Research On Separated Filling Screen Tube Artificial Borehole Wall Sand Control Technology

This dissertation invented Separated Filling Screen Tube Artificial Borehole Wall Sand Control Technology,a new type of sandcontrol technology,which can simplify the processes,reduce sandcontrol cost and increase the productivity of oil wells.A standard for choosing the materials of soluble tube was firstly established,basing on which PLA-T was selected.Besides,soluble tube and separated filling screen tube were designed and three-dimensional models were constructed by Solidworks.Highly-efficient degradation agents for soluble tube were invented according to the characteristic of PLA-T that the recipe for inorganic degradation agent is 35.71%wt~40%wt Sodium Hydroxide Solution and the one for organic is Acetone : DMF : Ethidene Diamine = 3 : 2 : 5.This dissertation evaluated the effect of temperature and concentration on the degradative behaviors of inorganic degradation agent and organic degradation agent's resistance to temperature,dilution and salinity simulating reservoir conditions.Experimental results shows that the degradative behaviors of inorganic degradation agent is influenced obviously that 70% degradation time ranges from 3.5h to 4h when temperature is 50? and concentration is 34%~38% and it ranges from 1h to 3h when temperature is 60?~70? and concentration is 20%~40%.Organic degradation agent has excellent performance resisting to temperature,dilution and salinity and 70% degradation time ranges 9min to 92 min under the condition that temperature is 50 ? ~80 ?,concentration is 70%~90% and salinity is 0mg/L~100000mg/L,which can make filling screen tube separated highly-effectively.This dissertation researched on the degradation mechanism of organic highly-efficient degradation agent through scan electro microscope.The experimental results shows that the superficial structures of PLA-T particles experience smooth surface,cracks,crevices,multiple crevices,irregular crevices and crevices/holes successively and at the beginning of degradative reaction the increasement of the contact area between PLA-T particles and degradation agent influences more than the decrease of degradation agent concentration,so degradation velocity keeps increasing to the peak value when the decrease of degradation agent concentration starts to influence more than the increasement of the contact area and after that degradation velocity keeps decreasing to the end of degradation.