scholarly journals Application of Clustering System to Analyze Geological, Geotechnical and Hydrogeological Data Base according to HC-System Approach

2017 ◽  
Author(s):  
Lilik Eko Widodo ◽  
Tedy Agung Cahyadi ◽  
Sudarto Notosiswoyo ◽  
Eman Widijanto
Keyword(s):  
Hydraulic Conductivity ◽  
Fractured Rocks ◽  
System Approach ◽  
Fractured Rock ◽  
Porous Rocks ◽  
Permeability Index ◽  
Depth Index ◽  
Rock Quality ◽  
Good Interpretation ◽  
Hydrogeological Data

Highly fractured rocks at Grasberg Mining in PT Freeport Indonesia (PTFI) lead to fractured groundwater flow media. Hydraulic conductivity of fractured rock has more complexity than that of porous rocks media. In this study, hydraulic conductivity (K) has been estimated according to HC-System based on Rock Quality Designation (RQD), Lithology Permeability Index (LPI), Depth Index (DI) and Gouge Content Designation (GCD). Numerical model of HC-System at Grasberg Mining in general can be expressed by the equation K = 2 x 10-6 x HC0.5571. The RQD data can be grouped into three ranges, i.e. first group that dominates over 80 % of the RQD data with K ranging between 1.9x10-8 – 2.3x10-7 m/s, second group that is within 40 – 80% of the RQD data with K falling between 2x10-8 – 7.2x10-7 m/s, and third group that takes part less than 40 % of RQD data with K ranging between 2.1x10-8 – 1.9x10-6 m/s. Based on the lithology, the hydraulic conductivity of rocks can be assinged as follows: igneous rock with K ranging 6.8x10-8 – 1.9x10-7 m/s, and sedimentary rock with K ranging 2.2x10-8 – 1.9x10-6 m/s. HC-System demonstrates good interpretation of hydraulic conductivity by means of clustering method, which uses geological and geotechnical data for hydrogeological characterization

scholarly journals Fractal Analysis of Permeability of Unsaturated Fractured Rocks

2013 ◽  
Vol 2013 ◽  
pp. 1-5
Author(s):  
Guoping Jiang ◽  
Wei Shi ◽  
Lili Huang
Keyword(s):  
Hydraulic Conductivity ◽  
Fractured Rocks ◽  
Water Retention ◽  
Fractured Rock ◽  
Fractal Theory ◽  
Saturation Curve ◽  
Geometric Pattern ◽  
Unsaturated Hydraulic Conductivity ◽  
Fractured Medium ◽  
Fracture Apertures

A physical conceptual model for water retention in fractured rocks is derived while taking into account the effect of pore size distribution and tortuosity of capillaries. The formula of calculating relative hydraulic conductivity of fractured rock is given based on fractal theory. It is an issue to choose an appropriate capillary pressure-saturation curve in the research of unsaturated fractured mass. The geometric pattern of the fracture bulk is described based on the fractal distribution of tortuosity. The resulting water content expression is then used to estimate the unsaturated hydraulic conductivity of the fractured medium based on the well-known model of Burdine. It is found that for large enough ranges of fracture apertures the new constitutive model converges to the empirical Brooks-Corey model.

scholarly journals Studi Literatur Pendugaan Nilai Konduktivitas Hidraulik Dengan Menggunakan Data Uji Hidraulik Lapangan Dan Data Loging Geoteknik

2017 ◽  
Author(s):  
Tedy Agung Cahyadi ◽  
Irwan Iskandar ◽  
Sudarto Notosiswoyo ◽  
Lilik Eko Widodo
Keyword(s):  
Rock Quality Designation ◽  
Permeability Index ◽  
Slug Test ◽  
Depth Index ◽  
Rock Quality ◽  
Packer Test ◽  
Content Index

Konduktivitas hidraulik merupakan parameter yang sangat penting dalam pemodelan aliran airtanah. Parameter tersebut dapat diambil melalui pengujian packer test dan slug test . Mahalnya operasional pelaksanaan pengujian tersebut, memberikan dampak minimnya data kondutivitas hidraulik di lapangan. Konduktivitas hidraulik pada batuan yang terkekarkan memiliki kompleksitas (derajad heterogenitas dan anisotropi) yang lebih tinggi dibandingkan dengan konduktivitas hidraulik pada batuan sedimen. Untuk mengatasi minimnya data konduktivitas hidraulik, dalam studi literature ini akan dilakukan cara prediksi nilai konduktivitas hidraulik dengan menggunakan pendekatan metode HC-System. HC-System merupakan metode empirik yang melibatkan data-data geoteknik menduga nilai konduktivitas hidraulik di daerah yang tidak ada data pengukuran (terbatas pada titik pengukuran geoteknik). Data geoteknik tersebut terdiri dari Rock Quality Designation (RQD), Lithology Permeability Index (LPI), Depth Index (DI), and Gouge Content Index

Tight Jurassic Carbonate Reservoir Characterization and Fluid Typing Identification by Integrating Magnetic Resonance, Elemental Spectroscopy and Micro-Resistivity Image Data in Umm Ross Field, West Kuwait, Case Study

2021 ◽  
Author(s):  
Said Beshry Mohamed ◽  
Sherif Ali ◽  
Mahmoud Fawzy Fahmy ◽  
Fawaz Al-Saqran
Keyword(s):  
Magnetic Resonance ◽  
Reservoir Characterization ◽  
Clay Content ◽  
Effective Porosity ◽  
Carbonate Reservoir ◽  
High Resistivity ◽  
Permeability Index ◽  
Rock Quality ◽  
Porosity And Permeability ◽  
Bulk Volume

Abstract The Middle Marrat reservoir of Jurassic age is a tight carbonate reservoir with vertical and horizontal heterogeneous properties. The variation in lithology, vertical and horizontal facies distribution lead to complicated reservoir characterization which lead to unexpected production behavior between wells in the same reservoir. Marrat reservoir characterization by conventional logging tools is a challenging task because of its low clay content and high-resistivity responses. The low clay content in Marrat reservoirs gives low gamma ray counts, which makes reservoir layer identification difficult. Additionally, high resistivity responses in the pay zones, coupled with the tight layering make production sweet spot identification challenging. To overcome these challenges, integration of data from advanced logging tools like Sidewall Magnetic Resonance (SMR), Geochemical Spectroscopy Tool (GST) and Electrical Borehole Image (EBI) supplied a definitive reservoir characterization and fluid typing of this Tight Jurassic Carbonate (Marrat formation). The Sidewall Magnetic resonance (SMR) tool multi wait time enabled T2 polarization to differentiate between moveable water and hydrocarbons. After acquisition, the standard deliverables were porosity, the effective porosity ratio, and the permeability index to evaluate the rock qualities. Porosity was divided into clay-bound water (CBW), bulk-volume irreducible (BVI) and bulk-volume moveable (BVM). Rock quality was interpreted and classified based on effective porosity and permeability index ratios. The ratio where a steeper gradient was interpreted as high flow zones, a gentle gradient as low flow zones, and a flat gradient was considered as tight baffle zones. SMR logging proved to be essential for the proper reservoir characterization and to support critical decisions on well completion design. Fundamental rock quality and permeability profile were supplied by SMR. Oil saturation was identified by applying 2D-NMR methods, T1/T2 vs. T2 and Diffusion vs. T2 maps in a challenging oil-based mud environment. The Electrical Borehole imaging (EBI) was used to identify fracture types and establish fracture density. Additionally, the impact of fractures to enhance porosity and permeability was possible. The Geochemical Spectroscopy Tool (GST) for the precise determination of formation chemistry, mineralogy, and lithology, as well as the identification of total organic carbon (TOC). The integration of the EBI, GST and SMR datasets provided sweet spots identification and perforation interval selection candidates, which the producer used to bring wells onto production.

Effect of seawater intrusion on radioactive strontium (90Sr) sorption and transport at nuclear power plants

2018 ◽  
Vol 106 (2) ◽  
pp. 147-160
Author(s):  
Seeun Chang ◽  
Wooyong Um ◽  
Won-Seok Kim ◽  
HyunJu Kim
Keyword(s):  
Ionic Strength ◽  
Seawater Intrusion ◽  
Fractured Rocks ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Fractured Rock ◽  
Column Experiments ◽  
Rock Samples ◽  
Batch Sorption

Abstract Batch sorption and column experiments were conducted to investigate and compare sorption and transport behavior of 90Sr on the assumption of seawater intrusion at nuclear power plants. Batch sorption experiments were carried out on fractured rocks and bedrocks using synthetic groundwater and seawater both spiked with 90Sr. In general, higher 90Sr sorption occurred on fractured rock samples than on bedrocks, because of the presence of weathered secondary minerals (iron oxide and clay) on fractured rock surfaces. However, one particular bedrock sample (WSP-B) which has higher porosity and carbon amount than fractured rock samples also showed the higher 90Sr sorption than its comparable fractured rocks. For all batch sorption studies, 90Sr sorption distribution coefficient, Kd decreased from groundwater to seawater environment due to the higher ionic strength of seawater (6.4×10−1–7.7×10−1 M) compared to groundwater (4.0×10−3–6.0×10−3 M). The three different ionic strength solutions were used in column experiments, and the results showed that transport behavior of Sr through a fractured rock had similar sorption trend to batch sorption results. The highest mobility (or least retardation) for Sr was found for 100% seawater solution compared to the highest retardation (or least mobility) for 100% groundwater solution. These sorption and transport data of Sr on solid materials contacted with various ionic strength solutions corroborate empirically defensible information for assessment of radioactive contamination in groundwater below the NPP sites located nearby shores. In addition, the experimental data will be incorporated to improve transport models of 90Sr in the subsurface environment for severe nuclear accidents.

scholarly journals A Novel Numerical Model for Fluid Flow in 3D Fractured Porous Media Based on an Equivalent Matrix-Fracture Network

Geofluids ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Chi Yao ◽  
Chen He ◽  
Jianhua Yang ◽  
Qinghui Jiang ◽  
Jinsong Huang ◽  
...  
Keyword(s):  
Porous Media ◽  
Fluid Flow ◽  
Hydraulic Conductivity ◽  
Fractured Rock ◽  
Fracture Network ◽  
Numerical Approach ◽  
Porous Matrix ◽  
Fractured Porous Media ◽  
Hydraulic Aperture ◽  
Matrix Fracture

An original 3D numerical approach for fluid flow in fractured porous media is proposed. The whole research domain is discretized by the Delaunay tetrahedron based on the concept of node saturation. Tetrahedral blocks are impermeable, and fluid only flows through the interconnected interfaces between blocks. Fractures and the porous matrix are replaced by the triangular interface network, which is the so-called equivalent matrix-fracture network (EMFN). In this way, the three-dimensional seepage problem becomes a two-dimensional problem. The finite element method is used to solve the steady-state flow problem. The big finding is that the ratio of the macroconductivity of the whole interface network to the local conductivity of an interface is linearly related to the cubic root of the number of nodes used for mesh generation. A formula is presented to describe this relationship. With this formula, we can make sure that the EMFN produces the same macroscopic hydraulic conductivity as the intact rock. The approach is applied in a series of numerical tests to demonstrate its efficiency. Effects of the hydraulic aperture of fracture and connectivity of the fracture network on the effective hydraulic conductivity of fractured rock masses are systematically investigated.

scholarly journals Fluid pressure diffusion effects on the excess compliance matrix of porous rocks containing aligned fractures

2020 ◽  
Vol 222 (1) ◽  
pp. 715-733
Author(s):  
Gabriel A Castromán ◽  
Nicolás D Barbosa ◽  
J Germán Rubino ◽  
Fabio I Zyserman ◽  
Klaus Holliger
Keyword(s):  
Seismic Velocity ◽  
Fractured Rock ◽  
Finite Thickness ◽  
Practical Importance ◽  
Fluid Pressure ◽  
Porous Rocks ◽  
Compliance Matrix ◽  
Pressure Diffusion ◽  
Reservoir Permeability ◽  
Wide Range

SUMMARY The presence of sets of open fractures is common in most reservoirs, and they exert important controls on the reservoir permeability as fractures act as preferential pathways for fluid flow. Therefore, the correct characterization of fracture sets in fluid-saturated rocks is of great practical importance. In this context, the inversion of fracture characteristics from seismic data is promising since their signatures are sensitive to a wide range of pertinent fracture parameters, such as density, orientation and fluid infill. The most commonly used inversion schemes are based on the classical linear slip theory (LST), in which the effects of the fractures are represented by a real-valued diagonal excess compliance matrix. To account for the effects of wave-induced fluid pressure diffusion (FPD) between fractures and their embedding background, several authors have shown that this matrix should be complex-valued and frequency-dependent. However, these approaches neglect the effects of FPD on the coupling between orthogonal deformations of the rock. With this motivation, we considered a fracture model based on a sequence of alternating poroelastic layers of finite thickness representing the background and the fractures, and derived analytical expressions for the corresponding excess compliance matrix. We evaluated this matrix for a wide range of background parameters to quantify the magnitude of its coefficients not accounted for by the classical LST and to determine how they are affected by FPD. We estimated the relative errors in the computation of anisotropic seismic velocity and attenuation associated with the LST approach. Our analysis showed that, in some cases, considering the simplified excess compliance matrix may lead to an incorrect representation of the anisotropic response of the probed fractured rock.

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

2013 ◽  
Vol 405-408 ◽  
pp. 2123-2129
Author(s):  
Yuan Yao Li ◽  
Rong Lin Sun ◽  
Ren Quan Chen
Keyword(s):  
Hydraulic Conductivity ◽  
Scale Effects ◽  
Fractured Rock ◽  
Water Pressure ◽  
Hydroelectric Station ◽  
Tracer Test ◽  
Test Results ◽  
Hydraulic Test ◽  
Water Seepage ◽  
Pressure Tests

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.

Correlation of Outcrop Hydraulic Conductivity with its Aquifer: A Case Study of the Phu Phan Sandstone in Northeast, Thailand

2014 ◽  
Vol 931-932 ◽  
pp. 823-828 ◽  
Author(s):  
Thidarat Cotanont ◽  
Chalong Buaphan ◽  
Kamonporn Kromkhun
Keyword(s):  
Hydraulic Conductivity ◽  
Groundwater Modeling ◽  
Fractured Rock ◽  
Groundwater Resources ◽  
Pumping Test ◽  
Fracture Analysis ◽  
Northeast Thailand ◽  
K Value ◽  
Single Well ◽  
Order Of Magnitude

Fractured rock aquifers provide the most extensive groundwater resources in Northeast Thailand. The hydraulic conductivity (K) of these aquifers controls the flow of water and is therefore, an essential parameter for groundwater modeling and management. K values may be directly determined by conducting pumping tests at the aquifer or by performing fracture analysis using data acquired from outcrops. The K value at outcrop should be greater than that at aquifer of deeper position due to the effect of aperture reduction by overburden compression. The goal of this study was therefor to find the correlation between K values determined from outcrop with those directly measured at an aquifer. This study was conducted on the Phu Phan sandstone aquifer at the Huay Luang watershed, Udon Thani Province of Northeast Thailand. The orientation, aperture, and spacing of fractures were measured at four outcrops and used for determining the K values by fracture analysis. Single well pump test data from 17 wells in the Phu Phan aquifer (30-120 m depth) were analyzed to obtain transmissivity (T) and K. Both sets of the K values, from outcrop and aquifer, were correlated using the plotting position of Weibull. Both plots were linear on a semi-log scale but the outcrop curve was steeper. Lognormal distributions fitted both plotting positions quite well. These results show that for the same probability value, K values found from the pumping test to be about an order of magnitude smaller than K values determined from outcrop data.

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