表面稠化酸的防砂作用研究

表面稠化酸是将稠化剂(PAM)、交联剂(GL-5)加到酸中配制而成,它具有缓速酸化和防砂作用。该酸通过稠化剂的体相稠化作用,控制氢离子的扩散速度,具有很好的缓速作用;随着H+的不断消耗,通过稠化剂与交联剂在砂粒表面适合的pH值(pH=3~5)下的交联作用形成冻胶膜(表面稠化),该膜是一种很好粘弹体,弹性大于粘性,对砂粒表面润湿,通过氢键及静电引力加强对砂粒表面的吸附,限制砂粒运移,达到防砂目的;该膜可以进一步控制H+的扩散速度,达到进一步缓速目的,保证表面稠化酸酸化深远地层。对表面稠化酸的防砂机理及防砂效果进行了评价,提出了将酸化与防砂有机结合的新思路。

STUDY ON FUNCTION OF SAND CONTROL OF SURFACEVISCOUS ACID

Surface viscous acid has been prepared by mixing thickening agent (PAM) and cross-linking agent (GL-5) with acid, which has the function of retarding reaction rate and sand prevention. At the beginning, the acid can retard the reaction rate by controlling the diffusion velocity of H+ in the body phase densification of the thickening agent. And with the consuming of H+, the acid can control sand and retard reaction further by forming gel film (surface thickening) on sand grain surface as a result of cross linking the thickening agent and cross linking agent under proper pH value (pH=3-5). The gel film is a good viscous-elastic material whose elasticity is stronger than its viscosity, and can wet the sand grain and adsorb on the surface of sand grain by hydrogen bond and electrostatic attraction. As a result, the motion of the sand grain is restricted. Also the film can control the diffusion rate of H+ further in order to retard the reaction rate and make the surface viscous acid reach the formation far away. The mechanism and effect of the acid for sand control have been evaluated and a new thinking that acidizing and sand control can be combined organically has been put forward in this paper.