BARRAMUNDI–1: A CASE HISTORY IN FRACTURE ANALYSIS AND SEAL INTEGRITY IN THE BASS BASIN

2001 ◽  
Vol 41 (1) ◽  
pp. 71
Author(s):  
R.P. Crist ◽  
J.R. Conolly ◽  
L.D. Robinson
Keyword(s):  
Shear Wave ◽  
Oil And Gas ◽  
Detection Methods ◽  
Stress Axis ◽  
Seal Integrity ◽  
Late Tertiary ◽  
Potential Reservoir ◽  
Wave Event ◽  
Background Gas ◽  
Coal Measures

Barramundi–1 was drilled to test a faulted rollover structure with thick potential reservoir sands in the top Eocene Eastern View Coal Measures. A structure-wide AVO anomaly was mapped corresponding to these sands and this suggested the presence of a valid hydrocarbon trap.Barramundi–1 reached a total depth of 2,100 m on October 2 1999 after penetrating a thick reservoir sand sequence in the Eastern View Coal Measures within the T27/P permit operated by GLOBEX Far East.No significant hydrocarbons were encountered. Log analysis showed that large borehole breakouts occur below 1,400 m in thick Eastern View sands and background gas was observed to decrease. Dipole Sonic Imager (DSI) logs also showed that the amplitude of the fast shear wave event was attenuated from 1,250–1,450 m and was erratic in amplitude below this depth.The Compressional Velocity (Vp) to Shear Wave Velocity (Vs) ratios showed large variations over short intervals in the break out zones.It was concluded that Barramundi–1 failed to contain commercial hydrocarbons due to the seal failure caused by late Tertiary movement which has manifested itself both as fractures and faults, with a principal stress axis that trends northeast–southwest.An AVO anomaly mapped across the Barramundi structure has probably been caused by a combination of lithological and stress anisotropy in thick Eastern View sands at depths below 1,500 m, as observed by ovalisation occurring on the Caliban log analysis.It was concluded that the stresses would add to anisotropic effects in the rocks and consequently direct hydrocarbon detection methods such as AVO have to be used with caution.The central Bass Basin has generated both oil and gas. More wells need to be analysed using seal integrity methods in order to fully determine the reason for the failed trapping mechanism at Barramundi. This could eventually lead to a fault seal model that would allow exploration to successfully continue.

scholarly journals Geological Characteristics of Unconventional Gas in Coal Measure of Upper Paleozoic Coal Measures in Ordos Basin, China

2016 ◽  
Vol 20 (1) ◽  
pp. 1-5 ◽  
Author(s):  
Jinxian He ◽  
Xiaoli Zhang ◽  
Li Ma ◽  
Hongchen Wu ◽  
Muhammad Ashraf
Keyword(s):  
Shale Gas ◽  
Coalbed Methane ◽  
Oil And Gas ◽  
Ordos Basin ◽  
Tight Sandstone ◽  
Gas Reservoir ◽  
Unconventional Gas ◽  
Geological Characteristics ◽  
Upper Paleozoic ◽  
Coal Measures

<p>There are enormous resources of unconventional gas in coal measures in Ordos Basin. In order to study the geological characteristics of unconventional gas in coal Measures in Ordos Basin, we analyzed and summarized the results of previous studies. Analysis results are found that, the unconventional gas in coal measures is mainly developed in Upper Paleozoic in Eastern Ordos Basin, which including coalbed methane, shale gas and tight sandstone gas. The oil and gas show active in coal, shale and tight sandstone of Upper Paleozoic in Ordos Basin. Coalbed methane reservoir and shale gas reservoir in coal measures belong to “self-generation and self- preservation”, whereas the coal measures tight sandstone gas reservoir belongs to “allogenic and self-preservation”. The forming factors of the three different kinds of gasses reservoir are closely related and uniform. We have the concluded that it will be more scientific and reasonable that the geological reservoir-forming processes of three different kinds of unconventional gas of coal measures are studied as a whole in Ordos Basin, and at a later stage, the research on joint exploration and co-mining for the three types of gasses ought to be carried out.</p>

Fossil flowers and leaves of the Ebenaceae from the Eocene of southern Australia

1985 ◽  
Vol 63 (10) ◽  
pp. 1825-1843 ◽  
Author(s):  
James F. Basinger ◽  
David C. Christophel
Keyword(s):  
Guard Cells ◽  
Epidermal Cells ◽  
Fossil Leaves ◽  
Extant Species ◽  
Late Tertiary ◽  
The Family ◽  
Fossil Flowers ◽  
Subsidiary Cells ◽  
Clay Lenses ◽  
Coal Measures

Numerous flowers and a diverse assemblage of leaves are mummified in clay lenses in the base of the Demons Bluff Formation overlying the Eastern View Coal Measures. Fossil localities occur in the Alcoa of Australia open cut near Anglesea, Victoria, Australia. Flowers are tubular, less than 10 mm long, and about 5 mm wide. Four sepals are connate forming a cup-shaped calyx. Four petals are fused in their basal third and alternate with sepals. Flowers are all unisexual and staminate. Stamens are epipetalous and consistently 16 in number, arranged in 8 radial pairs. Pollen is subprolate, tricolporate, and about 32 μm in diameter. The exine is smooth to slightly scabrate. A rudimentary ovary occurs in some flowers. Sepals usually have a somewhat textureless abaxial cuticle with actinocytic stomata. Some sepals, however, have frill-like cuticular thickenings over some abaxial epidermal cells and some subsidiary cells with pronounced papillae overarching guard cells. One of the more common leaf types found associated with the flowers is characterized by the same peculiar cuticular thickenings and overarching papillae on subsidiary cells that occur on sepals. This cuticular similarity indicates that flowers and leaves represent a single taxon. Leaves are highly variable in size and shape but are consistently entire margined, with pinnate, brochidodromous venation. The suite of features characterizing the flowers is unique to the Ebenaceae. Flowers of many extant species of Diospyros (Ebenaceae) closely resemble the fossil flowers. Fossil leaves, too, are typical of leaves of extant Diospyros. Both flowers and leaves are considered conspecific and have been assigned the name Austrodiospyros cryptostoma gen. et sp. nov. The Anglesea fossils represent one of the earliest well-documented occurrences of the Ebenaceae and are the earliest known remains of Ebenaceae from Australia. They support the hypothesis of a Gondwanan origin for the family with late Tertiary diversification in the Malesian region.

EXPLORATION IN THE COOPER BASIN

1989 ◽  
Vol 29 (1) ◽  
pp. 366 ◽  
Author(s):  
R. Heath
Keyword(s):  
Oil And Gas ◽  
South Australia ◽  
Mature Stage ◽  
Small Contribution ◽  
Terrestrial Source ◽  
Seismic Acquisition ◽  
Proterozoic Basement ◽  
Gas Fields ◽  
Coal Measures ◽  
Cooper Basin

The Cooper Basin is located in the northeastern corner of South Australia and in the southwestern part of Queensland. The basin constitutes an intracratonic depocentre of Permo- Triassic age. The Cooper Basin succession unconformably overlies Proterozoic basement as well as sediments and metasediments of the Cambro- Ordovician age. An unconformity separates in turn the Cooper succession from the overlying Jurassic- Cretaceous Eromanga Basin sediments.The Permo- Triassic succession comprises several cycles of fluvial sandstones, fluvio- deltaic coal measures and lacustrine shales. The coal measures contain abundant humic kerogen, comprising mainly inertinite and vitrinite with a small contribution of exinite. All hydrocarbon accumulations within the Cooper Basin are believed to have originated from these terrestrial source rocks.Exploration of the basin commenced in 1959 and, after several dry holes, the first commercial discovery of gas was made at Gidgealpa in 1963. To date, some 97 gas fields and 10 oil fields, containing recoverable reserves of 5 trillion cubic feet of gas and 300 million barrels recoverable natural gas liquids and oil, have been discovered in the Cooper Basin. Production is obtained from all sand- bearing units within the Cooper stratigraphic succession.The emphasis of exploration in the Cooper Basin is largely directed towards the assessment of four- way dip closures and three- way dip closures with fault control, but several stratigraphic prospects have been drilled. Furthermore, in the development phase of some gas fields a stratigraphic component of the hydrocarbon trapping mechanism has been recognised.Improvements in seismic acquisition and processing, combined with innovative thinking by the explorers, have facilitated the development of untested structural/stratigraphic plays with large reserves potential. Exploration for the four- and three- way dip closure plays in the Cooper Basin is now at a mature stage. However, reserves objectives are expected to continue to be met, with the expectation of a continuing high success rate.Selected new plays are expected to be tested within a continuing active exploration program as exploration for oil and gas in the Cooper Basin refines the search for the subtle trap.

THE HYDROCARBON POTENTIAL OF THE PENOLA TROUGH, OTWAY BASIN

1995 ◽  
Vol 35 (1) ◽  
pp. 358 ◽  
Author(s):  
R. Lovibond ◽  
R.J. Suttill ◽  
J.E. Skinner ◽  
A.N. Aburas
Keyword(s):  
Early Cretaceous ◽  
Seismic Data ◽  
Oil And Gas ◽  
Direct Detection ◽  
Source Rocks ◽  
Well Control ◽  
Potential Reservoir ◽  
Half Graben ◽  
History Of

The Penola Trough is an elongate, Late Jurassic to Early Cretaceous, NW-SE trending half graben filled mainly with synrift sediments of the Crayfish Group. Katnook-1 discovered gas in the basal Eumeralla Formation, but all commercial discoveries have been within the Crayfish Group, particularly the Pretty Hill Formation. Recent improvements in seismic data quality, in conjunction with additional well control, have greatly improved the understanding of the stratigraphy, structure and hydrocarbon prospectivity of the trough. Strati-graphic units within the Pretty Hill Formation are now mappable seismically. The maturity of potential source rocks within these deeper units has been modelled, and the distribution and quality of potential reservoir sands at several levels within the Crayfish Group have been studied using both well and seismic data. Evaluation of the structural history of the trough, the risk of a late carbon dioxide charge to traps, the direct detection of gas using seismic AVO analysis, and the petrophysical ambiguities recorded in wells has resulted in new insights. An important new play has been recognised on the northern flank of the Penola Trough: a gas and oil charge from mature source rocks directly overlying basement into a quartzose sand sequence referred to informally as the Sawpit Sandstone. This play was successfully tested in early 1994 by Wynn-1 which flowed both oil and gas during testing from the Sawpit Sandstone. In mid 1994, Haselgrove-1 discovered commercial quantities of gas in a tilted Pretty Hill Formation fault block adjacent to the Katnook Field. These recent discoveries enhance the prospectivity of the Penola Trough and of the Early Cretaceous sequence in the wider Otway Basin where these sediments are within reach of the drill.

scholarly journals High-Pressure Hydrogen Sulfide Experiments: How Did Our Safety Measures and Hazard Control Work during a Failure Event?

Safety ◽  
2020 ◽  
Vol 6 (1) ◽  
pp. 15 ◽  
Author(s):  
Kayode I. Adeniyi ◽  
Herman H. Wan ◽  
Connor E. Deering ◽  
Francis Bernard ◽  
Molly A. Chisholm ◽  
...  
Keyword(s):  
Hydrogen Sulfide ◽  
Oil And Gas ◽  
Control Strategies ◽  
Sewage Treatment ◽  
Detection Methods ◽  
Safety Standards ◽  
Hazard Control ◽  
Failure Event ◽  
Ring Seal ◽  
Control Work

Hydrogen sulfide (H2S) is a hazardous, colorless, flammable gas with a distinct rotten-egg smell at low concentration. Exposure to a concentration greater than 500 ppm of H2S can result in irreversible health problems and death within minutes. Because of these hazards, operations such as oil and gas processing and sewage treatment that handle or produce H2S and/or sour gas require effective and well-designed hazard controls, as well as state-of-the-art gas monitoring/detection mechanisms for the safety of workers and the public. Laboratories studying H2S for improved understanding must also develop and continually improve upon lab-specific safety standards with unique detection systems. In this study, we discuss various H2S detection methods and hazard control strategies. Also, we share our experience regarding a leak that occurred as a result of the failure of a perfluoroelastomer O-ring seal on a small stirred autoclave vessel used for studying H2S hydrate dissociation/formation conditions in our laboratory, and discuss how our emergency response plan was activated to mitigate the risk of exposure to the researchers and public.

EVALUATION OF HYDROCARBON SEEPAGE IN THE GREAT AUSTRALIAN BIGHT

2002 ◽  
Vol 42 (1) ◽  
pp. 371 ◽  
Author(s):  
H.I.M. Struckmeyer ◽  
A.K. Williams ◽  
R. Cowley ◽  
J.M. Totterdell ◽  
G. Lawrence ◽  
...  
Keyword(s):  
Oil And Gas ◽  
Liquid Hydrocarbon ◽  
Structural Features ◽  
Long Distance ◽  
Seal Failure ◽  
Late Tertiary ◽  
Geological Information ◽  
Sar Data ◽  
Active Tectonism ◽  
Great Australian Bight

The regional assessment of hydrocarbon seepage is built around a combination of Radarsat and ERS Synthetic Aperture Radar (SAR) data, acquired during 1998 and 1999, as part of a collaborative project between Geoscience Australia, Nigel Press Associates, Radarsat International and AUSLIG (specifically the Australian Centre for Remote Sensing). In total, 55 Radarsat Wide 1 Beam Mode scenes and one ERS scene from the Great Australian Bight (GAB) region were analysed. The data were integrated with regional geological information, and other hydrocarbon migration and seepage indicators such as reprocessed and reinterpreted legacy Airborne Laser Fluorosensor (ALF) data, to provide an assessment of the possible charge characteristics of the region.The results of the study suggest that active, though areally restricted, liquid hydrocarbon seepage is occurring within the Bight Basin. The majority of seepage slicks occur along the outer margin of the major depocentre, the Ceduna Sub-basin, in areas where significant Late Tertiary to Recent faulting extends to the seafloor. Very little evidence of seepage was observed on the SAR data above the main depocentre, which is an area of minimal Late Tertiary to Recent faulting. Reprocessed ALF data reveal three main areas with relatively dense fluors. Although they are not directly coincident with locations of seepage interpreted from SAR data, their distribution support the pattern of preferred leakage along the basin margins.Integration of regional geological models with the results of this study suggests that structural features related to active tectonism have focused laterally migrating hydrocarbons to produce active seepage at specific locations in the basin. Where these features are absent, seepage may be passive and/or be governed by long distance migration to points of seal failure. Together with oil and gas shows in exploration wells, observations from this study provide further evidence that liquid hydrocarbons have been generated in the Great Australian Bight.

The Vesta oil and gas field, Vulcan Sub-basin, Timor Sea, Australia

2012 ◽  
Vol 52 (1) ◽  
pp. 163
Author(s):  
Grant Ellis
Keyword(s):  
Late Jurassic ◽  
Oil And Gas ◽  
High Heat ◽  
Gas Generation ◽  
Gas Field ◽  
Late Tertiary ◽  
Oil And Gas Field ◽  
Half Graben ◽  
Oil Source ◽  
Hydrocarbon Charge

The Vesta oil and gas field is located in the Swan Graben of the Vulcan Sub-basin. The structure consists of a number of separate tilted fault blocks located on a northwest-trending accommodation zone that forms a high, separating the southeast-dipping half-graben of the Swan Graben North from the northwest-dipping half-graben of the Swan Graben South. Drilled in 2005, Vesta–1 intersected a 17 m thick oil-bearing slope-fan sandstone of the Late Jurassic Elm Sandstone in the Lower Vulcan Formation. Drill-stem testing flowed oil and gas and indicated that the reservoir is normally pressured surrounded above and below by over-pressured claystone. In 2007, Vesta–2 intersected gas-bearing sandstone in a separate fault compartment. Understanding the geometry of the hydrocarbon-bearing Elm Sandstone reservoir has proved a challenge due to the very poor 3D seismic imaging, the variable sandstone thickness and quality, and abundant evidence of thin steeply-dipping injected sandstones above and below the main reservoir sandstone. The Lower Vulcan and Upper Vulcan Formation claystone provides the vertical and lateral seal for the Elm Sandstone. This thick seal has protected the Vesta oil and gas accumulations from the effects of the Late Tertiary tectonism, which had a significant effect on the integrity of the palaeo-oil filled closures on the adjacent Eclipse Trend. Three phases of hydrocarbon charge of the Vesta structure have been identified with oil-source correlation indicating a Lower Vulcan Formation marine source. The source interval intersected in Vesta–1 is presently post-mature, with oil and gas generation associated with high heat flow in the Late Jurassic. Expulsion of hydrocarbons from the source was most likely compaction-driven, with gas expulsion in the Early Cretaceous, and oil expulsion much later with increasing hydrocarbon saturation.

De-Risking Thermal Induced Sustained Annulus Pressure to Safeguard Optimal Production

2021 ◽  
Author(s):  
Sunday Maxwell-Amgbaduba ◽  
David Ogbonna ◽  
Femi Obakhena ◽  
Onyedikachi Okereke ◽  
Ihuoma Green ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Oil And Gas ◽  
Oil And Gas Industry ◽  
Acoustic Monitoring ◽  
Pressure Monitoring ◽  
Passive Acoustic Monitoring ◽  
Seal Integrity ◽  
System Integrity ◽  
Passive Acoustic ◽  
Bean Size

Abstract Sustained Annulus Pressure (SAP) is a common production constraint in the oil and gas industry, it is usually caused by impaired seal Integrity within the wellbore system resulting in barrier failures. In peculiar scenarios the thermal expansion creates pressure build-up in the annulus as well which can equally impair the integrity of the wellbore. In this paper the results of downhole and surface pressure monitoring surveys are presented, the objectives aim at determination of both downhole leaks and verification the influence of thermal expansion into a wellbore system integrity in a field located onshore Niger Delta. SAP in a producing well was earlier recorded during routine annular pressure monitoring in 2017 during the production rate increase by changing the bean size from 18/64" to 24/64". Initial diagnostics observed pointed towards SAP resulting from a possible downhole seal integrity issue leading to a leak to the surface. While putting the well on stream with current bean size and the pressure regime for both THP and CHP was observed. Pressure with time analysis showed annulus pressure builds up rapidly while flowing and bleeds off within 30 min from 700 psi to 0 psi when well shut in. Downhole logging and sensitive passive acoustic monitoring was conducted, the survey aimed to detect barrier failures by capturing its acoustic leak patterns under shut-in and bleeding off condition. Considering the suspected leak behaviour, the data acquisition included the procedure to build up the annulus pressure by flowing the well and monitoring the annulus discharge. Integrity logs survey and passive acoustic monitoring confirmed there were no downhole failures and after several bleed-offs when Tubing choke was beaned down to 18/64" no annulus pressure build-up was observed from the Well head gauge on the Casing head confirming the source of the sustained annulus pressure is driven by the temperature expansion of the annulus fluid. Remedial action and recommendation after Simulation were to de-risk the well at a controlled bean size to mitigate SAP and optimally flow the well.

The extent of methane emission associated with the natural gas industry in southeastern Poland.

2021 ◽  
Author(s):  
Paweł Jagoda ◽  
Jarosław Nęcki ◽  
Jakub Bartyzel ◽  
Piotr Korbeń ◽  
Michał Kud ◽  
...  
Keyword(s):  
Natural Gas ◽  
Methane Emission ◽  
Oil And Gas ◽  
Science Studies ◽  
Oil And Gas Industry ◽  
Detection Methods ◽  
Current Phase ◽  
Large Area ◽  
Gas Wells ◽  
Gas Industry

&lt;p&gt;Goal of the CCAC project is to observe urban emission of natural gas over Canada and different countries in Europe. Our team was responsible for the Silesia and Sub-Carpathia regions in southern Poland. In this presentation we will focus on the methane emission measurements from gas pipelines, storages, gas wells as well as gathering and processing facilities, which was realized by our team in years 2018-2020.&lt;/p&gt;&lt;p&gt;South eastern Poland is rather rural part of the country with rich history of oil and gas industry going back to the XVI-th century. Currently Carpathians and Carpathian Foredeep regions gas industry produces 1.35 BILLIONS of m&lt;sup&gt;3&lt;/sup&gt; [1]&lt;/p&gt;&lt;p&gt;The measurements have been carried out since summer 2016 mainly with Micro-Portable Greenhouse Gas Analyzer &amp;#8216;Los Gatos Research, MGGA-918&amp;#8217; mounted on board of a car. We also had capability to deploy analyser in difficult terrain with its own power supply. During our measurements our team visited over 300 gas wells. We found that over half of these sites show elevated methane concentrations which can be attributed to either gas well itself or soil fractures around site. Transects paths were designed to follow pipelines. This allowed us to monitor possible leaks from the natural gas infrastructure. However there are numerous possible sources in close proximity of pipelines. We will discuss detection methods and variability study for dozens of transects. As of the 2017 only 9 gathering and processing facilities report release which states the emission of 1.8*10&lt;sup&gt;6&lt;/sup&gt; m&lt;sup&gt;3&lt;/sup&gt; CH&lt;sub&gt;4&lt;/sub&gt; per year. One of the focus points of our project was to estimate how uncertain were methane emission from O&amp;G in Poland which at current phase concludes methane emission of 7.5-40 kt CH4/year&lt;/p&gt;&lt;p&gt;During the presentation we will outline challenges in carrying out measurements with GPM, OTM 33a methods that were performed alongside large-area screening. We are developing oversized flow chamber method. Mobile structure is built in the shape of a dome. It has the radius of 3 meters which gives the chamber volume of 49 m&lt;sup&gt;3&lt;/sup&gt;.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;This work was funded under the Climate and Clean Air Coalition (CCAC) Oil and Gas Methane Science Studies.&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;[1]PSG, &amp;#8222;Bilans zasob&amp;#243;w z&amp;#322;&amp;#243;&amp;#380; kopalin w Polsce wg stanu na 31 XII 2019 r,&amp;#8221; PIG-PIB, Warsaw, 2020.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;

SILURIAN REEF OF THE LEDYANSK UPLIFT AS A POTENTIAL RESERVOIR OF HYDROCARBONS IN THE NORTH OF THE SIBERIAN PLATFORM

2020 ◽  
pp. 13-22
Author(s):  
I. A. Varaksina ◽  
Keyword(s):  
Siberian Platform ◽  
Oil And Gas ◽  
High Capacity ◽  
Reservoir Properties ◽  
The North ◽  
Formation Stage ◽  
Potential Reservoir ◽  
Upper Silurian ◽  
Primary Porosity ◽  
Gas Potential

The results of the lithological study of the Silurian sediments drilled in by wells within the Ledyansk uplift in the north of the Siberian platform are presented. It is found that in the early Silurian time on the territory under consideration a large organogenic buildup corresponding to typical Silurian reefs of a stable shelf was formed, the formation stage of its framework was confined to Wenlock. In Late Silurian, against the background of regression, the reef formations were overlain by lagoon-sebkha clayey-evaporite deposits. It is shown that the heterogeneity of the section affected the distribution of reservoir properties. The high primary porosity of the reef framework contributed to the processes of dissolution, stylolization, fracturing and formation of a high-capacity reservoir. The combination of various voids led to the development of a complex reservoir. The saline-sulfate rocks of the Upper Silurian – Lower Devonian act as a seal. The question of the prospects for the oil and gas potential of the Silurian reef deposits is of particular relevance in view of the wholesale development of organogenic buildups on the Siberian platform in the Wenlock time.

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