Case History of First Liner Drilling Application in Romania

Ali QureshiWell Delivery Team Leader-Team-5OMV Petrom S.A.

Bucharest, 28th April 2016

| Liner Drilling Application – Bucharest, 28th April 2016

Agenda

• Introduction

• Background (well design, prognosis etc.)

• Sequence of Events

• System Specs

• Conclusions and Recommendations

2

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Romania

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Well Design

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Well Design Casing objectives:

1) 13 3/8” Surface Casing @ Sarmatian formation top:

1- Support unconsolidated top formation

2- Isolate active shale in Meotian formation

3- Implement CwD Technology

2) 9 5/8” Production Casing @ Salt formation top:

Case off long Sarmatian formation open hole section.

3) 7” Production Liner @ T2 formation top:

Case off and isolate Salt formation section.

4) 6” OH Section

Drill 6” hole through T2, T1 and Paleozoic formation with mud weight 1.20 - 1.25 SG

NADF to avoid losses in Paleozoic formations.

13 3/8” Surface CSG

9 5/8” Production CSG

7” Production Liner

6” OH section

KCl mud 1.15 – 1.2 SG

NADF mud 1.25 – 1.35 SG

NADF mud 1.8 – 1.85 SG

NADF mud 1.2 – 1.25 SG

Romaian

Dacian

Pontian

Meotian

Sarmatian

Jurassic / Salt

Triassic

Paleozoic

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Well Prognosis

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PlannedWell Path

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What happened? (1 of 2)

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• Drilled through Sarmatian and Badenian formations; encountered aggressive salt layer @

4238mMD.

• Bit got stuck in salt @ 4239mMD. Jarring and pumping fresh water pills didn’t work. MW

1.35sg (NADF).

• Cut and retrieve string; 20m fish left in hole. TOF @ 4219m.

• Pump and set cement plug above fish. Dressed down top of cement to 4150mMD, then ran

and cemented 9 5/8” casing above fish.

• Drilled out shoe-track, kicked-off from 4163m, 56m above TOF, to perform side-track #1.

• Drilled through salt with 1.73sg to section TD @ 4326mMD; MW limited by losses in

exposed sand layers below 9 5/8” casing shoe. POOH.

• Ran 7” liner, equipped with reamer shoe; stood up at 4245mMD (HUD).

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What happened? (2 of 2)

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• POOH liner to perform wiper trip.

• RIH dumb iron BHA, accidentally side-tracked from 4245mMD in open hole (side-track #2)

while trying to ream obstruction; POOH, switch to directional BHA and drilled ahead through

salt to casing point at 4326mMD.

• RIH 7” liner; could not pass salt layer. POOH and set another cement plug @ 4022mMD.

• Drill out cement to 4157mMD.

• RIH directional BHA, side-track hole again from 4157mMD (side-track #3). Drill to top of

salt, POOH BHA.

• RIH 7” liner with casing bit and rotating liner hanger system. Drilled through salt successfully

from 4238mMD – 4255mMD (17m); average ROP 5 m/hr. No further progress possible.

• Cemented liner in place.

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Mud Log from the problematic section

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Liner Drilling Parameters Chart

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Actual Well Trajectory in Reservoir Section

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Liner Drilling Bit

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System Specs

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Weatherford Liner Hanger System:

• Hydraulics Set Rotating Liner Hanger System

• Premium Liner System with Dual Plug System and Top Set Packer

• Type R Running tool, MX Ball Seat

7” Liner:

• 32PPF, TN110HS, TN Blue

• M/U Torque: 13,000 ft-lbs

Top of Shoe Tract 4224m

Previous Casing Exit

True Vertical

Description

Hanger Slips

Measured

Measured

3930m

Liner Shoe

Section TD

True Vertical

Measured True Vertical

4254m

4254.8m 4252.7m

4252m

Measured True Vertical

Measured True Vertical

4247m

4226m

4251m

Liner Systems Central Europe

End of Job Report

Well Schematic

Measured True Vertical

Depths

Top of Liner

Packer Element

3922m

N/A

True Vertical

3923m

N/A

3929m

Measured

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Conclusions and Recommendations

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• Drilling with liner (DwL) helped to cross the problematic salt layer and

facilitated drilling ahead to the targeted reservoir.

• It was first such application in Romania; promising technology to case

off problematic formations.

• Stronger bit could have drilled further; bit selection can be improved.

• 7” liner and Liner hanger system worked fine; no issues encountered.

• Some pressure fluctuations were observed while drilling, could be from

bit nozzles washing out but cannot be confirmed.

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Thank you!

Any Questions?

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