L6-DD Fundamentals and Directional Well Planning

7/28/2019 L6-DD Fundamentals and Directional Well Planning

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Lecture

6:

DIRECTIONAL

DRILLINGDirectional Drilling Fundamentals &Directional Trajectories

Arun S Chandel

Assistant [email protected]

09997200339

1


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Segments of Deviated Well


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Major Directional Well Profiles


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Directional Drilling Terminologies

KICK-OFF POINTThe kick off point is defined as the point below the surface locationwhere the well is deflected from the vertical. The osition of the kick

off depends on several parameters including: geologicalconsiderations, geometry of well and proximity of other wells.

The maximum permissible build up /drop off rate is normally

determined by one or more of the following: The total depth of the well Maximum torque and drag limitations Mechanical limitations of the drill string or casing Mechanical limitations of logging tools and production strings.

T h e o p t i m u m b u i l d u p a n d d r o p o f f r a t e s i n c o n v e n t i o n a l

d i r e c t i o n a l w e l l s a r e i n t h e r a n g e o f 1 . 5 0 t o 30 p e r 1 0 0 f t ,

a l t h o u g h m u c h h i g h e r b u i l d u p r a t e s a r e u s e d f o r h o r i z o n t a l a n d

m u l t i l a t e r a l w e l l s .


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INCLINATION ANGLE

The inclination angle of a well at any point is the angle the wellboreforms between its axis and the vertical, see Figure 11.11.

MEASURED DEPTH

from one reference point to the survey point. Measured depth isalso known as Along Hole Depth and is measured with the pipetally or by a wireline.

True vertical depth (TVD) is the vertical distance measured from

a reference point to the survey point. TVD is usually referenced to

Northing: Horizontal distance between one survey point and theRKB, measured to the North. A distance to the South is generally

eno e as e ng nega ve.

Easting: Horizontal distance between one survey point and theRKB measured to the East. A distance to the West is eneralldenoted as being negative.


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Azimuth & Departure

The azimuth of a wellbore at any point is defined as the direction of thewellbore on a horizontal plane measured clockwise form a northreference. Azimuths are usually expressed in angles from 0-360 ,measure rom zero nor .

Azimuths can also be expressed in a quadrant system from 0-90measured from north in the northern quadrants and from south in thesouthern quadrants. The azimuth reading of 135 equates to S45 E inquadrant readings.


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Azimuth and departure


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N

AB

C OEW

84

tD

n

D

1852

S

AZIMUTH = 272.6 de rees

0

.

eD


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HorizontalDeparture:

2 2

t e nD D D= +

Azimuthof

the

well ( )= 1tan eD

n


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Given the following grid coordinates, determine the departureand azimuth of the target from the surface location.

Grid Coordinates: Target6,334,400.00 N (m)200 600.00 E m

Grid Coordinates: Surface

6,335,000.00 N (m), .


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Circular Functions


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Circular Functions


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Radius of curvature


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Radius of curvature


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Build-up Rate Formula


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Determining End of Build


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J-Profile (departure >R)


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J-Profile (departure < R)


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S-Profile (R1+R2 < total target displacement)


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S-Profile (R1+R2 > total target displacement)


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Whats Best?


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ManualDesign:Build&HoldTrajectory(JProfile)


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ManualDesign:Build&HoldTrajectory(JProfile)

To carry out the geometric planning for a Type Iwell, Figure 11.13, the following information isrequired:

-

Target Co-ordinates

TVD of target

TVD to KOP

Build-u rate


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Base Equations

Using the detailed trigonometry shown in Figure 11.13, themaximum inclination angle max for type I trajectory can becalculated for two cases:


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Base Equations


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Base Equations


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Problem:Build&HoldTrajectory(JProfile)

Following data is given for a directional offshore

we r e as -pro e:

Kick-off point (K) = 1000

Build Rate BUR = 2.50 100

Target data

True vertical depth (V3) = 9500Northings (Dn) = +3507

Eastings De = -1752


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Find the following:

1.Horizontal Departure (D2)

2.Azimuth of the well ( )

.

4.End of build at TVD (V2)

5.End of build at departure (D1)

6.Measured depth at end of build (OE)

.


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O

CK

A

v1

R

B

Rv2

E

v3

xy

T

D2

1

L6-DD Fundamentals and Directional Well Planning

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