A re-crosslinkable composite gel based on curdlan for lost circulation control

Lost circulation is a vital and challenging problem in oil and gas well drilling. In this study, a new lost circulation material was successfully synthesized via a facile method: the re-crosslinkable composite gels consisting of curdlan and copolymer of SMA-AM-AA crosslinked by hydrophobic association. The re-crosslinking time, rheology property, swelling behavior of re-crosslinkable composite gels were systematically studied, and the physicochemical properties were characterized by FT-IR, SEM and TGA. The results show that the re-crosslinking time can be accelerated by increasing the re-crosslinking temperature and concentration of re-crosslinkable particles. The introduction of curdlan and iron ions can improve the storage modulus of the re-crosslinked gels. Compared with conventional gel materials, re-crosslinkable gels show better bearing-resistance capacity in fracture. Moreover, the plugging mechanism of re-crosslinkable composite gels in fracture was analyzed. The result shows that the re-crosslinkable composite gels have broad application and potential in oil and gas well drilling.