特殊盐岩地区钻井液技术

泌阳凹陷是南襄盆地内一个次凹陷，同一井筒钻遇了多层碱岩、芒硝和石膏矿藏。由于长期注水开采，钻井过程中井涌、井漏、盐溶解等井下复杂问题频繁发生。采用抗盐PAC聚合物钻井液和饱和碱钻井液，并利用地下高压饱和芒硝水，配成了芒硝无固相钻井液。现场应用表明，芒硝无固相钻井液抑制了盐层的缩径阻卡，再配合密闭取心技术，碱心收获率大于88．9％；机械钻速由原来的3．75～5．10m／h提高到7．62～9．60m／h，钻井周期由原来的58d下降到28d左右，钻井液成本大幅度下降。

Drilling Fluid Technologies for Special Salt Rock Drilling

The Biyang Depression is a sub-depression in the Nan-Xiang Basin,in which the same bore hole may penetrate several layers of alkaline rocks,Glauber's salt and gypsum.Water kicks,mud losses and salts dissolution occur frequently during drilling because of long-term production through water injection.A solids-free mud prepared from Poly Anionic Cellulose(PAC) mud,base-saturated mud and saturated water from underground was used to drill wells in this area.Field application shows that this drilling mud can inhibit the dissolution of the formation salts.Using sealed coring method,the recovery of core was as high as 88.9%,and rate of penetration was increased from 3.75-5.10 m/h to 7.62-9.60 m/h.Drilling time has been reduced from 58 days to 28 days using this drilling mud,and the mud costs were greatly reduced,accordingly.