Oil Search : Completion of Drilling at P’nyang South 2 ST1

Completion of drilling at P'nyang South 2

ST1

(ASX:OSH | ADR: OISHY | POMSoX: OSH)

16 January 2018

The P'nyang South 2 ST1 well, located in PRL 3 in the North-West Highlands of Papua New Guinea, reached a total depth of 2,725 metres1 on 7 January 2018. As previously reported, the well, which is being operated by Oil Search on behalf of the PRL 3 joint venture, has encountered gas in good-quality Toro and Digimu sands, while the Emuk sands appear to be largely water-bearing.

Peter Botten, Oil Search's Managing Director said:

"We are pleased with the P'nyang South 2 ST1 results, which confirm the extension of the P'nyang field to the south-east. The PRL 3 joint venture is evaluating the well results, including the implications for 1C and 2C gas resource volumes in the field. Oil Search is confident that the well's primary objective, to migrate 2C contingent gas resource to 1C contingent resource in this area, to support marketing and financing activities for LNG expansion, will be met."

A recertification of the field's gas resources by an independent expert is underway and is expected to be completed in the second quarter of 2018. The joint venture is also working with the Department of Petroleum to progress the offer of a Petroleum Development Licence (APDL 13) over P'nyang, currently subject to an application. In addition, work is continuing on selecting the optimal development concept for the field.

The well is presently being plugged and abandoned, as planned.

1 MDRT - measured depth from rotary table

Oil Search Limited

Head office

Sydney office

Mailing address

Incorporated in

Papua New Guinea ARBN 055 079 868

Port Moresby Papua New Guinea

1 Bligh Street Sydney NSW 2000 Australia

GPO Box 2442 Sydney NSW 2001 Australia

Tel: +61 2 8207 8400 Fax: +61 2 8207 8500www.oilsearch.com

Participants1

Oil Search affiliates 38.5%

ExxonMobil affiliates 49.0%

NOEX (an affiliate of JX Nippon) 12.5%

Total 100.0%

1 Gross interests pre-Government and landowner back-in, rounded to one decimal place.

PETER BOTTEN, CBE Managing DirectorFor further information, please contact:Ann Diamant

General Manager, Investor Relations and Communications

Tel: Mob:

+612 8207 8440 +61 407 483 128

Stephanie Chu

Senior Investor Relations Advisor

Tel: Mob:

+612 8207 8542 +61 481 038 179

P'nyang South 2 ST1 Update -16 January 2018www.oilsearch.com

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