Low-permeability Sandstone Reservoir Water Flooding Effect Evaluation And Methods Research

In China, 1/4 proven reserves of all the proven reserves is in low permeability reservoir. How to develop low permeability reservoir efficiently is of great significance. The original elastic energy in low permeability reservoir is generally small, so all the oil fields early or late adopt water flooding to keep the pressure of the low permeability reservoir. But the geology in all the low permeability reservoirs is very complex. How to water flood to get the best development effect is always what people concerns about. Therefore, evaluating the water flooding effect of low permeability reservoir scientifically is of great importance to deepen the water flooding and offer reliable reference of carrying out the measures of exploring the potential reserves as well as increase the oil recovery. Drawing lessons from the evaluation methods and principles of water flooding in exploring the middle-high permeability reservoirs, taking the fact that all the tow permeability reservoirs are of threshold pressure gradient(TPG) into account, with the methods of oil reservoir engineering, system engineering, fuzzy mathematics and principle of hierarchy analysis, we firstly produce 4 methods to determine the TPG of low permeability reservoir. With those 4 methods, we determined the TPG of Baobei block, Baolang oilfield. Then, we discussed the impact of TPG on the water flooding effect in low permeability reservoir. Finally, we evaluated the water flooding effect of low permeability sandstone reservoir innovatively and scientifically in three ways: potential of water flooding, effect of water flooding and man-controlled factors of water flooding. In each way, we created corresponding evaluation indices, evaluation criteria and calculating methods. And we produced evaluation index of increased rate of water cut innovatively in order to evaluate the containing water rising regular in low permeability sandstone reservoir. By analyzing the water flooding effect of Baobei block, Baolang oilfield, we got results that match produce, which proves that the evaluation indices, evaluation criteria and the calculating methods produced by this paper are reliable and applicable.