The New Evaluation Method Of Fuyang Oil Layer With Low-permeability In Daqing Peripheral Oilfield.

The proved reserve of Fuyang oil layer, with small-scale channel sand body, poor physical property and serious heterogeneity. The geological characteristics, reservoir characteristics of ultra low permeability reservoir are analyzed. The parameters impacting the development results are investigated using theory of non-Darey Porous media flow. Based on this, the rate-controlled mercury injection, nuclear magnetic resonance, porous flow theory of low-permeability reservoir and physical simulation were used to evaluate the reserves of low-permeability reservoirs, taking throat radius, percentage of mobile fluid, start-up pressure gradient as the evaluating indexes.The corresponding hierarchical appraisal methodand hierarchical demarcation line were set up. In order to quantitatively analyze the characteristics of the reservoir, the reservoir is tentatively evaluated with Principal Factor Analysis(PFA) and Fast Clustering Method(FCM). Firstly, the scores of the principal factors obtained by PFA are normalized; then, the normalized scores are multiplied with the weights of the corresponding principal factors and added to get the scores of the samples. The reservoirs are evaluated by applied FCM with the scores of the samples. This method has been successfully applied to the evaluation of low-permeability reservoirs in Daqing peripheral oilfield. Using this new classification method, the low-permeability reservoir are classified into three types and four sub-types. The three types include low permeability reservoir(I), extra-low permeability reservoir(II) and super-low permeability reservoir(III). The three types include low permeability reservoir(I), extra-low permeability reservoir (II),super-low permeability reservoir (III). Among them extra-low permeability reservoir and super-low permeability reservoir are the main reservoir types, they are divided into two sub-types respectively.