Directional Drilling Technology

OVERVIEW

• Directional drilling has long been accepted as a means of controlling well bore deviation. In earlier times, it was primarily used as a remedial operation, either to deviate around stuck tools, bring a well bore back to vertical, or for relief well drilling.

OVERVIEW

• The first step in any directional drilling project is to develop a proper well plan.

• Most directional well plans contain a build interval to a required inclination. This average inclination is then maintained into the target or expected production zone. Some well plans also incorporated a drop section near the bottom such that the production zone is penetrated at, or near, vertical.

OVERVIEW

• Once the inclination in the well bore has reached the planned average angle, rotary drilling will resume with well stabilized, or packed, assemblies. This type of assembly is designed to resist making any changes in inclination or direction.

Definition Directional well is the science of

deviating a well bore along a planned course to a subsurface target whose location is a given distance and direction from the vertical.

normally Inc>5 degree, with the planned direction & target

The reason for drilling the directional well

For engineering requirementFor engineering requirement

for for more production & lower more production & lower costcost

Multiple target

zones

1.The reason : for

engineering requirement

Relief well

drilling

Straight hole

control

Side trackingSalt dome Salt dome drillingdrilling

Inaccessible locations

Extended reach drilling

Offshore production well drilling

The all the applications

• Conventional directional wells 3--15% more cost than vertical wells 10--150% more production than vertical wells

• Conventional horizontal wells 10--40% more cost than vertical wells 300--500% more production than vertical

wells

2.The reason - more production & lower cost

• exposure in vertical hole: 10m

• dir.well (400 ): 13.1m ,600: 20m, 800: 57.6m

• horizontal well (300--500m lateral): 300--500m or more

Example: Thick 10m reservoir

Vertical hole400600800

• save rig site area:

Example: Onshore cluster wells (4--10 wells)

--increase only 10--40% area compare with 1 well.

• Reduce oil-pipeline length(branch line)

• greatly reduce operation & maintenance cost

Advantages of directional wells

• Conventional directional well

• Cluster well

• High angle well

• Horizontal well

• ERD (Extend reach drilling)

• Multilaterial well

• Slim-hole

Types of directional wells

Conventional directional well

• Normal type

“J”

Vertical section

Building section

Tangent section

target

Conventional directional well

• Type

“S” Continuous

Vertical section

Building sectionTangent section

dropping section

holding section

targettarget

CLUSTER WELLS

Horizontal well and ERD tech.

Multi lateral well

How to drill directional well

• Well design

• Equipment &tools

• Trajectory control

Well design

2 Dimension DesignFor Slant Well

L1 Measured Depth of Kick Off pointB1 Build Rate at StartI1 Maximum Angle L2 Length of Hold Section

2 Dimension Design For S Well

Kick-off

L1

L3

L2

B1

B2I1

I2

L1 Measure Depth of Kick OffB1 Build section I1 Maximum Angle L2 tangent(hold) sectionB2 drop sectionI2 Final InclinationL3 Final Hold section

Directional well trajectory design

Directional well trajectory design

Best result

PROFILE --Multi-target of directional well

设计

1--RIH weight (simulate)

2-- POOH weight (simulate)

3--off bot. Rot.torq (simulate)

4--actual RIH weight

5--actual POOH weight

6--actual off bot. Rot.torq

T & Q analysis --12-1/4” hole

Equipment &tools

Equipment• Single shot (high temperature)

• Electronic multi shot• SST -Survey Steering tool

• MWD (measure while drilling)

• Gyro orientation and survey

• LWD (Logging while drilling)

• Geo steering

Single shot

• One run only get one survey

• usually for vertical hole /shallow section of dir.well

• very low cost• easy to use

Single shot reading

Electronic multi shot

BatteryESS electronics

Computer Printer

•One run get plenty of survey data

•use it just before tripping out

•use it with no pump on

•low cost & easy to operate

Survey instruments--SST

MWD RIGUP

MWD

MWD RIG-UP

•Measure while drilling (orient /rotary /sliding)

•Survey in bore-hole

•save drilling timerun in with drill-string, continuous take survey while drilling and transmit data to surface in real-time through mud pulse

3 TYPES OF MWD PULSE

Positive pulse negtive pulse continuius pulse

Gyro

Gyro orientation and survey

LWD

•Logging while drilling•Directional Drilling

•Evaluation (GR, Res, Neu, Den) - Wireline Replacement•Geosteering•Horizontal and Extended Reach Well Logging

DGR®

sensorEWR®

sensor

SFD®

servicesensor

CN®

servicesensorX/OPulser

EWR-PHASE 4™ sensor

LWD Tool Combinations

Geosteering Tool (GST)

GST Features and Benefits

Planned Well Trajectory

GeoSteering

Steering 30 ft behind

Directional tools Down Hole MotorsDown Hole Motors Nonmagnetic Drilling CollarsNonmagnetic Drilling Collars

Bent SubsBent Subs

StabilizersStabilizers

Casing Section Mill & Side Tracking Casing Section Mill & Side Tracking Tools Tools

Conventional down-hole tools

Mud motor

Adjustable stab.•Adjustable gauge stabilizers allow changes in the build or drop tendencies of directional drilling assemblies in rotary mode without tripping to reposition stabilizers or change the gauge.

•The inclination tendency of the BHA can be manipulated while in rotary mode.

•More time rotating means more efficient weight transfer, better hole cleaning

• higher quality wellbores with greater reach capacity all with fewer trips for BHA changes.

•Suited for extended-reach and horizontal well applications.

How AGS Works

• The AGS tool operates by extending pistons located in the full-wrap stabilizer blades. A simple indexing system cycles alternately between full and undergauge positions and holes the tools in position as long as the pumps are on. With pumps off, the pistons retract below the blade diameter. Turning the pumps on again extends the pistons to the next position.

Trajectory control

building section• Conventional rotary techniques and equipment

are first used to drill down to the kick-off point. • special mechanical deflection tools are tripped

into the well and oriented in the proper direction. These tools are used to initiate correct deflection and direction of the well bore. Depending on the situation, deflection tools may continue to be used throughout the entire build interval.

• modified rotary building assemblies may be utilized to continue drilling the build section

• Choose proper KOP• choose proper B.rate • Formation is not too hard• To control bit drilling along designed hole

profile have to use

-- proper BHA /drilling parameter

-- Special down hole tools & survey system• Trajectory predicate and software

building section

Old way for orientation

bent sub + dyna drill bit jetting

building section

5"DP

5"HWDP 196

8"FJ &J AR

8"DC 47 8"MWD 8"NMDC 9.5

16- 3/4"STAB

9- 1/2"PDM

17- 1/2"BIT

•Using PDM + Bent sub /steering motorBHA

Steerable drilling System & trajectory control

PDC/ bitDownhole motor

MWD/survey tools

steerable drilling BHA

Building with PDM motor (sliding)

building section

• good hole condition

• Keep toolface steady (smooth drilling)

• true Az=surveyed Az±mag.decl.

• Keep Az steady before finish building.

Drill tangent section

• Once the inclination in the well bore has reached the planned average angle, rotary drilling will resume with well stabilized, or packed, assemblies. This type of assembly is designed to resist making any changes in inclination or direction.

dropping section

• If the well plan calls for the inclination to be decreased near the bottom of the well, rotary dropping assemblies may be used to drill the well to its planned depth.

• Choose proper BHA depends on drop rate

• Choose proper drop point• choose proper drilling parameters

dropping section

5"HWDP 180

8"FJ &J AR

8"DC 63

8- 1/4"STAB 6- 1/2"MWD 6- 1/2"NMDC 9

8- 1/4"STAB

6- 1/2"S. DC +SUB

8- 1/2"BIT

•We can use pendulum or steering motor BHA•Decide length from bit to1st Stab according to drop rate required.(.5--10 /30m drop rate choose S.DC with3.5--5m length)

Conventional BHA

bitmotorBent/sNMDCDCjarHWDP

DP

BUILDANGLE

BUILDANGLE

HOLD/ BUILD

HOLD/ DROP

HOLDANGLE

DROPANGLE

DROPANGLE

Changes in Directional Drilling Practices

Late 1970’s Newest in

world

Late 1980’sSingle Shot/

wire-lineSteering Tool

Bent Sub

Straight Motor

MWD

SteerableBentHousingMotor

MWD

Motor withAt-BitInclination/Gamma

Cluster well technology

--Bohai fast drilling project

Cluster well technology

• Cluster wells is a group of directional wells (1 vertical well) at a rig-site

• distance between well slots is about 1.5 -- 5 m

• save time & cost

Cluster well technology•350m difference at pay-zone

•1850m disp for longest hole

•Control 10.75 km2

of produced area in

JZ9-3W oil field

3D PROFILE OF CLUSTER WELLS

Applications of cluster well

• Increase oil field integrated benefit

• increase recovery speed

• increase drilling speed

• optimize rig position

Batch drilling of cluster wells

1.SLOT: 4 X 4

2.DIST BETWEEN SLOTS:1.5 X 1.7

Batch drilling of cluster wells

1

11

168

14613

124

15

1029

7

5

3

1.batch drilling for surface casing:

jump for slots

2.cementing with no rig time

3. 4.9 hrs complete surface casing jobs

(SZ36-1-J in 1994)

Horizontal well and ERD tech.

Horizontal Well Type ClassificationHorizontal Well Type Classification

• Short Radius: 1°-9°/M

special downhole tools

• Medium Radius:6°-22°/30M

some special downhole tools

• Long Radius: 1.5°-5°/30M

Steerable Assemblies

Short Radius

45' 200'

Medium Radius

300' 2,000'

Long Radius

1,400' 4,000'

Radius ClassificationsRadius ClassificationsHole Size 2 - 5

deg/100 ft6 - 20

deg/100 ft21 - 60

deg/100 ft61 - 180

deg/100 ftTool Size

12.25" Long Radius MediumRadius

7.75" - 8"

9.875" Long Radius MediumRadius

6.75" - 7.75"

8.5" Long Radius MediumRadius

IntermediateRadius

6.5" - 6.75"

6 - 6.75" Long Radius MediumRadius

IntermediateRadius

Short Radius 4.75"

4.75" MediumRadius

IntermediateRadius

Short Radius 3.5" - 3.75"

3.75" - 4.5" IntermediateRadius

Short Radius 2.875"

Horizontal ApplicationsHorizontal Applications• Increase Formation Exposure

•Minimize Water and Gas Coning

Horizontal ApplicationsHorizontal Applications• Vertically Fractured Reservoir Formations

Basic Horizontal Well ProfilesBasic Horizontal Well Profiles

• (a) Single Build

Long and Medium Radius• (b) Double Build

Long Radius:Where Shallow Hole Does Not Support High Build Rates

• (c & d) Build-Hold-Build

Long Radius, Multi-well Structures

Medium Radius

Short Radius-- Advantages

• Shorter curve section

• Minimum departure allows accurate structure definition

• KOP is closer to the reservoir

• Multiple laterals possible from a single well

• Minimum measured depth

• Easy reentry of existing wells

Short Radius-- Disadvantages

• Specialized drilling equipment

• Unconventional drilling techniques

• Restricted hole sizes (4-1/2” - 6-1/2”)

• Poor azimuth control in horizontal section (rotary)

• Presently cannot be logged

• Completion options are limited

• Time consuming (multiple BHA changes/low ROP)

Medium Radius- Advantages

• Less down-hole exposed compared to long radius

• May result in less torque and drag

• Long reach may be achieved compared to short radius

• Wider range of completion options compared to short radius

• Less restriction on hole sizes compared to short radius

• Multiple laterals possible from a single well

Medium Radius-- Disadvantages

• Some specialized tools may be required such as double-bend BHA

• Difficult hole cleaning in building section• Bending stresses cause more rapid

fatigue of BHA• Non-API connections and more expensive

casing and tubing may be needed• Large dogleg severity restricts logging

and completions options

Long Radius-- Advantages

• Lower dogleg severity

• Long lateral section

• Higher departure possible from surface location

• Adaptation of conventional techniques and equipment

• Improved performance due to more rotary drilling

• Fewer restrictions on hole/equipment sizes

• Can be drilled with steerable motor assemblies

Long Radius

Disadvantages:• Well path must be controlled over a greater

length• Potential for more problems due to length of

openhole section exposed• Greater overall measured depth• Possible cost increase• More casing required

QK17-2 West

cluster wells

QK17-2 East

ERD wells

ERD in Bohai China