INTEGRATING REAL-TIME GEOMECHANICS INTO DRILLING OPERATIONS

KYLE GRAVES, SR ENGINEERING ADVISOR, PERTH D&C TEAM MARCH 6 2014

Why What Aha Moments How What’s in it for you

INTEGRATING GEOMECHANICS INTO DRILLING? REALLY??

2

We were planning a very challenging ERD well. Recent Key Failure 2012 – Bambra 10H Lots of Horizontal / High Angle Wells on the NW Shelf

Use offsets and good practices – meet objectives – in most cases

Some wells are more difficult than others – that’s normal right?

WHY BOTHER?

3

BAMBRA 10H – PLAN VS OFFSETS – RESULTS

4

Proposed Bambra 10H & 11H vs. wells reviewed in OWR

MEM RESULTS FOR BAMBRA 10H Previous Apache rock mechanics model Schlumberger MEM (January 2013)

Bambra 10H Hindcast, with MW, ECD and swab loads shown

Static EMW in high-risk zone in several places

But ECDs kept EMW at low-medium risk level when drilling

Results are explainable … • Absence of problems while drilling is not surprising, • But problems on trip out to be expected with 1.25 sg MW

In hind-sight, needed at least 1.35 sg MW from start, increasing to > 1.40 sg near section TD

High Probability of Well Failing to Meet Objectives with Current Design

We were well into the Taunton Planning at this stage Decided to revisit our MEM and see if it would impact our

design Based case plan

Drill pilot hole with 1.25 SG mud Drill 12 ¼” to land with 1.25 SG mud Drill 8 ½” lateral with 1.15 SG mud

AHA MOMENT – SHOULD WE REVISIT OUR TAUNTON DESIGN BASED ON THIS?

7

MECHANICAL EARTH MODEL THE BASIS FOR ACCURATE GEOMECHANICS ANALYSES

Seismic

Core Data

Drilling Data

Wireline & LWD Logs

Analysis and Design for:

WBS Sanding

Frac Design Compaction Subsidence

Res. Simulation Etc.

Results

In Situ Stresses & Pore Pressure

Pp σ h σ Hσ V

0 100In Situ Stresses W N E

Stress Direction σh

Fault

Regional Trend

In Situ Stresses & Pore Pressure

PpPp σ hσ h σ Hσ Hσ Vσ V

0 100In Situ Stresses W N E

Stress Direction σh

Fault

Regional Trend

B. Downhole Stresses

Input Data

A. Mechanical Properties

Mechanical Earth Model

Youngs Modulus

Poisson’s Ratio

UCS…..

History Match

Bore

hole

Imag

es

SHmax

Sv

Shmin

SHmax?

8

TAUNTON 5H MEM

9

Well: Taunton-5

Field: Taunton

Air Gap: 32.0 mWater Depth: 17.0 m

Pore PressureCollapse

Least Stress

Made by:SMW Date:1/22/2013

Mea

sure

d D

epth

(RK

B),

m

Mud Weight (RKB), SG0.8 1 1.2 1.4 1.6

1500

2000

2500

3000

3500

Production Casing9.625''@1864

3862

Relationship of Collapse Gradient to Angle and Direction

3 iterations – multiple meetings needed to get to this point

PLANNED TAUNTON 5/5H AND KEY OFFSET WELLS: TAUNTON-2 AND TAUNTON-4

BATH-1

Planned Well Taunton-5H

10

Taunton-2 and Taunton-4 wells have been considered as the offset wells for constructing the Mechanical Earth Model for the planned well Taunton-5H

How does Taunton-5H model compare to Taunton-2L experience ? • Here is Taunton-2L MW-ECD window • With drilling MW & ECDs

Wellbore Stability Interpretation : 1. Pack-offs in Muderong & high angle hole are

explainable

2. 1.20 sg MW is too low

11

12¼” ECDs & swab, with 1.25 – 1.33 sg MW

With 1.25 sg MW, there will be some tunnel failure in the Muderong Fm, but risk level will likely be OK • This is lowest MW that should be considered

With 1.33 sg MW, all risk is removed • Since there is no risk of losses, this is Schlumberger’s

preferred / recommended MW to be used

Final Version of MEM Indicated we might have problems if we stuck to base case plan

Especially in the 8 ½” Lateral section in the Mardie

Make sure model honors offset data Take a calculated risk in the pilot hole Select a mudweight in the low angle pilot hole to initiate breakout

Measureable breakout Test for percieved conservatism in MEM

Optimize mud weight for lateral Low risk of breakout impacting well objectives or operations in 38 deg pilot hole

Calibration Methods Use Density Image Logs Perform XLOT at 13 3/8” and 9 5/8” shoes Use time lapsed caliper data

Use updated MEM for drilling the 2000m long reservoir section

Provide support in the field and in the office – K&M

DECISION MADE TO USE THIS LEARNING ON TAUNTON 5H

13

Requested a Pilot Hole MEM – all work to date was considering a horizontal hole – stresses would be less in a 38 degree hole – chose MWs to cause slight breakout – calibrate model – react accordingly

PILOT HOLE ATTACK PLAN

14

PILOT HOLE - DRILLING 12¼” TO CORE POINT (811M–1523M)

GEOMECHANICS UPDATE Initial Model

Updated Model

Geomechanics model was updated after processing LWD

data from drilling run. Updated model shows

significantly more risk of collapse

XLOT Fracture Closure Pressure

12¼” TD TRIP OUT OF HOLE TO LOG PILOT HOLE

1.35 SG Selected as there was little downside – hi fracture gradient

TAUNTON 5H 12 ¼” HOLE LANDING

18

DRILLING 12¼” SECTION TO 1668M TD Drilled to section TD without issue,

and good hole cleaning parameters 1000 – 1200 gpm 160 – 170 RPM Backreamed ½ stand prior to

connections

TD called just in top of Mardie GS Generally good ROP, with some slow

spots – instantaneous ROP f/ 5 – 105 m/hr

FFs: PU & TQ = 0.30, SO = 0.25

DRILLING 12¼” SECTION TO 1668M TD Potential indications of

diminished hole cleaning and/or wellbore instability Spike in FFs at ~1300m Increased ECD/ESD near end of

run Increasing MW near TD (possibly

hole cleaning related)

No cavings noted while drilling with MW 1.35 – 1.36

Increasing ECD/ESD

12¼” SECTION – TRIP OOH TO RUN CASING

Difficulties noted backreaming

Circulated 8 B/U with 160 RPM and 1200 gpm For 2 – 3 B/U, large quantity of cuttings

over shakers At 5 B/U, increase in cuttings noted, and

10% - 15% cavings At 8 B/U, still some cuttings over shakers,

cavings at 5%

Attempting to POOH on elevators, drag increased over 3 stands to 40k at 1568m

RIH 3 stands to 1643m and circulated 2 B/U at 160 RPM and 1200 gpm. Still some cuttings flow over shakers at 2 B/U

Attempted again to POOH on elevators. Again saw drag after a few stands – overpull up to 30k at 1590m

RIH to bottom and began backreaming out of the hole

9⅝” CASING RUN Good run in, although FFs

increased with depth CH FF – 0.15 OH FF increased from ~0.3 to

~0.4, then further increased to 0.60 in the bottom of the Muderong

Tight spot at 1342m entering the Muderong Shale, which fell of quickly

No losses while running in Ran in and set casing at

1663m

Updated T-5H prediction (12 ¼” section), Based on updated T-5 pilot hole results

& corrected PP

Previous T-5H prediction (for 12¼” section), based on T-2

Previous recommendation for MW = 1.30 –

1.35 sg Prefer 1.33 sg

Forward recommendation for MW = 1.42 –

1.47 sg Prefer 1.45 sg

MEM UPDATE AFTER 12 ¼” LANDING

Previous 8½” ECDs vs MEM, with 5½” dp, for +/- 6m uncertainty • 1.32 sg is minimum MW (again, NO allowance for swab)

Updated 8½” ECDs vs MEM in Reservoir, for 5½” dp • 1.20 sg is adequate MW

MEM UPDATE FOR 8 ½” HOLE AFTER XLOT

Good news – updated MEM indicated we could drill with a lower MW than originally thought

WE asked if there was a sensitivity to the XLOT result – there would be – good thing we asked

MEM UPDATE FOR LATERAL SECTION RESULTS

25

9 5/8” SHOE - XLOT RESULTS

LOP = ~1.68 sg

Closure = ~1.63 sg

• Closure pressure less than 1.7 SG use 1.25 SG mud weight – if higher we could stay with the 1.2 SG mud weight

• Observed lower closure pressure than expected (lower minimum horizontal stress)

• Updated rock mechanics modeling based on this data showed smaller MW window than previously estimated (see next slide)

• MW increased to 1.25 sg given increased collapse gradient in revised model

Birdrong Sandstone

Updated 8½” ECDs vs MEM in Reservoir, for 5½” dp • 1.20 sg is adequate MW

T-5H 8-1/2” Section Model Update after T-5P TD logs

Model Update of T-5P with XLOT closure pressure

XLOT Closure Pressure=

1.64 sg

What has changed? 1. XLOT Closure pressure

came at 1.63-1.65 sg (lower than expected).

2. Loss curve has moved to the left.

3. MW to prevent breakout has increased to 1.25 sg

What was this model based on? 1. T-5P logs 2. XLOT closure pressure at 13-3/8”

shoe = 1.73 sg

GM- 5H (post 9-5/8” XLOT) For T-5H 8-1/2”

Updated with T-5H 9-5/8” XLOT results

GM- 4H (post coring) For T-5H 8-1/2”

based on T-5 ST2 results

27

Interval drilled successfully 2083m

Two unplanned trips Multiple passes for FE data No issues tripping in to

bottom, although ran out of weight at 3630m and had to ream to bottom. SO FF – 0.30 PU FF – 0.32 TQ FF – 0.39

SUCCESS DRILLING 8 ½” HOLE

28

A complex well was drilled to total depth The lower completion was stuck while running and

the well was lost Primary Objectives not met Structure came in high – glimmer of hope This information will be useful in the future for any

subsequent Taunton work

FINAL OUTCOME

29

A Mechanical Earth Model is useful for planning complex wells

The MEM needs to be calibrated with offset data Multiple iterations typically required Lots of stakeholders input needed You can collect data to validate the accuracy of the

MEM Hint – if your offsets indicate some drilling problems –

backreaming out of hole – tight hole – look into the possibility of geomechanical issues

CONCLUSIONS – WHAT’S IN IT FOR YOU?

30

INTEGRATING REAL-TIME GEOMECHANICS INTO DRILLING OPERATIONS

KYLE GRAVES, SR ENGINEERING ADVISOR, PERTH D&C TEAM AUGUST 6, 2013