Attaka field, a giant offshore oil field located 12 miles from the shore of East Kalimantan in Indonesia was discovered by Union Oil of California (UNOCAL) in August 1970. Attaka field is considered a giant oil field having 1023 MMBOE of recoverable reserves.
General Soeharto, the president of Indonesia at that time, inaugurated the Attaka field and the Santan terminal on 22 January 1973.
Santan terminal is the onshore complex where the crude oil from the Attaka field is processed and stored before it is exported by oil tankers. Santan terminal is also where the produced gas is processed before it is sent to Badak LNG for liquefaction.
Unocal along with its 50-50 partner, Inpex, operated the Attaka field until it was acquired by Chevron. Pertamina Hulu Kalimantan Timur assumed the operatorship of the field beginning on 25 October 2018.
Here are the interesting facts about the Attaka unit:
- Two years after its discovery, the Attaka field started producing oil in November 1972, making it the first offshore field in Indonesia.
- It has 10 platforms, 6 of which are remote wellhead platforms producing oil and gas from 109 wells.
- Five subsea wells were completed in 1981-1984 to produce the oil accumulation in areas out of reach of the existing remote platforms. These are the first subsea completions in Indonesia and in Asia.
- Following the first discovery well, the Attaka Well 1A, seven appraisal wells were drilled to assess to size and potential of the hydrocarbon accumulation.
- The huge Attaka reservoir, formed in the very prolific Kutei basin, is a faulted anticline. It has an areal closure of 8000 acres. Attaka field is one of five super-giant fields discovered in the Kutei basin.
- Its oil reserves are attributed to oil found in 22 separate sands at a depth between 2800 feet and 7600 feet.
- Attaka sands have very high permeability. It is as high as 5 Darcy in some wells.
- Attaka field daily oil production was 110,000 BOPD at its peak and gas production was 150 MMSCFPD.
- A significant milestone was reached when cumulative oil production of 600 million barrels was recorded at 6:42 PM on March 7, 2001. Cumulative gas production in that same year was 1.3 trillion SCF.
- Attaka field has more than 50 sands with variable oil reserves. Reservoir sand thickness ranges from 5 to 100 feet. To produce them economically, multiple zone completion method using dual tubing strings and multiple packers was selected. This method allows the engineers the flexibility to select from which of the 2 to 4 perforated zones in each well they would like to produce from.