BRIDGING THE GAP IN THE OIL AND GAS EXPLORATION PROCESS BETWEEN PETROLEUM SYSTEMS AND PLAY RISK ANALYSIS

An executive information system and GIS software tool has been developed that provides a rapid evaluation of the geologic probability of an effective play fairway. “Effective” in this sense means that there is adequate charge, reservoir, seal, and structure to hold at least some minimum threshold of accumulated and producible oil or gas in a play fairway. The input to this tool comes from basin framework and petroleum systems analyses. A petroleum systems analysis is typcially regional in scale and follows the deposition, maturation, and migration history from the reference of a single source rock. A play fairway analysis consists of a collection of genetically-related oil or gas prospects that can span multiple reservoirs with multiple seals that were charged by the same set of one or more source rocks.

Probabilistic maps are calculated based on the results of petroleum systems modeling and composite probability maps of effective reservoir, seal, and charge are produced. A composite map of effective reservoir is calculated across the play fairway from individual component probability maps. The composite probability of seal is based on seal presence and fault leakage or fault sealing capability. The composite probability of source rock is based on the presence of source rock, Initial TOC, and the maturation history. The last components include trap geometry (structure) and timing and migration. These are all combined, considering independent and dependent parameters resulting in a composite probability map within the play fairway. Data quantity and quality are used to quantify the probability of effectiveness of the individual play components.

The techniques and workflow embodied in this software have become an integral part of the exploration and development process for an important national oil company. Explorationists analyzing play fairways with this tool create “living documents” that are updated as new data is acquired. This provides management with a consistent product created by a consistent methodology that allows rapid evaluation of those plays that qualify for further economic analysis with more detailed play risk software. While developed for oil and gas exploration, this software could equally be applied in other extractive industries such as mining.