Prediction of Pre-Salt Carbonate Reservoirs in Kenkiyak, Kazakhstan presented by Zhenglian Pang

Abstract

The main paying layers in the Carboniferous from Kenkiyak oilfield are beneath the very thick Permian salt layers. Influenced by velocity differences of salt domes and surrounding rocks in pre-salt formations, seismic events distortion is so serious that structural imaging and reservoir prediction are rather difficult. In order to solve the problems in carbonate reservoir prediction of Carboniferous oil reservoirs,a geological genetic prediction method is proposed in this paper, in which reservoir prediction of different geologic origins will optimize seismic prediction technologies matching with their geology background. Firstly, through seismic data processing and velocity field study, the interference caused by the very thick salt dome can be eliminated. Then based on origin analysis of reservoir geology and its geological conceptual models, the features and correlations of logging and seismic of reservoirs with different origins can be figured out. So seismic prediction methods are optimized. The macroscopic qualitative prediction of reservoirs with different origins is conducted according to litho-facies prediction - karst prediction - fracture prediction procedures. And a refined geological model of reservoir development is established. Lastly, guided by the refined geological reservoir model, multi-parameter inversion and multi-attribute neural network inversion techniques are adopted for quantitative prediction of reservoir thickness and porosity, and distribution of favorable reservoirs. The results show that:（1) The structure of the pre-salt Carboniferous oil reservoir is a large nose-type structure pitching out in the northwest and uplifting in the southeast, in which four local highs and three phases of fractures develop.（2）The main facies are platform margins, open platforms (including shoals and sags), platform marginal slopes and open shelf facies, and favorable reservoirs are mainly distributed in platform margin shoal accompanying multi-stage faults faults. (3) Karst reservoirs with vertically zoned and planar division features are dominant in various types of reservoirs, which develop within 200m from the top surface and in karst slope. (4) The effectiveness about structural, karst and diagenetic fractures in the Carboniferous depends on how much they is filled, and the distribution of fractures is closely related to regional faults with three groups.

AAPG Datapages/Search and Discovery Article #90332 © 2018 AAPG International Conference and Exhibition, Cape Town, South Africa, November 4-11, 2018