Production from basemen reservoirs; Examples

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Production from basemen reservoirs; Examples

Post by FANARCO »

Oil is produced from basement rocks in a number of countries including China, Vietnam, former USSR (West Siberia), Ukraine, Indonesia, Libya, Algeria, Morocco, Egypt, USA, Brazil and Venezuela.

In this thread we will highlight the production from Indonesia, USA and Venezuela.

Although oil production from basement rocks is not a common occurrence worldwide, there is significant oil production from such reservoirs in a number of countries.

Two fields in Indonesia, Beruk Northeast and Tanjung, serve as examples that commercial volumes of oil can be produced from basement in Indonesia. Indeed, recent successful exploration for gas in South Sumatra has reinforced the concept that basement is a valid exploration target in Western Indonesia and that whenever possible, wells drilled through the Tertiary objectives should be deepened into basement to evaluate possible oil or gas accumulations.

In Kansas, oil is produced from fractured quartzites whereas in California, oil is produced from fractured schists. In Venezuela, prolific oil wells produce from fractured Granite in the La Paz and Mara oil fields.
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Re: Production from basemen reservoirs; Examples

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INDONESIA


Oil production from pre-Tertiary basement rocks is rare within the Tertiary back arc (foreland) basins of Western Indonesia.
The Beruk Northeast field is the only field in the prolific Central Sumatra Basin that produces from basement (Koning & Darmono, 1984).

The field was discovered in 1976 by the drilling of Beruk Northeast No. 1 which tested 1680 BOPD from fractured basement quartzites.

Approximately 2 million barrels of oil have been produced from quartzites, weathered argillites and weathered granite.

The basement rocks have K/Ar radiometric age dates varying from Early Permian to Early Cretaceous, indicating a complex pre-Tertiary geologic history.

The Beruk Northeast field presents challenging production problems due to the great variability in reservoir rocks, the presence of at least four separate oil-water contacts, and a possible unrecognized water bearing fracture system.

The Tanjung field in the Barito Basin, South Kalimantan, was discovered in 1938 and has produced over 21 million barrels of oil from pre-Tertiary basement rocks.

Oil occurs in volcanics, pyroclastics, and metamorphosed sandstones and claystones, which are locally deeply weathered and fractured.

The Beruk Northeast and Tanjung fields share many similarities. For example, both fields occur within faulted anticlines.

The overlying thickness of Tertiary sediments in both fields is less than 2000 meters. The likely oil source rocks for these fields are the adjacent and deeper Tertiary shales.

The Beruk Northeast and Tanjung fields indicate that pre-Tertiary basement is a valid oil exploration objective in the Tertiary basins in Western Indonesia and that, whenever feasible, exploration wells in these basins should be drilled into basement.

Indeed, exploration targeted for basement hydrocarbons has met with recent success in South Sumatra, where operator Gulf Indonesia has reported the significant Suban gas discovery. Three wells drilled in 1999 in the Suban field have defined a gas pool located within fractured pre-Tertiary granites. Gas flow rates of 26 MMCFGPD were obtained from the Durian Mabok-2 well. Test data combined with seismic mapping indicates a gas pool with a minimum gas column of 500 meters covering an area of at least 72 square kilometers (Gulf Indonesia, 1999).
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Re: Production from basemen reservoirs; Examples

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UNITED STATES

In Kansas, oil is produced from Precambrian basement rocks in the Central Kansas uplift. The Precambrian rocks include quartzite, schist, gneiss and granite, however fractured quartzite is the reservoir rock most often penetrated since it occurs on the summits of many buried Precambrian hills (Landes et al, 1960).

Basement oil pools include the Orth, Ringwald, Kraft-Prusa, Beaver, Bloomer, Trapp, Eveliegh and Silica fields.

The source rocks are flanking Cambro-Ordovician shales or overlying Pennsylvanian shales.

Production from fields such as the Orth and Ringwald field is relatively low at production rates varying between 120 and 190 BOPD.

In California, oil is produced from basement consisting of fractured Jurassic schists.

Fields which contain basement reservoirs include the Playa Del Rey, El Segundo, Santa Maria, Wilmington and Edison fields.

Relatively few wells produce from basement rocks alone; most are multiple completions in both the basement schist and overlying schist conglomerate and Tertiary sandstones.

The majority of the oil-producing schists are in a relatively high position and have usually undergone weathering and erosion, thus increasing the porosity (Landes et al, 1960). The wells in the Edison field had an average production rate of about 1,000 BOPD and cumulative production in the field has exceeded 20 million barrels of oil. The
Wilmington field has produced more than 22 million barrels of oil from basement with ratesof production varying from 1,200 to 2,000 BOPD.
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Re: Production from basemen reservoirs; Examples

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Very informative, thankyou,
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Re: Production from basemen reservoirs; Examples

Post by FANARCO »

VENEZUELA

Within Venezuela's Maracaibo basin, oil is produced from granitic and metamorphic basement rocks in the La Paz and Mara fields, which are located 50 km northwest of Lake
Maracaibo. The depth to basement in the two fields ranges from 2750 to 3500 meters.

These two fields occur along the crest of a northeast-southwest trending, strongly folded and faulted anticline (Stevenson, 1951).

Approximately one billion barrels of oil have been produced on a combined basis from both fields from Cretaceous limestones as well as from Paleocene and Eocene sandstones.

In addition, both fields have also produced significant volumes of oil from basement.

The La Paz field was discovered in 1923 and has cumulative oil production from basement of 246 million barrels and estimated remaining reserves of 81 million barrels (Talukdar & Marcano, 1994).

During the initial development of the field, wells were drilled into basement with an average penetration of 500 meters (Chung-Hsiang P'an, 1982).

Maximum initial production was 11,500 BOPD and the average initial production was 3,600 BOPD.

The Mara field, discovered in 1944, lies on the northeastern extension of the La Paz anticline and has produced 27 million barrels of oil from basement. Remaining reserves are estimated at 5 million barrels.
Average penetration into basement was 360 meters and initial production averaged 2,200 BOPD. The combined production from basement rocks in these fields exceeded 75,000 BOPD. Cores of basement rocks show intense fracturing, most commonly in vertical planes, and many core recoveries are poor (Smith, 1955). The oil source rocks are overlying Upper Cretaceous La Luna marine shales which are immature at the fields but which are mature to the south of the fields
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Re: Production from basemen reservoirs; Examples

Post by anindaghosh2207 »

Excellent Compilation and very Informative. :D :D :D

May I request you to please provide some info on the challenges and limitation of basement production. I have never worked on basement reservoirs and every where I've read about the success stories of basement oil.

Could you please throw some light on the limitation and challenges associated with it.

Thank you.
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Re: Production from basemen reservoirs; Examples

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anindaghosh2207 wrote:Excellent Compilation and very Informative. :D :D :D

May I request you to please provide some info on the challenges and limitation of basement production. I have never worked on basement reservoirs and every where I've read about the success stories of basement oil.

Could you please throw some light on the limitation and challenges associated with it.

Thank you.
Aninda,

Appreciate your contribution.

Actually, there are no clear standard rules in Basement development due to very limited fields/regions as well as in many case not economical to produce.
But we can say generally the term "Net pay thickness" is not available in Basement reservoirs and the main player is vertical relief (The crest of the reservoir to the bottom)

The Basement reservoir is not a sedentary rock so, it is not a layers, it is like a dome

Image

Rule of thumb the minimum vertical relief is 1000 meter. Yes 1 Km reservoir.

Good Geological/Geomechanical description should be implemented in order to locate the sweet spot (the highly fractured area) to hit the reservoir in the best quality.

The world's top basement producer Country is Vietnam and we can dedicate a new thread for Cuu Long Basin and White Tiger field..
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Re: Production from basemen reservoirs; Examples

Post by anindaghosh2207 »

Dear Fanarco,

Thank you very much for your elaborate description.

It is indeed very useful for all the readers in the forum.

Hats off to you.

Regarding Cuu Long Basin and White Tiger field, please start the new thread. This will be a very good learning for every body.

Regards,
Aninda
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