水平定向钻孔壁稳定性影响因素分析

Influencing Factors for the Horizontal Directional Drilling Hole Wall Stability

水平定向钻技术广泛应用于长输油气管道工程的非开挖领域,而钻孔失稳成为人们最为关注水平定向钻技术的问题之一。钻孔失稳会阻碍施工的正常进行,延长施工周期,增加成本。通过对以往水平定向钻施工中的孔壁稳定性进行综合分析,确定影响钻孔孔壁稳定性的3个关键因素:工程地质条件、泥浆性能和施工工艺。对于这3个关键因素进行了详尽的理论分析,确定各影响因素的技术指标,以及总结指标超标可能产生的一系列孔壁失稳风险。为应对孔壁稳定性影响因素最终导致的各种技术问题,分别制定了相应的解决措施,如给定定向钻施工扩径比和回拖速度,以给施工承包商在今后的工程施工中提供经验教训,降低施工中的钻孔缩径、塌孔和超径风险,提高水平定向钻施工的一次成功率。

At present,horizontal directional drilling technique has been widely used in long-distance oil and gas pipeline project trenchless field.The pilot hole instability has become one of the most concerns of this technique because pilot hole instability obstructs the construction,extend construction period,and enlarge the cost.The comprehensive analysis of horizontal directional drilling pilot hole wall stability shows that geological conditions,mud performance and construction process are the three critical factors for the hole wall stability in horizontal directional drilling installation.For these three critical factors,detailed correspondent theoretical analysis has been made to find out the technical indexes and summarize a series of hole wall instability risks.In order to deal with all kinds of technical issues due to hole wall stability factors,each measure has been drawn up,such as：recommending overcut ratio and pullback speed.The final results have provided the contractor with construction experience,and reduced the risk of drawing down,hole collapse and oversized hole,improving the successful rate of horizontal directional drilling in one time.