Malaysian Journal of Geosciences (MJG)

THE ECONOMIC IMPACTS OF REHABILITATION OF SELABAT MUDFLATS NATURE RESERVE, KUCHING, SARAWAK

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mjg.01.2020.19.21

ABSTRACT

THE ECONOMIC IMPACTS OF REHABILITATION OF SELABAT MUDFLATS NATURE RESERVE, KUCHING, SARAWAK

Journal: Malaysian Journal of Geosciences (MJG)
Author: Mukrimah Abdullah, Mohd Parid Mamat, Abang Ahmad Abang Morni, Thanlany Kamri, Lim Hin Fui

This is an open access article distributed under the Creative Commons Attribution License CC BY 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited

DOI: 10.26480/mjg.01.2020.19.21

Coastal erosion is a concern to coastline management, and it affects the socio-economic well-being of local communities. The rehabilitation of Selabat Mudflats Nature Reserve (SMNR) in Sarawak is one of the most impressive achievements of the “Mangrove and Suitable Tree Species Planting at the National Coastline Program” implemented by the Ministry of Natural Resources and Environment (NRE). The rehabilitation efforts began in 2009, where 20 hectares of Rhizophora mucronata were planted and followed by an additional 1.7 hectares of Casuarina equisetifolia. Previously, this area was a sandy coastline where coastal erosion occurred every year causing local loss of land and properties. However, through conservation and rehabilitation efforts, this area was restored and is now able to generate more income for local communities as well as playing a protective role against coastal erosion caused by coastal waves and strong winds. In 2016, this study was conducted to assess the economic impacts of SMNR rehabilitation. The findings from a sample of 42 households showed that the income generated for local communities around SMNR amounted to RM250, 320 per month or RM3, 003,840 per year. A non-user survey of 401 samples was also conducted, using Contingent Valuation Method to estimate the economic value of SMNR rehabilitation. The result showed the economic value of rehabilitation of SMNR was RM39 million for the year 2016 or RM195, 980 per hectare. These findings showed that the function of rehabilitation and conservation of mangroves forests against coastal erosion brings positive economic impacts. Rehabilitation and conservation of mangrove areas in Malaysia should be given more attention as global warming and rising sea level are going to have negative impacts on coastal settlements. Wise decision-making in the utilisation and allocation of limited resources is important particularly in the context of conflict between conservation and other development that led to its destruction.
Pages 19-21
Year 2019
Issue 1
Volume 4

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mjg.01.2020.13.18

ABSTRACT

MINERAL CHEMISTRY AND GEOCHEMISTRY OF HYPERSTHENE-BEARING DIORITE FROM ERUSU AKOKO, SOUTHWESTERN NIGERIA

Journal: Malaysian Journal of Geosciences (MJG)
Author: E. J. Oziegbe, V. O. Olarewaju, O. O. Ocan

This is an open access article distributed under the Creative Commons Attribution License CC BY 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited

DOI: 10.26480/mjg.01.2020.13.18

Samples of mafic intrusive rock were analyzed for their mineralogical and chemical properties. The textural relationship was studied using the petrographic microscope, elemental composition of minerals was determined using the Electron Microprobe and the whole rock chemical analysis was done using the XRF and ICP-MS. The following minerals were observed in order of abundance; pyroxene, amphibole, plagioclase, biotite, opaque minerals, quartz and chlorite, with apatite and zircon occurring as accessory mineral. Two types of pyroxenes were observed; orthopyroxene (hypersthene) and clinopyroxene. Texturally, amphiboles have inclusions of plagioclase and pyroxene. The plagioclase has undergone sericitization. The chemical composition of the pyroxene is En51.95Fs44.53Wo3.52, biotite has Fe/(Fe+Mg):0.42, Mg/(Fe+Mg):0.59, and plagioclase is Ab63.5An34.55Or1.95. Whole rock chemistry shows a chemical composition; SiO2: 45.15 %, Al2O3: 14.04 %, Fe2O3: 16.01 %, MgO: 5.65 %, CaO: 7.58 % and TiO2: 3.59 %. There is an enrichment of LREE and a depletion of HREE. Based on the minerals, mineral chemistry and the geochemistry of the studied rock, the rock is mafic and hydrous minerals formed by hydration recrystallization of pyroxene. The rock has extensively retrogressed but has not been affected by any form of deformation.
Pages 13-18
Year 2019
Issue 1
Volume 4

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mjg.01.2020.07.12

ABSTRACT

CLASSIFICATION OF HIGH-RESOLUTION SATELLITE IMAGES USING FUZZY LOGICS INTO DECISION TREE

Journal: Malaysian Journal of Geosciences (MJG)
Author: Ehsan Momeni, Mahmoud Reza Sahebi, Ali Mohammadzadeh

This is an open access article distributed under the Creative Commons Attribution License CC BY 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited

DOI: 10.26480/mjg.01.2020.07.12

In this paper, DTFL an image classifier based on Decision Tree and Fuzzy Logics is proposed. At the beginning of classification using DTFL, each pixel is located at the highest level of a decision tree where it belongs to the combination of all classes. DTFL transfers a pixel to a lower level of the decision tree where the pixel belongs to a combination of fewer classes. Decision-making about transfers is based on fuzzy logic with seven different membership functions including triangular-shaped, trapezoidal-shaped, π-shaped, bell-shaped, Gaussian, differential S-shaped and multiplicative S-shaped. Eventually, pixels will reach the lowest level of the decision tree where it belongs to only one class. For accuracy assessment, DTFL was used to classify a GeoEye-1 image. The overall accuracy of 96.14% and a kappa coefficient of 96.06% were reached by DTFL. In comparison, the overall accuracy of 89.91% and a kappa coefficient of 89.77% were reached by a Maximum Likelihood Classifier, MLC. In the case of applying a threshold in MLC to reach the same accuracy as DTFL, 8.73% of pixels take the non-classified label while using DTFL all the pixels get a proper label. The results indicate that the proposed classifier extracts more information from images.
Pages 07-12
Year 2019
Issue 1
Volume 4

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mjg.01.2020.01.06

ABSTRACT

SITE-DEPENDENT GEOLOGICAL MODEL FOR DENSITY ESTIMATION IN THE NIGER DELTA BASIN, NIGERIA

Journal: Malaysian Journal of Geosciences (MJG)
Author: Atat, J. G., Uko, E. D., Tamunobereton-ari, I., Eze, C. L

This is an open access article distributed under the Creative Commons Attribution License CC BY 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited

DOI: 10.26480/mjg.01.2020.01.06

Seismic and Well-log data covering three wells in tau(τ) Field in the Niger Delta were used for density modelling. Using Hampson Russell Software, Gardner’s and Lindseth’s relations were localized and subsequently transformed to obtain local fits constants for sand and shale lithologies which were used to achieved the final models. The seismic inversion was performed using four steps: well-to-seismic tie, geology model, acoustic impedance inversion and density prediction. A relationship was established between impedance and density. Pairing Gardner with those by Lindseth approaches and also obtained the average, the final models are ρ=0.1572Z_p^0.2126-16997Z_p^(-1)+1.5625 and ρ=0.09045Z_s^0.1935-7093.5Z_s^(-1)+1.4706 for sandstones lithology; ρ=0.3185Z_p^0.3103-6510Z_p^(-1)+1.42855 and ρ=0.16145Z_s^0.2308-34203.5Z_s^(-1)+1.42855 for shale lithology. These models yield a new concept which will contribute to global knowledge. In the absence of density log, these equations can be used to estimate density in the area.
Pages 01-06
Year 2019
Issue 1
Volume 4

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mjg.01.2019.61.65

ABSTRACT

ATTENUATION OF WATER-BOTTOM MULTIPLES: A CASE STUDY FROM SHAL LOW MARINE IN THE NIGER DELTA, NIGERIA

Journal: Malaysian Journal of Geosciences (MJG)
Author: Dora B. Umoetok, Etim D. Uko, Aminayanasa P. Ngeri

This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited

DOI: 10.26480/mjg.01.2019.61.65

Three-dimensional (3D) seismic data in the shallow offshore Niger Delta was acquired and processed. The dataset at water-depth of 250m was masked by interbed multiples and water bottom multiples. The major differences exploited for the multiples removal were velocity discrimination, frequency, wavelength, periodicity, and predictability using predictive deconvolution and Radon techniques. The dominant frequency of the primary events varies between 3 and 120Hz having dominant amplitude ranging between -12dB and -45dB. The dominant frequency of the multiples ranges between 8 and 90Hz, while dominant amplitude ranges between -5dB and -45dB. Multiples were predominantly short-period with water bottom reverberation having high-frequency and high-amplitude. With the short-period and high-frequency content, the characteristics of the multiples were quite close to those of the primaries. Water-depth and geology are major generators of the waterbottom and interbed multiple energies in a marine environment. The multiple parameters established in this work would be required as inputs in the multiples-attenuation processing program for a better image of the subsurface geology.
Pages 61-65
Year 2019
Issue 1
Volume 3

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mjg.02.2019.43.51

ABSTRACT

DELINEATION OF SUBSURFACE STRUCTURES IN TOJA FIELD IN THE NIGER DELTA USING WELL-LOGS AND SEISMIC DATA

Journal: Malaysian Journal of Geosciences (MJG)
Author: Obioma Umunna, Etim D. Uko, Idara O. Akpabio

This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited

DOI: 10.26480/mjg.02.2019.43.51

The subsurface structures delineation of TOJA Field southwest Niger Delta using well-log and seismic data is here presented. The reflectivity seismic amplitude and acoustic impedance, spectra decomposition volume derivatives were used for reservoir delineation. Seismic data and well logs have been integrated through seismic inversion as part of the techniques deployed in the delineation of subsurface structures in the Niger Delta basin. Well logs were tied to seismic data using four wells from four fields in the Niger Delta. Reflectivity seismic data was inverted to generate a 3D distribution of P-impedance in the fields of interest. Fluid and lithology sensitivity analysis including cross-plotting, forward seismic modelling and Gassmann fluid substitution was performed to delineate various subsurface structures. The TOJA prospect is a footwall-closure located behind the main bounding fault, north of the TOJA Field. The Field’s structure is a fault-dependent footwall closure with a dip component in the shallow levels. The structure is bounded by three faults; a large east-west fault forms the boundary between the TOJA Field to the South and the TOJA North Field. This fault is relayed by a minor fault that delimits the south-western end of the accumulation. A northeast-southwest bounding fault separates the TOJA structure from the SATRA accumulations to the east and has a throw of between 200 and 400 ft. The results of this study can lead to a more cost-effective method for defining the Field Development Plan (FDP), through the use of seismically constrained reservoir information that would provide better well placement to achieve improved production.
Pages 43-51
Year 2019
Issue 2
Volume 3

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mjg.02.2019.23.32

ABSTRACT

AN INTEGRATED APPROACH TO GROUNDWATER QUALITY ASSESSMENT IN DETERMINING FACTORS THAT INFLUENCE THE GEOCHEMISTRY AND ORIGIN OF SANDSTONE AQUIFER SOUTHERN NIGER DELTA REGION OF NIGERIA

Journal: Malaysian Journal of Geosciences (MJG)
Author: M. O. Eyankware, O. O. Omo-Irabor

This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited

DOI: 10.26480/mjg.02.2019.23.32

Rapid industrialization and oil exploration activities is believed to have influence on groundwater quality globally, and Niger Delta Region of Nigeria is no exception. Hence, this research is conducted to evaluate factors that influence groundwater origin and its geochemistry. For the purpose of this study, 20 groundwater samples were collected (4 from borehole and 16 from hand-dug wells). The parameters used in the assessment include physical parameters; pH, total dissolved solid and electrical conductivity and chemical parameters such as; major cations and anions. From the findings it was observed that pH values fell within the slightly acidic range with the exception of sample location HG/08 with value of 7.01 which can consider to be neutral. The dominant factors that influence groundwater origin and geochemistry within the study area are mainly precipitation and weathering. From Gibb’s plot ninety percent (90 %) of groundwater chemistry is influenced by precipitation. While, Soltan classification showed that 98 % of groundwater belongs to (Na+ – SO42¯), hence it can be classified as deep meteoric (precipitation influence), while the remaining (2%) is of (Na+ – HCO3¯) its classified as shallow meteoric type. Lastly from relationship between Cl¯/HCO3¯ groundwater were slightly moderately affected by saline water intrusion.
Pages 23-32
Year 2019
Issue 2
Volume 3

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mjg.02.2019.33.42

ABSTRACT

PERMEABILITY-POROSITY TRENDS IN CAWC RESERVOIR SANDS IN THE NIGER DELTA NIGERIA, USING WELL-LOG DATA

Journal: Malaysian Journal of Geosciences (MJG)
Author: Chinedu S. Orji, Etim D. Uko, Iyeneomie Tamunobereton-ari

This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited

DOI: 10.26480/mjg.02.2019.33.42

Reservoir characteristics analysis in the onshore Cawthorne Channel (CAWC) oil field, Niger Delta is here presented. The aim of the research was to assess reservoir properties and their relationships. A suite of geophysical logs comprising gamma ray, resistivity, neutron and density logs from eight wells were used in the analysis. Three reservoirs sands were delineated and linked across all eight wells. The litho-stratigraphy correlation section revealed that each of the sand units spreads over the field are differs in thickness with some units occurring at greater depth than their adjacent unit, that is possibly an evidence of faulting. The results show volume of shale values range from 11% to 17% indicating that the fraction of shale in the reservoirs is quite low. The total porosity of the reservoirs ranges from 0.22 to 0.39 indicating a very good reservoir quality and reflecting probably well sorted coarse-grained sandstone reservoirs. The permeability of the reservoirs ranges from 288 mD to 1250mD and this suggests good reservoir horizons. The hydrocarbon saturation of the reservoirs ranges from 0.59 to 0.71 indicating that the proportion of void spaces occupied by water is low consequently high hydrocarbon production. Sand-shale lithology was calculated, with sandstone volume decreasing with increasing depth, while shale volume increases with depth. Porosity and permeability showed decreasing trend with depth for both sandstone and shale units in all wells with few exceptions. This could be as a result of low compaction by overburden pressure from overlying rocks. Plot of lithology versus depth reveals that shale lithology increases with depth, while sandstone decreases. Lithology versus porosity plots show an inverse relationship between permeability and shale volume and direct relationship between permeability and volume of sand. Lithology versus permeability shows that permeability and shale volume have an inverse relationship whereas permeability and volume of sand have a direct relationship. Permeability decreases exponentially with decrease in porosity in rock matrix made up of intercalation of sandstone and shale. The modelled equation of permeability and porosity is given by K = 0.053e32.934Ф. This implies that in the absence of core and well-log data, permeability can be estimated using only porosity data. The results of this work can be used as an exploration tool for the identification of prospective areas and also for feasibility studies during an appraisal activity.
Pages 33-42
Year 2019
Issue 2
Volume 3

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mjg.02.2019.12.22

ABSTRACT

IMPLICATION OF RESERVOIR CHARACTERISTICS BASED ON OVERVIEW OF STRUCTURE AND SEDIMENTOLOGY OF OUTCROPS ALONG BINTULU-NIAH-MIRI AREAS

Journal: Malaysian Journal of Geosciences (MJG)
Author: Jong E Cheng

This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited

DOI: 10.26480/mjg.02.2019.12.22

Six-day fieldwork was conducted in the north-west coast of Sarawak to examine the outcrops along Bintulu- Niah- Miri areas which cover southern part of Balingian Province and Baram Delta Province. The aim of this fieldwork is to synthesize the observations of structure and sedimentology of outcrops along Bintulu-Niah-Miri areas and discuss the implication of reservoir characteristics based on observation. The study was conducted by sketching the main structural elements of outcrops followed by detailed sedimentological analysis which include observation and facies description were conducted on different outcrops along Bintulu-Niah- Miri areas using sedimentary logs. The findings show that Bintulu- Niah- Miri areas outcrops consists of mixed-environment deposited succession with tidal and wave characteristic. This resulted in reservoir architect will be different and result in different in reservoir properties included horizontal and vertical permeability of fluids. Niah Cave is a good place to study the distribution of the types of breccia due to collapsed paleokarst at reservoir scale and also good analog for Central Luconia Platform where large resources of hydrocarbon have been discovered due to the its environment setting or forming process is same as Central Luconia Platform. In addition, Miri Airport Outcrop succession consist of Type 4- Fracture Create Flow Barriers which could lead to potential production problems.
Pages 12-22
Year 2019
Issue 2
Volume 3

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mjg.02.2019.07.11

ABSTRACT

ASSESSING SUSPENDED SEDIMENT YIELD IN THE SAF SAF GAUGED CATCHMENT, NORTHEASTERN ALGERIA

Journal: Malaysian Journal of Geosciences (MJG)
Author: K. Khanchoul, Z.A. Boukhrissa

This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited

DOI: 10.26480/mjg.02.2019.07.11

Many studies on sediment transport have been carried out on Algerian rivers but few studies have been undertaken in catchments of the Northeast of Algeria. The scarcity or discontinuity on sediment transport measurements reduces knowledge about soil loss. In some cases, researchers find often difficulties to apply the most suitable methods to estimate sediment load. The present work represents an assessment of suspended sediment yield from the Saf Saf catchment (322 km2) over 39 years. Long-term annual suspended sediment loads are estimated using non-linear power model, developed on mean discharge class technique as a sediment rating curve. There is a challenge to estimate suspended sediment load in the Saf Saf catchment, which is distinguished by rapid discharge variation. A second aim is to examine monthly and annual variations in discharge, suspended concentration, rainfall and load in this river and to find causes for these variations. The results show that the mean annual sediment yield is equal to 477 T km-2 yr-1 during the study period. Moreover, the long term variability analysis of sediment load seems to be very high from year to year depending on climatic conditions. The analysis of annual sediment load shows a decreasing trend along 39 years, mainly from 1997. Most sediment loads are transported during the winter season, which represents 78% of the total sediment load. The understanding of sediment transport relationships gained from this study should provide a good starting point for researchers and policymakers to begin addressing sediment issues within the catchment.
Pages 07-11
Year 2019
Issue 2
Volume 3

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