Field Hydraulic Tests Research Articles

Design of Remote Hydraulic Teaching System

In this paper, a set of remote hydraulic teaching experiment system is designed and developed based on the demand of teaching experiment of hydraulic related courses in colleges and universities, which can enable teachers or students to conduct experiment operation on the field hydraulic testing platform at the remote client, so as to facilitate teachers and students to carry out hydraulic teaching experiment and research. The main contents of this paper are as follows: according to the requirements of hydraulic servo control system related to the teaching experiment, the experimental project of remote hydraulic teaching experiment system is determined. Through the analysis and comparison of C/S and B/S software system architectures, the remote monitoring scheme based on B/S mode is determined. Completed the design of the hydraulic circuit of the hydraulic test bench, developed the field measurement and control system based on LabVIEW, and built the remote monitoring system based on B/S mode. The development of the remote hydraulic teaching experiment system was completed. The input signal response experiment and load characteristic experiment of the valve-controlled motor electro-hydraulic speed servo control system were carried out on the remote client to the field hydraulic experiment platform, and the experimental results were analyzed. The experimental process and results have reached the expected target and meet the demand of remote hydraulic experiment.

금정터널내의 지하수 유출량과 기저유출량 변화 분석

When constructing tunnels, it is important to understand structural, geological and hydrogeological conditions. Geumgeong tunnel that has been constructed in Mt. Geumjeong for the Gyeongbu express railway induced rapid drawdown of groundwater in the tunnel construction area and surroundings. This study aimed to analyze groundwater flow system and baseflow using long-term monitoring and groundwater flow modeling around Geumgeong tunnel. Field hydraulic tests were carried out in order to estimate hydraulic conductivity, transmissivity, and storativity in the study area. Following the formula of Turc and groundwater flow modeling, the annual evapotranspiration and recharge rate including baseflow were estimated as 48% and 23% compared to annual precipitation, respectively. According to the transient modeling for 12 years after tunnel excavation, baseflow was estimated as <TEX>$9,796-9,402m^3/day$</TEX> with a decreasing tendency.

Hydraulic Conductivity and Scale Effects Investigation in Basalt in the Dam Area of Xiluodu Hydroelectric Station, Jinshajiang River, China

Hydraulic conductivity (K) and scale effects in basalt in the dam area of Xiluodu hydroelectric station were investigated by three kinds of field hydraulic tests with different test scale, 2608 water pressure tests in single borehole, 54 water seepage tests in adit and groundwater tracer test. Statistical results show the high heterogeneity of fractured rock and K difference between two neighboring test intervals are often more than two orders of magnitude. However, there is a strong decreasing trend of hydraulic conductivity with the increase of vertical depth. Moreover, these three kinds of hydraulic test results demonstrate that hydraulic conductivity increases with the increase of test scale in heterogeneous basalt and the heterogeneous degree of K decreases with the increase of test scale. K from water seepage test in adit, with the test scale of 1-2 m, is dispersed from 0.00024 m/d to 3.46 m/d. K from water pressure test in single borehole, with the test scale of 4-7 m, is 0.0002-1.04 m/d. K from groundwater tracer test, with the test scale of 70-145 m, is concentrated between 0.46 m/d and 2.1 m/d. High heterogeneity of fractured rock and multi-level of fractures are thought as the major reason resulted in scale effects of hydraulic conductivity.

Cost-Effective Hydraulic Tomography Surveys for Predicting Flow and Transport in Heterogeneous Aquifers

This study shows how a cost-effective hydraulic tomography survey (HTS) and the associated data estimator can be used to characterize flow and transport in heterogeneous aquifers. The HTS is an improved field hydraulic test that accounts for responses of hydraulic stresses caused by pumping or injection events at different locations of an aquifer. A sequential data assimilation method based on a cokriging algorithm is then used to map the aquifer hydraulic conductivity (K). This study uses a synthetic two-dimensional aquifer to assess the accuracy of predicted concentration breakthrough curves (BTCs) on the basis of the Kfields estimated by geometric mean, kriging, and HTS. Such Kfields represent different degrees of flow resolutions as compared with the synthetically generated one. Without intensive experimentsto calibrate accurate dispersivities at sites, the flow field based on the HTS Kfield can yield accurate predictions of BTC peaks and phases. On the basis of calculating mean absolute and square errors for estimated K fields, numerical assessments on the HTS operation strategy show that more pumping events will generally lead to more accurate estimations of Kfields, and the pump locations need to be installed in high Kzones to maximize the delivery of head information from pumps to measurement points. Additionally, the appropriate distances of installed wells are suggested to be less than one-third of the ln(K) correlation length in x direction.

Field Hydraulic Tests Improve HPHT Drilling Safety and Performance

Summary For the Elgin-Franklin UKCS fields, drilling of the high pressure/ high temperature (HPHT) phase is critical due to the narrow margin between formation pore and fracturation pressures. This problem is accentuated by the extreme temperature (up to 205°C— 400°F) and pressure (up to 1,200 bar—17,400 psi). A new generation of down-hole pressure while drilling (PWD) tools allows a better real-time monitoring of the bottom-hole pressure, but cannot withstand the extreme temperature of the entire HPHT phase. Furthermore, down-hole and surface pressures are dependent on complex hydraulic phenomena which make predictions challenging. Consequently, it was decided to perform hydraulic tests before drilling the HPHT section of the well 22/30c-G4 (first Elgin development well), in order to quantify the surface and down-hole pressures and temperatures on several operating conditions: circulating (with and without pipe rotation), tripping and flow check. Gelation tests, trapped pressure as well as pressure transmission tests were also performed. Objectives of these tests were to better understand some complex down-hole physical phenomena, to prepare practical guidelines, before drilling HPHT sections, to check reliability and accuracy of new real-time PWD tools, and to collect accurate well data for further hydraulic software packages validation or improvement. These procedures led to great benefits, both in terms of safety and performance, when drilling the HPHT phases of the well: results were considered as highly positive. This paper details down-hole measurement procedures and results, operational guide lines, tools performances, lessons learnt, and explains how to cope with sources of possible discrepancies between actual values and software predictions.

Groundwater age analysis using tritium in gneiss of the Samkwang mine in Korea

Abstract Travel times of the groundwater in the gneiss near Samkwang mine in Korea were estimated through the field hydraulic tests, the development and the application of a mathematical model, and the analysis of tritium concentration of the groundwater sampled in the study positions. Results of this study are follows:(1) Through the field hydraulic test, the hydraulic conductivity in the gneiss of the syudied area is 1.7 x 10‐5 x Z‐1,3 m/sec (Z:depth from the surface, (m)) and the longitudinal dispersivity is 9.8 m. (2) The mathematical model to calculate the age of groundwater was developed considering the tritium concentrations of rainfall precipitated in the studied area for period 1961 ‐ 1993. (3) The ages of the groundwater in the tunnel 44, 92, 102, and 205 m below the earth surface were estimated at 2.0, 4.0, 4.5, and 9.0 years, respectively. These results were verified by the data on the tritium concentrations of the groundwater in the tunnel for period 1990 to 1993.