Shut-In Buid Up Pressure (SIBU) Wells to Revive Intermittent Floating Gas Producing Wells in Tunu, Mahakam Delta

Abstract

Tunu is a giant gas field located in the swamp area of Mahakam Delta, covering 75 km in length and 15 km in width. It has been producing since 1990 from approximately 1,200 wells which are located in 34 platforms. The field production is supported by 3 main factors: baseline, well intervention, and new wells or new projects. As the field matures, available perforation portfolio for performing well intervention decreases and finding new wells becomes more difficult due to reducing reserves per well. Therefore, maintaining baseline becomes the key factor in sustaining the field potential. One of the efforts to maintain the field baseline is through proper Shut-In Build Up Pressure (SIBU) Revive Wells Management.
Intermittent floating producing wells commonly found in gas wells are categorized as Shut-In Build Up (SIBU) Revive wells. The method aims to maximize producing time of the wells while minimizing flow below critical rate by pressurizing the downhole via hydrocarbon accumulation. It is currently the best method to recover reserves from floating gas wells with no remaining well intervention portfolio. However, due to the massive size of Tunu field, the biggest constraint to optimize the revival wells is the ratio of operator per area consuming time for manual action. Below are the best practices for SIBU-Revive Wells in Tunu:
a) Manual: Send Operator to check well parameters in field & open/close wells
b) Semi-Automatic: Engineers review well parameters via pressure temperature
transmitter real time, send operator to open/Close wells Daily identification of SIBU-Revive wells is important to decide revival well movements in order to optimize the gas production while increasing productivity of man hours & logistic, especially for manual action. Careful consideration on SIBU-Revive criteria to decide whether or not the wells are defined as SIBU-Revive wells is highly crucial. Planning of execution after reviewing well parameters for each identified SIBU-Revive well is important to decide whether the wells should be shut-in for building up the pressure (SIBU) or put on production (POP). Current study shows that compared to manual action, each modification for electrical semi-automatic Tunu SIBU-Revive system will save 15 hours of man hours. From SIBU-Revive Tunu wells daily, we maintain at average 30 flowing wells with average production 20 MMscfd, which is contribute to 4-7% Tunu production.