ABSTRACT: High-resolution reservoir stratigraphy of the Miocene Nurbani carbonate platform: designing an FDP for a heavy oil reservoir, offshore Sunda Shelf, Indonesia

Crevello, Paul¹, Robert K. Park², Syafru Syafar³, and Peter Colonomos⁴
(1) Petroleum Geoscience Consulting, Bandar, SB, BS 8675, Brunei 
(2) Kodeco Energy Co., Ltd, Jakarta, Indonesia
(3) YPF Maxus, Jakarta, Indonesia
(4) NITEC LLC, Denver, CO

The Nurbani reservoir is a Middle Miocene carbonate platform located on the western flank of the Sunda Basin. The field was discovered in 1983. Eight wells and 2D seismic delineated the elongate NNW-SSE-trending platform, which measures 2.3 by 6 km. Five wells tested oil at rates between 86 to 1747 BOPD over 200' of oil-saturated reservoir.

The platform stratigraphy varied through time, recording an initial transgressive low-relief ramp, an intermediate aggraded steep reef-rimmed platform, and finally a terminal platform that backstepped and eventually a drowned reef ramp. Reservoir architecture was defined within these first-order seismic bodies.

Well-log and core reservoir stratigraphy and 3D-visualualization were used to build coherent static high-resolution reservoir models. Core data and flow tests constrained petrophysical permeability models of reservoir flow units, barriers and flow simulations. Critical production concerns addressed in the field development plan (FDP) were the oil viscosity, isolation of the gas cap, fracture potential and vertical encroachment across permeability baffles and barriers, downlapping reservoir conduits, and side aquifer charge from a major basin-bounding fault system.

Simulations were performed to evaluate both natural depletion and steam injection. The static reservoir model was input into a black oil numerical simulator. Multiple scenario porosity-permeability models were applied. Prediction runs were made for well locations and horizontal reach of wells. The data were also converted to a thermal simulator in order to evaluate the merits of steam injection.

AAPG Search and Discovery Article #90913©2000 AAPG International Conference and Exhibition, Bali, Indonesia