三种常用物理堵漏材料的优选实验研究

应用（ＡＰＩ）ＤＳ－２堵漏仪对三种常用物理堵漏材料的堵漏效果进行了对比．结果表明：高失水堵漏剂（ＤＴＲ）能有效封堵渗透性地层及１ｍｍ以下的微裂缝，与核桃壳复配后，对付大中型裂缝的漏失十分有效；单向压力封闭剂能有效地封堵渗透性地层的漏失，但不适合裂缝性地层的防漏堵漏；单封与ＤＴＲ按３２的比例混配后，堵漏效果显著增加，二者再与核桃壳混配后对付大中型裂缝的漏失十分有效，其复配比为核桃壳：单封：ＤＴＲ＝３３２时堵漏效果十分好；增加物理堵漏材料的浓度可提高堵漏效果，但可封堵的最大裂缝或孔隙尺寸是一定的．一定的浓度，宽广的颗粒尺寸分布是物理堵漏的关键因素．

A Experimental Study on Optimization of Three Physical Lost Circulation Additives

The sealing effects of three lost circulation additives are compared with(AP2) DS 2 lost circulation instrument.It is shown that DTR can effectively seal permeable formations and the fractures whose width is less than 1mm.When it is mixed with walnut shells,the mixture can seal wider fractures.“Danfeng”is only suitable to permeable formations.When it is mixed with DTR in the ratio of 3∶2,the sealing effectiveness can be greatly increase.When it is mixed with DTR and walnut shells in the ratio of 3∶2∶2,the best result can be achieved.The experimental results also show that,as the concentration of lost circulation additives in drilling fluid increases,the sealing effectiveness increases,but the maximum sizes of fractures and pores is definite that can be sealed.Therefore,proper concentration and wide distribution of lost circulation additives particle sizes are two key factors to physical lost circulation.