New way to estimate of Achimov formation resource potential at a low level of study

Background. The Neocomian clinoform deposits of West-Siberian oil and gas province (WS), which state of exploration is uneven, is one of the fulfilment sources of Russian Federation’s hydrocarbon resource base. The most explored areas are in the south and middle parts of WS with the mature history of oil production and related to large regional uplifts. Though, zones of megadepressions and monoclines are poorly explored, mostly prospected with only few wells and   relatively rare seismic grid. These zones can potentially have rich resource base related to lithological objects and reservoirs of Achimov sequence represented by deepwater alluvial cone deposits.

These are geological reasons of poor exploration maturity of Achimov sequence: complexity of internal structure, poor reservoir parameters (porosity and permeability), high spatial heterogeneity that causes heterogeneity of lenses saturation and difficulties in predicting of perspective reservoirs out of large structural uplifts.

All these factors require using a variety of modifications of the density method when evaluating resource potential of objects.

Aim. Evaluation of resource potential of Achimov sequence object and taking into consideration all geological uncertainties and risks when performing economic-geological evaluation.

Materials and methods. The team of Gazprom neft companу group has developed an approach to probabilistic estimation based on density method, which allows correctly consider all major geological uncertainties when resource base evaluating.

Results. Approach design by Gazprom neft companу group has been successfully tested on real case object without any well data, but with 3D seismic grid. Results of this test formed the basis for production profiles estimation, forming program of geologic exploration activities and economic efficiency assessment within economic-geological evaluation.

Conclusions. The  methodology makes it possible to assess the commerciality of zones with partial and complete lack of geological and geophysical data and to justify the expediency of further appraisal of these zones. 

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