Browsing by Author "Wickrama, MADMG"

Now showing 1 - 20 of 24

item: Conference-Full-text
Analysing the relationship between skin and formation damage of an oil well (time depended)
(Department of Earth Resources Engineering, 2016-07) Ruwanpathirana, RS; Nagasinghe, RV; Welagedara, WWVP; Wickrama, MADMG; Senadhira, AMADM; Ratnayake, NP; Vijitha, AVP; Hemalal, PVA
The concept of skin and formation damage play a vital role in productivity of an oil well. The objective of this study is to introduce the effect of skin into the well flowing equation in transient state. The effect of formation damage zone on the well flowing pressure was introduced to the original solution of diffusivity equation by considering three scenarios. In the first scenario it was assumed that oil is flowing through the reservoir with average (effective) permeability. In the second scenario it was assumed that the oil is flowing with the permeability of reservoir till the boundary of formation damage zone and within the altered zone, oil is flowing with the permeability of damage zone. The third scenario is similar to the second scenario, however it was assumed that the oil is flowing within the altered zone with an average permeability. By considering the difference between calculated reservoir permeability for all three scenarios and assumed values, scenario three was selected as the most suitable way to introduce the effect of skin in to the well flowing equation in transient condition.
item: Conference-Full-text
Analysing the Relationship Between Skin and Formation Damage of an Oil Well (Time Depended)
(2016-08-22) Ruwanpathirana, RS; Nagasinghe, RV; Welagedara, WWVP; Wickrama, MADMG; Senadhira, AMADM; Ratnayake, NP; Vijitha, AVP
The concept of skin and formation damage play a vital role in productivity of an oil well. The objective of this study is to introduce the effect of skin into the well flowing equation in transient state. The effect of formation damage zone on the well flowing pressure was introduced to the original solution of diffusivity equation by considering three scenarios. In the first scenario it was assumed that oil is flowing through the reservoir with average (effective) permeability. In the second scenario it was assumed that the oil is flowing with the permeability of reservoir till the boundary of formation damage zone and within the altered zone, oil is flowing with the permeability of damage zone. The third scenario is similar to the second scenario, however it was assumed that the oil is flowing within the altered zone with an average permeability. By considering the difference between calculated reservoir permeability for all three scenarios and assumed values, scenario three was selected as the most suitable way to introduce the effect of skin in to the well flowing equation in transient condition.
item: Conference-Full-text
Analysis of Sri Lankan petroleum fiscal system - petroleum resources agreement - 2007
(Department of Earth Resources Engineering, 2019-08) Jayamal, KC; Fernando, CR; Niroshan, WKD; Wickrama, MADMG; Dissanayake, DMDOK; Samaradivakara, GVI
Economic structure of the World Oil and Gas Industry significantly differs from other industries due to the greater risk and uncertainties associated with the industry. Petroleum fiscal regime of a county defines the set of laws, regulations and agreements related to petroleum exploration and production. Since Sri Lankan basins are not much known to the petroleum world, attraction of technically and - economically capable International Oil Companies for the investment is highly dependent on the Sri Lankan petroleum fiscal terms. The main objective of the study is to analyze the existing Sri Lankan petroleum fiscal systems. Fiscal model created w i t h the MS Excel according to the terms defined i n 2007 was used to calculate cash flow of government and contractor, contractor and government takes, IIR value and payback period i n dynamic envirormient conditions. Behaviour of above parameters under three variable conditions (by varying price of oil, reservoir size and life span of the project) were used to decide the attractiveness of the fiscal system. Results show that contactor share is decreasing i n un-favourable conditions w i t h the terms defined i n 2007 fiscal system.
item: Conference-Full-text
Assessing the influence of microstructural features on deformation of rocks under triaxial loading
(Division of Sustainable Resources Engineering, Hokkaido University, Japan, 2024) Silva, SAV; Rathnapriya, RHDL; Riyasath, MSM; Dassanayake, ABN; Fujii., Y; Wickrama, MADMG; Iresha, H; Elakneswaran, Y; Dassanayake, A; Jayawardena, C
Assessing the influence of microstructural features on the deformation of rocks under triaxial loading is vital in rock engineering applications, aiding safe and efficient operations by predicting the deformation of rocks. Triaxial testing offers the simulation of stress conditions within a rock to examine the deformation of rocks with confinements. This research focuses on how microstructural features, such as cementing material and pore geometry, affect the deformation behaviour of rocks subjected to triaxial loading. Two rock types were considered in this study: Kimachi sandstone (medium hard clastic rock) and Bibai sandstone (hard clastic rock). The progressive failure behaviour under Hydro Mechanical (HM) coupling effect was analysed by stress-strain distribution and the fracture geometry was examined using CT images of the specimens which were tested under different confinements. Thin sections were analysed to examine the changes in porosity and the effect on the cementing material with the confinement. The results of the proposed approach reveal a clear influence of the effective confinement on the failure of rocks and how it influences the porosity and cementing material of rocks. It is found that the Bibai sandstone shows a brittle failure and a shearing deformation while Kimachi sandstone shows a brittle to ductile failure and shearing to compaction deformation with the confinement due to the less presence of cementing material within Bibai sandstone compared to Kimachi sandstone. Therefore, with the confinement, the porosity of Bibai sandstone increases while it decreases in Kimachi sandstone. The results highlight the differences in the failure mechanism of a particular rock type for the same effective confinement which is a result of only a partial contribution of the pore pressure on the failure. These findings provide valuable insight into the assessment of microstructural features on the deformation of rocks under triaxial loading, aiding in the development of safer and more efficient rock engineering operations.
item: Conference-Full-text
Cost reduction of quality controlling in metal quarrying
(Department of Earth Resources Engineering, 2011-11) Basnayaka, LR; Samarathunga, SPGN; Susantha, TKJ; Nawaneethan, M; Wickrama, MADMG; Samaradiwakara, GVI; Dassanayake, ABN; Ratnayake, NP; Abeysinghe, AMKB
Quality controlling of aggregates is a major concern in aggregate industry. Cost of quality controlling can be minimized via finding correlations between different test on aggregates and rocks. Los Angeles abrasion value test, Aggregate impact value test, Uni-axial compressive strength test, Point load index and Schmidt hammer rebound value test were performed on a total of 22 gneissic metamorphic rock samples, which were collected from selected two quarries in Meepe and Nebada areas of Sri Lanka to investigate correlations between these test parameters. Correlations were developed between each parameter to reduce the cost of quality controlling by means of regression analysis. The study found a strong correlation between Loss Angeles abrasion value test and Aggregate impact value test. By analysing correlation between tests, mineralogy and rock properties validity of this correlation can be proved for common application
item: Conference-Full-text
Designing and evaluating a casing program for petroleum wellbores
(2014-07-11) Wijesinghe, KADR; Hewavitharana, TD; Mahsoom, MSM; Wickrama, MADMG; Senadhira, AMADM; Ratnayake, NP
Due to high operational and financial risks associated with the investments in the petroleum industry, all precautions are taken by the operators to achieve a safe and cost effective well completion. Casing design of a drilling program is a critical element which contributes greatly to safety and cost of the operation. The objective of this research was to develop a casing design program which enables the user to evaluate casing design proposed or implemented in a drilling campaign. The developed casing design program consists of sequential criteria to select casing setting depth and establish optimum casing strength. Knowledge on local pore pressure gradient and facture gradient are essential to select the casing setting depths. Since both the factors are regional stratigraphy dependants, casing setting depth selection was designed in the way it allows user to assign variables for these parameters. Developed casing design program was validated with the casing design done by Rahman, S. Sand Chilingar, G. V(1995). Validation results shows that the casing design of Rahman and Chilingar and the casing design done with the use of developed program are having similar casing setting depths except in the case of conductor casing.
item: Conference-Full-text
Designing and evaluating a casing program for petroleum wellbores
(Department of Earth Resources Engineering, 2013-07) Wijesinghe, KADR; Hewavitharana, TD; Mahsoom, MSM; Wickrama, MADMG; Senadhira, AMADM; Ratnayake, NP; Hemalal, PVA
Due to high operational and financial risks associated with the investments in the petroleum industry, all precautions are taken by the operators to achieve a safe and cost effective well completion. Casing design of a drilling program is a critical element which contributes greatly to safety and cost of the operation. The objective of this research was to develop a casing design program which enables the user to evaluate casing design proposed or implemented in a drilling campaign. The developed casing design program consists of sequential criteria to select casing setting depth and establish optimum casing strength. Knowledge on local pore pressure gradient and facture gradient are essential to select the casing setting depths. Since both the factors are regional stratigraphy dependants, casing setting depth selection was designed in the way it allows user to assign variables for these parameters. Developed casing design program was validated with the casing design done by Rahman, S. S and Chilingar, G. V(1995). Validation results shows that the casing design of Rahman and Chilingar and the casing design done with the use of developed program are having similar casing setting depths except in the case of conductor casing.
item: Conference-Full-text
Developing a casing design for the extraction of petroleum in Mannar basin, Sri Lanka
(Department of Earth Resources Engineering, University of Moratuwa, 2020-12) Harshapriya, IMP; Maduranga, GMS; Sandaruwan, SAL; Wickrama, MADMG; Dissanayake, DMDOK; Dassanayake, ABN
To develop an economical casing design program for the Mannar Basin which is safe, and risk minimized, knowledge on Pore Pressure Gradient, Fracture Pressure Gradient, Casing Performance Properties and Casing Design Criteria’s are important. Previous studies present the Hottman and Johnson (1965) method and D-exponent method-Eaton (1975) as accurate methods to predict the pore pressure gradient of the Mannar Basin and the Eaton (1969) method as the most accurate method to predict the Fracture Pressure Gradient of the Mannar Basin. The data extracted from the final well reports and pressure reports of the pearl 1 well of the Mannar Basin are analyzed using the above models to accurately predict the Pore and Fracture pressure gradients of the Mannar Basin. A specific casing design program is developed to suit the conditions of the Mannar Basin by selecting the casing setting depths and sizes and calculating the casing performance properties of Burst, Collapse and Tension, concerning the predicted pore pressure and fracture pressure gradients.
item: Conference-Full-text
Developing a hydrogeological model for Aruwakkalu limestone mine, Puttalam
(Department of Earth Resources Engineering, 2011-11) Dayarathna, EAC; Pethum, LLDI; Sunanda, DJ; Wedisinghe, WMCC; Dassanayake, ABN; Wickrama, MADMG; Ratnayake, NP; Abeysinghe, AMKB
A hydrogeological model has been developed for the Aruwakkalu limestone mine to study the behaviour of groundwater flow, associate with specific problems within the mine, in this research. Groundwater flow model was constructed using Visual MODFLOW 3D Finite difference method. Five distinct types of material layers were identified for material property designation in the study area of the mine by using the borehole data report, which was completed in year 2008. The mine is mainly bounded by two water bodies; Puttalam lagoon and Kala Oya. Existing hydrogeology related data and the results of several field tests were used to develop the groundwater model initially with a conceptual model. Utilizing hydrogeological data gained from field works; specially the aquifer parameters gained from pumping tests, the model was developed and calibrated for steady state conditions. According to the model simulation, groundwater flow is mainly towards the west direction and it simulates sea water intrusions in some locations. Dewatering feasibility and cost associated with groundwater movement of the mine can be evaluated using the developed model by conducting predictive simulations.
item: Conference-Full-text
Development of a Pore Pressure and Fracture Pressure Gradient Prediction Model for few exploration blocks in Mannar and Cauvery Basins, offshore Sri Lanka
(2015-08-14) Jayasinghe, JMSTW; Kurukulasuriya, AC; Jayasinghe, WMTU; Wickrama, MADMG; Senadhira, AMADM; Ratnayake, NP
Availability of a pore pressure and fracture pressure gradient prediction model for petroleum well drilling is a basis for safety, cost effectiveness and the efficiency of the overall drilling program. Petrophysical data and measured pressure data of four wells previously drilled in the Mannar basin and Cauvery basin were reviewed to establish such a model for few petroleum exploration blocks in Sri Lanka. The pore pressure gradient prediction strategies used for the analysis are, Hottman and Johnson method, Ben Eaton method and D-exponent method. Hubbert and Willis method, Ben Eaton method and Matthews and Kelly method are the fracture pressure gradient prediction strategies used. Area specific variables including Poisson ratio and matrix stress coefficient were determined prior to fracture pressure gradient prediction. After a statistical analysis and comparison with well log data, a combination of Hottman and Johnson method and D-exponent (Eaton) method was selected as the best suited pore pressure gradient prediction model for the drilling area. The analysis of fracture pressure gradient strategies found that the Ben Eaton method is the best suited method for the area. After determining the suitable prediction methods, the Petrel software was used to visually interpret and analyze the results obtained. The research findings will help for future drilling operations and well planning in the specified area in Mannar and Cauvery basins.
item: Conference-Full-text
Development of a pore pressure and fracture pressure gradient prediction model for few exploration blocks in Mannar and Cauvery basins, offshore Sri Lanka
(Department of Earth Resources Engineering, 2014-07) Jayasinghe, JMSTW; Kurukulasuriya, AC; Jayasinghe, WMTU; Wickrama, MADMG; Senadhira, AMADM; Ratnayake, NP; Hemalal, PVA
Availability of a pore pressure and fracture pressure gradient prediction model for petroleum well drilling is a basis for safety, cost effectiveness and the efficiency of the overall drilling program. Petrophysical data and measured pressure data of four wells previously drilled in the Mannar basin and Cauvery basin were reviewed to establish such a model for few petroleum exploration blocks in Sri Lanka. The pore pressure gradient prediction strategies used for the analysis are, Hottman and Johnson method, Ben Eaton method and D-exponent method. Hubbert and Willis method, Ben Eaton method and Matthews and Kelly method are the fracture pressure gradient prediction strategies used. Area specific variables including Poisson ratio and matrix stress coefficient were determined prior to fracture pressure gradient prediction. After a statistical analysis and comparison with well log data, a combination of Hottman and Johnson method and D-exponent (Eaton) method was selected as the best suited pore pressure gradient prediction model for the drilling area. The analysis of fracture pressure gradient strategies found that the Ben Eaton method is the best suited method for the area. After determining the suitable prediction methods, the Petrel software was used to visually interpret and analyze the results obtained. The research findings will help for future drilling operations and well planning in the specified area in Mannar and Cauvery basins.
item: Conference-Full-text
Evaluation of weathering effect on engineering properties of Sri Lankan gneissic rock
(Department of Earth Resources Engineering, University of Moratuwa, Sri Lanka, 2022-12-23) Karunarathne, GKA; Weerasinghe, WMRT; Dukeraisan, AK; Niroshan, S; Gamsavi, K; Dassanayake, ABN; Chaminda, SP; Jayawardena, CL; Wickrama, MADMG; Jayawardena, CL
Weathering is a natural process common for all kinds of rock types that may occur due to either physical, chemical, or biological reasons. The applicability of rock in different engineering applications has a primary concern with their engineering properties that might have a significant influence from weathering effect. Characterizing such properties based on weathering effect on gneissic rocks of Sri Lanka is essential due to the wide existence and utilization of gneissic rocks. This study was conducted to understand the behavior of engineering properties such as uniaxial compressive strength, durability, hardness, pulse wave velocity, and mineralogical properties of gneissic rock with weathering effect. Engineering properties of gneissic rocks were determined using laboratory tests according to ASTM (American Society for Testing and Materials) for rocks in fresh and weathered states. Results showed that chemical weathering may have influenced gneissic rocks in both Kaduwela and Kudayala quarry sites since Mg percentage has decreased by the weathering effect. Formation of clay minerals with weathering is a significant characterictics of hornblend biotite gneiss in Kaduwela area, rather than the Garnet bearing biotite in Kudayala area. Mechanical properties such as strength and durability decrease when the fresh rocks exposed to weathering. Physical properties such as hardness, and Pulse velocity have decreased in weathered gneissic rock in both areas.
item: Conference-Abstract
Experimental investigation and performance optimisation of washing cycles for pre-processing of coal fly ash
(Department of Earth Resources Engineering, University of Moratuwa, Sri Lanka, 2022-12-23) Brinthan, K; Shivadhahini, S; Senadheera, UAG; Fernando, WAM; Jayawardena, CL; Jayasundara, DRT; Wickrama, MADMG; Jayawardena, CL
Coal Fly Ash (CFA), a by-product of thermal power plant combustion, has a profound focus among researchers due to its pozzolanic properties, porosity, wide chemical composition, and thermal stability. While being suitable for many applications (e.g., pozzolanic material, soil stabiliser, and structural fill), CFA is also a potential precursor for synthesising zeolites, broadly used in wastewater treatment. However, pre-processing is crucial due to the heterogeneous nature of CFA. This work focused on pre-processing CFA prior to wastewater treatment through continuous washing cycles at various operating temperatures. To this end, we studied the pH and conductivity of the solution after washing over multiple cycles, Sauter mean diameter, and the mineralogy of the settled CFA. The gathered results were analysed and optimised through response surface methodology. This was done to find the best combination of the number of washing cycles and temperature to remove soluble ions and increase the surface area of CFA particles. The analytical outcome revealed that five washing cycles at 70°C were adequate, with minimal soluble ions and maximum surface area. Evidently, these findings demonstrated significant improvements in the physical and chemical properties of CFA as a precursor for zeolite synthesis. Therefore, we recommend further studies on this front to extend the effective usage of CFA for the synthesis of commercial zeolites to be used for wastewater treatment.
item: Conference-Full-text
Exploration of ilmenite potential in and around Kalu and Benthara river mouths with special reference to the variation of TiO2 content along a selected strech of Kalu Ganga
(Department of Earth Resources Engineering, 2006-10) Kumara, HANHM; Medagoda, CJ; Sivakala, S; Sugaraj, K; Wickrama, MADMG; Vijitha, AVP; Dissanayake, DMDOK; Rathnayake, NP; Karunaratne, S; Dissanayake, DMDOK; Ratnayake, N; Chaminda, SP
Although Ilmanite, Rutil, Zircon and Monazite occurs in beach sand of Sri Lanka, the sufficiently concentrated deposits for economic exploitation have been only identified yet in and around Pulmoddai, Baruwala and Kudremalai beaches. Of these, Pulmoddai is the largest beach sand deposit ever found in Sri Lanka, which is estimated to contain nearly, 4,000,000 tons of raw sand. However it has been noticed that beach mineral sand occurrence in many other parts of the country and detail investigation has not been carried out yet in those areas. Exploitation has been carried out only in Pulmoddai which is located near the rebels control areas. Since 1998 with production coming to a stand still, the Pulmoddai plant which a government own company is confined to selling its existing stockpile with Zircon and Rutile being bagged and transported to Colombo and exported. Therefore finding an alternative source to supply the demand of the export market to earn foreign exchange is a prior necessity of the country. Therefore this study was carried out to identify ilmenite potential in and around Kalu and Benthara river mouths and investigation has been carried out to identify the variation of Ti02 content in ilmenite along the Kalu Ganga track by sand sediment analysis. Gravity and the magnetic separation processes were employed for the processing of the sand samples. Results show that the particle size of Ilmenite in both river mouths deposits were reported in the range of+ l25J.lIl1to +250~tm sizeand this may mainly depend on grain size, flow velocity of the river, distance travel as well as energy of the sea waves. Variation of the titanium content in ilmenite along the Kalu Ganga can be concluded may due to the replacement of Fe in Ilmenite with another foreign element available in the river.
item: Conference-Full-text
An exploratory factor analysis on issues and constraints in Sri Lankan aggregate quarry industry
(Department of Earth Resources Engineering, University of Moratuwa, 2021-12) Kodithuwakku, KKSN; Munaweera, SPM; Thanojan, T; Jayasundara, DRT; Jayawardena, CL; Senadhira, AMADM; Wickrama, MADMG; Dissanayake, DMDOK; Jayawardena, CL
Mining activities are influenced by stakeholders such as regulators, operators, service providers, customers, residents, and other interest groups. The governing bodies seem to fail to adopt a stakeholder inclusive approach to gain the balance between the interest of the stakeholders and the organisational plans and revenues. Such issues are known at the surface level, but no solid quantitative approach has been used to scientifically prove their existence and associations. Thus, this study aims to find the issues with statistical evidence. Convenient sampling was used due to time restrictions and new work norms to pick a substantial number of respondents. A numerical assignment and logical ordering to qualitative data were done to perform the quantitative analysis. Factor analysis was used to find the principal components and the variables which mainly loaded the components showed significant interpretable correlations. The most significant factors associated with issues in quarry operations and management are found in terms of quality, reliability, and usage of monitoring, application of safety measures, quarry type based hazardous conditions, planning and maintaining quarry activities, combatting drilling issues via site planning, use of initiation technique by quarry type, the impact of environmental and social issues, handling public complaints and strategies to improve quarry operations.
item: Thesis-Abstract
Forecasting of wind power generation using wind speed and temperature for thambapawani wind farm in Sri Lanka
(2023) Gunathilaka, MDCP; Wickrama, MADMG; Jayasundara, DTR
Wind power generation is a rapidly growing renewable energy resource in the world, both on a small and large scale. By integrating wind power generation systems, it helps to maintain grid stability, meet renewable energy targets, reduce greenhouse gas emissions, and promote economic growth while enhancing energy security by diversifying energy sources. Due to the intermittent nature of the wind and the influence of several weather parameters such as wind direction, ambient temperature, humidity, atmospheric pressure, the utilization of energy produced by the wind is challenging while maintaining the grid stability. Addressing this challenge involves the development of accurate forecasting models. Hence, in this study, accurate wind forecast models are built using two main weather parameters: wind speed and temperature for the newly implemented largest on-shore wind farm, "Thambapawani", A univariate model is built for the active power variable using the Seasonal Autoregressive Integrated Moving Average (SARIMA) method. Two different Vector Autoregressive (VAR) models were built with average wind speed and average temperature. However, all these models fail to grasp the intermittent nature of wind power alone. Therefore, hybrid models were generated using the above-mentioned models as mean models and Generalized Autoregressive Conditional Heteroskedasticity models as conditional variance models. All hybrid models were validated using the same test data set and evaluated with one of the goodness of fit tests called the root mean squared test. In this research, the forecasting horizon is 48 hours and the data resolution is 1 hour. The hybrid model of SARIMA (1,1,1) (1,1,1)24 with GARCH (1,1) is selected as the best-fit model that has the lowest RMSE value compared to the other two hybrid models in order to forecast wind power generation at “Thambapawani” Wind Farm in Sri Lanka. Keywords: wind power, grid stability, SARIMA, VAR, GARCH
item: Conference-Full-text
Image analysis approach to determine the porosity of rocks
(Department of Earth Resources Engineering, 2023-08-28) Varnasuthan, S; Fernando, WTM; Dahanayaka, DS; Dassanayake, ABN; Wickrama, MADMG; Illankoon, IMTN
Accurate characterisation of rock porosity is essential for assessing its strength and durability. This study explores both conventional and image analysis methods for determining rock porosity of two types of rocks, Bibai sandstone, a hard clastic rock and limestone, a soft rock. Conventional methods for determining rock porosity involve physical measurements and laboratory analysis, while image analysis methods utilize advanced imaging techniques such as CT scans or SEM to assess porosity based on visual information extracted from rock images. While various image analysis approaches exist to determine rock porosity, questions arise as to which approach is applicable and whether the results are comparable to current conventional methods. Hence, this study focuses on comparing the accuracy of alternative image analysis approaches. Representative rock chips from each core sample were examined using SEM, and 2D porosity was evaluated through image processing with ImageJ software. The Avizo visualisation software was employed to assess Bibai sandstone samples' porosity from CT images. The research offers insights into the pros and cons of each approach, contributing to the enhancement of accuracy and efficiency in rock porosity evaluation, particularly in geology, mining, and civil engineering applications
item: Conference Full-text
Impact of water saturation model on the reservoir estimation ; a case study on dorado and Barracuda Wells in Mannar Basin, Sri Lanka
Wijesuriya, HTTB; Abeysinghe, RYGK; Roshanthan, S; Wickrama, MADMG; Ratnayake, NP; Vijitha, AVP; Senadhira, AMADM; Senevirathne, BSMCK; Abeysinghe, AMKB; Dassanayake, ABN; Elakneswaran, y; Abeysinghe, AMKB; Dassanayake, ABN; Elakneswaran, y
Fluid carrying properties of rocks (permeability) and the interaction between fluid and rock that influence the flow of the fluids(porosity and saturation) are required to evaluate the maximum recovery and producibility of any petroleum reservoir. Determination of Water Saturation (Sw) is a critical and complex petro physical calculation, as there are number of independent methods used to calculate the same. The objective of this research was to analyse the impact of water saturation model on the reservoir estimation, using the well-log data of Dorado-1 well and Barracuda well in Mannar Basin, Sri Lanka. First, quick look analysis was done with the welllog data. Then the saturation of water in pay zones were calculated using five water saturation calculation approaches namely Archie’s equation, Equivalent Model, Indonesia model, Dual Water Model and Juhasz model. For both wells the highest water saturation values were found with Dual Water Model and Juhanz model, 0.89 for the Dorado well and 0.83 for Barracuda well. While Equivalent model gave the lowest saturation value, 0.46, for Dorado well and the Archie’s model estimated the lowest value of 0.60 for Barracuda well. Except the results of Dual Water Model and Juhasz model, all other models estimated different values for water saturation. This leads to a considerable difference in reservoir estimation. Therefore, for a reservoir it is important to establish the most suitable water saturation calculation method to estimate the volume of reservoir correctly.
item: Conference-Full-text
Leveraging the performance of washing cycles to enhance the preprocessing of coal fly ash
(Department of Earth Resources Engineering, 2023-08-28) Galappaththi, RY; Hissalle, LPAD; Chamith, PLS; Wickrama, MADMG; Fernando, WAM; Jayawardena, CL
Coal is relatively cheap and abundant fossil fuel contributing to 40% of the world's electricity production. However, coal combustion generates a significant number of by-products, majority being the coal fly ash (CFA). The heterogeneous nature of CFA poses significant challenges in its value-added applications hence, requiring appropriate preprocessing treatments which are expensive and technically savvy. Therefore, this research aims to improve CFA's suitability for the application of value-added products through a technique called “washing cycles” which wash the CFA multiple times using distilled water under a controlled environment with continuous and vigilant monitoring to ensure accuracy throughout the entire process. To optimise this washing cycle process, parameters such as the number of washing cycles, stirring time, and temperature were analysed, and the results were optimised through surface response methodology. The analytical findings on the optimization process demonstrated that a suitable pre-treatment involved employing five washing cycles with a stirring time of 7.5 minutes. Furthermore, varying the temperature did not yield a substantial effect on the effectiveness of washing cycles, since the precipitation of Ca2+ ions even complicate the preprocessing. Therefore, we recommend conducting additional investigations into the efficient use of pre-processed CFA to produce value-added applications adhering to circular economy and sustainability.
item: Conference-Full-text
Machine learning-based prediction of machine hours and fuel consumption: a case study in Aruwakkalu limestone quarry, Sri Lanka
(IEEE, 2023-12-09) Surangani, RKH; Dawalagala, HS; Reval, SS; Rodrigo, MAJ; Wijerathnayake, WMNC; Wickrama, MADMG; Wedage, WN; Abeysooriya, R; Adikariwattage, V; Hemachandra, K
The machine hours are of paramount importance in the mining sector as they directly impact production levels, operational costs, and overall efficiency. Accurate prediction of machine hours and fuel consumption using machine learning techniques relies on the availability of a comprehensive historical database. This prediction study focuses on a site-specific context and is specifically applicable to large-scale open pit limestone mines, such as the renowned Aruwakkalu Limestone Quarry in Sri Lanka. The scientific objective involves analyzing the accuracy of algorithms and utilizing a highly precise model to predict machine hours and fuel consumption based on monthly tonnage of limestone. This scientific study utilizes four machine learning algorithms: decision tree, linear regression, LGBM (Light Gradient Boosting Machine) regressor, and random forest. The assessment utilizes monthly report data from the quarry spanning a three-year period. Subsequently, the chosen model is applied to predict machine hours and fuel consumption based on tonnage. Findings reveal that the decision tree algorithm demonstrates remarkable accuracy for dump trucks compared to other methods, while the LGBM regressor performs better for excavators and dozers. For predicting fuel consumption, LGBM outperforms dump trucks; decision tree excels in excavators; random forest achieves dozer accuracy.