FE 02-14 Intro to Directional Drilling

Nội dung text: FE 02-14 Intro to Directional Drilling

1. Vertical Hole: Definition • No hole is drilled exactly vertically from spud to TD • It is generally accepted that a straight or vertical well is one that: – Stays within the boundary of a “cone”, as specified by the client (usually about 3 degrees) – Does not change direction rapidly (no more than 3 degrees per 100 feet of hole) and form a “dogleg”
2. Deviation Control: Definition • The process of keeping the hole contained within a prescribed limit relative to the hole angle
3. Directional Wells: Multiple Wells From Platforms • Most common application of directional techniques
4. Directional Wells: Drilling Inaccessible Locations • Targets are located under riverbeds, just offshore, under cities, etc.
5. Directional Wells: Salt Dome Drilling • Used to reach zones lying beneath the overhanging cap of the salt dome
6. Directional Drilling Measurements • Magnetic Single Shot - records inclination, direction and tool face on sensitized paper or photo film • Magnetic Multishot - capable of taking numerous survey records in one run (usu. while POOH); usually dropped down the string and landed on a NMDC • Steering Tool / MWD - Used when a mud motor, bent sub or housing is used • Gyroscopes – used when magnetic surveying tools can’t be used because of magnetic interference of nearby casing
7. Deflection Tools • Whipstock – openhole and casing • Jetting Bits • Positive Displacement Motors/Turbine with Bent Sub
8. Horizontal Drilling: Inverted Drillstrings • In horizontal wells, drillstrings are typically run inverted, with no drill collars. The drill pipe is run in compression, and heavy weight pipe is normally placed in the more vertical portion of the borehole to provide weight to the BHA
9. Measurement While Drilling (MWD): Uses • Directional survey measurements • Availability of near real-time wireline-type information • Geosteering (horizontal drilling application that utilizes resistivity measurements to identify bed boundaries and fluid changes and allows the drillstring to remain in the reservoir)