钻井液用新型可酸溶加重剂的制备与应用

Development and Application of New Acidsoluble Aggravating Agent for Drilling Fluid

以羟基磷灰石为原料,六偏磷酸钠为改性剂,制备了一种可酸溶加重剂。采用FTIR对其化学结构进行表征,对改性后加重剂的酸溶性、Zeta电位以及润湿性进行了评价,并对其配制的钻井液的流变性、滤失性以及储层保护效果进行了评价。实验结果表明,10%盐酸作用下改性加重剂的溶解率可达88.27%;采用该改性加重剂的钻井液具有良好的流变性和降滤失性;采用该改性加重剂的钻井液污染的岩心经10%盐酸浸泡2h后,渗透率恢复值>90%,表明改性加重剂参与形成的泥饼可被酸性工作液有效溶解和清除,从而保护储层。

An acid-soluble weighting agent was prepared using hydroxyapatite as raw material and sodium hexametaphosphate as modifier.The chemical structure of sample was characterized by FTIR.The acid solubility,Zeta potential,and wettability of the modified weighted agent were evaluated.Finally,the influence on the rheology and the filtrate loss of drilling fluids as well as the reservoir protection effect was analyzed.The results indicated that the solubilization rate of the modified weighting agent under 10%HCl solution was up to 88.27%.Drilling fluids with modified weighting agents had good rheology and filtration loss reduction properties.The permeability recovery value of the core contaminated by the drilling fluid mixed with modified weighting agent was>90% after soaking in 10%HCl solution for 2 h,which showed that the mud cake formed by the participation of modified weighting agents could be effectively dissolved and removed under the effect of acidic,thus protecting the reservoir.