The Research And Application Of Casing-Loss Solid Sand Plugging Agent

Currently used has a certain strength of plugging agent is mainly cement,epoxy resin,unsaturated resin,phenolic resin,urea-formaldehyde resin,melamine condensation and so on,but with different features,combined with the requirements of the project and various performance of the resin,the proposed use of urea modified phenolic resin as solid sand blocking agent,it has the following characteristics: the initial viscosity can be adjusted,ensure smooth injection.The curing time is controllable and sufficient injection time is guaranteed.High curing strength,can effectively stabilize fracture.The system is water-soluble and does not contain solid particles,which can effectively enter the small pore channels.The preferred sand-fixing agent is a urea-modified phenolic resin,which has characteristics such as adjustable initial viscosity,controllable curing time,high curing strength,and water solubility.The optimum reaction conditions for the synthesis of sand-slug plugging agent: formaldehyde addition 50%,phenol addition 23%,modifier urea addition17%,NaOH addition 7%,catalyst resorcinol addition 3%.The reaction temperature was 60°C and the reaction time was 120 minutes.The initial viscosity of the sand plugging agent is less than 50 mPa·s,and citric acid is selected as the cross-linking agent of the sand consolidation agent.The curing time can be controlled within 28 minutes to 1549 minutes.The curing intensity is 15.4 MPa to 18.7 MPa.The rate is less than 3 x 10-3 ?m2.Indoor testing and evaluation of the sand-stripping plugging agent was carried out,and the on-site construction process and operation and specifications for use of the sand-sanding agent were determined.From November 15,2017 to November 26,2017,five on-site wells were constructed: high169-45 well,high 165-45 well,south 3-3-47 well,South 5-2-134 well,South 1-4-Zengshui22 well,both achieved a success rate of 100%.