绳索取心工艺在盐矿深部钻探中的应用研究

Application Research on Wire-line Core Drilling Technology for Deep Drilling in Salt Mine

摘要:

宁夏固原硝口-寺口子盐矿地层复杂，上部古近系清水营组存在厚约150 m的红色泥岩夹石膏层，水敏性强，孔壁稳定性差，易出现坍塌和缩径，造成卡钻和抱钻事故；下部白垩系乃家河组含芒硝矿层及岩盐矿层，揭露厚度达380多米，水溶性强，孔壁易溶蚀形成“大肚子”、护壁难、钻进效率低、取心质量差。针对以上施工难题，从钻孔结构、钻头选型、钻井液和钻进参数等方面着手研究，建立了一套适合盐矿施工的绳索取心钻进工艺技术，有效地维护了孔壁稳定，实现了高效、高质、安全钻进，为今后施工类似钻孔积累了经验。

Abstract:

The formations are complicated in Xiaokou-Sikouzi salt mine of Ningxia, there is a red mudstone gypsum strata about 150m in thickness in the upper Qingshuiying Formation of the Paleogene with strong water sensitivity and poor hole wall stability, which is prone to cause collapse and hole shrinkage and results in the accidents of drill sticking and burying; the lower Najiahe Formation of Cretaceous contains mirabilite and rock salt deposits, the exposing thickness is more than 380 meters with strong water-solubility and the hole walls are easily corroded to form “big belly”with difficult wall protection and low drilling efficiency and poor coring quality. In view of the above construction problems, the research is carried out on the drilling structure, bit selection, drilling fluid and drilling parameters, on this basis, a set of wire-line core drilling technology suitable for salt mine construction is established, which is effective to maintain the hole wall stability and realize high efficiency, high quality and safe drilling.