Pub Date : 2013-08-20DOI: 10.4172/2329-6755.1000125
S. Salehi, T. Mannon
Improving well design has and always will be the primary goal in drilling operations in the oil and gas industry. To address this issue, an analysis of wellbore stability and well design improvement has been conducted. This study will show a systematic approach to well design by focusing on best practices for mud weight window projection for a field in Mississippi Canyon, Gulf of Mexico. The field includes depleted reservoirs and is in close proximity of salt intrusions. Analysis of offset wells has been conducted in the interest of developing an accurate picture of the subsurface environment by making connections between depth, Non-Productive Time (NPT) events, and mud weights used. Commonly practiced petro physical methods of pore pressure, fracture pressure, and shear failure gradient prediction have been applied to key offset wells in order to enhance the well design for a proposed well. For the first time in the literature, the accuracy of the commonly accepted, seismic interval velocity based and the relatively new, seismic frequency based methodologies for pore pressure prediction are compared. Each of these methods is compared to the petro physically derived mud weight windows for the key offset wells and the proposed well in this field, showing higher reliability in the frequency based approach. Additionally, the interval velocity method yielded erroneous results in a fast-rock-velocity channel zone and the near salt proximity environments, whereas the frequency Based method appeared unaffected by either of these factors.
{"title":"Application of Seismic Frequency Based Pore Pressure Prediction in Well Design: Review of an Integrated Well Design Approach in Deep Water Gulf of Mexico","authors":"S. Salehi, T. Mannon","doi":"10.4172/2329-6755.1000125","DOIUrl":"https://doi.org/10.4172/2329-6755.1000125","url":null,"abstract":"Improving well design has and always will be the primary goal in drilling operations in the oil and gas industry. To address this issue, an analysis of wellbore stability and well design improvement has been conducted. This study will show a systematic approach to well design by focusing on best practices for mud weight window projection for a field in Mississippi Canyon, Gulf of Mexico. The field includes depleted reservoirs and is in close proximity of salt intrusions. Analysis of offset wells has been conducted in the interest of developing an accurate picture of the subsurface environment by making connections between depth, Non-Productive Time (NPT) events, and mud weights used. Commonly practiced petro physical methods of pore pressure, fracture pressure, and shear failure gradient prediction have been applied to key offset wells in order to enhance the well design for a proposed well. For the first time in the literature, the accuracy of the commonly accepted, seismic interval velocity based and the relatively new, seismic frequency based methodologies for pore pressure prediction are compared. Each of these methods is compared to the petro physically derived mud weight windows for the key offset wells and the proposed well in this field, showing higher reliability in the frequency based approach. Additionally, the interval velocity method yielded erroneous results in a fast-rock-velocity channel zone and the near salt proximity environments, whereas the frequency Based method appeared unaffected by either of these factors.","PeriodicalId":344421,"journal":{"name":"Journal of Geology and Geosciences","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121308654","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2013-08-19DOI: 10.4172/2329-6755.1000124
Oladunjoye Ma, Akanji Ao, Akingbesote Ot
Fast growing population of Alakuta-Awotan area of Ibadan has warranted the need to develop the water availability in the area. The area lies within the basement complex terrain of southwestern Nigeria typified by banded gneiss and minor intrusion of pegmatite and quartz vein. This study was carried out to characterize the aquifer units and anisotropic properties of fractures for evaluation of groundwater development in the area. Hydro-geologic investigation was carried out on forty-five wells to study the groundwater system and dynamics in shallow aquifers. This study was integrated with twenty-two Schlumberger vertical electrical soundings to further investigate the different subsurface geo-materials with the aim of delineating the thickness and continuity of the aquiferous zone. Six radial soundings were conducted to study the directional properties of the anisotropic rock and thus indicate the orientation of fractures and extent of the fracturing. Measured static water level and well head varied from 0.8 to 9.9 m and 182 m to 209 m respectively indicating that groundwater generally flow towards the eastern and southwestern parts from two main discharge sites in the northwestern part of the study area. Interpretation of the twenty-two Schlumberger vertical electrical soundings generally shows three layered earth structure notably top soil, saturated/sandy/lateritic clay and weathered/fractured/fresh basement which are mostly of the “H” curve type. Overburden isopach map revealed that the depth to the bedrock varies from 3 to 23 m. The main aquifer (weathered basement) is relatively shallow and most wells in the study area terminate in the second layer. The main water - bearing unit in the area of study is the weathered basement and the fractured basement which are within the second and third geoelectrical layers respectively. The weathered/fractured basement resistivity values vary from 62 Ohm-m and 9807 Ohm-m with thickness values ranging from 2.2 m to 36 m. Polygons produced from six radial sounding showed the predominant structural trends of fractures on the banded gneiss. The radial resistivity survey results show that there is significant anisotropy between 0 - 50 m depth generally striking NE-SW, NW-SE and N-S showing the major structural trend of basement fractures. Coefficient of Resistivity Anisotropy ranges between 1.03 and 1.38. Variation of apparent resistivity is strongest at the eastern and southern parts of the study area with coefficients of 1.33, 1.38, and 1.30. This relatively high coefficient of anisotropy implies higher- permeability anisotropy. The directionality of the trends could be responsible for the depressions in the weathered/ fractured basement. The regions with thick weathered/fractured basement/depressed zones are likely to be most promising sites for borehole drilling.
{"title":"Groundwater Exploration in Alakuta-Awotan area of Ibadan, Southwestern Nigeria","authors":"Oladunjoye Ma, Akanji Ao, Akingbesote Ot","doi":"10.4172/2329-6755.1000124","DOIUrl":"https://doi.org/10.4172/2329-6755.1000124","url":null,"abstract":"Fast growing population of Alakuta-Awotan area of Ibadan has warranted the need to develop the water availability in the area. The area lies within the basement complex terrain of southwestern Nigeria typified by banded gneiss and minor intrusion of pegmatite and quartz vein. This study was carried out to characterize the aquifer units and anisotropic properties of fractures for evaluation of groundwater development in the area. Hydro-geologic investigation was carried out on forty-five wells to study the groundwater system and dynamics in shallow aquifers. This study was integrated with twenty-two Schlumberger vertical electrical soundings to further investigate the different subsurface geo-materials with the aim of delineating the thickness and continuity of the aquiferous zone. Six radial soundings were conducted to study the directional properties of the anisotropic rock and thus indicate the orientation of fractures and extent of the fracturing. Measured static water level and well head varied from 0.8 to 9.9 m and 182 m to 209 m respectively indicating that groundwater generally flow towards the eastern and southwestern parts from two main discharge sites in the northwestern part of the study area. Interpretation of the twenty-two Schlumberger vertical electrical soundings generally shows three layered earth structure notably top soil, saturated/sandy/lateritic clay and weathered/fractured/fresh basement which are mostly of the “H” curve type. Overburden isopach map revealed that the depth to the bedrock varies from 3 to 23 m. The main aquifer (weathered basement) is relatively shallow and most wells in the study area terminate in the second layer. The main water - bearing unit in the area of study is the weathered basement and the fractured basement which are within the second and third geoelectrical layers respectively. The weathered/fractured basement resistivity values vary from 62 Ohm-m and 9807 Ohm-m with thickness values ranging from 2.2 m to 36 m. Polygons produced from six radial sounding showed the predominant structural trends of fractures on the banded gneiss. The radial resistivity survey results show that there is significant anisotropy between 0 - 50 m depth generally striking NE-SW, NW-SE and N-S showing the major structural trend of basement fractures. Coefficient of Resistivity Anisotropy ranges between 1.03 and 1.38. Variation of apparent resistivity is strongest at the eastern and southern parts of the study area with coefficients of 1.33, 1.38, and 1.30. This relatively high coefficient of anisotropy implies higher- permeability anisotropy. The directionality of the trends could be responsible for the depressions in the weathered/ fractured basement. The regions with thick weathered/fractured basement/depressed zones are likely to be most promising sites for borehole drilling.","PeriodicalId":344421,"journal":{"name":"Journal of Geology and Geosciences","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130513221","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2013-07-30DOI: 10.4172/2329-6755.1000123
Qadeer Ahmad
Penobscot is located in the Sable Island, Sable sub basin Canada. The Scotian Basin lies on the North American Plate. It is a classic passive, non-volcanic conjugate margin. It represents over 250 million years of continuous sedimentation recording the region’s dynamic geological history from the initial opening of the Atlantic Ocean to the recent post-glacial deposition. It contains the lithology ranging from Mesozoic era to Cenozoic era (Figure 1) [1].
{"title":"Mitigation Exploration Risk of Jurassic Reservoir by Seismic Inversion,Penobscot Area, Sable Sub Basin Nova Scotia, Offshore, Canada","authors":"Qadeer Ahmad","doi":"10.4172/2329-6755.1000123","DOIUrl":"https://doi.org/10.4172/2329-6755.1000123","url":null,"abstract":"Penobscot is located in the Sable Island, Sable sub basin Canada. The Scotian Basin lies on the North American Plate. It is a classic passive, non-volcanic conjugate margin. It represents over 250 million years of continuous sedimentation recording the region’s dynamic geological history from the initial opening of the Atlantic Ocean to the recent post-glacial deposition. It contains the lithology ranging from Mesozoic era to Cenozoic era (Figure 1) [1].","PeriodicalId":344421,"journal":{"name":"Journal of Geology and Geosciences","volume":"87 1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125719132","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-11-07DOI: 10.4172/2329-6755.1000E106
G. Xue
{"title":"Open Access Journals of Geo-science for Electrical and Electromagnetic Exploration","authors":"G. Xue","doi":"10.4172/2329-6755.1000E106","DOIUrl":"https://doi.org/10.4172/2329-6755.1000E106","url":null,"abstract":"","PeriodicalId":344421,"journal":{"name":"Journal of Geology and Geosciences","volume":"144 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116395524","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-10-10DOI: 10.4172/2329-6755.1000E105
S. Skias
{"title":"A Societal duty for Geoscientists of our Times: Communicating Experience and Innovation towards Improving Society's Resilience to Natural Hazards","authors":"S. Skias","doi":"10.4172/2329-6755.1000E105","DOIUrl":"https://doi.org/10.4172/2329-6755.1000E105","url":null,"abstract":"","PeriodicalId":344421,"journal":{"name":"Journal of Geology and Geosciences","volume":"65 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126882048","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-09-03DOI: 10.4172/2329-6755.1000E103
Q. Zhuang
Greenhouse gas cycling is an important component of earth system models that are used to project our future climate. Major physical, chemical and biological processes and controls of greenhouse gas cycling are often incorporated into biogeochemistry models of these gases. In particular, the hydrological cycle has long been linked to these models. However, more adequate hydrological models are still critically needed.
{"title":"Hydrological Dynamics are Critical to Greenhouse Gas Cycling","authors":"Q. Zhuang","doi":"10.4172/2329-6755.1000E103","DOIUrl":"https://doi.org/10.4172/2329-6755.1000E103","url":null,"abstract":"Greenhouse gas cycling is an important component of earth system models that are used to project our future climate. Major physical, chemical and biological processes and controls of greenhouse gas cycling are often incorporated into biogeochemistry models of these gases. In particular, the hydrological cycle has long been linked to these models. However, more adequate hydrological models are still critically needed.","PeriodicalId":344421,"journal":{"name":"Journal of Geology and Geosciences","volume":"86 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124747928","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.4172/2329-6755.1000116
Bahia M. Ben Ghawar, F. S. Elburas
Critical property that affects wellbore stability, perforation depths and hydraulic fracturing is Poisson’s Ratio (PR). Porosity and resistivity are the main petrophysic properties routinely are measured for any reservoir rock. In this approach utilize wireline data (GR, R, On and ρb) to classify shaly reservoir and predicate PR values. Therefore, range of shale content (over 20%) has PR over 0.2. while shale content (less than 20%) equivalent to PR equal to 0.18. According to variety of shale content percentage throw up change of PR values. This technique applied on one of major shaly sand reservoir rock, producer in Libyan oil fields, Hawaz at Murzuq basin, south-west of Libya; as a case study.
{"title":"Reservoir Subdivision and Prediction of Poisson's Ratio According to Wireline Data (Hawaz Reservoir, Libya): Case Study","authors":"Bahia M. Ben Ghawar, F. S. Elburas","doi":"10.4172/2329-6755.1000116","DOIUrl":"https://doi.org/10.4172/2329-6755.1000116","url":null,"abstract":"Critical property that affects wellbore stability, perforation depths and hydraulic fracturing is Poisson’s Ratio (PR). Porosity and resistivity are the main petrophysic properties routinely are measured for any reservoir rock. In this approach utilize wireline data (GR, R, On and ρb) to classify shaly reservoir and predicate PR values. Therefore, range of shale content (over 20%) has PR over 0.2. while shale content (less than 20%) equivalent to PR equal to 0.18. According to variety of shale content percentage throw up change of PR values. This technique applied on one of major shaly sand reservoir rock, producer in Libyan oil fields, Hawaz at Murzuq basin, south-west of Libya; as a case study.","PeriodicalId":344421,"journal":{"name":"Journal of Geology and Geosciences","volume":"221 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115905138","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.4172/2329-6755.1000121
H. Rehman, Umarnawaz khan, Sohail Khan Jadoon, M. Sayab
Fractal is a mathematical set that has a fractal dimension that usually exceeds its topological dimension and may fall between integers. They represent the idea of detailed self-similar repetition at same scale or they may nearly be the same at different scales. Fractals are geometrical objects with the fractal dimension (D). Their fractal geometry deals with the objects and spaces. They occupy space (x, y, z) of any dimension greater than or equal to the dimension of the objects. In this study, hydrothermally altered zones of porphyry copper deposits of Reko-Dik, Chagai Belt, are taken into account to see whether alternation patterns follow any fractal law. Rowan et al. (2006) carried out detailed spectral analyses of different alteration zones nicely exposed around the Reko-Dik. We have used the same images as base map in our calculations for spatial analysis. A refined box-counting method is used, where the number of boxes N(r) containing the alteration versus the box size (r) repeatedly tested. To start with, the scaling properties of box size (r) were taken at 0.5 km interval, following 0.5 km addition in each analysis ending at 5 km. The spatial distributions of hydrothermally altered zones show following fractal dimension values: (D) for argillic (D=1.0 ± 0.05), phyllic (muscovite + jarosite) (D=1.2 ± 0.04), phyllic (muscovite) (D=0.8 ± 0.05), propylitic (D=1.2 ± 0.04), and siliceous (D=0.8 ± 0.07). Further work is in progress to refine the D values using improved box-counting method.
分形是一个数学集合，它的分形维数通常超过其拓扑维数，并且可能落在整数之间。它们代表了在相同尺度上详细的自相似重复，或者在不同尺度上几乎相同。分形是具有分形维数(D)的几何对象。它们的分形几何处理对象和空间。它们占据的空间(x, y, z)的任何维度大于或等于对象的维度。本研究以察改带Reko-Dik斑岩铜矿热液蚀变带为研究对象，考察其蚀变模式是否遵循分形规律。Rowan等人(2006)对Reko-Dik周围暴露的不同蚀变带进行了详细的光谱分析。在空间分析的计算中，我们使用了相同的图像作为底图。使用了一种改进的盒计数方法，其中包含更改的盒数N(r)与重复测试的盒大小(r)。首先，箱体尺寸(r)的标度特性以0.5 km为间隔，然后在每次分析中添加0.5 km，最终达到5 km。热液蚀变带空间分布的分形维数为:泥质(D=1.0±0.05)、叶质(白云母+黄钾铁矾)(D=1.2±0.04)、叶质(白云母)(D=0.8±0.05)、丙质(D=1.2±0.04)、硅质(D=0.8±0.07)。进一步的工作正在进行中，以改进盒计数方法来完善D值。
{"title":"Fractal Pattern of Different Alteration Zones in Porphyry Copper Deposits of RekoDik, Chagai Belt, Pakistan","authors":"H. Rehman, Umarnawaz khan, Sohail Khan Jadoon, M. Sayab","doi":"10.4172/2329-6755.1000121","DOIUrl":"https://doi.org/10.4172/2329-6755.1000121","url":null,"abstract":"Fractal is a mathematical set that has a fractal dimension that usually exceeds its topological dimension and may fall between integers. They represent the idea of detailed self-similar repetition at same scale or they may nearly be the same at different scales. Fractals are geometrical objects with the fractal dimension (D). Their fractal geometry deals with the objects and spaces. They occupy space (x, y, z) of any dimension greater than or equal to the dimension of the objects. In this study, hydrothermally altered zones of porphyry copper deposits of Reko-Dik, Chagai Belt, are taken into account to see whether alternation patterns follow any fractal law. Rowan et al. (2006) carried out detailed spectral analyses of different alteration zones nicely exposed around the Reko-Dik. We have used the same images as base map in our calculations for spatial analysis. A refined box-counting method is used, where the number of boxes N(r) containing the alteration versus the box size (r) repeatedly tested. To start with, the scaling properties of box size (r) were taken at 0.5 km interval, following 0.5 km addition in each analysis ending at 5 km. The spatial distributions of hydrothermally altered zones show following fractal dimension values: (D) for argillic (D=1.0 ± 0.05), phyllic (muscovite + jarosite) (D=1.2 ± 0.04), phyllic (muscovite) (D=0.8 ± 0.05), propylitic (D=1.2 ± 0.04), and siliceous (D=0.8 ± 0.07). Further work is in progress to refine the D values using improved box-counting method.","PeriodicalId":344421,"journal":{"name":"Journal of Geology and Geosciences","volume":"137 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132401662","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.4172/2329-6755.1000E107
G. Iovine
{"title":"Some Considerations on Available Approaches to Risk Mitigation","authors":"G. Iovine","doi":"10.4172/2329-6755.1000E107","DOIUrl":"https://doi.org/10.4172/2329-6755.1000E107","url":null,"abstract":"","PeriodicalId":344421,"journal":{"name":"Journal of Geology and Geosciences","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123318768","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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