地浸钻孔施工中低伤害钻井液的设计及应用

在低渗透砂岩铀矿层钻孔施工所用泥浆中添加和筛选了降滤失剂及碳酸钙暂堵颗粒,并分别进行了泥浆改进前后的静态和动态滤失试验,对岩芯进行了伤害评价及解堵措施研究。室内试验结果表明,暂堵剂能有效阻止泥浆中的固相侵入矿层,减轻泥浆对矿层渗透率的伤害。盐酸酸化解堵后,其渗透率恢复率提高了50%～150%。在泥浆中加入1%CMC后,滤液对矿层污染深度可控制在6cm以内,可采用扩孔方法将伤害清除。现场试验也表明,该泥浆大大降低了泥浆对矿层的滤失量和污染深度,酸化后对矿层可以解堵,对保护矿层起到了较好的效果。

Design and application of drilling fluid of light damage for drilling in situ leaching

It is conducted about the study and screening of drilling fluid by static and dynamic percolation test,with comparing the damage extent of permeability of cores for common mud and improved mud that is added additive of percolation-proof to and granule of calcium carbonate to.The indoor test indicates that temporary screening and clogging granule can improve the restore ratio of core permeability,and the additive of percolation-proof of 1%CMC can reduce the damage depth of core to 6cm,which can be cleaning out by chambering.The field test shows that the preferred drilling fluid reduces the percolation extent obviously and prevents the formation from damage.