Experimental Study Of Toughness-Enhanced Thermo Sensitive Composite Alkali Lignin Gel Used For Plugging At High Temperature

Fracture-vug reservoir are widely distributed in the world,and the output is huge.The fracture cave is mainly reservoir space,which is characterized by various forms,large size and uneven distribution,and the edge and bottom water is easy to output from the high angle fractures.At present,there are many defects such as poor temperature resistance and salt resistance,short operation time,poor water control and oil stabilization in the domestic conventional profile control system.Concerning this problem,study of the thermos sensitive composite alkali lignin gel plugging system is proposed in this paper.The system is characterized by the addition of a toughening agent in the alkali lignin gel system,using the special molecular chain structure of the toughening agent to increase the toughness of the gel,it is also a kind of water shutoff agent,which can increase the strength of the gel system at the same time.The optimal concentration of different components by means of orthogonal experiments like alkali lignin,cross-linking agent and toughening agent was determined: 5.0% alkali lignin + 3.0% Urotropin +1.0% Phenol + 0.5% Toughening agent,gelation time 22 h and the gel strength 0.052 MPa.By discuss the value of different elements such as concentration,pH value,temperature and salinity on the gelling properties and stability of the system in the paper,the results show that the performance of this system is stronger,the PH range of gelling is wilder and the salt-resistant ability is better.Nice plugging performance and long watercontrol validity was remarked through the sand-filled pipe physical model.Also,the elastic modulus and creep recovery test showed that the addition of the toughening agent improved the ability of the internal structure of the gel system to resist the slip deformation.It is clearly to see that,through the infrared spectra the toughening agent does not have the appearance of new peaks before and after the addition,the addition of the toughening agent did not produce new functional groups in the infrared spectra,that is to say the toughening is mainly based on the physical change.In this presentation,the field process of plugging on L block XX well was designed,and achieved good results.