Petrophysical Properties Evaluation and Lithology Definition of the Tight Oil Formation in Western Siberia

Abstract

Abstract

The tight oil development in Western Siberia is mainly related to the Bazhenov formation with billions of tonnes of geological oil resources. During last five years all major oil companies in Russia are doing pilot projects for Bazhenov formation development including field development with vertical wells, horizontal wells, horizontal wells with multistage fracturing, fireflooding and thermo-gas stimulation. All these pilot projects have similar problems related to the difficulties with petrophysical properties evaluation and producing interval identification.

The paper describes results of new method of complex petrophysical properties evaluation of tight oil formations with use of the well logs and core data. The main goal of new method is providing lithology identification and production potential allocation withing Bazhenov formation, defining its rock properties and developing petrophysical correlations. The research was done using actual data from sufficient number of wells in Western Siberia that could confirm the confidence of the proposed methodology.

Integrated approach is suggested. This approach includes integrated data analysis starting from seismic data analysis, well log data analysis, acoustic logging data simulation. Forward modeling of acoustic field around the well is used. Structure of the fractured formation is estimated using inversion and acoustic field modelling. The methodology includes the following steps: preliminary analysis of the standard well logs, analysis of cross-plots of the resistivity, gamma-ray and hydrogen index as well as distribution of these properties and analisys of the core data if available. The proposed method provides way to lithology definition of the tight oil formation and following petrophysical properties evaluation for localisation of the producing intervals and providing more success ratio not only for pilot projects but also for future full field development.

AAPG Datapages/Search and Discovery Article #90260 © 2016 AAPG/SEG International Conference & Exhibition, Cancun, Mexico, September 6-9, 2016