Study Of Log Interpretation Methods Of Thin-Poor Waterflooding Reservoir Of Sa'ertu Oilfield, Daqing

This paper has been prepared in response to the challenges met in the development of high water cut Sazhong area of Daqing oilfield in terms of water flooding development strategies and infilling drilling as well as residual oil characterization, like increased complexity in residual oil and gas distribution, shift of development series from thicker pays to thinner pays of inferior quality (i.e. pay zones less than 1.0 m in thickness) resulting in less evident water-flooding characteristics on logging curves due to low vertical resolution and shallower lateral detective depth for conventional logging suits, therefore making interpretation of thinner poor pays inaccurate and posing a bottleneck problem for reservoir management. Therefore it is of critical significance to carry out the study of interpretation method for water-flooding thinner poor pays in Sazhong area of Daqing oilfield, integrating geology, logging, lithofacies, well test, core data, dynamic and static data to increase the accuracy of logging interpretation for thinner poor pays which have been water flooded. Major conclusions have been listed as follows:1. A systematic set of logging interpretation method applicable for sand stone reservoir of multiple development series has been established, especially the systematic logging evaluation model incorporating the geological characteristics of thinner poor pays, thus accuracy of logging interpretation could be increased and this method is highly applicable for water-flooding logging interpretation.2. Through petrophysical experiments and theoretical simulation, conductivity mechanism of water-flooding pays during re-injection of produced water have been analyzed systematically for the first time.3. Employment of high resolution processing, deep and shallow 3 lateral resistivity joint inversion as well as value assumption from different zones plus the data from sealed core samples have been done to establish fine logging interpretation model incorporating formation parameters from zones constrained by geological setting.4. Interpretation method has been established based on the sealed core data from monitoring wells and conductivity mechanism in the process of water flooding under reservoir conditions has been taken for reference and lithofacies analysis technology has also been introduced, and decrease method of dynamic resistivity, identification method for water flooding model, analysis technology of priority movement of fluids have been employed to establish static interpretation standards for water flooded pays and dynamic evaluation technology.5. Application effects of new technologies like high definition array induction, P-NMR, CHFR in thin-poor pays which have been water flooded.Technical means and methodology in this paper is applicable for logging interpretation of thin-poor pays in water flooded oilfields, which can be referenced when it comes to logging interpretation of similar water flooded formations and will open new vistas for logging interpretation sector, bring in numerous benefits.