Performance Evaluation Of Efficiency Temporary Plugging Agent Used For Steering Refracturing

In the process of reservoir development,along with the increase in number of mining,first fracturing oil recovery will continue to reduce,the wells returned to the initial low efficiency state.If we continue using conventional methods multiple fracturing pressure,it will remain open the old fracture,so that it will not achieve significant yield.The fracturing technology is the current method to change the situation of old well wih low efficiency and inefficient comparison.The important mechanism of this technology is to squeeze a part of the temporary formation of temporary plugging agent temporarily plug the old cracks,shut down pressure for some time after the opening of complex cracks network,or temporary plugging agent into the hole or seam,forcing it to generate new Cracks,and then strengthen the new high oil and gas zone "communication" to improve the transformation of gas wells.At present,the crack steering has three main methods: 1)ground stress reversal;2)directional perforation induced 3)temporary plugging to the fracturing process.In this paper,the stress distribution of the reservoir before repeated fracturing is determined from the analysis of the stress field,and the calculation model of the influence of the original stress,the initial artificial fracture and the pore pressure on the original stress field is established.And the crack extension criterion,the study of natural cracks and extension of the situation.The nature of the temporary plugging agent is excellent,and it determines the success of the fracturing process in the seam.Due to the influence of the geostress field and the natural fractures,the temporary plugging agent must have some special properties.In this paper,several novel water-soluble temporary plugging reagents were tested,and their experiments were carried out by comparing their static(solubility,compatibility,surface activity,etc.),dynamic(temporary plugging rate,blocking rate)The results show that there are two kinds of efficient temporary plugging agents 9(SCJXSG ? BJ-APJEL)which meet the requirements of temporary construction and fracturing.The experimental results show that:(1)SC-JXSG and BJ-APGEL,which have a mass fraction of 3%,are slowly dissolved at 30 ?,and can be dissolved at 60 ? ~ 80 ? for several hours.(2)Dynamic evaluation experiment,under the conditions of 60?,injection volume 1PV,mass fraction of 3%,the SC-JXSG and BJ-APGEL two temporary plugging agent,the total amount of insoluble content is only 5.19% Temporary plugging rate can be up to 98%;under the conditions of 80 ?,reverse injection of 10 PV formation of water seepage,the blocking effect is not very good,located between 50% to 80%.Compared with the temporary blocking of cracks and matrix,SC-JXSG temporary plugging agent on the temporary plugging effect is better,BJ-APGEL temporary plugging agent on the matrix temporary plug effect is better.