical depth
BUR and DOR are defined in?
degrees/30m or 100ft
What are typical BUR and DOR rates?
1-2.5 degrees/30m
example 2.2/30m BUR or -3.2/30m DOR
Define Turn rate
the rate a well turns in azimuth (expressed in degrees/30m or 100ft)
Define measured depth
measured depth from surface to the actual well path.
Define course length
Drilled distance between any 2 points in a directionally drilled wellbore
Define horizontal displacement
distance between any 2 points along a well bore projected onto a horizontal plane or plan view.
Define azimuth
Angle in the horizontal plane measured clockwise from a fixed reference direction (true north)
What is the quadrant bearing of a well?
angle in the horizontal plane measured from either a North or South reference direction towards either or west, defining the direction of the well bore.
When are J-type wells drilled?
where it is not possible to locate the surface location directly above the target or the multi well platform.
What sections are in a J-type well? Draw it!
Straight section, a build section, a tangent section straight to target
When are S-type wells drilled?
to improve the efficiency of the well and to assist in the location of a blown out well. (ensure accuracy in bottom hole spacing in offshore drilling)
What sections are in an S-type well? Draw it!
straight section, build section, tangent section, drop section
What sections are in a horizontal well?
bore with straight section a build section, a tangent section, a second build section, and a horizontal plane
What is spider plot and why is it used?
Viewed directly down a multi-well structure.
Used to show the relationship of the wells with respect to latitude and departure
Describe two instances where it might be necessary to drill directional well?
drilled where a vertical well is required and there is some limitation on the surface.
- offshore structures
- Environmentally sensitive area
- surface obstructions
List the data you will require to be able to properly plan a directional well. Which of the rig parameters are different from a vertical well and why?
Data
- Geology
- Offset well information
- Potential productivity
Parameters
- BHA tools
- Drill pipe/collar
- Mud types
different parameters which are different from vertical wells -derrick -drawworks -setback capabilities mud pump capabilities
In a standard directional plot the predicted well course and the after the fact course are both plotted beginning in one corner of the plot. What does this corner represent.
Represents the surface location
