盐膏层用高密度有机盐钻井液的研究与应用

Study and application of high density organic salt drilling fluid for gypsum/salt bed.

YTK5 2井是塔里木盆地羊塔克 5构造上的一口开发井 ,该井在 φ 2 15 .9mm井眼内存在 2 5 0m(4 80 0～5 0 5 0m)的盐膏层。通过室内试验优选 ,使用密度为 1.30～1.36 g/cm3 的有机盐水溶液为基液 ,可以配制出密度为 2 .0～ 2 .3g/cm3 的有机盐钻井液 ,能够满足盐膏层钻井液的需要。现场应用表明 ,该钻井液流变性好 ;抑制性强 ,能控制井径扩大率在 5 %左右 ;机械钻速快 ,明显高于近年完井的邻井YTK5 1和YTK5 1T井 ;抗盐、钙、钻屑的污染能力强 ,在没有排放钻井液的情况下顺利穿过盐膏层 ;具有极强的抗水泥浆污染能力 ;解决了饱和NaCl聚磺钻井液滤失量控制与流变性的矛盾 ,也解决了固相含量与流变性的矛盾 ;维护简单 ,对金属无腐蚀 。

Well YTKS-2 is a development well in Yangtake structure of Tarim Basin, with a gypsum/saltbed as thick as 250 m existing in the φ 215.9 mm hole. To meet requirements of drilling fluid for above layer experiments were made in lab, and organic salt drilling fluid was prepared based on organic salt solu-tion with density of 1.30～1.36 g/cm 3 , the fluid's density was conditional within 2.0～2.3 g/cm 3. Field using revealed that this fluid had following advantages:good rheological property, strong inhibition, controlling the hole diameter enlargement rate at about 5% ; the penetrate rate was evidently higher than adjacent wells of YTK5-1 and YTK5-1T; the ability to prevent itself from sodium, calcium and cuttings con-tamination was excellent, for drilling through the gypsum/salt bed was successful without mud dischar-ging; it had prominent anti-cementing slurry contamination ability; no problems appeared between the fil-trate and the rheological property control of saturated NaC1 polysulfonate drilling fluid, nor did between the solid concentration and the rheological property control; maintenance was simple; it produced no corro-sion to metal tools, and it was environmental friendly.