若尔盖铀矿田漏失层空心微珠泥浆试验研究

Experimental Study on Cenosphere Mud for Leakage Zone of Ruoergai Uranium Ore Field

摘要:

若尔盖铀矿是我国四大基本类型铀矿田之一，矿层为灰岩、硅灰岩，圈团状纵向裂隙发育，长孔段失返性全漏失，泥浆性能难以维护，孔壁失稳，堵漏花费大量的人力、物力。为提高钻进效率，针对地层漏失机理，通过降低漏失压力实现平衡钻进，分别开展了空气泡沫、微泡沫泥浆以及空心微珠等低密度泥浆体系的研究和试验。实践表明，空心微珠低密度泥浆体系是一种适合若尔盖铀矿田漏失层钻进的泥浆体系。

Abstract:

Ruoergai uranium deposit is one of the four basic types of uranium ore fields in China, the formations are limestone and silicon limestone with the development of groups longitudinal fissures. There was no mud return while drilling in such kind of formation because of the total lost circulation. It was very difficult to maintain mud properties and borehole stability and a lot of manpower and material resources were spent on this. Based on the analysis on the mechanism of lost circulation, a technical measure was put forward. The basic idea is to reduce leakage pressure for balanced drilling. The research and experiments were carried out on air bubbles mud, micro-bubble mud and cenospheres mud systems. The practice shows that the cenospheres low-density mud system is suitable for drilling operation in Ruoergai uranium ore field.