Stratigraphic Forward Modelling for South WestCollie Hub

[摘要] A stratigraphic forward model of the time period from 250 Ma to 182 Ma (Olenekian to Pliensbachian - Base Wonnerup equivalent to top Eneabba equivalent ) has been created in that part of the South Perth basin that is a candidate area for geological sequestration of carbon dioxide (the subject of the existing Schlumberger static and dynamic model). We used the CSIRO Sedsim stratigraphic forward modelling software constrained by available well and seismic data and previous published and restricted geological studies. The goal was to determine the distribution of grainsize and primary porosity (and permeability via the same transfer function used by Schlumberger) of Triassic and Lower Jurassic sediments below seismic resolution and away from well data across the study area around the Harvey-1 well. The research targeted the significant current risk involved in applying traditional oil-field reservoir characterisation tools to the construction of static geological models of saline formations. As stated in the latest US DoE document on CCS,“…. The successful characterization of a site is the most important step in ensuring the safe and economic operation of a CO2 GS site.” [2010 DoE Site Screening, Selection, and Initial Characterization for Storage of CO2 in Deep Geologic Formations. DOE/NETL-401/090808, November 2010].The project has demonstrated an alternate workflow for producing a static reservoir model for geological sequestration of CO2. The workflow was based on limited well and seismic data constraints, and used the Sedsim stratigraphic forward modelling software to translate a conceptual geological model into a cellular geological volume. This volume will form the basis of a reservoir flow simulation of CO2 injection into the Lesueur Sandstone. Two models have been produced; a 5000 m grid over the 75 km x 40 km area, and within this, a nested 500 m grid over the Collie Hub dynamic model area of 15 km x 10 km.A blind test of porosity distribution at the Harvey-1 well location suggests that the model may be suitable for use as the basis of a dynamic reservoir simulation.Output from the model consists of:•3D interactive visualisations in SedView format. •ASCII files in various formats with grain-size, porosity, facies, stratigraphic age, sorting, sand fraction etc. that can be used to generate pseudo-well logs, synthetic seismic sections, permeability and porosity volumes, etc. at the spatial resolution of the grid and the vertical resolution of the depositional events or a fixed vertical scale as required.•Movies of basin formation from 250 Ma to 182 Ma.As with any model, it is incomplete at several levels, and will need to be updated as new information become available. However it is hoped that this initial attempt to predictably model facies distribution, porosity and permeability (below seismic resolution and away from well data) will stimulate further use of the stratigraphic forward modelling approach, both at the regional and field scale, for geological sequestration of carbon dioxide, as well as petroleum systems and aquifer-constrained geothermal projects.

[发布日期] 2013-06-04 [发布机构] CSIRO

[学科分类] 地球科学(综合)