Research On Application Of HDD To Soil Environmental Remediation

Contaminated soil is very harmful to humans, not only influences crop growing, and also impact humans health through vegetable and its production, and produces multilayer harm of humans being survival environment through underground water and infectant movement. Horizontal Directional drilling (HDD) can be used in survey, measurement, remediation and supervising, enhance technology level of soil environmental remediation and supervising.Application of HDD to soil environmental remediation is constructing horizontal directional well using HDD for soil environmental supervising remediation, including soil environmental survey sampling, inspecting while drilling, remediation etc.Western developed nations,'just like America begin research on soil environmental sampling (HDDS), measuring while drilling (EMWD), supervising, remediation of soil vacuum extraction (SVE), biology vent (BV), air sparing (AS) etc. using guide/horizontal directional drilling technology, in 90 age last century.In the view of introduce of Current situation and development foreground of HDD technology and soil environmental remediation technology, soil environmental survey, supervising and remediation technology using HDD, and application of HDD to soil environmental survey, supervising and remediation, research content has been put forward in the paper.The paper had carried out research on soil environmental HDD sampling, developing and completing of remediation horizontal direction well, flow field model of soil gas and vapor stripping of volatile organic compounds (VOCs) of SVE using horizontal direction well, and its field experimentation. These research achievements of the paper as follows:(1) Sampling Technology Using HDDKey problem of sampling using HDD is that sampling tool enters original guide hole, and gets sample of destine position. From guide principle, the paper has carried through force analysis sampling using HDD. In order to sampling tool enter original track of guide hole, curvature radius of sampling hole trajectory is greater than 3 times of curvature radius of guide hole trajectory,sampling tool is not suitable to long, at sometime, sampling tools is tripped in using guide technics, state parameters of drilling tool is measured while tripping. According as mechanics analysis result of guide drilling, the paper has designed guide bit structure, drilling tool structure and assembly of drill tool of sampling using HDD. The sampling technology using HDD has provided a suit of available technical solution for sampling underground soil where are bar (building, river etc.) in the earth's surface.(2) Developing Technology of Horizontal Directional WellOn basis of surface condition and soil contamination distributing, that horizontal directional well of soil environmental remediation reasonably choose blind well developing or continuous well developing has been analyzed in the paper. Underground pipeline assembly, continuous well:riser (grout pipe, inflate pipe etc.)+ packer (gas inflate packer, bowl shape packer)+ screen pipe+ packer+ riser, blind well:riser (grout pipe, inflate pipe etc.)+ packer (gas inflate packer, bowl shape packer)+ screen pipe+ guide head, has been designed and manufactured. According to technical demand of soil remediation, gas inflate packer and bowl shape packer has been designed and manufactured in the paper. Applying theory mechanics and soil mechanics, thrust force of blind well installing pipeline had been calculated and analyzed, construction technology and adaptability of blind well had been studied, construction technology and optimizing method of blind well developing has been given out.Applying theory mechanics and soil mechanics, back drag force of continuous well installing pipeline had been calculated and analyzed, construction technology and adaptability of continuous well had been researched, construction technology and optimizing method of continuous well developing has been provided. On the basis of Environmental demand of soil remediation, a kind of environmental mud system suitable for drilling horizontal directional well of soil remediation:water+3-5% synthetic sodium clay + 0.3%-0.6 GSP-2+0.4-0.6% GLUB+ or HPT-1+ or lost circulation additive has been studied and given out. The well developing technology has provided a suit of available technical solution for developing of horizontal directional well of soil environmental remediation.(3) Completing Technology of Horizontal Directional WellAccording to structure of horizontal directional well of soil environmental remediation, the paper has studied insulation mechanism of packer, analyzed working mechanism of gas inflate packer and bowl shape packer, and designed insulating construction technology of them. referring to well cementation of conventional drilling technology, cementing of horizontal directional well, pressure balance cementing and cementing technology have been researched, cementing materials has been chosen, grouting design has been given out. Refer to the technics of washover principle of water well, washover principle and technology of horizontal directional well of soil environmental remediation has been studied and resigned; refer to fracture technology of petroleum drilling engineering, fracture media and technics, wellhead installing structure of the horizontal directional well have been preliminarily resigned. The completing technology has provided a suit of available technical solution for completing of horizontal directional well of soil environmental remediation.(4) Research on Horizontal Directional Well DisposingThe paper takes Soil Vacuum Extraction for example, provides flow field model and (VOCs) movement model of soil environmental remediation SVE;sets up flow field model of horizontal directional well, gives finite difference solution method, calculates and analyses flow field rule; study VOCs movement model and finite difference solution method, analyses influence factor of VOCs removing; analyses design method of horizontal directional well of SVE, givs design principle, its enhancing technology and adaptability.These research achievements in the paper has provided technology scheme for horizontal directional drilling sampling, and horizontal directional well developing & completing of SVE, AS, BV etc in soil environmental remediation, fill the gap of application of HDD to soil environmental remediation in our country.