•Pulsed flow can transport more cuttings than constant flow during horizontal drilling.•The effect of flow pulsation frequency on particle transport is not very significant.•Both Flow velocity and ...pulsation amplitude play important roles in facilitating cuttings removal.•Asymmetric flow pulsations have lower interphase energy transfer losses.
Cuttings deposition and removal has always been a key issue in horizontal directional drilling due to its correlation with numerous problems such as rate of penetration, reduction and stuck pipe.In this paper, the relationship between the impulse flow generated by a fluidic jet hammer and cuttings removal was discussed. A Eulerian-Eulerian two-fluid model was used to simulate the cuttings transport in horizontal wells on a sliding grid basis. Results show that the flow pulsation induced by a fluidic hammer contributes to easier cuttings transport. Compared to constant flow, impulse flow showed a 22.03% improvement in more optimal borehole cleaning with the same system inlet flow rate. In addition, the asymmetric flow pulsation was more sensitive to amplitude than the sinusoidal waveform pulsation flow, and as amplitude increased, the average exit flow rate of cuttings increased by 30.95%. Cuttings transport in annular is sensitive to rate of penetration, average velocity of pulsation, pulsation amplitude and cuttings size. The effect of pulsation frequency seems to be not much significant, probably because the frequency or other parameters used in this work did in the range of optimal particle-carrying frequency. These findings can provide references for the utilization of downhole pulsating fluids by drilling tools.
Soil and groundwater contamination has become a key issue in urban redevelopment. It is particularly difficult to use heavy equipment for the remediation of restricted sites or areas contaminated by ...factories that are still in operation. In this case, horizontal wells are considered a potentially useful technology as they can potentially remediate contamination areas located below buildings and other surface/subsurface obstacles. This research first introduces the principles and advantages and disadvantages of direct push injection, improved slant well, high-pressure rotary jet technology, horizontal reactive media treatment wells, and horizontal directional drilling well. The key aspects for promising in-situ remediation techniques were summarized as remediation well design, remediation agent injection technology and drill pipe and well wall sealing technology. Based on the requirements for key technologies, a novel multi-branch horizontal well in-situ remediation process was proposed, which integrates vertical/horizontal directional drilling, rotary injection, and expansion sealing techniques, and relevant supporting drilling and injecting equipment were developed. A bench test and field test were conducted to test drilling tool performance, drilling accuracy, and injection radius of influence. The results showed that the developed supporting drilling tool met the process requirements and could complete multi-branch horizontal well remediation engineering construction. The deviation between the measured depth and the design depth of the multi-branch horizontal well constructed using this technology was less than 9%, and the deviation between the depth displayed by the guidance instrument and the measured depth was less than 1%. The injection radius of influence in the test field measured from the monitoring wells was greater than or equal to 5 m. The results of this research can provide an effective method for the remediation of contaminated sites.
•Summarizing the key aspects of the implementation measures for in-situ remediation.•A novel multi-branch horizontal well in-situ remediation technology was proposed.•The feasibility of the technology has been demonstrated through field trials.
•Axial and circumferential strain gauges were installed inside the steel pipe.•Pipe strains were recorded along the drill path during pullback and presented.•Recorded strains showed that an elastic ...state governed these installations.•Circumferential stresses calculated from strain data were greater than predictions.•High variability in recorded strains and stress due to downhole condition.
Horizontal directional drilling (HDD) technology is becoming a popular method for steel pipeline construction and replacement in oil and gas industry. There is a combination of axial and circumferential stresses and strains imposed on the product pipe during HDD installations. Limited research has been done to analyze the stresses and strains on the steel pipe during installation. A more detailed investigation is required to evaluate the stresses and strains developed during installation to ensure the structural safety of pipelines while identifying areas for design improvement. This paper discusses a strain monitoring program which was utilized in two major HDD installations, including 762 mm O.D. steel pipe in crossings over a kilometer. The strain measurements were presented in the form of pipe strains along the drill path over time for installation. Stress–strain relationships for pipe installation were developed and installation stresses were calculated using the strain measurements. Then, the calculated stresses from strain data were compared with expected theoretical values determined based on current design practice as developed by Pipeline Research Council International (PRCI). High variations in recorded strains and stresses imposed on the pipe were observed in both case studies. The strain monitoring and stress calculation discussed in this paper provides some details on the expected behavior of steel pipes during HDD installations.
To improve the accuracy of formation inversion by cuttings during tunnel geological investigation using horizontal directional drilling technology, this study focuses on the correlation of cutting ...transportation features and formation spatial locations based on a tunnel geological investigation project. This study mainly draws the following conclusions: The different cuttings' migration modes are determined according to the cutting's migration settling velocity, Fei Xiangjun's critical velocity theory, and Larsen's minimum return velocity theory. The migration of cuttings in the annulus is bedload, a small number of cuttings are suspended load, and the little remaining is cutting's bed. The newly generated cuttings at the drill bit tooface would come out as suspended load first with drilling fluid in the field. The cutting suspended moving mode was established based on the material transportation theory, the freesuspension, and the movement equations of cutting particles. According to the recorded data of car
The waste slurry generated during Horizontal Directional Drilling (HDD) has detrimental effects on water sources, soil, and organisms. Existing studies lack quantitative analysis and assessment of ...the environmental hazards of waste slurry. The treatment of waste slurry is usually done by physical curing or chemical curing agents. The treatment effect of these treatments is unsatisfactory or not environmentally friendly enough. Research on the application of Microbially Induced Calcite Precipitation (MICP) in waste slurry purification can help provide innovative solutions. This study began by acquiring the basic properties, mineral composition, and particle size distribution of the waste slurry through experiments. The effects of different concentrations of waste slurry on soil chemical properties were compared, including the measurement of total dissolved solids (TDS), turbidity, and heavy metal ion concentrations of waste slurry supernatant. Additionally, the environmental impact of the waste slurry was assessed from an electrochemical, turbidity, and ionic composition perspectively. A combination formulation containing 2.8 wt% urease, 5 wt% urea, and 3.5 wt% calcium chloride was used to purify the waste slurry. The supernatant of the MICP treated waste slurry undergoes electrochemical testing to evaluate the effectiveness of MICP technology for slurry treatment. The findings indicate that both chemical additives and stratum contaminants significantly contribute to slurry pollution. When the waste slurry constitutes more than 40 wt% of the soil mass fraction, the electrical conductivity (EC) of the soil surpasses the threshold of 1000 μs/cm, and the pH level rises to approximately 9.5, rendering it unsuitable for plant growth. Moreover, the TDS, turbidity, and heavy metal ion concentrations in the waste slurry supernatant exceed the permissible environmental discharge limits. Notably, the concentration of arsenic (As) exceeds the national standard by 18 times, cadmium (Cd) by 20 times, and selenium (Se) by 208 times, posing a high risk of environmental pollution. However, the comparison of ion concentrations in the supernatant before and after MICP treatment reveals that MICP demonstrates effective cementation and co-precipitation of heavy metal ions. MICP purified 66.6 % of arsenic (As), all cadmium (Cd), 75 % of phosphorus (P), and 76 % of selenium (Se) from the waste slurry supernatant. The results of this research contribute to the quantitative evaluation of the environmental hazards of waste slurry. It also helps to promote the application of MICP in waste slurry purification.
Geotechnical parameters required for estimating the maximum allowable annular pressure (Pmax) in horizontal directional drilling (HDD) are often empirically determined based on the results from the ...standard penetration test (SPT). Despite the benefits of SPT, its use in practice could be challenging as the geotechnical parameters determined based on SPT results vary largely depending on the choice made for SPT correlations. Such variability within the geotechnical parameters could result in a high degree of uncertainty within the estimates of Pmax in HDD. In this paper, an SPT-based algorithm is developed to study the variation in estimates of geotechnical parameters and Pmax due to the choice made for SPT correlation. Sensitivity analysis conducted using the SPT-based algorithm presents significant variations in both estimates of geotechnical parameters (relative ranges vary from 11% to 1516%) and Pmax (relative ranges vary from 10% to 1313%) for cases where the understanding of soil behavior and characteristics is insufficient. Error analysis conducted based on the errors in the geotechnical parameters determined using SPT correlations and the corresponding estimates of Pmax presents that the two types of errors are found closely related for most cases; however, exceptions also exist for the cases with the SPT correlations related to modulus of elasticity. Based on the results of the error analysis, suggestions for the use of SPT correlations are made for determining the input geotechnical parameters required for estimating the Pmax in HDD, and they are applied to a case study related to the hydraulic fracture experiments to demonstrate their usefulness in a real-world example. The case study presents high precision (R2 > 0.81) in the estimates of Pmax obtained by following the suggestions for the use of SPT correlations. In remark, the estimates of Pmax made based on some SPT correlations are found nearly equal to the measurements of annular pressure at hydraulic fracture, confirming that the SPT-based algorithm and the suggestions for the use of SPT correlations provided herein are reasonably reliable for estimating the Pmax in HDD. These results highlight the challenges with using empirically determined geotechnical parameters in the design of HDD and provide practitioners with valuable information for evaluating the stability of the HDD borehole.
•Challenges with using empirical method for estimating Pmax in HDD is studied.•Sensitivity of Pmax estimate to the choice made for SPT correlation is analyzed.•An SPT-based algorithm for calculating Pmax is developed for the sensitivity analysis.•Errors in the SPT correlations and the corresponding estimates of Pmax are analyzed.•Based on the quantified results, suggestions for the use of SPT correlations are made.
•The mechanical properties of pipes installed with HDD method under traffic loads are analyzed.•Static and dynamic traffic loads are considered.•Compared with traditional open-cut method.
The present ...study investigates the mechanical behavior of pipes installed via horizontal directional drilling method, a typical trenchless method for highway-crossing pipeline installation, under traffic loads. The effects of both stationary and moving vehicles are considered in the analysis. Results from the static analysis indicate that the pipe experiences maximum stress at its top, with minimum stress at its bottom. Furthermore, the stress change in soil is more significant than that in the pipeline as the vehicle weight increases. When a moving vehicle passes over the pipeline, the stress of the pipeline remains relatively constant. No significant change in pipe stress is observed with changes in vehicle weight and speed. However, when the vehicle speed approaches 100 km/h, the maximum soil stress decreases significantly. Conversely, the pipe stress is higher when the vehicle is stationary compared to when it is moving. A comparison is made between the mechanical behavior of pipes installed via horizontal directional drilling and open-cut methods under traffic loads, with the results revealing that the stress of pipelines installed via horizontal directional drilling method is higher than those installed via open-cut method in both static and dynamic analyses. Nonetheless, the stress variation amplitude of pipelines installed via horizontal directional drilling method is smaller during vehicular passage, thus indicating a lower possibility of fatigue failure caused by traffic loads.
•The mechanical behavior of pipes installed by HDD under seismic load is analyzed.•The mechanical behavior of pipes installed by HDD and open-cut methods is compared.•The effects of transverse and ...axial seismic load are revealed.
The present study investigates the mechanical behavior of high-pressure pipelines installed through horizontal directional drilling (HDD), a crucial trenchless installation method, under seismic loads. Utilizing the finite element method and artificial viscoelastic boundary conditions, this paper analyzes the stress response of pipelines subjected to seismic loads in two directions. The seismic loads are applied using the response spectrum method, and the pipeline stress is analyzed in time history. A comparison of the stress in pipelines installed through the HDD method and the traditional open-cut method is conducted, and the impact of earthquake magnitude on pipeline stress is evaluated. The results indicate that the pipeline stress is greater when the seismic acceleration acts transversely, with bending deformation being the dominant mode of response. A 9.29% increase in maximum stress is observed for each increment in earthquake magnitude. Furthermore, the stress in pipelines installed through the HDD method is 48% lower than that of pipelines installed using the open-cut method when subjected to transverse seismic loads.
•Field test on a double-layered horizontal directional drilled ground heat exchanger.•Numerical modeling was used to investigate the effect of water injection.•Water injection improves the ...performance of ground heat exchanger.•Injection rate, place, temperature, and the permeability affect the performance.
Ground Heat Exchangers (GHEs) drilled using Horizontal Directional Drilling (HDD) technology have been proven to be a cost-efficient way of installing ground source heat pump systems (GSHP). They can also be installed in places where conventional horizontal ground heat exchanger (HGHE) would not be possible e.g., due to lack of land.
In this research, a double layered horizontal borehole was installed as a GHE in Saga City, Japan. The two holes had a diameter of 114.3 mm and a length of 59 m and 56 m, respectively, while reaching depths of 5 m and 9.5 m. A polyethylene pipe with an outer diameter of 60 mm was inserted as a borehole heat exchanger (BHE). In March 2022, a two days thermal response test (TRT) showed the influence of rainfall on the system. A numerical model developed in FEFLOW based on the GHE dimension and the region's geology was validated using the measured temperatures of the heat medium at the return point and outlet of the GHE during the TRT. The validated model was then used to carry out sensitivity analysis examining different conditions of water injection into the borehole. The result of the sensitivity analysis showed that water injection into the borehole can improve the performance of the system and reduce the temperature change of the heat medium. Varying the injection rate can improve performance to a certain degree and the injection point has a strong influence on the performance. The injection temperature was also found to play a role in the performance, but even high temperatures in the case of heating showed significant improvement. Lastly, the influence of permeability was investigated and showed that impermeable layers are more favorable for injection compared to permeable layers.
Introduction Trenchless horizontal directional drilling is widely used in power cable line project to cross natural or artificial obstacles at present.Multiple cable protection tubes need to be laid ...successfully at one time in engineering applications. It is defined as multiple pipelines pulling crossing, and it is widely used because of it's excellent economic and environmental protection advantages. However, there is only the calculation method of single pipe pullback force of plastic pipe at present. This paper aims to study the calculation method of pullback force of multiple pipelines. Method This paper was based on a 220 kV cable line project in the Pearl River Delta. This project used horizontal directional drilling to cross the national first-class waterway for twice at the same place, and most of the crossing stratum was plastic clay layer. The calculation method of single pipe pullback force was used for analysis in the project, and the change curve of pull back force was measured on site during the implementation. Result The comparative analysis between theoretical calculation and measured results shows that: under the condition of plastic clay layer, the measured pullback force of multiple pipelines is 4～6 times that of single pipe with the same weight and envelope diameter. The straight-line pullback of pipelines is very important to reduce the pullback force and implementation risk. Conclusion In this paper, the concept of multiple pipelines pulling and the calculation reference value of pulling force in trenchless horizontal directional drilling crossing project can provide a reference for the crossing design and construction of similar projects in the future.
