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Field Investigation Methods
Published in Mark Edward Byrnes, Field Sampling Methods for Remedial Investigations, 2023
The slug test is a simple field method in practice. A slug test is performed by abruptly displacing a known volume of water within the wellbore water column and monitoring the water-level changes until they return to static conditions as water moves into (or out of the well). Displacing the volume of water in the wellbore is typically performed by withdrawing (or inserting) a solid cylinder of known volume from (into) the water column. The water column can also be displaced by pressurizing the air space in a well casing using pressurized gas (e.g., nitrogen) to depress the water column to a new equilibrium level and then instantaneously releasing the pressure. Following pressure release, changes in water level are monitored until they return to static conditions. During pressurization, both the water level pressure and the pressurized gas are monitored when depressing the water column. The advantage of pneumatic tests is much greater control and variation in the imposed stress level.
Aquifer Analysis
Published in Christopher M. Palmer, Principles of Contaminant Hydrogeology, 2019
Instantaneous well testing or “slug” testing can be used to measure hydraulic conductivity around boreholes, such as production, monitoring to test wells (Bouwer, 1989). The slug test is relatively quick and inexpensive, and can be used to collect data from a site and make estimates of transmissivity from the hydraulic conductivity. Hydraulic conductivity of an aquifer can be estimated from the rate of rise or fall of the water level in a well after a slug of known volume is either instantaneously introduced or removed from the existing water column (see Figure 1). The main advantages of performing slug tests as opposed to pumping tests are: Less expensive to perform.Less equipment needed.Less time to obtain data in the field.Shorter data interpretation/reporting time.Can be used where pumping data may not work (i.e., low-yield conditions).Can be used in small-diameter wells.
Basic Principles
Published in Kathleen Sellers, Fundamentals of Hazardous Waste Site Remediation, 2018
In a slug test, a known volume of water is added to or removed from a well. The resulting change in the water level is measured over time to estimate the transmissivity (and thus hydraulic conductivity) in the vicinity of the well. Because a slug test affects the aquifer only in the vicinity of the test well, it does not provide a highly reliable estimate of aquifer properties. Slug tests are typically used in shallow unconfined aquifers, although they can also be used in confined aquifers. Slug tests are often performed early in a site investigation, when highly reliable data are not necessary. They cost relatively little to perform.
A new reliability evaluation method of injection/falloff testing interpretation in coal reservoir based on FAHP and cloud model
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2020
Shiyue Fang, Yue Chen, Yuan Bao, Xinhui Yang, Dongmin Ma
Although cloud model and FAHP-based comprehensive evaluation method has been seldom used in the reliability evaluation of IFT interpretation, while it has been widely used in safety risk assessment (He 2018), effectiveness of virtual reality training system (Zhang, He, and Mitri 2019) reservoirs evaluation (Zhu et al. 2019a), quality evaluation of simulation teaching (Yang et al. 2019), et al. They could provide an effective methodological reference for the reliability evaluation of IFT interpretation. The steps of the cloud model and FAHP-based comprehensive evaluation model are clear and intuitive. Some indicators calculations can be calculated by the data-processing software such as Excel, SPSS, and Origin. The cloud model calculation and graphing, matrix operation can be performed by means of programming tools such as MATLAB and Python. In this paper, the proposed model was constructed within the origin 9.0 and MATLAB R2013b programming environment and was implemented in a CPU core with eight 3.1-GHz processors (Intel(R) Core (TM) i5-4440). Thus, the feasibility of the method is strong. It can further improve the objectivity and credibility of the evaluation results. It is conducive to get more accurate permeability values and benefit to the quality control of well testing. It can also provide a scientific methodological reference for reliability evaluation of other testing interpretation of oil, gas, CBM, water injection, and geothermal well, such as, drawdown and buildup test, drill-stem test, tank test, slug test, and so on. Therefore, the applicability of the method is wide.