辽西杨家杖子煤田绳钻应用小泵量机理解析

杨家杖子煤田位于辽西,施工区普遍存在＂硬、脆、碎、漏＂及严重缩径、孔壁坍塌等复杂地层,困扰着煤田绳索钻探在该区的应用。通过现场观察和理论分析得出,钻进效果与钻进技术参数钻压、转速、泵量之间不是简单的线性关系,钻压、转速与钻进效果是不可逆的,而唯独泵量与钻进效果是能够可逆的,通过泵量的改变的改变可以改变钻进效果,据此提出了使用小泵量（38L/min）的思路。实践证明,应用小泵量后,钻进效率提高到1.68m/h,金钢石钻头的寿命提高到70～90m,水泵的机械磨损和易损件的损耗也相对降低,孔内事故率由1.7%降为零,机械事故率由2.1%降至0.2%,各项经济技术指标满足了地质工作的需要,获得了良好的经济效益。

Application Mechanism of Small Pump Flow in Wireline Coring Drilling in Yangjiazhangzi Coalfield

The Yangjiazhangzi coalfield is situated in the western Liaoning Province,complex strata of ＂hard,brittle,broken and leaking＂ with serious borehole shrinkage and sloughing are widely existed in the drilling site,thus have restricted the application of wireline coring drilling in the area.From site observation and theoretic analysis have elicited that the relation between drilling effect and drilling technical parameters of bit pressure,rotary speed,and pump flow is not simply linear.Relation between bit pressure,rotary speed and drilling effect is nonreciprocal,only the pump flow reciprocal,thus through changing of pump flow,drilling effect can be changed,for reasons given above,the thinking of small pump flow（38L/min） put forward.Practices have shown,after using small pump flow,penetration rate can be improved to 1.68m/h;life of diamond bit can be 70~90m as high;mechanical wear and wearing part wastage of pump relatively lowering down;down-hole trouble rate lowering from 1.7% to zero;mechanical failure rate from 2.1% to 0.2%.Econotechnical norms have satisfied the needs of geological works,and good economic benefits obtained.