Study On The Displacement And Well Pattern Evaluation System In Water Flooding Oilfield

During the late stage of water flooding oilfield,the remaining recoverable reserve is still considerable.While this development stage faces lots of problems such as reservoir heterogeneity is more apparent,the efficiency of reservoir displacement decline obviously,and oil production decreases sharply in the production well.So it is of great importance to evaluate the well-pattern and displacement system during the late stage of water flooding.This article will establish a more perfect well pattern evaluation system to evaluate displacement degree on the basis of the existing evaluation indexes and considering the limitations of them.First,adapt multi-index in consideration of reservior heterogeneity and its changes,that is cumulative evaluation index and instantaneous evaluation index,the new evaluation system can not only reflect the characteristics of the reservoir,but also reflect the displacement process and strength.Secondly,deduce the calculation methods of each index,calculate the distribution of each evaluation index at different grid point in the reservoir,and analyze the general distribution law of each index at different reservoir locations.Thirdly,establish the multi-index comprehensive evaluation system method.Analyze the difference degree of each index in the reservoir to evaluate the equilibrium level of displacement.use homogeneous reservoir as a template to form a frequency distribution curve criteria and compare actual oilfield with it to access if the well pattern match the formation well.And then integrate the evaluation index to make a comprehensive evaluation of well pattern.Last,using P2 oilfield as an example,establish five-spot well pattern and arrayed well pattern,comparatively analyze the well pattern and the displacement effect,then give the corresponding adjustments propose.This example can fully verify the reliability of the evaluation system...