The Comprehensive Evaluation Of Reservoir In Weixian Layer System Of Kotovskoye Oil Field In Russia

Reservoir synergistic evaluation is the main content of research on reservoir geology developing recently. And the quanlity of the reservoir has effects directly on the production of oil layers, waterflood response and the final recovery efficiency. So the synergistic evaluation of reservoir takes an important part in reservoir description. In order to meet the needs of oil/gas exploratory development, the study on synergistic evaluation of reservoir is more and more interdisciplinary and comprehensive. Kotovskoye oil field has simple structure, and the reservoir characteristic is the key factor of controlling the distribution of productive oil reservoir. So the reservoir characteristic in the oil field needs deeply studying. This paper classifies and evaluates the reservoir, studies the distribution of every sub reservoir, analyzes how the reservoir characteristic controls the production performance, and predicts the productive parts of the oil field using the method of systematical cluster analysis in fuzzy mathematics by statisticing and integrating the evaluation parameters.The main conclusions of the paper can be declared as follows:1. The reservoir of Weixian layer system in Kotovskoye oil field is made up of sandstone and silt sandstone, with slight greywacke and carbonate rock. The sandstone has high porosity and permeability while the silt sandstone has moderate porosity and low permeability. On vertical level, the bottom has high porosity and high permeability and the upper part has moderate-to-high porosity and moderate-to-high permeability.2. The reservoir of this system layer is classified to four parts using the method of fuzzy cluster analysis, and the productive parts are concentrated in the classes of I and II.3. The quality of the reservoir is controlled by the sedimentary process. So the reservoir with high quality in the oil field mainly distributes in the sand flat, sand crest and tidal flat. But the reservoir with low quality grows in the mud flat.4. Almost all productive wells meet the interval with high porosity and high permeability, which has thick sandstone, long effective thickness, small quantity of clay.5,The distribution characteristic of productive parts are contained by overlapping the counter maps of the porosity and the maps of the permeability and the maps of the effective thickness with the structure maps and micro-sedimentary facies maps using the method of versatile information superimpose. In other words, the productive parts are mainly located in the layers of C-III-1 and C-V, which sheet-like distribute and other layers has odd distribution which has small areas. The achievements of this paper will be a reference for the reservoir synergistic evaluation of the whole oil-field. Then this will be guide and applicability for the exploratory development and deploying wells in the oil-field. Meanwhile, this will play an important role as replenishment for the reservoir evaluation in other oil basins of the oil region.