1

The Turbodrill -

An introduction

2

Typical Steerable Turbine

3

Forces and Load Support

4

Moving Disc

Fixed Disc

Moving Disc

Spacer Front Bearing

Labyrinth

Thrust Bearing

Flexible Shaft

Bent Housing

Front Bearing Stabiliser

Bit Box Stabiliser

Turbodrill Bearing Section

Thrust Bearing Components

5

PDC Thrust Bearing

( …or, animated…….)

6

Turbodrill features…

7

Leakage Flow Exits to Annulus

Turbine Shaft

Pressure Equalising Leakage Flow

Micro Annulus

Balance Drum

Housing

Main Mud Flow into Turbodrill

Balance Drum Assembly

Motor Section

Main Flow to Motor Section

Turbodrill Balance Drum Assembly

8

Downhole motors: Turbodrill competitors…

9

Turbodrill and PDM Drive Function

10

PDM Main Technical Features

• Torque / Speed range defined by lobe ratio• Slow enough for tricone bits• Torque variable via WOB• Low pressure demand on rig pumps – 150 psi per stage• Most technology available “over the counter”• Relatively easy to build adequate tool.

But… . . .

11

PDM Main Technical Features, continued

But… . . .

• Motor section limits life and power• Significantly affected by temperature• Readily damaged by stalling• Hydraulic noise, poor radial balance affects MWD

12

Turbodrill Technical Features

• Very high power potential• Intrinsically reliable / Long Life• Near perfect radial balance• No reliance on elastomers for power I.e. heat-proof• Fluid coupling effect.

But… . . .

13

Turbodrill Technical Features, continued

But… . . .

• Speeds too high for tricone bits• High power output - at expense of flow rate • Little application in top hole?• Building a viable and reliable turbodrill is difficult.

14

PUMP PRESSURE DISTRIBUTION12-14" HOLE SECTION

0

500

1000

1500

2000

2500

3000

3500

4000

4500

500 550 600 650 700 750 800 850 900 950

FLOW RATE (GPM)

PRES

SUR

E (P

SI)

Available For TurbineParasitic Losses

Following On…..

15

Turbodrill & PDM . . . .

. . . .What’s the difference?

16

Well bore quality

17Borehole Image with typical profile

generated by PDM + RockbitBorehole Image with typical profile

generated by Turbine + long gauge bit

Reduced hole spiralling effects & smoother well bore.(Hole spiralling negatively impacts measurements, mud, cement, casing running, etc.)- data from image tools would indicate less spiralling than competitors (primarily PDM’s + Rock BIts)

Well bore quality: smooth ? …

18

Well bore quality: Hole Spiralling 1…

19

Well bore quality: Hole Spiralling 2…

20

Well bore quality: Hole Spiralling problems…

21

LONG GAUGE PIN CONNECTION.

NEAR BIT STABILISER.

BOTTOM BEARINGSTABILISER

BOX END SHAFT

LONG GAUGE PIN CONNECTION.

SHORT GAUGE PIN CONNECTION

BOX END SHAFT

BIT BOXSTABILISER

BOTTOM BEARINGSTABILISER

BOTTOM BEARINGSTABILISER

BOX-UPLONG GAUGE BIT.

BOTTOM BEARINGSTABILISER

4.6Ft *

2.6Ft *

2.2Ft*

1.4Ft*

(* typical- may vary)