UNLOCKING A CARBONATES RESERVOIR RIDDLE: A POST MORTEM OF THE K-2 APPRAISAL WELL DRY HOLE IN THE SALAWATI BASIN, WEST PAPUA, INDONESIA

摘要

The Kais carbonate formation has been explored and developed as an oil and gas producing formation in the Salawati basin area since 1939. In 2000, the JOB Pertamina- Santa Fe successfully discovered hydrocarbons in the K structure with the K-1 exploration well, which tested with a result of 900 BOPD with good reservoir properties though several pay zone intervals. In 2013, the JOB Pertamina-Petrochina drilled the K-2 appraisal well in the K structure flank to confirm reserves, and hydrocarbons showed in drill cuttings but well testing results showed a poor accumulation of hydrocarbon. This resulted in many questions that ,. needed to be answered, such as what was the underlying explanation for these results? Also, is the K-l and K-2 reservoir still on the same built up reef body? Is the fault sealing or leaking? Is the hydrocarbon migration enough to full fill the structure? This paper discusses how to answer these questions using a static geological model. To perform the static model, good data was provided after the K-2 well had been drilled. An open hole logging measurement has been taken from the K-2 well, including an advance log such as FMI, dipole sonic and MDT. Also, conventional core has been taken from K-2 well and laboratory analysis has been conducted. The K-l well has a good quality of wire line log and also has a sidewall core taken from several depths including a pay interval. This data was evaluated through a multidiscipline study and concluded with interpretation gathering by building a static model of the K structure. A geological concept has been built using the pattern of the secondary porosity appears. Rock type model has been built by guided of facies model, and following property of reservoir been built by guide of rock type model. Then, the complexity of carbonate can be simplified and successfully show how hydrocarbons accumulated in the K structure and explain the results of the K-2 appraisal well.