Abstract

Analysis of reservoir characterization data are essential for understanding and managing the

subsurface hydrocarbon. Given that the Nubian Formation is one of the main hydrocarbon

formations in the Sirt basin, its petrophysical properties were examined at three wells (Q2-97, 3V3

and 3V4). The FlexInLog software is used in the current study to evaluate the petrophysical

characterizations using well logs and core analysis results. Petrophysical parameters such as

volume of shale, clay minerals type, porosity, permeability and fluid saturation, in addition to the

volume of matrix are evaluated by using the well log data. Sandstone, siltstone, mudstone, and

shale make up the majority of the Nubian Formation's lithology. The upper and lower Nubian

sandstone Formations are primarily composed of the clay minerals illite and chlorite, with minor

amounts of kaolinite and montmorillonite. 3. The effective porosity of Well Q2-97 is the highest,

averaging 9.9%; it reaches 7.6% in the 3V3 well and 6.52% in the 3V4 well. However, well 3V4

had the lowest average permeability value of 0.7 mD, whereas well Q2-97 had the highest average

of 2.3 mD. The 3V4 well, with a hydrocarbon saturation of 49%, has the largest net pay thickness,

reaching 324 feet. The 3V3 well followed it with a net pay 273 feet and high rate of hydrocarbon

saturation reached 66%. Compared to the other two wells, the Q2-97 well has the least amount of

net pay thickness, reaching 235 feet.Abstract

Analysis of reservoir characterization data are essential for understanding and managing the

subsurface hydrocarbon. Given that the Nubian Formation is one of the main hydrocarbon

formations in the Sirt basin, its petrophysical properties were examined at three wells (Q2-97, 3V3

and 3V4). The FlexInLog software is used in the current study to evaluate the petrophysical

characterizations using well logs and core analysis results. Petrophysical parameters such as

volume of shale, clay minerals type, porosity, permeability and fluid saturation, in addition to the

volume of matrix are evaluated by using the well log data. Sandstone, siltstone, mudstone, and

shale make up the majority of the Nubian Formation's lithology. The upper and lower Nubian

sandstone Formations are primarily composed of the clay minerals illite and chlorite, with minor

amounts of kaolinite and montmorillonite. 3. The effective porosity of Well Q2-97 is the highest,

averaging 9.9%; it reaches 7.6% in the 3V3 well and 6.52% in the 3V4 well. However, well 3V4

had the lowest average permeability value of 0.7 mD, whereas well Q2-97 had the highest average

of 2.3 mD. The 3V4 well, with a hydrocarbon saturation of 49%, has the largest net pay thickness,

reaching 324 feet. The 3V3 well followed it with a net pay 273 feet and high rate of hydrocarbon

saturation reached 66%. Compared to the other two wells, the Q2-97 well has the least amount of

net pay thickness, reaching 235 feet.

Abstract—The majority of Neoproterozoic rocks exposed in southern Libya, are comprised of intrusive coarse-grained porphyritic, two-mica, and high K-calc alkaline granite. The Jabal Fezzan Granite (JFG) is located in southwestern Libya. In this study, trace elements and whole-rock geochemistry have been used to understand the origin and the process of petrogenesis of the studied granites. The JFG is high-Si, Rb, Y, Nb, and (ASI values greater than 1.1). Mineralogically, it is characterized by the presence of minor muscovite and biotite and a lack of hornblende, exhibiting features of S-type granites, and having a character that belongs to an alkali-calcic series. According to geochemical value, light REE-enriched, characterized by moderate

enrichments in LREE (La/Sm), HREE, and weak negative Eu-anomalies. The geochemical modeling of the reveals that the JFG derived from the melting of the crust and underwent high fractional crystallization of plagioclase and K-feldspar at (H-P) conditions (750–980°C/1–4 GPa). The Jabal Fezzan (JFG(~50%) ) formed during Pan-African orogenic events during the destabilization of the interior Saharan metacraton due to compression stress and transpressive movements along pre-existing weakness and reactivation of shear zones inherited from Paleoproterozoic evolution. The Neoproterozoic basement forms the northernmost margin of the intracratonic Muruzq Basin, as evidenced by (greenschist facies) and intruded granitic rocksderived at the syn-collision stage (630–540 Ma)

(JFG) .

ABSTRACT - This study aims to determine and investigate the provenance of the source rocks and the depositional setting of the Kikhla Formation, Lower Cretaceous, northwestern Libya. It is mainly composed of mature quartzitic sandstone alternating with conglomerate and clay. The study proved that the sandstone is yellow-white in color and commonly carries quartz granular and small fragments of silicified wood. The environmental deposition is under differing fluvial conditions and by a large braided river. Texturally, the Kikhla sandstone is poorly cemented, coarse to very coarse grained and strongly unimodal and is classified as litharenite and subarkose by the modal composition, which is supported by geochemical studies. According to petrography and geochemistry, the Kikhla sandstone was deposited in a passive continental margin basin, mainly from granitic sources. On the basis of major elements

ratios, and petrographic interpretation, the source rocks are most likely recognized as granites that were exposed via rifting. The CIA

(Chemical Index of Alteration) values (73.28-93.97) indicate a high degree of chemical weathering, which could be attributed to the

arid climate conditions in the source area and mainly controlled by the source-rock provenance, hydraulic sorting during transport and

deposition, diagenesis and depositional environment. According to chemical investigations, sandstone exhibits significant

concentrations of SiO2, Na2O>K2O, and Fe2O3, which is compatible with the modal data.

Keywords: Active continental margin. Kikhla Formation. Quartzitic sandstone. Chemical weathering. Hydraulic sorting. Source-rock provenance.

 The groundwater aquifers in Azintan, northwestern Libya suffer from an acute shortage of water. The groundwater was evaluated to determine its suitability for drinking and irrigation purposes from major two aquifers in north and south of Azintan area. This study carried out to assess the groundwater quality and to identify major affecting variables. Twelve samples from the two aquifers were collected. The two aquifers were collected and analyzed for total dissolved solid (TDS), electrical conductivity (EC), pH, Ca²⁺, Mg²⁺, Na⁺, K⁺, Cl^-, SO4^2-, CO3^2- and HCO3^-. The results show that, the groundwater in many places is dominated by higher concentrations of Cl^-, SO4^2- and HCO3^-. Two water types were recognized in this region are Cl-SO4- Na-Ca and Cl-SO4-Na. Gibbs and Piper method, as well as the hardness, soluble sodium percentage and the permeability index all have been used to assess the diagram quality of the groundwater of aquifers. Further, the multiple correlations and Cluster Analysis of groundwater quality parameters were carried out for further classification and interpretation of the groundwater quality. Finally, water qualities in the study area are compared with Libyan standards and WHO guidelines of drinking water and irrigation  purposes.

This study considers the diagenetic processes and the depositional settings of Lower Jurassic gypsum of the Bi'r Elghanem Formation in the northwestern of Libya. The paleo-environment study has revealed a variety of depositional environment ranging from lagoonal to fluvial deposit and evaporitic basins, which become intensely saline as a result of evaporation due to (semi-) arid environments. Samples were analyzed using elemental analysis, statistical evaluation such as Multiple Correlations, Principal Component Analysis, and mineralogical evidence to determine their mode of environmental deposition, mineralogical and geochemical composition. The geochemical results indicate that gypsum has evidence of mineral substitutions and displacement, suggesting a homologous mechanism for lithofacies and subsequent textural change. The development of gypsum minerals in a variety of lithologies and textures is aided by eustatic fluctuations in lake water level due to regional tectonism and climate.

Lithostratigraphically, the Sidi As sid Formation (Upper Cretaceous) in the El Zintan section (JabalNafusah, NW Libya) consists of three units: upper marl, middle marl with intercalations of dolostone, and lower dolostone. Based on crystal size and shape, three types of dolomite have been classified. Fine crystalline dolomite (D1) consists of nonplanar dolomites, fine to medium crystalline dolomite (D2), and very coarse, consisting of mostly planar dolomites (D-3). The Cathodoluminescence technique also showed that most of these dolomites have bright yellow to red and dull orange luminescence and zoning. Based on X-ray diffraction (XRD), all dolomites are relatively well ordered and non to nearly stoichiometric dolomite. The stable isotopic studies and element analysis show that the major elements such as sodium (D1: 412.166 ppm; D2: 175 ppm; D3: 420 ppm), strontium (D1: 107 ppm; D2: 85 ppm; D3: 81.2 ppm), manganese (D1: 271 ppm; D2: 91 ppm; V3: 242 ppm), and iron (D1: 4856.66 ppm; D2: 373 ppm; D3: 3287 ppm) and the values of the stable isotope of oxygen (D1:-2.202‰; D2:-2.131; D3:-4.359‰) and carbon (D1: 2.080; D2: 2.076‰; D3: 1.581‰). The values of major elements and depletion of the carbon and oxygen isotopes can be related to the effects of temperature diagenetic, and mesosaline reflux of dolomitizing fluids during the early diagenesis. These dolomites originated in a tidal environment in this Formation. The major sources of magnesium for the dolomites are seawater and hypersaline fluids.

The groundwater aquifers in Azintan, northwestern Libya suffer from an acute shortage of water. The groundwater was evaluated to determine its suitability for drinking and irrigation purposes from major two aquifers in north and south of Azintan area. This study carried out to assess the groundwater quality and to identify major affecting variables. Twelve samples from the two aquifers were collected. The two aquifers were collected and analyzed for total dissolved solid (TDS), electrical conductivity (EC), pH, Ca2+, Mg2+, Na+, K+, Cl-, SO42-, CO32- and HCO3-. The results show that, the groundwater in many places is dominated by higher concentrations of Cl-, SO42- and HCO3-. Two water types were recognized in this region are Cl-SO4-Na-Ca and Cl-SO4-Na. Gibbs and Piper method, as well as the hardness, soluble sodium percentage and the permeability index all have been used to assess the diagram quality of the groundwater of aquifers. Further, the multiple correlations and Cluster Analysis of groundwater quality parameters were carried out for further classification and interpretation of the groundwater quality. Finally, water qualities in the study area are compared with Libyan standards and WHO guidelines of drinking water and irrigation purposes.

The Aqaba complex located at the southeastern of Jordan, exposes coexisting mafic-felsic association typical of syn-to pre-plate collision magmatism. The bulk of the pluton is made of quartz monzonite, granite and granodiorite. New U-Pb zircon dating revealed a synchronous emplacement of the granite (605 ± 4.6 and 617±3.7 Ma), granodiorite (613 ±4.4, 612 ±3.6 and 611.8±4.9 Ma) and quartz monzonite (608± 5.4 Ma). The whole-rock geochemistry indicate that the source for the quartz monzonite, granite and granodiorites could have been a continental arc-derived from mantle sources and mature metagreywackes. Melting of this crustal material was subduction related , which could have been an enriched mantle-derived melt contaminated. The Aqaba complex is a part of a the Arabian-Nubian Shield (ANS) are juvenile in character, Neoproterozoic, including in addition five large plutonic suites ; Rahma , Darba , Rumman,Urf and Yutum suite. The genesis of these suites were likely induced by mantle-derived magma in the shallow crust while their spatially and temporally discrete emplacement at shallow levels was probably related to the (extensional) of lithospheric boundaries, which represent a feasible fertile source for such granitoids.

الملخص

مجموعة صخور النوبية الرملية هي واحدة من أهم التكوينات الحاملة النفط والغاز في حوض سرت العبادي [1]. وتتكون المجموعة من الرواسب غير البحرية من العصر الطباشيري السفلى وتنقسم إلى ثلاثة تشكيلات. الحجرالرملي النوبي السفلي ، والحجر الرملي العلوي النوبي والطبقة الصخرية الطينية تفصلهما اثنين من الأحجار الرملية، محليا تقسم الحجر الرملي النوبي السفلى و النوبي العلوي، مفصولة بالصخر الزيتي الأوسط. تحديد الصخور الحجرية له معنى مهم لتقدير احتياطي النفط من حيث كفاءة الخزان والقدرة على التخزين.ان تحديد هوية المعدنية للصخور من سرود الابار مهم جدا ،حيث عملت مقارنة بالرسم البياني ρma و ΔTma والعلاقة التحليلية لمعرفة بنية التركيب المعدني للخزان الرمل الصخري، وعرض البيئة الترسبية الرئيسية المؤثرة. بالإضافة إلى تأثيرات معدن البيرايت، في المواد العضوية في جميع هذه الخزان المدروسة بن غوار بم [2]. وبالتالي، فإن مجموعة متنوعة من قيم العلاقات البيانية ساهمت في ذلك خصوصا في المعادن الطينية الموجودة في هذا النوع من الخزانات. هذه الدراسة استندت إلى بيانات سرود الابار لاكثر من 872 Q2 قدم 646 3V3 قدم ، من أسفل إلى أعلى وفقا للخصائص الترسيبية والبيتروفيزيائية. وتمت عمل التحليل المتاحة (بالاضافة لقطع العينات في تكوين الحجر الرملي النوبي السفلي) من بعض الآبار التي تم حفرها في تراكيب 3, 59 V وفقا لعلم الرسوبيات والبترولوجيا والعمليات الدياجينيتيك التي ارتبطة بالتحليل مع النتائج التي تم الحصول عليها من تفسيرسرود الابار . تحليل هذه السجلات استنادا إلى نتائج العلاقات البيانية المختلفة، بدعم من التحقيق البيتروغرافيك و الديجينيتيك، سمح بتحديد نوعية المعادن، وتحديد معادن الطينية في التكوين، وتقدير البيئة الترسيب. هذا التكوين تشمل الآبار 3v3 ،3v4، Q1و Q2. تحليل سرود الابار تم من خلالها الحصول علي معلومات هامة ,حيث الكوارتز نجده في كل النطاقات والطين الناتج من العمليات التحويرية نتج عنه الكاولينات في الجزء العلوي من منطقة الدراسة .أما معدن الاليت والسمكيتات الناتج من تحلل الطين والملتحم بالكلسيات والكاولينيات في الجزء الأوسط من النطاق والمونتومورليت و الاليت - الكاولينيات في الجزء السفلي . المادة اللاحمة لتكوين النوبه تكونت أساسا من إعادة التبلور للكوارتز و معها الانهيدرايت والكلوريت وبعض معادن الطين( الكاولينيات والكلورايت مع الاليت- سمكيتات ). الفحص البيتروغرافي يظهر أن الرمال هي مكوانات معدنية وتم نضوجها. وأسفرت العمليات الدجينية عن أنواع مختلفة من الإسمنت والكلوريت. إن التأكد من تحديد المعادن وتقدير التغيرات الترسيبية باستخدام مختلف العلاقات البيانية المتاحة والبيانات المستمدة من تحليل الكور اللنوبي السفلي هي رمال عادت متوسطة الحجم. وتعكس هذه القيم تكوين الكوارتز / الكاولينيت الأخير ووجود كربونات الحديد (على سبيل المثال سيديريت و / أو أنكيريت) والبيريت في السابق. تم تأكيد هذه الخصائص من قبل العلاقات البيانية (ماتريكس الكثافة) بالمقابل و (مقطع امتصاص عرضي من السرد). و (مؤشر امتصاص الكهروضوئية) ضد سجل TH / K وتأكيد الكاولينيت كاحد معادن الطينية الأكثر شيوعا. وتظهر مختلف القطع المتقاطعة التي تم الحصول عليها من تحليل سجلات أشعة جاما الطيفية. أن الحجر الرملي يتميز وبوفرة الثوريوم ، وكميات ضئيلة من البوتاسيوم واليورانيوم المحلي، وتفسر على أنها تشير إلى البيئة القارية النهرية. كميات أعلى من البوتاسيوم والصخر الزيتي الوسطى تحدد بيئة ترسيبة البحيرية.

AAPG "Siliciclastic Reservoirs of the Middle East" GTW took place from 15-16 May 2017 at the Grand Hyatt Amman Hotel in Jordan.

The workshop was dedicated to knowledge sharing, exchanging ideas and workflows pertaining to exploration and development of siliciclastic reservoirs in the Middle East region. 44 industry professionals from 9 countries and 16 companies attended the workshop. The 15 presentations which formed the technical program covered the following topics:

• Integrated Stratigraphic Techniques and Studies: A Better Way of Correlation
• Understanding the Depositional Environments and Processes of Clastic Reservoirs
• Structure, Geomechanics and Fluid Flow Properties of Siliciclastic Reservoirs
• Diagenetic Controls on Reservoir Quality: Assessment and Prediction

Core provided by National Petroleum Company, Jordan and Saudi Aramco was on display throughout the workshop. The core was carefully selected to compliment the technical program and participants had time each day to view and discuss the core samples.

Highlights of the workshop included two inaugural keynote speeches delivered by:

• Sa'id Al Hajri, Saudi Aramco, AAPG Middle East Past President
• Abdulkaker Abed, Professor of Geology, University of Jordan

All of the attendees also benefitted from informative breakout discussion sessions, held at the end of each day.

The workshop was followed by an optional two-day field trip to Wadi Rum (17-18 May 2017), led by Ahmed Masri, Ministry of Energy and Mineral Resources, Jordan.

We would like to take this opportunity to sincerely thank Saudi Aramco as the Platinum Sponsor of this workshop.