drilling with casing 01

8/22/2019 Drilling With Casing 01

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BBL Dri llShoeTM

Information PackMay 2002 Version

CONTENTS

1. Overview of Drilling with Casing

2. What is a DrillShoe?

3. Facts and Figures about DrillShoes

4. Applications & Case Histories

5. Quality6. Cutting Structures

7. Hydraulics

8. DrillShoe Nose

9. DrillShoe Body

10. Running Procedures

11. Technology Developments

This Information Pack has been produced as an Introduction to BBL DrillShoes.The technology incorporated in these tools is new and is developing quickly.

If in any doubt, please contact the BBL staff listed below.

This version is accurate as of the date printed above.

Further revisions will be made as and when required.

BBL Downhole Tools Ltd Mike Wardley +44 1224

293656Suite 9, McNeil Business Centre [email protected]

Greenbank Cres., Jim Bain +1 713 973 9014

Aberdeen [email protected] 3BG Mitch Bavidge +44 1224 293663

Scotland [email protected]: +44 1224 293660

Fax: +44 1224 293669


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1. Overview of Drilling with Casing

Drilling with Casing is a new technology where the casing string is used as the drill stringinstead of drill pipe. To date, the technology has had limited exposure in worldwide oilfield

terms, with probably less than 200 applications. With the exception of a few experimental

wells, casing has been used to drill specific sections of the wellbore, rather than the entire

hole.

Drilling with Casing comes in two flavours. In one arrangement, a hydraulic motor islatched into the lowermost casing joint along with a packer. The casing is advanced by

pumping through the motor, in much the same way as slide drilling is accomplished

conventionally on drill pipe. When TD is reached, a retrieval tool is run, which has to be

latched into the BHA. Overpull is applied to recover the BHA.

BBL have adopted a different approach. With the BBL system, the casing is simplyrotated, in exactly the same way as drill pipe. A crossover to the top drive is used to

transmit torque. The unique feature of the BBL system is that the drill bit (DrillShoe)is fully drillable this means that once the section is completed, there is no drill bit to

recover through the casing. Cementing can begin immediately and then the next bit is run

and drills-out the shoe track in exactly the same way as a conventional operation.

The BBL system is currently targeted at soft to medium-soft, straight hole sections which

are capable of being drilled with a single bit run. Ongoing and future developments arediscussed in section 11.


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9-5/8 x 12-1/4 DrillShoe with

Tungsten Carbide HVOF

Cutting Structure

2. What is a DrillShoe?

A DrillShoe is BBLs term for a Drillable Casing Drill Bit. The

DrillShoe is made up to the casing in the same way as a conventional drill

bit would be made up to a drill string.

The DrillShoe has a two part construction;

A body, which has the casing connection and a gauge sectionmade from steel, &

A nose, which is made from aluminium alloy, upon which is

mounted a drillable cutting structure.

The two parts are threaded and locked together and the tool is supplied

as a unit, as shown.

In the applications to date, two cutting structures, composed of denseTungsten Carbide or Thermally Stable Diamond have been used.

The nose of the DrillShoe has flow ports or nozzles strategically

positioned to clean and cool the cutting structure and flush away thecuttings up the annulus.

The entire unit is fully drillable with PDC or roller cone drill bits.

When the casing is rotated, the cutting structure cuts the rock with a

shearing action, in the same way as PDC cutters on a

conventional drill bit.

When TD is reached cementing can begin immediately a

non-return valve may be incorporated in the DrillShoe and / or

float collars in the casing string.

After waiting-on-cement the next drill bit is run and drills

through the shoetrack and DrillShoe before entering virgin

formation.


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3. Facts and Figures about BBL DrillShoes

Invented in Nov 1999 for drilling in surface casing in the Gulf of Thailand

Designed in collaboration with Unocal Thailand

First tool run in Jan 2000

Became the Standard Technique in the Gulf of Thailand by Apr 2000

Patents applied for in 1998/99/2000

Smallest Tool (to date) 5 x 6-3/4

Largest Tool (to date) 20 x 24

48 tools run to Nov 2000 with eight customers with a 100% success rate

A total of 68 tools delivered (to Nov 2000)

The Original 1999 Design

This design (7-5/8 x 9-7/8) had HVOF cutting

structure on high blades and a Cutrite

reaming action.


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4. Applications & Case Histories

Applications to date have been extended to drilling-in surface casing from jack-ups and

platforms, second strings after setting conductor pipe or drilling with liners. In the Gulf of

Thailand, the Standard Procedure for drilling and setting surface casing is to use a DrillShoe.

- Gulf of Thailand - Jan 2000 Case History No.1

Well No. Yala 6

Casing String 9-5/8 Surface Casing

Connection Buttress

Distance Drilled 690 ft

On-Bottom Time 2.3 hrs

Average ROP 300 ft/hr

Running Parameters

WOB 0-10 klbs

RPM 60-150

Torque 2 - 7 kftlb

Flow 790 gpm

Comments

Coal stringers caused torque spikes and reduced overall ROP.

Drilled-out with BB452 in 15 mins Pulled-back and Reamed DrillShoe Bit Damaged

- Gulf of Thailand - Feb 2000 Case History No.2

Well No. Arthit 15-3X


Connection Buttress


Total / On-Bottom Time 6.0 / 1.3 hrs


Running Parameters

WOB 2-12 klbs

RPM 50 90

Torque 1 - 2 kftlb

Flow 870 gpm

Comments

Very fast run.

Drilled-out with BB452 in 10 mins - No Damage to Bit.

- Chevron Thailand - May 2000 Case History No.3


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Well No. Kung 2


Connection Buttress


IADC Time 2.9 hrs

IADC ROP 239 ft/hr

Running Parameters

WOB 2-10 klbs

RPM 50 90

Torque 1 2.5 kftlb

Flow 870 gpm

Comments

Overall ROP reduced, slow progress through rotary with straked casing.

Drilled-out with PDC bit - No Damage to Bit.

- Vietnam - Jun 2000 Case History No.4

Well No. 48/95-TDD-1X


Connection Buttress


Total / On-Bottom Time ? / 2.5 hrs


Running Parameters

WOB 4-16 klbs

RPM 110

Torque 0.5 2.0 kftlb

Flow 850 gpm

Comments

First 550 ft, drilled at 460 ft/hr

Slowed down over last 180ft Firmer Formation


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- Unocal Indonesia - Jul 2000 Case History No.5

Well No. YN-23HZ


Connection Buttress


On-Bottom Time 1.3 hrs


Running Parameters

WOB 24-13 klbs

RPM 40 100

Torque 1 3.5 kftlb

Flow 400-800 gpm

Comments

Drilled thru three sand stringers at about 30 ft/hr

Drilled-out with PDC bit - No Damage to Bit.

- Chevron USA - Nov 2000 Case History No.6

Well No. Viosca Knoll 70 #1 WB1

Casing String 13-3/8 Second String

Connection Buttress

Distance Drilled 729 ftROP Variable (>400 ft/hr in sand / < 50 ft/hr in Gumbo)

Running Parameters

WOB 2 - 15klbs

RPM 50 - 60

Torque 2 3 kftlb

Flow 930 gpm

Comments

Drilled out with Roller Cone Bit

Design has been improved to cope with Gumbo

First Run with

Diamond (TSP)

Cutting Structure

First Gulf of Mexico Run


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- Phillips Australia - Nov 2000 Case History No.7

Well No. Coleraine ZOCA 96-16

Casing String 7 Liner

Connection New Vam

Distance Drilled 179 m

Running Parameters

Torque


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5. Quality and BBL

BBL has ISO9001 accreditation covering Design and Manufacture of Drill Bits and

Downhole Tools. BBL gained accreditation in 1993. BBL is accredited by Det Norske

Veritas (DNV). DNV is one of the worlds leading quality assurance organisations.

All BBL DrillShoes are manufactured to set procedures and a Certificate of Conformance is

issued with all tools.

Where the thread is cut before despatch from BBL, we will include a copy of the third party

licensees thread certificate.

All tools are drifted to API 5CT Specifications or to special drift requirements if specified in

the order.


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6. Cutting Structures

Two cutting structures are available and field proven; tungsten carbide and thermally stable

diamond. Both cutting structures have been designed to be fully drillable with any type of

oilfield drill bit, without damage to the drill bit cutters.

1st

Generation tools utilise a hard and dense layer of tungsten carbide (TC) as the cutting

structure. The layer can be between 0.006 and 0.120 thick depending on application. TheTC is applied using a proprietary process known as High-Velocity-Oxy-Fuel (HVOF), the

photograph below shows the TC being applied to a 1 subsea gate valve. HVOF tools are

designed for the very softest of oilfield formations.

The HVOF process involves firing minute particles of TC at the workpiece at supersonic

speeds. Upon impact the particles weld themselves to the workpiece. The result is a hard,

non-porous coating which has a very high bond strength to the underlying material.

BBLs 2nd

Generation tools utilise thermally stable diamond (TSP) where the formations are

too firm for HVOF. TSP has about 10x the hardness of TC and is able to drill formations

effectively where TC would wear out. Pre-formed monolithic pieces of TSP are attached to

the aluminium nose by a proprietary process.

Applications of these cutting structures to drillable tools have been patented by BBL.

7. Hydraulics

Originally, all DrillShoes were run with open ports. This was because interchangeable drill bit

nozzles are constructed from tungsten carbide and are simply not drillable. Typically the TFA

with open ports has been about 5 sqin, to avoid eroding the soft aluminium nose of theDrillShoe. The DrillShoe pressure drop is about 40 psi and the HSI is


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8. DrillShoe Nose

The leading end of the DrillShoe is termed the Nose. The nose of the shoe is fully drillable

with any standard oilfield bit.

An Aluminium material has been specifically chosen to allow the bit to drill through the noseeasily. In addition, BBL DrillShoes incorporate chipbreakers into the tool nose to ensure that

the aluminium cuttings do not birds-nest the drill bit.

Chipbreaker Holes Small Chips during Drill-Out

(Note: The material and internal design of the Nose are identical to the Award Winning BBL

Reamer Shoe. Over 1250 of these tools have been run worldwide with not a single instanceof bit damage when drilling-out).


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9. DrillShoe Body

All DrillShoes are box-up. The tool has a single-piece integral box connection, BBL does

not use a coupling, and the casing pin can be stabbed straight into the tool.

DrillShoe bodies are made from AISI 4145 steel, unless otherwise specified. This is thesame grade of steel as used for the manufacture of drill collars.

In terms of casing grades, 4145 is superior to P110. So for a casing string of P110 or

lesser grade, the tool is inherently stronger than the casing. Even if the casing grade is

higher, say Q125, the DrillShoe is never the weak link in the chain, since wall sections are

always thicker than the corresponding casing. If required, BBL can supply minimum burst andcollapse pressures for DrillShoes.

Stabiliser blades are a feature of all DrillShoes. BBL DrillShoes incorporate ground

Tungsten Carbide stabiliser blades as standard. The blades stabilise the DrillShoe in thesame way as the Gauge Pads on a Drill Bit.

At the uphole end of the stabiliser blades, a backreaming facility is included as standard.

These Cutrite carbide blades ensure that the tool can be used to back-ream if necessary.

This feature is particularly useful in swelling shale formations, where the formation may be

continuously moving.

The hard faced stabiliser blades provide good stand off at the shoe for an improved cementjob.


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10. Running Procedures (typical)

General Information and Recommendations

The tool is set with high density, HVOF tungsten carbide or Thermally Stable Diamond (TSP)

cutting structure on the front and tops of the blades. The nose of the tool is constructed from

aluminium alloy, which is fully drillable with any type of oilfield drill bit. This tool is very aggressiveand will drill very quickly with low WOB. Aggressive Drilling Tools can generate high torque for

low weight. It is recommended that WOB be kept to a minimum until the torque response

of the DrillShoe is known. This may take a few joints. Applying high weight, too early, may

over-torque the casing connections.

On no account sho u ld the too l be set on bot tom unless

ful l pum p rate and rotat ion have been achieved.

Preparation Prior to RunningUnpack the tool and make the following checks:

Check and record the serial number, tool size and type Confirm no damage to aluminium nose or cutting structure Check that the ports are clear Remove thread protector and check for damage Confirm that there is no debris inside the tool

Making-Up to the Casing Drilling String

Stand the DrillShoe box-up on a rubber mat or wooden board Stab in the casing joint and make-up to normal torque

Pick-up and run casing as per normal procedure until one joint fromtagging bottom.

Make-up casing joint with water bushing

Initiating the Drilling Process

Pump at high flow rate rotate as per the product recommendations Zero the weight indicator, record pump pressure and rotary torque Run down slowly to the mudline, carefully monitoring WOB, torque and pressure

It is recommended that the first joint is drilled down with minimum weight to

establish the hole and give lateral stability to the casing string.

Drilling Ahead Always kick in the pumps and rotate before going to bottom

Increase weight gradually to achieve desired ROP Remember that excessive WOB will reduce tool life

Monitor pump pressure carefully, an increase may indicate bit balling. Pick up off bottom,

rotate at max rpm, and stop and start the pumps several times to try to wash the DrillShoe

clean of cuttings

Drilling Out with a Bit

The aluminium nose is best drilled with med WOB, low RPM and maximum flow rate (if

run on a PDM, reduce flow rate to give a maximum of 150rpm total) Expect to take 5 20 minutes to drill through the nose

Once into the rathole proceed as per the drill bit manufacturers recommendations Do NOT rotate when pulling BHA up thru the shoe unless absolutely necessary


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Drilling Out with a DrillShoe The aluminium nose is best drilled with very low WOB, low RPM and max. flow rate.

Expect to take 10 30 minutes to drill through the nose Once into the rathole proceed as per the product recommendations above Do NOT rotate when pulling BHA up thru the shoe unless absolutely necessary

11. Summary of Ongoing & Future Developments

Displaceable / Retractable Cutting Structures

It is expected that formations harder than medium-soft may require an even more competent

cutting structure than Drillable Diamond. For these applications BBL are developing a

DrillShoe with a PDC cutting structure that is displaced into the annulus after reaching TD.

The next drill bit simply has to drill through an aluminium nose of the DrillShoe and does notencounter any hard obstructions.

Steerability

BBL is looking beyond applications to straight hole drilling and are developing steerable

versions of the DrillShoe. These tools will be run on an orientable BHA suspended below the

casing shoe. Steering is done by orienting the casing and pumping through the motor. To drill

straight ahead, both the casing and the motor are rotated.

At TD the BHA is pulled back to surface, leaving the DrillShoe latched to the casing shoe.

Since the DrillShoe incorporates a non-return valve, cementing can proceed immediately.

Retrievable/Replaceable DrillShoe

The current ranges of DrillShoes are required to drill the entire section to TD. A failure to

succeed may involve pulling the casing string. BBL is actively engaged in a development

process to enable recovery and replaceability of the DrillShoe. This range of tools will allow

the possibility of casing-drilling multi-bit wellbore sections, combined with the advantage of

DrillShoe drilllability.

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