Caribbean Sea
Fault structure and hydrocarbon prospects of the Palawan basin on the southeastern margin of the South China Sea based on gravity, magnetic, and seismic data
Zhang, Chunguan (Xian Shiyou University, Xian Shiyou University, National Engineering Research Center of Offshore Oil and Gas Exploration) | Liu, Shixiang (CNOOC Research Institute) | Yuan, Bingqiang (Xian Shiyou University, Xian Shiyou University) | Zhang, Gongcheng (CNOOC Research Institute)
In order to study the structural features and hydrocarbon prospects of the Palawan basin in the South China Sea (SCS), the authors collected and collated the existing gravity and magnetic data, and obtained edge recognition information from potential. Combined with the seismic profile data, this paper analyzed the features of the gravity and magnetic anomalies and the edge recognition information of the potential fields, determined the fault system, and delineated favorable areas for oil and gas exploration in the Palawan basin. The results showed that four main groups of faults with NE, NW, near EW, and near SN trends developed in the Palawan basin and adjacent areas in the SCS. The NE-trending fault was the regional fault, while the NW-trending fault was the main fault. The NW-trending fault often terminated at the NE-trending fault, indicating that the NW-trending fault was formed later. This investigation has characterized two different types (Type I and Type II) of exploration favorable areas based on characteristics observed. The most notable characteristic of these exploration favorable areas was that they were located in the high value zones of the local anomaly of Bouguer gravity anomaly, and their development was obviously controlled by the faults. The amplitude of gravity anomalies was higher and the gradient of the gravity anomalies was steeper, and there were oil and gas wells and fields distributed in Type I favorable areas for exploration. Compared with Type I favorable areas, the amplitude of gravity anomalies was relatively small and the gradient of the gravity anomalies was relatively gentle corresponding to Type II favorable areas.
- Asia > China (1.00)
- Asia > Philippines > Palawan (0.28)
- Phanerozoic > Mesozoic (1.00)
- Phanerozoic > Cenozoic > Paleogene (0.46)
- Geology > Structural Geology > Tectonics > Plate Tectonics (1.00)
- Geology > Structural Geology > Fault (1.00)
- Geology > Rock Type (1.00)
- Geology > Geological Subdiscipline > Economic Geology > Petroleum Geology (1.00)
- Geophysics > Magnetic Surveying (1.00)
- Geophysics > Gravity Surveying > Gravity Acquisition (0.67)
- South America > Venezuela > Caribbean Sea > Tobago Basin (0.99)
- Asia > Philippines > Palawan > South China Sea > Northwest Palawan Basin > West Linapacan Field (0.99)
- Asia > Philippines > Palawan Basin (0.99)
- (2 more...)
- Reservoir Description and Dynamics > Reservoir Characterization > Seismic processing and interpretation (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Exploration, development, structural geology (1.00)
- Reservoir Description and Dynamics > Formation Evaluation & Management (1.00)
- (3 more...)
Shallow-water carbonate structures are characterized by different shapes, sizes and identifying features, which depend, among other factors, on the age of deposition and on the carbonate factory associated with a specific geologic period. These variations have a significant impact on the imaging of these structures in reflection seismic data. This study aims at providing an overall, albeit incomplete, picture of how the seismic expression of shallow-water carbonate structures has evolved through deep time. 297 shallow-water carbonate systems of different ages, spanning from Precambrian to present, with a worldwide distribution of 159 sedimentary basins, have been studied. For each epoch, representative seismic examples of shallow-water carbonate structures were described through the assessment of a selection of discriminating seismic criteria, or parameters. The thinnest structures, commonly represented by ramp systems, usually occurred after mass extinction events, and are mainly recognizable in seismic data through prograding clinoform reflectors. The main diagnostic seismic features of most of the thickest structures, which were found to be Precambrian, Late Devonian, Middle-Late Triassic, Middle-Late Jurassic, some Early Cretaceous pre-salt systems, #8220;middle#8221; and Late Cretaceous, Middle-Late Miocene and Plio-Pleistocene, are steep slopes, and reefal facies. Slope-basinal, resedimented seismic facies, were mostly observed in thick, steep-slope platforms, and they are more common, except for megabreccias, in post-Triassic structures. Seismic-scale, early karst-related dissolution features were mostly observed in icehouse, platform deposits. Pinnacle structures and the thickest margin rims are concentrated in a few epochs, such as Middle-Late Silurian, Middle-Late Devonian, earliest Permian, Late Triassic, Late Jurassic, Late Paleocene, Middle-Upper Miocene, and Plio-Pleistocene, which are all characterized by high-efficiency reef builders.
- South America (1.00)
- North America > United States > Texas (1.00)
- North America > Canada (1.00)
- (5 more...)
- Phanerozoic > Paleozoic > Devonian (1.00)
- Phanerozoic > Mesozoic > Triassic (1.00)
- Phanerozoic > Mesozoic > Jurassic (1.00)
- (5 more...)
- Geology > Structural Geology > Tectonics (1.00)
- Geology > Sedimentary Geology > Depositional Environment > Marine Environment > Reef Environment (1.00)
- Geology > Rock Type > Sedimentary Rock > Carbonate Rock (1.00)
- (3 more...)
- Geophysics > Seismic Surveying > Seismic Interpretation (1.00)
- Geophysics > Seismic Surveying > Seismic Processing (0.93)
- Geophysics > Seismic Surveying > Surface Seismic Acquisition (0.67)
- Geophysics > Seismic Surveying > Seismic Modeling > Velocity Modeling (0.45)
- Materials > Chemicals (1.00)
- Energy > Oil & Gas > Upstream (1.00)
- Government > Regional Government > North America Government > United States Government (0.45)
- South America > Venezuela > Caribbean Sea > Gulf of Venezuela > Gulf of Venezuela Basin > Cardon IV Block > Perla Field (0.99)
- Oceania > Australia > Western Australia > Western Australia > Timor Sea > Browse Basin (0.99)
- Oceania > Australia > Western Australia > North West Shelf > Timor Sea > Browse Basin (0.99)
- (82 more...)
John Eastwood has been an SEG member since 1993. He graduated from the University of Waterloo in 1987 (BSc honors co-op physics) and from the University of Alberta in 1992 with a PhD in geophysics. Eastwood worked for ExxonMobil/Imperial Oil for more than 30 years. He started his career in research where he pioneered the use of active and passive seismic monitoring in oil sands. He led ExxonMobil research groups in quantitative geophysics, seismic imaging, and acquisition. Eastwood also spent time in ExxonMobil's production company as geoscience manager for Canada East, and in exploration as manager pursuit and capture for Canada. Eastwood led ExxonMobil's resurgence into seismic imaging and FWI including the re-establishment of Exxon's leading position in high-performance computing. Eastwood was recognized in 1998 with the J. Clarence Karcher Award for outstanding contributions from a young geophysicist. He has received the Best Paper in The Leading Edge award (and Honorable Mention) as well as Best Paper from the Canadian Society of Exploration Geophysicists. He has five patents and numerous publications.
- North America > United States > Texas (1.00)
- North America > Canada > Alberta (0.68)
- North America > United States > Texas > Permian Basin > Yeso Formation (0.99)
- North America > United States > Texas > Permian Basin > Yates Formation (0.99)
- North America > United States > Texas > Permian Basin > Wolfcamp Formation (0.99)
- (37 more...)
Effect of Water Saturation on Failure Behaviour of Mudstones Under High Pressures
Iyare, U. C. (Los Alamos National Laboratory) | Frash, L. P. (Los Alamos National Laboratory) | Carey, J. W. (Los Alamos National Laboratory) | Blake, O. O. (The University of the West Indies) | Ramsook, R. (Trinity Exploration and Production)
ABSTRACT Water as pore fluid is an important factor that influence rock deformation and failure behaviour. This paper presents an experimental study on the effects of water saturation on the failure behaviour of mudstones at high confining pressures. Triaxial compression experiments were performed at confining pressures up to 130 MPa, on dry and water-saturated mudstone samples. Results including stress-strain curves, failure strength, and failure modes, showed that the mudstones experienced brittle, brittle-ductile transition, and ductile failure behaviour as the confining pressure increases. The results also revealed that water significantly weakened the rock, thereby reducing the failure strength and causing the rock to become ductile at lower confining pressure compare to dry conditions. Furthermore, in water-saturated conditions, the brittle-ductile transition behaviour is accompanied by shear band fractures and ductile flow, as opposed to shear fractures to shear band fractures in dry conditions. The findings of this study could provide valuable information for optimizing hydraulic fracturing techniques and improving production efficiency in unconventional oil and gas reservoirs by identifying the conditions and depths of the transition from brittle to ductile failure behavior. INTRODUCTION Crustal rocks typically contain some form of pore fluid, and most of these fluids are water (Price, 1975). Understanding how pore fluids affect the mechanical properties of rocks is crucial in solving a range of problems in geotechnical and geological applications. For example, water's significant impact on the strength and deformability of rocks has been linked to many rock engineering hazards like landslides (Iverson, 2000). Water has been shown in numerous studies to weaken the mechanical strength of various types of rock, including mudstone, sandstone, granitic rocks, and quartzite. (Cai et al., 2019; Lu et al., 2017; Wasantha and Ranjith, 2014). When rocks are saturated with water, they become weaker and more prone to failure. This is because water can act as a lubricant between the individual particles, reducing the frictional forces that hold the particles together. As a result, the rock may experience reduced strength, stiffness, and cohesion, as well as an increased risk of creep, plastic deformation, and failure rates (Brantut et al., 2013; Chen et al., 2019; Wong et al., 2016).
- North America > United States (0.47)
- North America > Trinidad and Tobago (0.28)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Mudrock (1.00)
- Geology > Geological Subdiscipline > Geomechanics (1.00)
- South America > Venezuela > Caribbean Sea > Eastern Venezuela Basin (0.99)
- North America > United States > Oklahoma > Anadarko Basin > Cana Woodford Shale Formation (0.99)
- Oceania > Australia > Victoria > Bass Strait > Gippsland Basin (0.91)
- North America > Trinidad and Tobago > Trinidad Field (0.91)
Lithofacies and Diagenetic Controls on Tight Silty and Sandy Upper Triassic Reservoirs of the Heshui Oil Field (Ordos Basin, North China)
Hu, Chenlin (School of Geology and Mining Engineering and Xinjiang Key Laboratory of Geodynamic Processes and Metallogenic Prognosis of the Central Asian Orogenic Belt, Xinjiang University) | Han, Changcheng (School of Geology and Mining Engineering and Xinjiang Key Laboratory of Geodynamic Processes and Metallogenic Prognosis of the Central Asian Orogenic Belt, Xinjiang University (Corresponding author)) | Tian, Jijun (School of Geology and Mining Engineering and Xinjiang Key Laboratory of Geodynamic Processes and Metallogenic Prognosis of the Central Asian Orogenic Belt, Xinjiang University (Corresponding author)) | Fu, Zhiqiang (School of Geology and Mining Engineering and Xinjiang Key Laboratory of Geodynamic Processes and Metallogenic Prognosis of the Central Asian Orogenic Belt, Xinjiang University (Corresponding author)) | Ma, Jinghui (School of Geology and Mining Engineering and Xinjiang Key Laboratory of Geodynamic Processes and Metallogenic Prognosis of the Central Asian Orogenic Belt, Xinjiang University (Corresponding author)) | Algeo, Thomas J. (Department of Geology, University of Cincinnati)
Summary Tight oil, present in reservoirs of low porosity and permeability, can be regarded as a kind of unconventional resource. The tightening process in this kind of reservoir is controlled by the lithology and diagenetic history of the host formation. Upper Triassic Yanchang Formation siltstones and sandstones are the main reservoirs for hydrocarbon accumulation in the Heshui Oil Field (HOF), southwestern Ordos Basin. The reservoirs exhibit low porosity, low permeability, and strong heterogeneity. In recent years, numerous drillcores have been recovered from these units, but the porosity-permeability characteristics and burial history of these silty and sandy reservoirs have not yet been reported in detail. In this study, an integrated analysis of the lithofacies, diagenesis, and reservoir characteristics of the siltstones and sandstones was achieved using a combination of core and thin section, grain size, scanning electron microscopy (SEM), X-ray diffraction (XRD), δC and δO, mercury intrusion capillary pressure (MICP), and porosity and permeability data. Our primary goals were to quantify the porosity-permeability characteristics of these silty and sandy reservoirs, restore their diagenetic histories, and examine the paragenetic relationship of reservoir tightness to hydrocarbon accumulation. The silty and sandy reservoirs represent braided river delta facies consisting of compositionally and texturally immature sediments. In the burial environment, they underwent complex diagenetic processes that reduced porosity from an initial average of ~38% to the present ~8%. Porosity-destructive processes included compaction (~ –12.5%) and cementation (~ –21%), with increases in porosity related to grain dissolution (~ +2.2%) and tectonic fractures (~ +1.1%). The reservoirs underwent four diagenetic stages: (1) Penesyngenetic and Eogenetic A Stage (Late Triassic-Early Jurassic); (2) Eogenetic B Stage (Late Jurassic); (3) Early Mesogenetic A Stage (Early Cretaceous); and (4) Late Mesogenetic A Stage (Late Cretaceous to recent). Hydrocarbon charging of these reservoirs occurred in three pulses. Existing pore space was partly filled by hydrocarbons during the Eogenetic B Stage. A second hydrocarbon charging event occurred during the Early Mesogenetic A Stage, when residual primary intergranular pores and secondary dissolution pores were filled. A third hydrocarbon charging event occurred during the Late Mesogenetic A Stage, when the reservoirs were tight. Siltstone beds deposited in delta front environments are the main future exploration targets in the Chang 6 to 8 members. The results of this study provide a useful reference framework for future exploration of hydrocarbon resources in the Upper Triassic Yanchang Formation of the HOF, as well as potential insights into the evolution of similarly tight reservoirs in other basins.
- Asia > China > Shaanxi Province (0.86)
- Asia > China > Gansu Province (0.86)
- Asia > China > Shanxi Province (0.73)
- (2 more...)
- Phanerozoic > Mesozoic > Triassic > Upper Triassic (1.00)
- Phanerozoic > Mesozoic > Cretaceous (1.00)
- Geology > Sedimentary Geology (1.00)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Mudrock (1.00)
- South America > Venezuela > Caribbean Sea > Gulf of Venezuela > Gulf of Venezuela Basin (0.99)
- South America > Argentina > Patagonia > Golfo San Jorge Basin (0.99)
- North America > United States > Wyoming > Laramie Basin > Niobrara Formation (0.99)
- (30 more...)
Opportunities for Producing Hydrogen and Low-carbon Fossil Fuels from Venezuelan Conventional and Unconventional Hydrocarbon Reservoirs: An Idea in Times of Energy Transition to Net Zero-Carbon
Rodriguez, Fernancelys (Independent Consultant) | Belhaj, Hadi (Khalifa University of Science and Technology) | AlDhuhoori, Mohammed (Khalifa University of Science and Technology)
Abstract Venezuela has a big potential for the generation of energy from renewable resources (e.g. water, wind, solar, biomass, etc.), geothermal reservoirs, and from its huge reserves of hydrocarbons in conventional and highly viscous oil reservoirs. Due to the great efforts being made by several countries worldwide to reduce the emission of greenhouse gases and global warming, the production of clean fuels (e.g. hydrogen) with low-carbon content to reach net zero is a great challenge, but yet of keen interest, for the Venezuelan industry. The objective of this article is to review most of the relevant techniques and propose potential scenarios/technologies for the reduction of greenhouse gases and the generation of clean fuels from reservoirs in Venezuela. The methodologies that have been envisaged in various industry and research segments in hydrogen and low-carbon fuels include, but are not limited to, steam reforming, pyrolysis, gasification, combustion, CCUS, oil, etc. A detailed description of each technology along with relevant scenarios and main conclusions are given. Also, the processes and procedures undertaken in these clean fuel generation technologies are addressed in this article to cover advances made in various industry disciplines and to highlight potential future breakthroughs. For the Venezuelan particular case, the following major scenarios are predicted for the generation of clean fossil fuels: 1) production of hydrogen from natural gas with CO2 capture and storage in aquifers or in depleted hydrocarbon reservoirs, 2) use of the produced or sequestered CO2 for Enhanced Oil Recovery (EOR) in reservoirs with production decline, 3) production of clean fossil fuels from upgrading techniques and applicable EOR methods (e.g. in-situ combustion), 4) perspectives for the generation of hydrogen from renewable resources, among others. The application of each of these technologies/scenarios is closely linked to underlying technical feasibility and economics. This article presents an approach to producing hydrogen and low-carbon fossil fuels, upstream and downstream, with CO2 capture and storage. The sequestered CO2 could then be used in miscible gas floods in conventional oil reservoirs for improved recovery, despite the possible effect on asphaltene precipitation and related flow assurance issues. Reconversion schemes for existing flow lines and new infrastructure designs would be necessary for the application of hydrogen and low-carbon fuel technologies, which would involve significant investments in terms of OPEX and CAPEX.
- Europe (1.00)
- North America > Canada (0.93)
- Asia > Middle East (0.93)
- (2 more...)
- Overview (0.67)
- Research Report (0.46)
- Materials > Chemicals > Commodity Chemicals > Petrochemicals (1.00)
- Energy > Renewable (1.00)
- Energy > Oil & Gas > Upstream (1.00)
- South America > Venezuela > Monagas > Eastern Venezuela Basin > Maturin Basin > Santa Barbara Field (0.99)
- South America > Venezuela > Monagas > Eastern Venezuela Basin > Maturin Basin > Carito Field (0.99)
- South America > Venezuela > Miga Field (0.99)
- (13 more...)
Understanding and Preventing Incomplete Shunted Open Hole Packs in Trinidad's Colibri Field
Tibbles, Raymond (DuneFront) | Wassouf, Phil (DuneFront) | Govinathan, Kesavan (DuneFront) | Campbell, Patrick (Shell International Exploration & Production, Inc) | Daniel, Vijay (Shell Trinidad & Tobago) | LaPointe, Michael (Shell International Exploration & Production, Inc) | Rattananon, Pichate (Shell Trinidad & Tobago) | Zhang, Ying (Shell International Exploration & Production, Inc)
Abstract Three out of four shunted gravel packs in Colibri suffered from severe losses near the end of the gravel pack and failed to achieve a final screenout even though as much as 50% excess gravel was placed. This study uses reservoir, completion, and bottom hole gauge data to understand why the final screenout was not achieved and how to ensure complete packing/final screen-outs in the future. The evaluation started with building representative models for each well in a gravel pack simulator to predict the pressures and packing mechanisms downhole. The data used in the models included the relevant completion and reservoir data. The model was then used in conjunction with the treatment records (surface pumping data and bottom hole gauge data) to evaluate the packing extent and sequence for different parts of the openhole. This evaluation pinpointed the time and location where losses occurred as well as the extent of openhole packing in each section. Various theories were formulated to describe the observations and one theory was selected as the most likely. The evaluations showed a consistent packing behavior across all the wells in which the screens were initially covered without the aid of shunts from toe to heel with much less gravel than required to fill the annulus void. After this initial packing stage, shunt packing began, and additional packing in all of the sections occurred. During this part of the packing process, losses began which resulted in all of the final slurry exiting the open hole into the reservoir. Based on the analysis, the most likely cause of the strange packing behavior was the combination of low screen inflow area, relatively low gravel permeability, higher fines content in the natural gravel sand and high gravel carrier fluid viscosity, which resulted in a high pressure drop across the pack/screen interface. The one well which achieved a final screenout had a lower pumping rate, resulting in lower pressure drop.
- Asia (0.93)
- North America > United States > Texas (0.28)
- South America > Venezuela > Caribbean Sea > Tobago Basin (0.99)
- South America > Brazil > Campos Basin (0.99)
- North America > Trinidad and Tobago > Trinidad > North Atlantic Ocean > Columbus Basin > East Coast Marine Area (0.99)
- (5 more...)
- Well Completion > Sand Control > Screen selection (1.00)
- Well Completion > Sand Control > Gravel pack design & evaluation (1.00)
- Well Completion > Hydraulic Fracturing (1.00)
Chevron, along with service companies Schlumberger, Halliburton, Baker Hughes, and Weatherford, has been granted a 6-month extension of its US sanctions waiver allowing it to maintain its existing assets in Venezuela, but not much else. In mid-May, the Biden administration seemed to signal a possible softening of its sanctions position on Caracas considering the US ban on Russian oil imports that President Biden signed into law on 11 April 2022, leading some media to speculate that Chevron might soon be greenlighted to start selling Venezuelan heavy crude again to US refineries. But the extension issued by the US Treasury Department on 27 May contained the same restricted terms of the previous extension which allowed Chevron and other companies covered in the order to only preserve their assets in Venezuela while forbidding them to drill, lift, buy, or process Venezuelan crude or oil products, or to interface with Venezuelan officials. The newest extension restricts Chevron to only conducting "transactions and activities necessary for safety or the preservation of assets in Venezuela," including those related to the safety of staff and the integrity of operations, participation in shareholder and board meetings, and payments on third-party invoices, local taxes, utility services, and salaries, Reuters reported. The document also authorizes oilfield service companies Halliburton, Schlumberger, Baker Hughes, and Weatherford International to maintain their assets in Venezuela.
- North America > United States (1.00)
- South America > Venezuela > Capital District > Caracas (0.27)
- South America > Venezuela > Orinoco Oil Belt (0.16)
- Government > Regional Government > North America Government > United States Government (1.00)
- Energy > Oil & Gas > Upstream (1.00)
- South America > Venezuela > Zulia > Maracaibo Basin > Ayacucho Blocks > Boscan Field > Rob-l Formation (0.99)
- South America > Venezuela > Zulia > Maracaibo Basin > Ayacucho Blocks > Boscan Field > Misoa Formation (0.99)
- South America > Venezuela > Zulia > Maracaibo Basin > Ayacucho Blocks > Boscan Field > Icotea Formation (0.99)
- (4 more...)
Abstract Ensuring shale stability while drilling the reservoir and completing a well is critical to guarantee well integrity and to enable the reservoir to product at its maximum potential. Drill-in fluid type, completion brine, and shale inhibitors play an important role in maintaining well integrity and preventing formation damage as they have different effects on shale. Reactivity of shale samples from offshore Gulf of Mexico was studied using several reservoir and completion fluids. The shale was first characterized using X-Ray diffraction (XRD) and X-Ray fluorescence (XRF). Then, the effect of fluids on shale was determined by performing several tests including linear swell meter (LSM), capillary suction time, and cuttings dispersion. Water-based (WB) and oil-based (OB) drill-in fluids, synthetic formation water, and completion brines with and without shale inhibitor were used to study the shale reactivity. XRD and XRF test showed presence of 5wt% illite and 6wt% kaolinite in the shale sample. Performance tests conducted on the shale samples showed a similar trend of high reactivity with improvements when inhibitor is added. Some brines showed poor synergistic effects when inhibitors were present in the fluid formulation. The type of drill-in fluid has a large impact on the LSM test results. Type of brine in the WB drill-in fluid also showed a major influence on the shale behavior. Oil-based drill-in fluids are commonly used to drill sections with very reactive shales. Nevertheless, water-based fluids are sometimes required due to performance preferences, environmental concerns, economic and logistic reasons, and/or synergistic effects with logging tools. Filtrate invasion and drill-in fluid/completion brine losses could cause detrimental effects in the reservoir if the fluids have not been designed to inhibit the shale hydration and swelling or fines migration. Therefore, improving the clay inhibition and shale stability while using water-based fluids is fundamental when drilling through reactive shale sections. Performing a comprehensive test matrix to determine the feasibility of using water-based fluids is imperative. Achieving excellent inhibition for a very reactive GOM formation shale while maintaining performance is possible when a precise and well-engineered combination of brine/shale inhibitor in the drill-in and completion fluids are found.
- North America > Mexico (1.00)
- North America > United States > Texas (0.47)
- South America > Venezuela > Caribbean Sea > Eastern Venezuela Basin (0.99)
- North America > Mexico > Veracruz > Sureste Basin > Salina Basin (0.99)
- North America > Mexico > Tabasco > Sureste Basin (0.99)
- (2 more...)
Royal Dutch Shell expects to sign a production-sharing contract for the 2.7-Tcf Manatee offshore gas field in Trinidad and Tobago. The country's Energy Minister Stuart Young confirmed the contract has been negotiated and is hoping the operator signs on in the coming weeks. The field is part of the 10-Tcf Loran-Manatee complex that straddles Trinidad and Tobago's maritime border with Venezuela. Young said it "is going to be the single largest new gas production contract and gas production in TT [Trinidad and Tobago] for decades." Gas volumes could start flowing as early as 2025, but this depends on the speed at which the parties can install infrastructure.