Tạp chí Khoa học Kỹ thuật Mỏ - Địa chất

Developing a Saturation Height Function (SHF) for the classified Hydraulic Flow Unit, a case study from the Middle Miocene Carbonate reservoir in the Song Hong Basin, Vietnam

Dung Trung Nguyen — 2024-03-11

The Middle Miocene carbonate is the main gas bearing reservoir in the
southern part ofthe Song Hong basin. Carbonate reservoirs present challenges
for engineers and geologists to characterize because of their complexity due to
depositional and diagenetic processes. The log based calculated water
saturation Sw for this complex carbonate reservoir bears a lot of uncertainties
due to its heterogeneity that strongly affects to m and n values in the water
saturation equation. As the calculated Sw strongly affects the Hydrocarbon
Initially In Place (HIIP) estimation, the production performance prediction,etc.,
the alternative method using the Saturation Height Function (SHF) based on
the capillary pressure was introduced. The SHF building process uses the
combination of the result of HFU classification and permeability prediction
given by machine learning methods, which have become a very useful tool for
complex reservoir characterization such as carbonate reservoir for decades.
Our obtained results allowed us to subdivide the carbonate reservoir into 5
Hydraulic Flow Unit (HFU) by using unsupervised machine learning methods,
and then the capillary pressure (Pc) curves were classified and a proper
saturation-height function using Skelt Harrison equation was assigned to
individual HFU after testing with common SHF equations.The HFU number for
each individual point was predicted based on the log data measured along the
borehole using the supervised machine learning techniques while the Sw was
calculated using the chosen SHF model and the FWL defined on log curves and
pressure data from RCI measurement. The Sw computed from the SHF model
is reliable and can be used for water saturation estimation for the whole field
for known FWL and predicted HFU numbers

Researching and applying open-source WebGIS technology to build national-standard vector geographic database management software

Yen Quoc Phan — 2024-03-11

Geographical database management is a crucial component of spatial data infrastructures (SDIs) and is used by government organizations in provinces, regions, and countries. It plays an important role, especially during the 4.0 technology revolution and digital transformation to build e-government and digital government. A complete and scientific management of geographical databases is the most crucial core foundation of a system. The article applies open-source WebGIS technologies such as Geoserver map server, PostGIS data management software, Python programming language, Vue, and Openlayers map library to build spatial data management software. Spatial data is mainly in vector form, built according to national geographic database standards (QCVN 42: 2020/BTNMT). The system has main functional groups such as user account authorization and user groups; and geographic database management, including seven groups: borders, geodesy, population, topography, traffic, surface cover, and hydrology. In addition, the administration of some thematic classes such as drafting plans, managing equipment and units, etc., are performed. The software system is built in a service-oriented manner, serving as the core foundation to facilitate the development of many geo-portal applications

Mineralogical and geological characteristics and potential of iron resources in Tan An area, Yen Bai province

Khang Quang Luong — 2024-03-11

The Tan An area in Yen Bai province, located in northwestern Vietnam, is known for its high potential for iron deposits. The region has several iron occurrences, including Tan An, Nghia Hung, Buu Village, and Tran Phu Farm. The authors conducted a comprehensive study of the region using various geological and mineralogical analysis techniques to better understand the iron mineralization process. Their findings indicate that iron mineralization in the area is the result of metamorphic and hydrothermal processes characteristic of magnetite-quartzite and hematite types. The iron content in the orebodies varies from medium to high values, with an average range of 27.5÷63.7%. These results provide valuable insight into the prospect of iron resources in the Tan An region, serving as a foundation for identifying the most promising areas for further exploration. To estimate the iron resources in the study area, the Huvo method was used, yielding a total estimated amount of 11.4 million tons of Fe-metal, including 2,028,026 tons in the Tran Phu Farm area, 360,611 tons in the Buu Village area, 426,534 tons in the Nghia Hung area and 8,605,065 tons in the Tan An area at iron resource level 334a. These findings provide a preliminary assessment of the potential iron resources in the area. The study's results are significant, providing valuable information for future iron exploration and development activities in the Tan An region. With this knowledge, mining companies and investors can make informed decisions about the feasibility of mining iron in the area. Additionally, the study's results may lead to the creation of new jobs in the mining industry, benefiting the local economy and the region as a whole

Foraminifera in the Holocene sediments at the shallow sea from Phu Loc (Thua Thien Hue) to Hoi An (Quang Nam) (0÷60 m of water depth)

Chi Kim Thi Ngo — 2024-03-11

The shallow sea (0÷60 m of water depth) from Phu Loc (Thua Thien Hue) to Hoi An (Quang Nam) belongs to the internal shelf in Central Vietnam. This is quite a good geological structure for the land-sea interaction study, especially during the Holocene. Therefore, it is necessary to study the geological history of the area during the Holocene period. Foraminifera is the subject of geological studies to solve the environmental problems of sedimentary, stratigraphic, and paleogeography. However, at present, the research documents on Foraminifera in the sediments in Vietnam in general as well as in the research area in particular are still very modest. This paper presents research results of Foraminifera fauna in Holocene sediments from Phu Loc (Thua Thien Hue) to Hoi An (Quang Nam) (0÷60 m of water depth). 93 species, belonging to 48 genera, 28 families and 5 suborders Foraminifera have been identified based on the analysis of 59 available samples. Miliolina Delage et Hérouard, 1896 has 06 families, 18 genera and 40 species; Rotaliina Delage et Hérouard, 1896 has 12 families, 15 genera and 29 species; Textulariina Delage et Hérouard, 1896 has 03 families, 05 genera and 07 species; Lagenina Delage et Hérouard, 1896 has 03 families, 04 genera and 07 species; Globigerinina Delage et Hérouard, 1896 has 04 families, 06 genera and 10 species. The quality of the benthonic Foraminifers is dominant, clearly showing the geological environment of the shallow sea near shore, where the hydrodynamic regime is high and the salt concentration is not stable

Cobalt in the regolith upon Nui Nua ultramafic Massif

Thanh Trung Nguyen — 2024-03-11

Cobalt (Co) Metal plays an increasingly important role in the battery and engine manufacturing industry for electric cars. Previously most of Co was mined as by-product in copper ore deposits in Central Africa. Recently, the proportion of Co extracted from other sources such as weathering-derived mines on ultramafic rocks is increasing. In Vietnam, Cobalt has been discovered in Cu-Ni ore deposits in the Northeast and Northwest Regions. The literature shows that cobalt is found in small amounts in ultramafic rocks. During the weathering process of ultramafic rocks, Co ions will be priority adsorbed in the hydroxide colloids of Mn and Fe (goethite and asbolan). In the regolith upon Nui Nua Masif, Ni content increased dramatically (several times) from 0.19% in bedrocks up to 1% in some locations, while cobalt content just increased only slightly (from 0.02% in bedrock to 0.05 regolith, rarely up to 0.1%). The results of the previous analysis of weathered crust samples of ultramafic rocks of Nui Nua massif by several authors show that, unlike Ni which is presented in both silicate minerals and Fe-Mn oxide/hydroxide, cobalt ions tend to be concentrated in Fe-Mn oxides/hydroxides. Our SEM analyses combined with EDS show some remarkable results: the Co content in some specific minerals is quite high from 1.12÷4.67% (denominator). This is only a preliminary result and it is necessary to conduct more work to further detailed studies defining the Co potential in weathering products of ultramafic rocks of Nui Nua massif as well as in the areas where other ultramafic rocks are developed. Recently, research confirmed that there is a significant Co-Ni occurrence discovered in Mau Lam Valley (Southwest of Nui Nua Massif)

In situ U-Pb isotopic dating method on titanite, and application to determine REE-Fe-Cu mineralization age of the Sin Quyen deposit, Lao Cai province

Dac Xuan Ngo — 2024-03-11

Titanite (CaTiSiO5) is an important common accessory mineral in hydrothermal deposits, with appreciable amounts of U and Th incorporated into their structures for age dating. Titanite crystals are usually larger than zircon and monazite and may have zoning in texture and geochemistry which represent different parageneses likely related to multiple hydrothermal or mineralization events. In line with the development of laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) that has high sensitivity and spatial resolution, in-situ U-Pb isotopic dating method on titanite has become a powerful tool to investigate the ages of different zones from a mineral. Titanite typically accommodates a significant amount of Rare Earth Elements (REEs) and High Field Strength Elements (HFSEs) and the titanite generated from different origins exhibits distinct trace element geochemistry. Therefore, the trace element geochemistry of titanite can serve as an indicator of its formation environment. Titanite occurred in different mineralization stages of the Sin Quyen deposit, making it a suitable mineral for investigating the timing of mineralization. In this paper, we present the U-Pb age of titanite from different stages of the Sin Quyen deposit used to constrain the timing and origin of such events. The hydrothermal titanites are dated by in situ LA-ICP-MS technique and have U-Pb ages of 873±12 Ma and 844±12 Ma which indicate two mineralization/hydrothermal events at the same time, respectively. These ages from the Sin Quyen deposit are well correlated with regional tectono-thermal events during the long-lived Neoproterozoic subduction in the western Yangtze Block

Unconfined compressive strength assessment of soil-cement mixtures in Hai Duong city

Thang Hong Do — 2024-03-11

The unconfined compressive strength (qu) of the soil-cement mixture (S-CM) depends on many factors, in which the soil type and the cement content (%CM) are very important factors. The soil type determines the fine particle content and affects the effectiveness of soil-cement mixture. Meanwhile, %CM has a direct influence on the qu of the S-CM. The cost of foundation treatment methods for small and medium-sized constructions depends on the reasonable cement content. This paper presents the unconfined compressive strength of S-CM for five common cohesive soils in Hai Duong city (soft clay, soft clayey sand, soft sandy clay, clayey sand mud, and sandy clay mud) with four cement contents (7%, 10%, 15%, and 20%). The research results show that the clayey sand (mbQ21-2hh) has the highest improvement efficiency compared to other soils, i.e., soft sandy clay (abQ23tb), soft clay (mQ21-2hh), sandy clay mud (mbQ21-2hh), and clayey sand mud (amQ21-2hh). The clay content has a great influence on the qu of S-CM. With the required value of qu28 = (8.0÷10.0) kG/cm2 (at 28 curing days), the reasonable cement content (% CM) is varied from 8% to 13% for soft sandy clay (abQ23tb), soft clay (mQ21-2hh), sandy clay mud (mbQ21-2hh), and clayey sand mud (amQ21-2hh); with the same value of qu28, the reasonable %CM is from 7.5 to 9.0% for clayey sand (mbQ21-2hh). The results are the scientific basis for recommending a reasonable %CM for each type of soil when designing to reinforce the foundation with soil-cement columns in Hai Duong city

Twin-tunnelling: Case studies in clay

Sam Divall — 2024-03-11

New developments in the theory and practice of tunnel construction are essential for the industry to progress but it is the relationship between these two areas that is equally as important. Tunnelling practice has greatly benefited from laboratory research; specifically, centrifuge modelling linked with field measurements. The wide body of work on the construction of single tunnels has led to the identification of parameters and techniques that are widely accepted for predicting and assessing the magnitude and extent of tunnelling ground movements. However, the usage of twin tunnels in urban areas for transportation purposes have increased and better understanding on the associated ground displacements are required. This paper firstly provides background to ground displacements due to single tunnel, twin tunnel constructions and common prediction methods used in practice. Then, it introduces recent technological advancements in centrifuge modelling, applied to the complex geotechnical events of twin-tunnelling, that has led to further insight. The tunnelling induced ground displacements obtained from twenty four case studies in clay around the world and eighteen centrifuge tests are presented for further analyses. From that, a comparison between the recent theories of proximity-dependent tunnelling-induced ground movements with case histories has been carried out to establish their validity and limitations. Published field measurements have been reanalysed taking into account newly discovered relationships between the tunnels’ proximity and the magnitude and extent of ground movements, reflected via volume loss and the settlement trough width, respectively. The applicability to field measurements of the additional volume loss prediction method (derived from consideration of the experiment work) for tunnelling in clay is assessed

Data processing in blast-induced ground vibration measurement issue with Kalman filter

Hieu Dao — 2024-03-11

Measurement data processing plays an important role in acquisition systems. Completely eliminating the error caused by noise is a difficult issue because correct data exists in noise. Besides, it is impossible to distinguish them clearly. For this reason, solutions to process and standardize data are always applied in the condition of paying close attention to the peculiarity and specific properties of the measured object and the factors affecting it. Blast-induced Ground Vibration wave data is one of the extremely important information in mining operations. It is used to evaluate the impact of the blasting on construction. Besides, it presents the efficiency of explosives as well as of the blasting and mining operation in general. For many particular cases, the physical and mechanical properties of the object to be broken (geological structure, physical and mechanical properties of the rock in the blasting area) are relatively image by knowing its waves. Furthermore, the parameters of the next blasting are also improved based on this data. Due to its important role, the requirement for automatic and highly accurate recording of blast-induced ground vibration data is an urgent issue in mining operations in Vietnam. In this paper, solutions to apply the Kalman filter to handle ground vibration wave data due to blasting were introduced. The work is done based on considering the properties and factors affecting the amplitude, frequency, and characteristics of ground vibration waves. Data is taken directly from the sensor without any processing. Therefore, it carries a lot of noise from many different causes such as the sensor structure, gravity, rock structure, the other sources of vibration at the same time, etc. The used sensor is a product of Nation Instrument (NI). The content of the article is the result of researching and building an automatic blast-induced

Effect of pore water chemistry on the ring shear behavior and the rate dependency of residual strength

Duong Thanh Nguyen — 2024-03-11

The rate dependency of residual strength plays an important role in the selection of residual strength parameters to design the remediation works for reactivated landslides. In the literature, it is shown that the rate dependency of residual strength depends on some factors such as types of soil, range of shear rates, range of effective normal stresses, and pore water chemistry. Recently, the effect of pore water chemistry on the rate dependency of residual strength soil has been examined. However, the ring shear behavior and the rate dependency of residual strength of soil having different pore fluids should be more evaluated. In this study, the effect of the pore fluids of distilled water and 1 M NaCl on the rate dependency of residual strength of kaolin clay was investigated in the Bishop ring shear apparatus. The ring shear tests were conducted at different shearing rates from 0.02 mm/min to 20 mm/min under the effective normal stress of 98 kPa. The research results showed that the pore fluid chemistry affected the shear displacement required to reach the peak strength, the vertical displacement, and the peak strength of kaolin clay. These parameters also exhibited rate dependency, especially at the fast shear rates. The research also indicated that the pore fluid chemistry had a significant effect on the rate dependency of residual strength. Accordingly, the rate dependency of residual strength of kaolin mixed with distilled water showed a positive tendency while that of kaolin with 1 M NaCl as the pore fluid was the neutral tendenc