講演
大水深Fold & Thrust地域でのMulti Azimuth-Broadband 3Dサイスミックの成果と貯留層分布評価への活用
―マレーシア 北西ボルネオ沖探鉱プロジェクト事例―
2015 年 80 巻 1 号 p. 12-18
詳細
2015 年 80 巻 1 号 p. 12-18
INPEX OFFSHORE NORTH WEST SABAH, LTD (INPEX) acquired an exploration right of block in deepwater offshore NW Borneo, Malaysia in 2012 and conducts exploration activities as an operator.
Large oil and gas fields have been discovered and developed in the Fold & Thrust Belt (FTB) in the deepwater NW Borneo. The Fold & Thrust Belts have been forming since Late Miocene, and in which exploration targets are Miocene to Pliocene deepwater turbidite sandstones. Assumed technical problems in the exploration work in this region are (1) uncertainty in interpretation of structural closure because of poor seismic image affected mainly by shallow gas or hydrate, located in its upper crest part, (2) distribution of turbidite sandstones in the Fold & Thrust Belt and (3) trapping mechanism which controls fluid type of fields. There remains an undrilled large anticlinal structure in the block because of geological risks mentioned above. INPEX is challenging to drill the structure solving these technical problems by applying the new high-end multi azimuth broadband 3D seismic technology.
New 3D seismic data achieved improved seismic data quality in bandwidth, S/N and deeper penetration and seismic images of fault surfaces and depositional facies. The seismic cube was used for the structural re-interpretation and the reservoir distribution study for finalizing the evaluation of drilling prospects and those locations. The geomorphological approach was applied to the reservoir intervals and depositional environment, sediment fairways and Net reservoir thickness/Gross interval map for those intervals were updated within the block which were integrated with regional geological understanding.
The post mortem analysis of upcoming drilling campaign should be incorporated for further understanding of regional petroleum system, trapping mechanism and sandstone distribution. The role of High-end 3D seismic will be more crucial to narrow the ranges of the geological uncertainties of undrilled structures and to make them possible drillable prospects in matured basin.
