钻井液离心机预防绳索取心钻杆内壁结垢研究

Research on the prevention of scaling on the inner wall of the wire-line drill rod by drilling fluid centrifuge

摘要:

针对钻杆内壁结垢严重制约绳索取心安全、优质、高效实施的技术难题，开展了金刚石绳索取心钻进钻杆内壁的结垢机理与影响因素综合研究，结果表明：当钻具结构与钻井液性能一定的情况下，钻井液中的固相含量与颗粒大小是影响钻杆内壁结垢的主要因素。金刚石岩心钻进所产生的岩屑粒径在5~100 μm之间，总体偏细，难以依靠自然沉降清除。为此，研制了TGLW系列小型离心机，现场试验表明：该离心机可使钻井液中固相颗粒的峰值从5~80 μｍ降到3~10 μｍ，固相粒度中值从11.189 μm降到3.513 μm，固相清除率达90%以上，控制钻井液固相含量在0.5%以下，既维护了钻井液性能、又预防了绳索取心钻杆内壁结垢。

Abstract:

In order to resolve the puzzle that the scaling on the inner wall of the drill pipe seriously restricts the safe， high-quality， and efficient implementation of wire-line core drilling， the comprehensive study was conducted on the scaling mechanism and influencing factors of diamond wire-line core drilling on the inner wall of the drill pipe. The results indicate that： When the structure of the drilling tool and the performance of the drilling fluid are constant， the solid content and particle size in the drilling fluid are the main factors affecting the scaling of the inner wall of the drill pipe. The particle size of rock cuttings produced by diamond core drilling ranges from 5 to 100μm， it is generally small and difficult to remove by the natural settlement. For the reason， the TGLW series small centrifuge is developed. Field tests have shown that the centrifuge can increase the peak value of solid particles in drilling fluid from 5~80μm to 3~10μm， the median particle size of the solid phase ranges from 11.189μm to 3.513μm， the solid phase clearance rate reaches over 90%， and the solid phase content of the drilling fluid is controlled below 0.5%， which not only maintains the performance of the drilling fluid but also prevents scaling on the inner wall of the wire-line drill rod.