SN Structure is one of structure in the oil & gas rich Kutai Basin of East Kalimantan, Indonesia. Since, well SN-1 was drilled then plugged (with oil shows) and SN-2 has just been drilled with target on the Pelarang anticline situated approximately 2.6 kms southeast of SN-1 then plugged and temporary abandoned. The primary objective of SN target was the shallow updip potential of the Late Miocene Balikpapan and Early-Middle Miocene Pulau Balang reservoirs.

In other well, SN-2 the target was 2,355 ftMD vertical well. On 12-1/4″ Open Hole section, there was gas peak and high pressure on depth 475-482 ftMD with MW slightly reach the LOT on last 13-5/8″ casing. While drilling there was a deals with well kick condition that should occurs with MW slightly reach 18 ppg (Last LOT reading). Occurs the kick, gas came out from separator then burnt out. For safety, it has to stop and set the casing 9-5/8″ to depth 738 ftMD, without DST activity. Further now, the SN structure has just shown that it has potential hydrocarbon on its subsurface which need more proven data to get the P50 and P90 for its structure.

Next 8-1/2″ open hole section, the operation must face the well with MW 17.1 ppg which with additional surface pressure, it slightly reach the MW LOT 18.2 ppg. At depth 1,170 ftMD, with MW 17.2 ppg there was kick and well control problem and for safe safety operation reasons, drilling finnaly has to stop. Then it was plugged from depth 1,170 ftMD to depth 738 ftMD and temporary abandonment, caused the MW to occurs the kick and well control has reached 17.6 ppg. On plan program, there is an open hole logging job to indicate and collect data on 8-1/2″ section. But the program cancelled just because the slurry and viscous of MW is very high and the tools can't go down deep to the target depth. SN-2 well now has suspended operation and there is no Testing operation on Well, with gas Hydrocarbon indications. For future, this well is planned for DST job on section depth 315 – 738 ft MD. Further now, the SN structure has just shown that it has potential hydrocarbon on its subsurface.

Its structure is more challenged caused there highly gas peak and some section must occurs kick and well control while drilling. This might caused by fault which acting as a seal, and has been used as a boundary for the P90 area used in the calculation of reserves for the SN-2 Prospect. Its structure must have some G&G studies for having some good parameter and indication, while drilling operation team must have a good design on well schematic and drilling program for the next well on SN structure. Which means have a good and perform of Drilling contractor and materials.

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