Study On Deep Profile Control Technology Of Water Injection Wells In Shannan Block 3

Shannan 3 block is a typical low porosity and low permeability reservoir with strong reservoir heterogeneity.In the process of long-term waterflooding development,the contradiction between layers and within layers is intensifying,which leads to worse waterflooding development effect,lower oil well productivity,and increase of comprehensive water cut.In order to further improve water flooding efficiency,water injection well profile control technology research is carried out in this block.Based on the investigation of water injection profile control technology at home and abroad,combined with the actual situation of the reservoir,the combination profile control system with polymer flooding and surfactant flooding was analyzed,and the indoor formula of deep profile control system was studied.A compound gel profile control agent and compound surfactant suitable for reservoir conditions of Shannan 3 block was developed,a flexible resistance to salt granular profile control agent was screened,and the laboratory performance evaluation of profile control agent system was proceeded.The laboratory evaluation results show that the compound gel profile control agent has the characteristics of good selection of sealing characteristics,high plugging rate,good heat resistance and salt resistance and good thermal stability,The screened retarding dilatation viscoelastic particle profile control agent has the characteristics of slow expansion speed,good salt tolerance,good water retention and suspension performance.The compound surfactant has the performance properties of 10^-3mN/m order of magnitude.On the basis of laboratory experiments,the composite gel profile control agent,flexible resistance to salt particle profile control agent and compound surfactant are combined slug,and the profile control process design suitable for Shannan 3 block was developed.The Shannan3-29 well group was selected in the block,and the pilot test of deep profile control was carried out.The water injection starting pressure after deep profile control measures was increased from9.2MPa to 15.6MPa after deep profile control measures.The water absorption index decreased from 27.0 m³/MPa to 13.9 m³/MPa and decreased by 48.5%before the measures.The cumulative output of the four wells corresponding to the borehole within six months reached 848 tons.The pilot test results shown that the developed composite gel profile control agent,compound surfactant,and screened flexible and salt-tolerant particle profile control agent could meet the needs of deep profile control in Shannan block 3 reservoir,the effect of increasing oil and precipitation is obvious,provide guidance for the application of the block profile control technology.