Database technology for geological modelling of hydrocarbon reservoirs

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The geological characteristics of subsurface sedimentary rocks control the amount of oil, gas and/or water present within them (as hydrocarbon reservoirs or aquifers), and how such fluids will flow. Petroleum geologists build three-dimensional numerical models to ascertain the likely amount and flow rates of oil and gas and optimum well locations. These models ultimately determine the success of different strategies of hydrocarbon production. Similarly, hydrogeologists develop corresponding geological models to predict water yield or contaminant transport, in order to inform aquifer exploitation and clean-up. The creation of these geological models is also required to assess the feasibility of programmes of underground carbon capture and storage. When these models are built, geologists have available only limited direct subsurface data with which to constrain the type and geometry of subsurface geological bodies with and thus their fluid-flow characteristics. To complement the sparse direct data, exposed outcrops of similar types of rocks, or modern sedimentary environments where comparable sediments are deposited, can be used as 'analogues' to hydrocarbon reservoirs or aquifers. These analogues provide proxy information regarding geological features that determine reservoir or aquifer heterogeneity. Within a reservoir or aquifer, these geological heterogeneities exert a primary control on well connectivity, flow rates, production behaviour and/or to clean-up strategies, thereby dictating how much oil or gas is likely to be produced from a reservoir, or whether contaminants are successfully removed from groundwater. Quantitative analogue data are required as input for constraining geological models of the subsurface. The derivation of this type of data from databases is an integral part of subsurface modelling workflows, but current approaches are inadequate because of the limited volume and quality of data stored in existing databases, and their current poor integration with existing modelling tools.The Leeds University IP consists of three different relational databases that contain analogue data about types of rock volumes that constitute the building blocks of geological models of reservoirs or aquifers; each database relates to a particular geological setting. All data are stored in a format that allows quantitative output to be produced, in forms that can be fed into all the common numerical methods used to build models of subsurface heterogeneity. The technology of the IP surpasses similar databases in terms of data standardisation, quantity, quality and format. The fact that a fuller characterisation of sedimentary heterogeneity is achieved by these databases enables the derivation of the output required by existing modelling algorithms: this makes the IP unique in its class. However, the current value of the IP is limited by the lack of integration with software platforms employed to generate and manage geological models of the subsurface, such as Schlumberger's Petrel. At present no existing analogue database produces output in a format readily digestible by the algorithms used in Petrel to generate geological models. Thus, the development of an interface for the optimal integration of the databases with Petrel is a key requirement for making the IP marketable. The ideal incarnation of the interface would be in the form of a Petrel 'plug-in' software component.Upon successful development, the IP will enable easy access and application of large volumes of high-quality data: this technology will aid geologists and engineers in the hydrocarbon and water-management industries in the generation of geologically sensible reservoir and aquifer models. The project will be undertaken by Luca Colombera, currently a post-doctoral research associate at Leeds, and supervised by Nigel Mountney, who is a sedimentologist and director of the Fluvial Research Group, and Bill McCaffrey (sedimentologist).