Effect Evaluation Of Water Plugging And Profile Control In J Oilfield

The target block in J Oilfield has turned into middle-high water cut development period.The efficiency of water flooding is reduced,and the contradiction of the plane is aggravated.In order to improve oil recovery and relieve the contradiction,the water plugging and profile control measures become one of the main methods.According to the characteristics of low permeability fractured reservoirs,through theoretical calculation and systemic analysis and summary of laboratory test data,dynamic and static data and testing data,the paper studies the change law of water cut and yield of the target block in J oilfield,and predicts the trend of each index.By comparing the indexes before and after measures,the paper studies the effect of water plugging and profile control on c ontrolling water cut rising rate and production decline rate,calculates increased value of field,decreased value of water production and effective period of measures in the study area and evaluates the effect of water plugging and profile control in field test.Based on the comparison of the development effect of the profile control wells in the study area,the influence of the factors such as reservoir permeability,heterogeneity,water cut before the profile and injection system on the profile control effect is studied.By means of statistical regression analysis,the relationship between profile control effect and influencing factors was studied quantitatively and the relationship chart between increased value of field and influencing factors is established.The results show that the law of water cut increasing of the target block in J oilfield has the characteristics of typical low permeability fractured reservoir,and the three types of water rising model are fracture,fracture-porosity and porosity.The water rising model of the overall block shows the characteristics of the fracture-porosity,which the water cut rising rate is high in the middle and low water cut stage,and the water cut rising rate slows down in the high water cut stage.At present,it is in the period of rapid increase of water cut.The different types of wells group of the target block have shown the effect of increasing field and decreasing water production after water plugging and profile control.After the measures,average cumulative decreased value of water production of 34 w ell groups is 2076.37m3,and the rate of water cut increase reduces 0.77 percentage points.The production decline law of the target block is hyperbolic decline type,and average cumulative increased value of field of 34 well groups is 784.29 t,and the effective period is about 19 months.The important influencing factors of water plugging and profile control include timing,injection system,reservoir permeability,thickness and fracture development.According to the result of influencing factors,the results of calculation are studied quantitatively,and the water cut and water cut non-uniformity coefficient has the greatest influence on the measure of oil increasing amplitude.According to the results of the quantitative calculation of the factors,the influence of the water cut before measures and the inhomogeneous coefficient of water cut on the amplitude of oil increase is the largest,and the influence of the reservoir permeability and thickness on the amplitude of oil increase is relatively small.The effect of water plugging and profile control technology in J oilfield can be better in the following situations: In the respects of area and wells selection,large reservoir thickness,high permeability and serious plane contradiction can be better;In the respects of water types,the type of porosity can be better;In the respects of measure timing,taking measures before medium water cut period(water below 60%)can be better;In the respects of profile system selection,association gel + precrosslinked particle + inorganic gel + compound plugging agent and weak gel + particle + inorganic system + sealing agent can be better.The completion of the project,a set of test method for evaluation which takes field production and water cut as mainly evaluate indexes.By studying the change rule of indexes under the condition of water flooding,and comparing the characteristics of the actual development index,the paper measures the increased value of field and decreased value of water production under the water plugging and profile control measures.The methods of calculating the indexes which depend on the seepage mechanism of low permeability oil field and the combination of theoretical analysis and oilfield development practice have a high application value.