Successful Practices of Environmental LG Vegetable Gum in Horizontal Directional Drilling

摘要

As one kind of drilling fluid additive, LG vegetable gum is easily obtained, comparatively cheap and harmless to the environment. This paper presents its performance parameters, action mechanism and successful practices in several horizontal directional drilling projects with the purpose of pipelaying. LG vegetable gum can be acquired from the leaves of natural Lauraceous plants. It has good filtration control ability, excellent lubricating capability and obvious anti-sloughing effectiveness. Basing on the lots of lab tests, its optimal amount in drilling fluid was determined as 2.0 weight percent. Its performances had also been confirmed by several core drilling engineering projects. Then the authors analyzed the fluid loss control and lubrication mechanism of LG vegetable gum. It has dual action mechanism of none-anionic and anionic filtration reducers for it has plant fibre and polysaccharose synchronously. Also it showed outstanding lubricating performance because it contains fat acid such as oleic acid and linoleic acid. Finally, the thesis presents the applied effectiveness of LG vegetable gum in varied horizontal directional drilling projects with the view of pipelaying such as Lumo Road project, 4th Gongye Road project and Tianxingzhou project which crossed the Yangtze River in Wuhan, China. It successively conquered technical challenges of friction decreasing in cohesive soil, borehole stability in water-sensitive clay and anti-sloughing in borehole with the diameter over than 1200 mm. We can see a promising future of it.