Play System from the Last Decade Discoveries in Indonesia Basins

Play System from the Last Decade Discoveries in Indonesia Basins*
By
Brahmantyo K. Gunawan¹, Sunjaya E. Saputra¹, M. Kusuma Utama¹, Cipi Armandita¹, and Johnson A. Paju¹

*Adapted from oral presentation at AAPG Annual Convention, San Antonio, Texas, April 20-23, 2008

¹Exploration Division of Planning Department, Executive Agency for Upstream Oil & Gas Business Activities Republic of Indonesia (brahmantyokg@bpmigas.com)

In the past 10 years hydrocarbon exploration histories in Indonesia, there are several significant hydrocarbon discoveries. Generally, the play concept has moved to the deeper target and older reservoir. There several new play concepts for the Eastern Indonesia area are thin-skinned thrust system in the turbidites in the Kalimantan deepwater, Miocene reef play in the Sulawesi area, and Jurassic sand in Papua and East Timor gap. In East Java basin there are two explorations targets that have been pursued for the last 10 years; they are Oligo-Miocene reef and volcaniclastic Pliocene sediments. Meanwhile in the Sumatra area the target has changed into the deeper target, which is Oligo-Miocene syn-rift sediments.

The successful discoveries have resulted in other companies learning from them and increasing their exploration activities in the past five years by developing new concepts in their blocks or acquiring new blocks in nearby areas. (Mahakam deep water block discovery has been resulted in other discoveries in the surrounding area, including in Tarakan deepwater area).

The new play exploration strategy by defining the new play concept from lessons learned from relatively recent discoveries has become the current model in the exploration activities. Therefore, understanding the play concept in new discoveries will immediately upgrade the opportunity to find hydrocarbons.

uAbstract
uFigures
uExploration history
uPlay types
uUnconventional types
uReferences
uAckn owledgments

Selected Figures

	Indonesian Tertiary basins.
	Sumatra back-arc deep clastic play.
	East Java deep carbonate and clastic play.
	East Java area, Mio-Pliocene volcaniclastic play.
	Kalimantan deep water pro-delta sand play.
	Eastern Indonesia / Australian continental related passive continental margin and collision play.

	1998-2007 discoveries.

Indonesian Exploration History Periods

1. Dutch Government (1865 – 1940)
Exploration by Dutch Government started at 1865 and first exploration well drilled 1872
First oil field discovery (Telaga Said, North Sumatra) 1885
Exploration target defined by outcrop mapping and shallow drilling technology

2. After Indonesian Independence (until early 1970)
Commercial working area operated by several companies
Discovery Duri, Talang Akar, Minas Field using simple exploration methods with increase in the production, lifting up to 1,000,000 BPOD

3. Early 1970
Start applied subsurface 2D seismic technology
Production lifting increased up to 1,600,000 BOPD

4. 1980 – 1990
Fluctuation HC Production (lowest in mid1980 and gradually increased until 1990)
2D and deep target drilling applied
mostly productive fields located in back-arc & deltaic passive margin setting

5. 1990 – now
Old fields started to deplete
2D / 3D and drilling technology improvement
triggering search for other targets (unconventional)

Play Types

In general, the exploration targets in Indonesia before 1990 are situated in Western Area and, mostly, discovery in Neogene Back-Arc Basin and Passive Margin Deltaic Setting,
called Indonesian Conventional (classic) Play Types , Including :
Classic Shallow Target
Classic Clastics
Classic Carbonates
Classic Stratigraphic & Combination

Thus Indonesian Unconventional Play Types are play types besides the conventional type,s as mentioned above.
The success unconventional plays, explored from 1990, are in:
Deep Oligo-Miocene ~ Rift Phase Clastics
Deep Oligo-Miocene ~ Carbonate
Deep water clastics (Pro-Delta)
Volcaniclastics
Pre-Tertiary & Basement
Collision Tectonic Setting Complex

Why Unconventional Type?

Oil production from mature field is declining.
Addition of new reserve from conventional (classic) play type is minor. No significant replacement of reserves for HC production.
Unconventional play type discoveries give larger new HC reserves and they are ready to develop.
Collision/Australian Continental Margin--Pre-Tertiary contributed most of HC reserves in last decade and need more exploration efforts.
Some frontier basins which have unconventional play type may trap “big fish” (high risk high reward, low risk low reward).

References

Nilandro and Baraclough, 2003, Principal Tectonic Elements Map of Eastern Indonesia.

Satyana, A.H., 2007, Central Java, Indonesia, a “terra incognita” in petroleum exploration; new considerations on the tectonic evolution and petroleum implications: Thirty-First Annual Convention and Exhibition Proceedings, Indonesian Petroleum Association, p. 105-126.

Acknowledgments

Deputy of Planning BPMIGASL: Mr. Achmad Lutfi; Head of Exploration Division:BPMIGAS: Mr. Bob Yulian; Heads of Exploration Region I, II and III BPMIGAS: Mrs. Nugrahani, Mr. Indro Purwaman, and Mr. Djumlati; Mr. Awang Harun Satyana and Mr. Elan Biantoro for Technical Contribution; Total E&P Indonesie; PetroChina International..

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