The Barik Haushi field is composed of two reservoirs at a depth of two km: Lower Gharif (LG) & Al-Khalata (AK). The field is divided into two areas based on shareholder ownership: the Main East Block is booked as non-associated gas and is fully owned by the Government of Oman; the West Block contains oil and associated gas and is jointly owned by the Government of Oman and private shareholders. The field was discovered in 1971 with first production from the West Block in 1986 via a well that was closed in after nine years due to well integrity failure. Production restarted in the Main East Block in 2005 via four vertical wells, two in each reservoir. The two vertical wells in AK soon watered out and were shut off and re-perforated in LG. Current production is 0.2 MMm3/d and 23 m3/d of condensates from the LG.
The latest multi-disciplinary study identified the possible presence of an oil rim in the Main East Block and a non-sealing fault between the two blocks. These alternative realizations impact resource reclassification and further development of the field. The available field data is inconclusive and acquiring additional new data in the short term is a challenge. The aim of this specific study is to develop the field in an optimum way, testing subsurface uncertainties through 3D dynamic reservoir simulation modeling. Firstly, a non-sealing fault scenario was considered. Several fault transmissibility sensitivities were performed to test intra-block cross-flow and model stability. Results show that dynamic equilibrium and stability could only be achieved by either keeping the same oil-gas contact with a non-sealing fault, or applying two different oil-gas contacts with a sealing fault. These two scenarios were further examined during a history matching exercise of production and pressure data. A fair history match could only be obtained for the fault-seal scenario. Secondly, the presence of an oil rim scenario in the Main East region was investigated in a similar manner. Three different scenarios were tested: a mobile oil case, a relatively low mobile oil case, and a case without an oil rim. Only the non-oil rim scenario was supported by a decent history match. This paper highlights how challenges that emerged because of data scarcity were tackled via a minimal cost approach through the use of 3D dynamic reservoir simulation modeling.