Synthesis And Properties Of Temperature-resistant Oil Well Cement Retarder

With the development of the oil industry,the field of exploration and development is expanding to deep oil and gas reservoirs,and the formation temperature increases with the depth of oil well.But the slurry used for deep wells,ultra deep wells and special wells often meet the problem that the thickening time and the rheological properties of the bottom cement slurry is shorted due to the high temperature circulating,as well as the cement slurry strength of the top develops slowly and prone to the phenomenon of super-retarding problems which caused by the large difference in temperature,all of these not only affect the quality of cementing,but also is not conducive to the safety of cementing construction.This article based on the hydration mechanism of cement slurry and the retarding mechanism of retarder,aimed at producing the high temperature retarder applied to deep well and ultra deep well.Firstly,molecular structure design was carried out from the point of view of high temperature retarding,and sodium p-styrene sulfonate as the main chain,carboxylic acid monomer as main retarding monomer,and through the introduction of a new type of functional monomer with temperature retardation,and two new type high temperature retarder were synthesized according to the free radical aqueous solution polymerization.and the synthesis conditions were obtained by controlling the variable method and orthogonal test under the conditions of thickening time,and respectively named the PSIH and LNS-1.Then,the molecular structure,heat resistance and the application performance of the two copolymer retarders were evaluated.The composition,molecular weight and functional group of the two polymers were characterized by XPS,FTIR and 1H NMR.The results showed that all the monomers were involved in the reaction,PSIH and LNS-1 were successfully synthesized.TG results indicated that both polymers have good temperature resistance and are supported further by the microstructure of the polymer solution.Comprehensive application performance description,high temperature(120～180 ℃)retardation effect of both copolymers is outstanding;In addition,PSIH dispersibility is good,with excellent large temperature difference performance,taking into account the high temperature thickening time and low temperature compressive strength,which can be applied to large temperature difference cementing.LNS-1 has a good high temperature stability,can effectively prevent the phenomenon of high temperature sedimentation,which is very favorable for deep wells,ultra-deep well cementing.Finally,this article studied the retarding mechanism of retarder by TG,XRD and SEM.The contents,composition and microstructure of cement paste of two kinds of retardants were compared with pure cement slury.Two kinds of copolymer retarder mainly through the formation of polymer film by adsorbing and chelating to impede the cement hydration process,and thus extend the thickening time to play a retarding effect.