Open Aquifer Research Articles

Capillary rise quantification improves irrigation performance in pear orchards

The shallow water table in Río Negro and Neuquén valley causes a capillary rise (CR) that modifies the water content in soil profile. Therefore, irrigation performance is expected to be affected by the capillary water input into the root zone. The aim of this study was to evaluate the effect of CR on surface irrigation performance during 2020-2021 growing season in a pear orchard. In a Bartlett pear orchard planted in 2003, three irrigation moments were evaluated, and irrigation sheets were calculated to obtain efficiency. Water table level (WTL) was measured monthly in an open aquifer piezometer. CR was calculated with the software UPFLOW. Soil water content was measured with a Frequency Domain Reflectometry (FDR) sensor at: 0.20 m, 0.40 m, and 0.60 m. Water use efficiency (WUE) and water productivity were calculated using pear crop yield and the irrigation sheets applied and the crop water demand, respectively. WTL was shallower in spring than in the rest of the season. The mean depth fluctuated between 0.70-1.20 m during spring, affecting irrigation performance. Data of FDR deepest sensor showed an increase of soil moisture due to CR. Capillary contribution negatively affects irrigation efficiency if it is not included in the water balance. Irrigation schedules can be re-arranged considering soil moisture and CR. In this way, the necessary water sheets could be applied in each crop development stage adjusted to water demand. Improving irrigation performance and WUE enables a sustainable water management strategy in pear production.

Pressure-derived storage efficiency for open saline aquifer CO 2 storage

Various approaches are used at the preliminary stage (before flow modelling studies) to evaluate the resources of saline aquifers for storing CO 2 . The two approaches used most commonly are the volumetric ‘open aquifer’ and ‘closed aquifer’ approaches, which provide the end members for the resources of a given aquifer store. We propose a novel approach based on extending the analytical aquifer methods, which have been routinely used for decades in the oil and gas industry, to CO 2 saline aquifer storage. The CO 2 storage resource is derived from the pore volume liberated by pressurization to accommodate CO 2 in the store, which is the sum of: (i) the volume of the store obtained by compression; and (ii) the volume of water outflow towards the regional aquifer. It enables the CO 2 storage resources and storage efficiencies for pressure-limited stores (meaning when the resource is not even more limited by CO 2 migration issues) to be estimated. Formalism is presented, as well as implications and limitations of the method. With this method, storage efficiencies are directly connected to closed store efficiencies that are corrected for the water outflux and pressure dissipation from the CO 2 store into the regional aquifer, reconciling the ‘closed’ and ‘open’ approaches. We present an application to the Havnsø saline aquifer structure in order to highlight the consequences of the CO 2 storage resource evaluation and also of appraisal and development phases.

Impacts of Contaminants on Groundwater Quality in Rukpokwu, Delta Region of Nigeria

This study investigated the characterization of borehole sediment and the impact of contaminants on groundwater quality in the Rukpokwu Community in the delta of Nigeria. The investigation supported by spatial data supported by GIS techniques provides a data baseline for the monitoring of organo-contaminants in groundwater quality in Rukpokwu. This low pH of the groundwater and irritation of the throat and mouth became a concern to the residents. This study is necessary because of the limited data on the level of organic contamination in groundwater in this section of the delta of Niger in Nigeria. So, there was a need to track the source of contamination in this part of the delta of Niger in Nigeria. These previous studies have suggested a highly permeable open aquifer in similar deltaic terrain. Ten (10) samples of borehole sediment and water collected at 30 m depth were being analyzed for textural and physicochemical characteristics. The parameters analyzed include Iron (Fe), Total Petroleum Hydrocarbon &Total Hydrocarbon Content (i.e., TPH and THC respectively) of borehole sediment in association with groundwater quality. Ten (10) sediment samples collected at a depth of 30m and were being analyzed for mean, sorting, skewness and kurtosis, using standard laboratory procedures. Coarse silt, poorly sorted and negatively skewed were the characteristics of the borehole silt. The Kurtosis suggested the leptokurtic and platykurtic nature of the sediment. The TPH and THC range from 0.58 to 0.85 mg/L and 1.26 to 2.84 mg/L respectively. The Fe and pH range in the sediment were 0.85 to 2.46 mg/L and 4.43 to 6.02 respectively. However, Fe in the groundwater ranges from 0.12 to 0.21 mg/L. The results were above the World Health Organization's acceptable contaminant level. Based on the piece of evidence provided by spatial data mapping and textural parameters, the characteristics of the borehole sediment significantly controlled the ingress of contaminants into the groundwater. The source of groundwater contamination is the abnormal concentrations of organic contaminants. These results significantly impact human health in the food chain. This study provides information to the environmental agency for a clean-up process.

Groundwater Survey Using Resistivity Method for Drought Mitigation in Bima Regency, West Nusa Tenggara

Groundwater Survey in Bolo District, Palibelo District, Woha District, Langgudu District, Wawo District, Sape District, Wera District, Bima Regency, and West Nusa Tenggara for drought mitigation has been implemented. The study area is located in the majority of hilly areas with soil vulnerable to drought. Water is abundant during the rainy season. However, during the dry season, the ground surface is cracked, and there needs to be more clean water. This situation is troubling the community and the Regional Government of Bima Regency. The study was conducted using the Schlumberger resistivity geoelectric configuration method. The measurement point is in seven sub-districts, with a total of 18 measurement points. Research location at 118,6305833 SL; -8,3008888889 EL up to 119,01925 SL; -8,704638889 EL or covers an area of ± 1,961 km2. The length of the path used is a maximum of 400 meters. Based on the results of geoelectric resistivity data, two types of aquifers are found, open aquifers with depths ranging from 1 m to 26 m and aquifers depressed with depths ranging from 70 to 115 m. In addition to geoelectric information data, drilling data is also used at points that can be reached by heavy equipment in Lanta Barat Village, Lambu District. At the drilling point, the presence of an aquifer layer is obtained at a depth of about 80 meters. Residents then use the discovery of the wellbore to meet their need for clean water.

Screening of future carbon storage sites – selecting the best spots

Subsurface carbon storage can occur in depleted oil and gas fields, in water-wet structures, or in open aquifers. All three types of storage sites present advantages and inconveniences, which will be reviewed in this talk. The selection of future sites for carbon storage balances storage capacity (how much CO2 can be stored), injectivity (how efficiently or fast CO2 can be stored), and containment risk (how safely CO2 can be stored). We present a rigorous uncertainty-based approach involving estimates of pore volume, pressure and temperature conditions and resulting fluid properties, and sealing and containment behaviour, to highlight areas with best potential for safe and effective carbon storage.

Srms Application to a Regional Open Aquifer: The Basal Aquifer of Western Canada

Srms Application to a Regional Open Aquifer: The Basal Aquifer of Western Canada

Fouling and clogging surveillance in open loop GSHP systems

Fouling and clogging are some of the major water quality problems encountered in open loop ground source heat pump (GSHP) systems and aquifer thermal energy storage (ATES) systems. Here we present a surveillance strategy that can detect if and identify where in the system fouling and clogging might be developing without having to shut off the heat pump. In the presented system design, the test requires a minimum of four temperature sensors and two pressure sensors to describe the performance of the four major heat source system components, namely, the production well, the injection well, the submersible pump and the groundwater heat exchanger. The surveillance procedure involves conducting a step-test with incremental increases in the groundwater flow rate while measuring the pressure and temperature responses in the system components. The performance of the newly constructed installation functions as a baseline for future tests. By conducting the test systematically during operation an altered performance of the system can indicate clogging or fouling issues. Even though the cause of the problem must be identified through other means, the surveillance procedure presented here allows the operator to plan necessary maintenance and avoid critical damage to the heat source system.

Analytic Assessment of the Water Table Drawdown, Seepage, and Back Pressure at Rudbar PSPP

The impoundment of the Rudbar dam raised underground water level. On the right bank, the elevation of the water table is monitored in exploratory boreholes. The water table has remained below the level of the reservoir. The lower level of the water table is due to underground tunnels and galleries that behave as drains. Special analytic developments have been carried out to analyze the behavior of the water table during impoundment. The peculiarity of the model is that it considers a draining tunnel in an open aquifer with a free water table. Two new equations are obtained: one for inflow of water and the other for the water table drawdown. These equations are used to assess the water table elevation in the exploratory boreholes, calculate the hydraulic conductivity of the rock mass from the measured seepage in the conveyance tunnel, and determine the efficiency of the sealing from the measured back pressure on the extrados of the drainage gallery. The comparison of the calculated hydraulic conductivity with the available information from measurements with packer tests and DFN predictions will reveal the importance of scale effects and uncertainties.

GROUNDWATER INVESTIGATION USING RESISTIVITY METHOD AND DRILLING FOR DROUGHT MITIGATION IN TULUNGAGUNG, INDONESIA

Research of the groundwater in Pakel, Bandung and BesukiSubdistricts, Tulungagung District has been implemented. The research area is located in the rice field area, previously an area of annual flooding inundation during the rainy season. This situation troubles the community and local government of Tulungagung District. During the dry season, the mud cracks, making it difficult as agricultural land. The research was done using Geoelectrical Resistivity Schlumberger configuration method. The measurement point is located in the three Subdistricts with a total of 19 measurement points. The study location is at 111.75988880EL; -8.2264166670 SL to111.84541670 EL; 8.1309166660 SL or covers an area of 101km2. The length of the track used is a maximum of 600 meters. Based on the results of the geoelectrical resistivity data, it was found two types of aquifers, which are open aquifers in depth ranging from 6 m to 21 m and a confined aquifer in depth ranging from 90 to 115 m. In addition to the geoelectrical information data, drilling was done at an accessible point by heavy equipment in the Gempolan Village, PakelSubdistrict. At the drilling point, artesian wells were obtained at a depth of 108 meters and can rise to 2 meters above the soil surface. The discovery of artesian wells is then used by residents to meet the needs of clean water considering that in this area most wells are smell and iron contain.

CO2 plume migration in underground CO2 storage: The effects of induced hydraulic gradients

The use of water production as a pressure mitigation tool in the context of CO2 storage is widely studied but the impact it might have on the migration behaviour of a buoyant CO2 plume is less well reported. To investigate this further two different scenarios were modelled. In the first, a single water production well was used to draw CO2 along the strike of an open aquifer with a regional dip. Large rates of water production (5–10 times the volume of injected CO2) were required to achieve only small displacements of the CO2 plume. The second scenario investigated to what extent an induced hydraulic gradient might spill CO2 already stored in a structural trap. Here the effects were more pronounced with over 90% of the CO2 being spilled at a water cycling rate of 10 Mt per year (corresponding to a hydraulic gradient of 1.28 bar/km). The modelling was tested by the real case at Sleipner where CO2 migration in the Utsira Sand is potentially impacted by water production at the nearby Volve field. Simulations concluded that the CO2 plume at Sleipner should not be materially affected by water production from Volve and this is supported by the time-lapse seismics.

Developing a playground as catchment area in effort to maintaining groundwater in Jaten village of Karanganyar district of Central Java, Indonesia

Changes in land use for housing indirectly disturb the hydrology balance of the area. Groundwater conservation efforts can be done by keeping the function the catchment area. One of the housing developer's obligations is providing open spaces (the playground) to play or activity of the residents. Playground in Bumi Graha Indah Housing, Jaten village, Karanganyar district, Central Java, Indonesia has a fundamental issue, that is, in the rainy season the water is difficult to seep due landfill process are not well planned. It causes the playground become in muddy conditions with tall grass, so that reduces the function as a playground and or activity the residents. In the dry season, the soil dry of landfill caused dust scattering and disrupt the activities of people around the playground. Lack of water resources lead watering process for solving the problem of dust during the dry season was considered ineffective. Structuring drainage combined with modified recharge wells can be used to catch water runoff housing. This modification of water catchment areas can make playground dry quickly after rain so the activities of people are not bothered when utilizing the open space provided. Surface runoff water absorbed in open aquifer so that the hydrological balance always be maintained. Adequacy groundwater in the area playground can be used to sprinkler dust and backup needs clean water residents by creating wells and reservoir stocks.

An Open-Source Toolchain for Simulation and Optimization of Aquifer-Wide CO2 Storage

Planning and execution of large-scale, aquifer-wide CO2 storage operations will require extensive use of computer modelling and simulations. The required computational tools will vary depending on the physical characteristics of the targeted aquifer, the stage of the project, and the questions asked, which may not always be anticipated in advance. In this paper, we argue that a one-size-fits-all simulation tool for the modelling CO2 storage does not exist. Instead, we propose an integrated toolchain of computational methods that can be used in a flexible way to set up adaptive workflows. Although a complete toolchain will require computational methods at all levels of complexity, we further argue that lightweight methods play a particularly important role in addressing many of the relevant questions. We have implemented a number of such simplified methods in MRST-co2lab, a separate module to the open-source MATLAB Reservoir Simulation Toolbox (MRST). In particular, MRST-co2lab contains percolation-type methods that within seconds can identify structural traps and their catchment areas and compute spill paths and rough estimates of trapping capacity. The software also offers two-phase simulators based on vertical-equilibrium assumptions that can forecast structural, residual, and solubility trapping in a thousand-year perspective and are orders of magnitude faster than traditional 3D simulators. Herein, we apply these methods on realistic, large-scale datasets to demonstrate their capabilities and show how they can be used in combination to address optimal use of open aquifers for large-scale storage.

Revealing the surface deformation induced by deep CO2 injection in vegetated/agricultural areas: The combination of corner-reflectors, reservoir simulations and spatio-temporal statistics

The performance of Permanent Scatterers PS Interferometry (PSI) analysis is highly limited where the presence of large vegetated cover (agricultural terrains/forests) reduces signal coherence. A possible solution relies on the installation on ground of artificial devices (Corner Reflectors CR) to complement the existing PS network. Yet, the number of such CRs (spatial density typically ~1/km2) can be limited when the deformation pattern affects a large area (tens of km2) especially for CO2 geological storage in open aquifers. In order to support the surveillance of such sites, we address here the question of how to estimate the spatio-temporal distribution of the ground displacements over the whole area using only the sparse CR+PS network. We propose to test the feasibility of the Geostatistics Output Perturbation (GOP) method, enabling to combine: 1. The results of the reservoir model calibrated on the limited number of ground displacements' time series and, 2. The spatial correlation between such calibrated results and the observations. A test case was constructed using the signal measured during CO2 injection (from 2004–2009) in the KB501 well of the In-Salah site, Algeria at only a few tens of spatial measurement points either corresponding to: 1. a “realistic” PS network selected in a highly vegetated region in western France or 2. a series of CR selected through a space-filling criterion. The comparison with the observations over the whole area confirmed that 80% of the temporal observations were fitted by the GOP method over the region defined by the CR network with a density of ~1CR/km2. Comparisons with the calibrated model results and with the direct application of a spatio-temporal kriging confirmed the better performance of GOP as well.

Review of CO2 storage efficiency in deep saline aquifers

At the time the IPCC Special Report on Carbon Capture and Storage was published in 2005, the concept of CO2 storage efficiency was not introduced yet and, consequently, no numerical values were published in the literature. CO2 storage efficiency is defined as the ratio of the volume of CO2 injected into an aquifer rock volume to the pore space in that volume and this concept has been first introduced in 2007 in regional-scale assessments of storage capacity in the United States and Europe. Since then many papers, reviewed in this article, have been published on the subject of efficiency of CO2 storage and associated values. CO2 storage efficiency depends on a multitude of factors that can be grouped into several categories: (1) Characteristics of the storage aquifer, such as in situ conditions of pressure, temperature and salinity, displacement characteristics of the CO2/brine system, lithology, porosity, permeability, heterogeneity and anisotropy, aquifer areal extent, thickness and boundaries; (2) Characteristics of the confining aquitards, mainly permeability and capillary entry pressure; (3) Characteristics of the CO2 storage operation, such as injection rate, duration of injection; number of injection wells, their orientation and their spacing, and injection strategy, including water production and/or injection; and (4) Regulatory constraints, such as maximum bottom-hole injection pressure, and definitions used to establish the volume of rock assigned for CO2 storage for a given project, such as scale of assessment (local or regional), relevant time (e.g., at cessation of injection or at plume immobilization), and relevant aquifer area (e.g., footprint of the CO2 plume itself, area where aquifer pressure is higher than a critical pressure, or area of tenure). Depending on the combination of factors listed above, values of storage efficiency as calculated to date and published in the literature vary in a wide range (from <1% to >10%, by a factor of 20 and even higher) and no single value or set of values can be universally used. Storage efficiency has both a spatial and a temporal dependency; being first pressure- and then space-limited; therefore it is critical in all assessments to specify the relevant aquifer area and time of reference. For closed aquifers, the cross-over time from pressure-limited to space-limited is achieved very quickly, and storage efficiency is based on the compressibility of the system. For open aquifers, a CO2 storage operation is most likely pressure-limited during its entire life. Storage resource estimates are theoretically time and space independent in the sense that the entire aquifer is considered, and the estimate represents what would be achieved if all the aquifer pore space would be accessible through a very large number of wells and over a very long period of time, much longer than a project life-time and the period of time needed to achieve climate stabilization. Volumetric estimates could be used for regional-scale evaluations of CO2 storage resources using values at the lower end of the spectrum of published values for storage efficiency. Dynamic estimates, based on numerical simulations that take into account operational and regulatory factors should be used for local-scale CO2 storage reserves estimates. Storage efficiency can be increased using storage engineering technology, such as water extraction and/or (re)injection, and the type and location of various injection and producing wells.

Using Pressure and Volumetric Approaches to Estimate CO2 Storage Capacity in Deep Saline Aquifers

Various approaches are used to evaluate the capacity of saline aquifers to store CO2, resulting in a wide range of capacity estimates for a given aquifer. The two approaches most used are the volumetric “open aquifer” and “closed aquifer” approaches. We present four full-scale aquifer cases, where CO2 storage capacity is evaluated both volumetrically (with “open” and/or “closed” approaches) and through flow modeling. These examples show that the “open aquifer” CO2 storage capacity estimation can strongly exceed the cumulative CO2 injection from the flow model, whereas the “closed aquifer” estimates are a closer approximation to the flow-model derived capacity. An analogy to oil recovery mechanisms is presented, where the primary oil recovery mechanism is compared to CO2 aquifer storage without producing formation water; and the secondary oil recovery mechanism (water flooding) is compared to CO2 aquifer storage performed simultaneously with extraction of water for pressure maintenance. This analogy supports the finding that the “closed aquifer” approach produces a better estimate of CO2 storage without water extraction, and highlights the need for any CO2 storage estimate to specify whether it is intended to represent CO2 storage capacity with or without water extraction

Maximizing Local Capillary Trapping During CO2 Injection

Local capillary trapping (LCT) occurs during buoyancy-driven migration of bulk phase CO 2 within a saline aquifer exhibiting spatially varying properties (permeability and capillary entry pressure). When the rising CO 2 plume encounters a region where capillary entry pressure is locally larger than average, CO 2 accumulates beneath the region. The benefit of LCT, applied specially to CO 2 sequestration, is that saturation of stored CO 2 is larger than the saturation predicted for other trapping mechanisms, yet the CO 2 is not susceptible to leakage through failed seals. In this paper, the effects of the injection rate, anisotropy, formation dip, aquifer types and residual gas saturation on the LCT saturation/mass were systematically investigated including the injection period. The domain with heterogeneous capillary pressure was generated by using geostatistical permeability realization and Leverett-J function to assign an individual drainage curve to each grid block. After injection, leakage was simulated that represents localized caprock breach induced by geochemical process or by stress/strain variation within the reservoir/caprock. The trend of the fraction of CO 2 above residual that remains trapped after seal rupture was evaluated. Residual and dissolution trapping were assessed and compared to LCT over time during and after injection. Results indicate that local capillary traps in the near-well region can be fully filled during injection in the domain. Moreover, they remain filled after post-injection buoyancy-driven flow ends. The flow regimes are dependent on the injection rate, but LCT mass fraction is almost insensitive to the CO 2 injection rate (gravity number). This implies that local capillary trapping is primarily determined by the geological model. Anisotropy does not change the LCT structures although it has some impact on the LCT CO 2 saturation and plume dynamics. Formation dip angle is demonstrated to be the most influential parameters on the structures and mass fraction of injected CO 2 held in LCT, as it changes the effective horizontal permeability correlation length. The key finding from this research is that LCT could be as significant as residual trapping in immobilizing CO 2 during the intermediate period in the open aquifer.

Semi-analytical Solution for Brine Leakage Through Passive Abandoned Wells Taking Account of Brine Density Differences

Both $$\hbox {CO}_{2}$$ storage and disposal of waste fluid (e.g., co-produced brine) in deep saline aquifers of sedimentary basins create large scale over-pressurization and tend to displace brine upwards if a vertical connection (e.g., an abandoned well) is present. This raises groundwater pollution issues of brine intrusion into shallower potable water aquifers. When saline brine from the deep aquifer is displaced upwards it lifts and replaces the a priori less saline, less dense water initially filling the connection, resulting in a weight increase that counters leakage. This article presents and explains an innovative semi-analytical solution to this problem of leakage between two aquifers connected by a passive well (represented by a porous column and/or an open wellbore) taking account of the effect of the density difference between lifting and lifted brines during both upward and downward flow. It is based on the linearization of brine density profiles against depth and on two improvements made to the approximate evaluation of convolution products introduced in Nordbotten et al. (Water Resour Res 40:W04204, 2004) for calculation of the pressurization induced by transient flows in open aquifers. The comparison with numerical simulations shows good agreement of results. Since the solution uses time discretization but no spatial grid, computation time is reduced by 3–4 orders of magnitude compared to numerical resolution. It does, however, require considering homogeneous aquifers of constant thickness and brine properties.

Dipping open aquifers—The effect of top-surface topography and heterogeneity on CO2 storage efficiency

The Forties aquifer underlying the North Sea is used as an exemplar base case to provide a quantitative framework for assessing the CO2 storage efficiency of dipping open aquifer storage units. Storage under a set of putative regulatory constraints is considered: pressure, migration distance and migration velocity. The effects of permeability, heterogeneity, aquifer dip and top-surface topography are all assessed and the results presented in terms of quantitative storage regimes. Permeability and aquifer dip are key determinants of storage efficiency, since they control the flow speed of the CO2 and the amount of pressure build-up. Heterogeneity reduces storage efficiency due to localised pressure build-up, if this is a constraint. However, where pressure does not limit capacity, vertical heterogeneity improves storage efficiency through boosting the lateral sweep of CO2. Top-surface topography introduces structural closures, regions of higher and lower dip than the model average, and channels. When compared to smooth models, structural closures increase efficiency and channels generally decrease efficiency. The net effect of all the competing topographical effects depends on which storage regime describes the smooth model. Overall, it is demonstrated that the storage regime and topography play important roles in determining storage capacity.

Biological Cr(VI) immobilisation in saturated aquifer zone using culture inoculated soil columns

Remediation of Cr(VI) requires the reduction of the mobile state [Cr(VI)], which exists in the natural environment as the oxyanionic species (CrxOy(z)(-)), to the less mobile trivalent state [Cr(III)], which readily forms the hydroxide precipitate [Cr(OH)3(s)] under natural pH conditions. In this study, Cr(VI) reduction is investigated using inoculated microcosm aquifer systems operated as fully submerged plug flow systems. The system was design to simulate the operation of a microbial contaminant barrier in the saturated zone of an open aquifer system. No organic carbon sources and no air was introduced to simulate Cr(VI) reduction under oxygen free conditions. The inoculated microcosm column operated at influent feed concentrations of 10, 20, and 40 mg/L, and a hydraulic retention time of 12 hours achieved complete removal of Cr(VI) over a 90 cm distance. Steady-state conditions were obtained in less than 48 hours under feed concentrations of 10 and 20 mg/L. Very little Cr(VI) reduction was observed in non-inoculated microcosm controls operated under identical conditions.

Implications of Alternative Post-injection Regulatory Guidance Upon CO2 Storage in Dipping Open Aquifers

To transfer responsibility for a CO2 storage site to the competent authority, the EU Storage Directive requires it to be demonstrated that CO2 will be completely and permanently contained and that the storage site is evolving towards a situation of long-term stability. As outlined in current EU guidance, there may be room for interpretation by both the national competent authority and the storage operator in the implementation of this part of the Directive. Here we postulate that, for storage in dipping open aquifers, the requirements of the Directive can be met by modelling various combinations of a boundary constraint, a migration velocity constraint and a constraint on the minimum fraction of injected CO2 that is likely to be trapped at a defined time (1000 or 10,000 years) after injection ceases. A key outcome is that there is a strong trade-off between storage efficiency and storage security when storage is maximised under different combinations of constraints. To increase confidence in security under all scenarios, modelling longer post-injection periods is desirable; however there may be computational limits to this.