An EOR Research On Polymer Flooding Of Jurassic Reservoir In Longdong Area

In this paper,the study objects are two Jurassic reservoir:southern number one district of Maling field and hua201 district in Huachi field.In the basis of the research on geologic reservoir features and current status of exploitation,in view of principal contradiction which exists in its development,proved the posibility of polymer flooding.Through the in-house experiment on salt endurance,viscosity,salty sensitive,viscosity-temperature characteristics,heat resistance,injectivity,sheafing strength and etc.Evaluating different polymer's performance,choosing the applied polymer according to the region of interest,numerical model,confirming the injection method and injection parameters,designing the scheme polymer flooding,and the design of ground supporting circuit is optimized.At last,evaluating the effect of polymer flooding through the minesites life of pilot in region of interest.Getting the main points as follows:(1) With the increase of Na⁺,the electric repulsion of carboxylic contention is repressed in polymer,the molecular line group is rolled,the viscosity of liquor is declined.With the increase of the Ca²⁺ content,the viscosity is declined sharply,when the concentration of Ca²⁺ is more than 150 mg/L,the decline tendency is flattened,the more Ca²⁺ concentration,the more serious viscosity losses,the existence of Ca²⁺ is bad for the polymer viscosity,under normal circumstances,concentration of Ca²⁺ is best controlled less than100mg/L;After adding Fe³⁺,flocculation and precipitation appeared obviously in the polymer solution,the more content of Fe³⁺ the more precipitation,so,in the preparation of polymer solution,it should be to strictly control the content of Fe³⁺ ion.(2) The polymer coreflooding experiments showed that injected the same pore volume under the same conditions,the greater the polymer concentration,the higher the degree of recovery to improve,the speed of the value of recovery increases with the concentration tends to slow down;Under the same conditions of polymer concentration,with the increase of injected polymer coreflooding,the recovery ratio also increases.The speed of the value of recovery increases with the injection rate tends to slow down. (3) Using the software of ECLIPSE polymer flooding module,analysed the effect of polymer flooding'factors.Large edge aquifer,high degree control of water drive,low saturation of residual active oil,high temperature reservoir and so on.These are the main factors to restrict the effect of polymer flooding in region of interest.(4) According to the result of in-house experiment and numerical modeling,field experiment polymer choose micro gel driving and polymer flooding.The range of polymer concentration is 1000～1500mg/L,their counterparts in the system of concentration range is 15.26～36.55mPa·s;From a technical and economic consideration,determine the amount of polymer;Considering the capacity of reservoir,fluid production force,development cycle,blocks of the overall economic benefits,oil production plans,improve the effect of polymer flooding and etc.,integrated to determine a reasonable speed of polymer solution injection.(5) The polymer experiments showed that the effect of the polymer flooding to decline water and fix water was outstanding,the situation of waterflooding changed for better,the recoverable reserves increased;Entry profile and liquid producing profile have been improved, expanded the swept volume,improved the situation of producing reservoir;The more orientations of oil well responses,the better effect.