bluuebunny/crossref_metadata_2025 huggingface dataset:
A NEW MODEL FOR THE HUTTON/BIRKHEAD RESERVOIR/SEAL COUPLET AND THE ASSOCIATED BIRKHEAD-HUTTON(!) PETROLEUM SYSTEM
Authors: Boult P.J. , Lanzilli E. , Michaelsen B.H. , McKirdy D.M. , Ryan M.J.
Published: August 2017

Biomarker analysis of source rocks and oils from the Permian and Jurassic of the central Patchawarra Trough and the Gidgealpa area, reveal that much of the oil in the Eromanga Basin may have a significant lateral migrational component and be of Jurassic (i.e. intra-Eromanga) origin. Differences in hopane signatures can be used to discriminate between palaeo-oil and presently migrating live oil, and to constrain migration pathways. Thus, in some locations the identification of new source kitchens has been made possible by a combination of seal and biomarker analysis taking into account stratigraphic inheritance on conventional structural drainage maps. 3D seismic, sequence stratigraphy, dipmeter interpretation and neodymium model age dating together with conventional correlation techniques, have provided a new model for the deposition of the Hutton Sandstone to Birkhead Formation transition in the Eromanga Basin. Analysis of seal and carrier bed properties through time, in combination with hydrocarbon geochemistry and thermal modelling, indicates that the Birkhead-Hutton (!)' petroleum system has produced significant quantities of oil in the Cooper Basin sector of the Eromanga Basin.A disconf ormity near the base of the Hutton/Birkhead transition has controlled the location of oil-prone source rocks within the Birkhead Formation and stratigraphically focussed migration along palaeo-topographic ridges. A diachronous influx of volcanic-arc-derived (VAD) sediment within the Birkhead Formation has been traced right across the productive part of the Eromanga Basin. This influx of VAD sediment is associated with the main seal to underlying accumulations within both the lower Birkhead Formation and Hutton Sandstone. Sands comprising VAD sediment, which are juxtaposed, form the weak link within the main seal. The sediments between the VAD influx and the underlying unconformity in many locations constitute a waste zone.Palaeo-oil columns are common beneath extant, live oil accumulations. This indicates that a possible decrease in seal potential of the VAD sediment has occurred over time. The main seals to underlying accumulations were originally static, water-wet capillary seals which, mostly through an alteration of wettability, changed to simple permeability seals for currently migrating oil. Seal analysis, biomarker studies and geothermal modelling indicate that a double migration pulse has occurred in some areas of the Eromanga Basin. Palaeo-oil columns are related to a Late Cretaceous charge, and live oil accumulations to presently migrating oil.
NOVEL PRODUCTION CONCEPTS FOR DEEP WATER AND ASSOCIATED HYDRODYNAMIC PROBLEMS
Authors: Thiagarajan K.P.
Published: August 2017

Offshore oil and gas production is now reaching to great depths, in excess of 1000 m, in the Gulf of Mexico and the Campos Basin, offshore Brazil. It will not be long before Australian companies look towards probable reserves in deeper waters that still remain within the Australian exclusive economic zone. Production concepts for deep and ultra deep water thus need to be studied and researched, and a constant watch should be maintained on developments around the world in this area.This paper presents two popular, and constantly evolving, concepts for deep water, namely: tension leg platforms (TLP) and spars. Tension leg platforms have been in existence for about 14 years, and are actively sought for deep water by worldwide operating companies. They are vertically moored by means of taut tethers which present interesting motion characteristics and unique hydrodynamic problems. Spar platforms are currently being installed for production purposes. These are large deep draft cylindrical structures moored by catenary or taut spread mooring systems. Physical details, advantages and limitations of both systems are discussed.While many aspects of these production systems are now understood, there are still several unknowns. Deeper waters translate to newer problems. Potential problems of the future are discussed in this paper, and research needs are highlighted.
THE IMPACT OF RECENT NATIVE TITLE DEVELOPMENTS UPON PETROLEUM EXPLORATION AND PRODUCTION
Authors: Williamson Professor Douglas
Published: August 2017

Native Title Act 1993 (Cth)—acknowledged defects-proposed amending legislation—right to negotiate process—offshore and onshore exploration and development distinguished—obligations other than under NTA not to interfere unduly with offshore native title rights—onshore right to negotiate process—criteria—availability of expedited procedure to enable proposed activity to proceed—recent decisions limiting practical availability of expedited procedure—Cox and Western Australia and Stirling Resources NL and others (NNTT, 27 October 1997)—proposed amendments to right to negotiate process—importance of amendments to petroleum explorers and developers.
OIL AND GAS INDUSTRY IN WESTERN AUSTRALIA
Authors: Meaton M.
Published: August 2017

The oil and gas production sector in Western Australia has grown dramatically in recent years and now represents the largest resource sector in the State economy. The industry has a very promising future but it faces a number of challenges if it is to achieve its full potential. Its production location in remote parts of the State confers both advantages and disadvantages. Chief among the disadvantages is the challenge of convincing the community and government of the benefits from the industry when many of those benefits are not apparent to the majority of the population. The emphasis in this paper is on economic impacts, social benefits and community attitudes.WA has produced about 820 million barrels of oil and 2000 million barrels of natural gas when gas is calculated in energy equivalent terms. Petroleum energy production has increased dramatically over the last 15 years and the State is now a substantial energy exporter. Petroleum sources provide the energy for over 85% of the final energy used in the State. Total industry investment over the last 18 years has been nearly $21,000 million for an average of $3.2 million each day. Direct employment by petroleum companies is around 2,500 people with flow-on employment in the services sector estimated at over 17,000 people. Petroleum companies have been major contributors to government revenue and to the development of remote regions in WA.
THE ORIGIN AND INFLUENCE OF OVERPRESSURE WITH REFERENCE TO THE NORTH WEST SHELF, AUSTRALIA
Authors: Swarbrick R.E. , Hillis R.R.
Published: August 2017

The dominant cause of overpressure in basins is rapid loading of fine-grained sediments in which incomplete dewatering leads to additional overburden load being supported partly by the pore fluids. The principal controls on the magnitude of overpressure created are permeability and compressibility of the fine-grained rocks, coupled with the loading or sedimentation rate. High magnitude overpressure requires rapid sedimentation and/or evolution of sediment permeability to nanoDarcy values at shallow depth. By contrast, most fluid expansion mechanisms can be shown to be ineffective at generating large magnitude overpressure at realistic basin conditions. Only gas generation (either directly from kerogen or by oil to gas cracking) has the potential to create large magnitude overpressure, and only if the connected reservoir volume is very restricted.The origin of overpressure in the North West Shelf, especially the Northern Carnarvon Basin has previously been suggested to be due to petroleum generation, principally because the top of overpressure is coincident with, or lies below, the hydrocarbon generation window. To achieve high magnitude overpressure by this mechanism requires large volumes of gas generative source rocks connected to reservoirs of extremely limited extent. The volume of reservoir rocks in the basins is relatively high, and gas generation appears to be only a secondary mechanism. The most likely origin of overpressure is burial of the Jurassic and Lower Cretaceous group sediments (including the Muderong Shale) with early development of the Muderong Shale as a pressure seal. Lateral stress cannot be discounted as an additional mechanism of overpressure generation. However, lateral strain appears to be significantly less than vertical strain.Overpressure has the potential to influence the petroleum system in the North West Shelf if there has been high magnitude overpressure for prolonged periods of geological time. Normally pressured units today may have had a history of overpressure in the geological past. Reservoir quality can be enhanced by overpressure, but trap seal integrity either strengthened or weakened by overpressure. Timing of maturation and migration of hydrocarbon can also be affected.
BARROW ISLAND OIL FIELD
Authors: Ellis G.K. , Pitchford A. , Bruce R.H.
Published: August 2017

The Barrow Island Field in the Barrow Sub-basin of the Carnarvon Basin was discovered in 1964 by West Australian Petroleum Pty Limited. It is the largest oil field in Western Australia. Appraisal drilling has defined in-place oil of 200 GL (1,250 MMBBL) and in-place gas of 16.5 Gm3 (580 BCF) primarily in the Lower Cretaceous Windalia Sand Member of the Muderong Shale and in- place gas of 14.5 Gm3 (515 BCF) in Middle Jurassic Biggada Formation. Additional hydrocarbon reservoirs have been discovered, including oil and gas in the Upper Jurassic Dupuy Formation, the Lower Cretaceous Malouet Formation, Flacourt Formation and Tunney Member, Mardie Greensand Member and M zones of the Muderong Shale and in the Upper Cretaceous Gearle Siltstone. Approximately 850 wells have been drilled to appraise and develop these accumulations, and to provide water source and water injection wells to enhance recovery. Production commenced in December 1966, with the first shipment of oil in April 1967. Although numerous hydrocarbon reservoirs have been developed, 95% of the 44 GL (278 MMBBL) of produced oil has been from the Windalia Sand.Structural development of the Barrow Island anticline occurred initially during the Middle Jurassic and continued intermittently during the Cretaceous and Tertiary. Initial charging of the Dupuy and Malouet formations with oil from the Upper Jurassic Dingo Claystone occurred in the Early Cretaceous prior to the development of the shallower closures. Periodic wrench- related movement on the Barrow Fault during the Early to Late Cretaceous produced closures at the Lower Cretaceous reservoirs and provided a catalyst for oil migration and charging of these closures. Significant amounts of an extremely biodegraded component, and several less biodegraded phases are present in the oil in the Windalia Sand, indicating several phases of oil charging of the Barrow structure from Middle and Upper Jurassic sediments. In the Tertiary, gas sourced from Triassic and Jurassic sediments migrated into the Barrow structure via a dilated Barrow Fault, charged the Middle Jurassic Biggada Formation and displaced some of the oil in the Lower Cretaceous reservoirs.
THERMAL HISTORY MODELLING AND TRANSIENT HEAT PULSES: NEW INSIGHTS INTO HYDROCARBON EXPULSION AND 'HOT FLUSHES' IN THE VULCAN SUB-BASIN, TIMOR SEA
Authors: Kennard J.M. , Deighton I. , Edwards D.S. , Colwell J.B. , O'Brien G.W. , Boreham C.J.
Published: August 2017

Thermal history data from wells in the Vulcan Sub- basin and adjacent platforms show clear evidence that many reservoir sections have experienced relatively shortlived, high- temperature flushes during the Late Tertiary. These transient heat pulses are related to slow migration of hot fluids and hydrocarbons from adjacent depocentres, or rapid flow of deep-seated brines during Late Miocene- Early Pliocene tectonic reactivation. The hot fluids have been focussed into structured reservoir sections via high- permeability pathways and reactivated faults. As a consequence, most exploration wells are not truly representative of the thermal regime of nearby source kitchens.In order to constrain the regional thermal and expulsion history of the region, and to address the issue of thermal pulses, burial history analysis of 44 wells and 18 depocentre sites was carried out. This analysis utilises a simplified transient heat pulse model developed as part of the WinBury™ burial and thermal geohistory modelling software. The transient and steady-state thermal history models are constrained by reflectance and fluorescence maturity data, together with apatite fission track analysis and fluid inclusion palaeo-temperature data.
THE STAG OIL FIELD FORMATION EVALUATION: A NEURAL NETWORK APPROACH
Authors: Crocker H. , Fung C.C. , Wong K.W.
Published: August 2017

The producing M. australis Sandstone of the Stag Oil Field is a bioturbated glauconitic sandstone that is difficult to evaluate using conventional methods. Well log and core data are available for the Stag Field and for the nearby Centaur–1 well. Eight wells have log data; six also have core data.In the past few years artificial intelligence has been applied to formation evaluation. In particular, artificial neural networks (ANN) used to match log and core data have been studied. The ANN approach has been used to analyse the producing Stag Field sands. In this paper, new ways of applying the ANN are reported. Results from simple ANN approach are unsatisfactory. An integrated ANN approach comprising the unsupervised Self-Organising Map (SOM) and the Supervised Back Propagation Neural Network (BPNN) appears to give a more reasonable analysis.In this case study the mineralogical and petrophysical characteristics of a cored well are predicted from the 'training' data set of the other cored wells in the field. The prediction from the ANN model is then used for comparison with the known core data. In this manner, the accuracy of the prediction is determined and a prediction qualifier computed.This new approach to formation evaluation should provide a match between log and core data that may be used to predict the characteristics of a similar uncored interval. Although the results for the Stag Field are satisfactory, further study applying the method to other fields is required.
LEGENDRE: MATURATION OF A MARGINAL OFFSHORE OIL DISCOVERY TO DEVELOPMENT PROJECT
Authors: Willetts J.M. , Mason D.J. , Guerrera L. , Ryles P.
Published: August 2017

Commercialisation of the Legendre hydrocarbon resources represents the culmination of over 30 years of exploration and appraisal and more recent development planning, following the discovery by the first well to be flow-tested on the North West Shelf, Legendre–1, in 1968. By application of 3D seismic, reservoir modelling and simulation techniques, horizontal drilling and innovative development options, the WA-l-P Joint Venture is confident of achieving an economic return on a relatively small resource base.The two separate accumulations, Legendre North and Legendre South, are together expected to contain some 14 million m3 (90 MMSTB) of oil-in-place. The oil column in the northern accumulation is 45 m at its maximum, whilst a 20 m column is present in the southern accumulation. Reservoir quality is generally very good with mostly massive sandstones with little or no internal stratification. The reservoir contains a light oil and aquifer support is expected from communication with the underlying Angel Formation sandstones.The subsurface development plan has been designed to optimise the recovery of the oil in place in the two accumulations. Production wells with horizontal sections of 750 m will be used to minimise drawdown and ensure good sweep. Production is expected at a plateau rate of 4,800 to 6,400 m3/d (30−40,000 BOPD). Produced gas will be disposed of by means of a re-injection well downdip of the producers.
BIOCHEMICAL AND CHEMICAL PARAMETERS FOR AQUATIC ECOSYSTEM HEALTH ASSESSMENTS ADAPTED TO THE AUSTRALIAN OIL AND GAS INDUSTRY
Authors: Gagnon M.M. , Grice K. , Kagi R.I.
Published: August 2017

Field assessments using biochemical and chemical markers in marine organisms will be necessary to provide the Australian Petroleum Industry with a realistic evaluation of the impact of their activities on the marine environment. In field investigations, wild or caged animals are sacrificed and their organs are collected in order to assess if industrial activities do have a significant adverse impact on the organisms' health. Biochemical markers of chronic exposure to contamination may include reversible effects such as induction of a detoxification system, or permanent effects such as damage to nuclear DN A. Studies of sentinel species using biochemical markers of exposure, complemented by chemical analyses provide a realistic holistic method for assessment of environmental health. This multidisciplinary approach has proven valuable in Europe and North America.This paper outlines the need for biochemical and chemical markers to assess environmental health in a dynamic milieu such as the North West Shelf of Australia. Selected biochemical markers for use by the oil and gas industry in field monitoring of ecological health, and the complementary chemical measurements focussed on persistent contaminants such as poly eye lie aromatic hydrocarbons (PAHs), are described. The biological and ecotoxicological significance of the biochemical markers applied in sentinel marine organisms is reviewed, and some limitations regarding their interpretation are stated. It is suggested that biochemical monitoring of the environment complemented with sophisticated chemical measurements can provide environmental managers working within the oil and gas industry with a system for ecotoxicological monitoring programs in offshore Australia.
PUBLIC ENVIRONMENTAL REPORTING FOR THE OIL AND GAS INDUSTRY
Authors: Wright R.A.D.
Published: August 2017

Acceptance by governments and the public is crucially important for high profile oil and gas exploration and production companies. Many people are pre-disposed against such companies because the environmental and social impacts of their activities are perceived to outweigh the benefits. Leading multi-nationals such as the Royal Dutch/Shell Group have seen the benefits of a recent concerted effort to engage their stakeholders. Shell and other multi-nationals are using public environmental reporting as a means of better communicating their performance. Public environmental reporting has been slow to be adopted in Australia but there may be advantages for oil and gas companies in Australia to be seen to be leaders in this field rather than laggards, particularly with the advent of compulsory public reporting as required by the National Pollutant Inventory.
THE PERSISTENCE AND EFFECTS OF NON-WATER-BASED DRILLING FLUIDS ON AUSTRALIA'S NORTH WEST SHELF: PROGRESS FINDINGS FROM THREE SEABED SURVEYS
Authors: Oliver G.A. , Fisher S.J.
Published: August 2017

The effects and persistence of non-water-based drilling fluids discharged into the marine environment were investigated at three locations on Western Australia's North West Shelf (NWS), namely the North Rankin 4A' (NRA) drilling platform, the Wanaea–6 production well and the Lynx–la exploration well. For the multiple-well drilling operation at NRA, acute biological effects at the completion of drilling were restricted to within 400 m in the direction of the prevailing current. High total petroleum hydrocarbon (TPH) concentrations within the NRA cuttings pile persisted between 1991 and 1993. Away from the cuttings pile itself, a consistent downward trend in TPH concentrations was evident, indicating an approximate half-life of one year for surface sediments. Three years after the completion of drilling at Wanaea–6, biological effects appeared to be limited to within 100 m of the cuttings discharge point, with background concentrations of TPH and trace metals occurring near 1,200 m in the direction of the prevailing current. Sediment hydrocarbon concentrations greater than 1 mg/kg were found to be restricted to within 200 m of the cuttings discharge point. Dramatic reductions in TPH and barium concentrations occurred in the 12-month period between the completion of drilling and the follow- up survey at Lynx–la. The reductions are attributed to sediment dispersal mechanisms which appear to play a major role in reducing sediment TPH and trace metal concentrations in mid-shelf water depths (70–80 m) on the NWS. The installation and presence of subsea production facilities may result in sediment redistribution and changed dispersal mechanisms, complicating the interpretation of the presence of contaminants within sediments.
LNG - PAST, PRESENT AND FUTURE
Authors: Dighton P.F.
Published: August 2017

The first 30 years of LNG export witnessed the development of large movements of natural gas between countries, underpinned by long-term sales contracts and strong relationships. Now the industry has matured, but is faced with the quantum leap of achieving commoditisation of LNG. This would require a break away from long-term contractual ties and the emergence of merchant shipping and merchant plant. This paper examines this trend and the impact upon future Australian exports in the context of emerging markets, low oil prices and intense competition.
PRODUCTION AND DEVELOPMENT HIGHLIGHTS IN 1998
Authors: Goodacre J.
Published: August 2017

1998 was a year of challenges and opportunities. A number of new significant developments started production, oil prices thudded to low levels in real terms and production of oil and LPG continued to grow by around 6%. This paper reviews the events of 1998, highlights the growth in production capacity and notes the innovations that have been implemented in the Australian environment. Clearly, despite difficult conditions, the industry in 1998 provided energy for growth.
RECENT EXPLORATION ACTIVITY IN NEW ZEALAND
Authors: Plume R.W.
Published: August 2017

The past 18 months in New Zealand have seen a relatively high level of exploration activity. A certain degree of cyclicity is part of the NZ exploration scene and derives from the fact that the industry in NZ is small and also from the nature of the permit regime. Significant developments during the period have been the discovery of commercial production outside the Taranaki Basin (the Kauhauroa field in the East Coast Basin) and the rediscovery of a potentially commercial oil accumulation in the Taranaki Basin (Maari). The level of activity is expected to continue at about the current level for at least the remainder of 1999.
EXPLORATION OPPORTUNITIES, EAST COAST BASIN, NEW ZEALAND
Authors: Frederick J.B. , Davies E.J. , Smith P.G. , Spancers D. , Williams T.J.
Published: August 2017

The Westech-Orion Joint Venture holds onshore Petroleum Exploration Permit 38329 and offshore PEPs 38325, 38326 and 38333 in the East Coast Basin, New Zealand. The Joint Venture holds 24,117 km2 covering Hawkes Bay and the Wairarapa shelf.The Westech-Orion Joint Venture has drilled six exploratory wells and five appraisal wells in the onshore East Coast Basin over a two year period. All wells encountered significant gas shows, with two wells discovering hydrocarbons in potentially commercial volumes. Each well was drilled on the crest of a seismically mapped structure, characterised by asymmetric folding over a northwest dipping thrust fault.Prior to this drilling program, the reservoir potential of the Wairoa area was inferred to be dominated by turbidite sandstones of the Tunanui and Makaretu formations (Mid-Late Miocene). The new wells show that the Mid Miocene and parts of the Early and Late Miocene pinch out across the 'Wairoa High'.One of the primary onshore reservoirs is the Kauhauroa Limestone (Early Miocene), a bryozoan-dominated, tightly packed and cemented limestone with dominantly fracture porosity. The other primary reservoir is the Tunanui Sandstone (Mid Miocene), which in well intersections to date comprises medium-thickly bedded sandstone, with net sand typically 40%. The sands have high lithic content, and are moderately sorted and subangular-subrounded.Abnormally high formation pressures were encountered in all wells, ranging up to 3,400 psi at 1,000 m. Crestal pressure gradients commonly exceed 70% of the lithostatic pressure gradient, despite the relative proximity to outcrop. The overpressure may reflect relatively young uplift of fossil pressures, with insufficient time for pressure equilibration within a generally overpressured system.The prospectivity of the area has been highgraded by recent maturation and reservoir studies in Hawkes Bay and by gas discoveries in Westech-Orion wells onshore northern Hawkes Bay. Maturation studies identified nine kitchen areas with oil migration commencing in the Late Miocene. Seismic stratigraphy and correlation with onshore wells identified offshore submarine fan deposits of Eocene, Early Miocene, Mid Miocene and Pliocene age.A 594 km2 exploration 3D seismic survey was acquired in Hawke Bay in April 1999, and 685 km of 2D seismic were acquired in March 2000. Preliminary interpretation of the 3D survey has yielded five prospects, each covering 20–90 km2. One prospect is a lowstand fan identified by stacked mounding and bidirectional downlap, correlated with the onshore Mid Miocene Tunanui Sandstone. High amplitude seismic events of Mid-Late Miocene ages are inferred to be pulses of submarine fan development, in places associated with direct hydrocarbon indicators (DHIs). High amplitude seismic events in the Pliocene include a package of high amplitude seismic reflectors interpreted as structurally trapped DHI truncated by a major unconformity.
DEEP-WATER OTWAY BASIN: A NEW ASSESSMENT OF THE TECTONICS AND HYDROCARBON PROSPECTIVITY
Authors: Moore A.M.G. , Stagg H.M.J. , Norvick M.S.
Published: August 2017

The northwest-trending Otway Basin in southeast Australia formed during the separation of Australia and Antarctica between the latest Jurassic and the Early Cainozoic. A new, deep-seismic data set shows that the basin comprises two temporally and spatially overlapping rift components:the mainly Late Jurassic to mid-Cretaceous, east-west trending, inner Otway Basin—comprising the onshore basin and most of the continental shelf basin; andthe northwest–southeast to north–south trending depocentres beneath the outer shelf and continental slope, extending from eastern South Australia to the west coast of Tasmania, and a relatively minor and ill-defined sub-basin underlying the continental rise in water depths greater than about 4,500 m. This rift system was most active from the mid-Cretaceous to Palaeogene, and was strongly affected by sinistral strike-slip motion as Australia and Antarctica separated.The continental slope elements contain the bulk of the sediment volume in the basin. From northwest to southeast, these elements comprise the Beachport and Morum Sub-basins, the north-south trending Discovery Bay High, and the Nelson Sub-basin which appears to be structurally and stratigraphically continuous with the Sorell Basin off west Tasmania.The reflection character of the crust and upper mantle varies widely across the basin, and there is a strong correlation between that character and the basin configuration. It appears that accommodation space beneath the slope basin was created largely by extension and removal of most of the laminated deep continental crust.There is encouragement for hydrocarbon exploration in the deep-water basin. Firstly, there are indications of diagenesis related to fluid flow in and above the strongly faulted Cretaceous section in the Morum Sub-basin. As an Early Cretaceous petroleum system is already proven beneath the continental shelf, this suggests that the same system is also active in deep-water. Secondly, existing sample data suggest that a second, Late Cretaceous petroleum system could be active where any source rocks are sufficiently deeply buried; this condition would probably be met in the Nelson Sub-basin.
FAULT ARCHITECTURE ANDTHE MECHANICS OF FAULT REACTIVATION INTHE NANCARTROUGH/LAMIN ARIA AREA OF THE TIMOR SEA, NORTHERN AUSTRALIA
Authors: Trupp M.J. de Ruig M. , Bishop D.J. , Kuek D. , Castillo D.A.
Published: August 2017

Fault-bounded Jurassic structures of the Timor Sea have in recent years been the focus of intensive oil exploration. A number of significant oil discoveries have highlighted the exploration potential of this area (e.g. Laminaria, Corallina, Buffalo, Elang, Kakatua), but the majority of tested structures are either underfilled or show evidence of a residual oil column, resulting from trap failure of previously hydrocarbon-bearing structures. Recent well results confirm that trap integrity remains the principal exploration risk in the Timor Sea.Fault reactivation of Jurassic hydrocarbon traps is related to late Miocene-Pliocene oblique collision between the Australian plate and the SE Asian plate complex, which caused widespread transtensional faulting. The sealing potential of fault-bounded traps is, to a large degree, controlled by the orientation of the fault plane relative to the late Miocene-Recent stress field. However, the location of potential hydrocarbon leakage pathways remains difficult to define due to the complex fault architecture and a limited understanding of the interaction between Jurassic faults and Late Tertiary tectonism.During the past few years, a wealth of new exploration wells and 3D seismic data has become available from the Laminaria High/Nancar Trough area. The use of 3D visualisation tools, seismic coherency filtering and other seismic techniques has greatly enhanced our understanding of the fault architecture of this area of the Timor Sea.The structural architecture of the Nancar Trough/ Laminaria High is made up of several different structural intervals that are stratigraphically separated and partially decoupled along thick claystone intervals. Fault blocks at Jurassic level are typically overlain by Tertiary en-echelon graben systems, often showing characteristic 'hourglass' structures in cross-section. Detailed mapping of these fault structures on 3D seismic data has shown that the Jurassic faults and overlying Tertiary faults areoften partially decoupled.Fault throw distributions indicate that the Mio-Pliocene faults have grown downwards instead of Jurassic faults propagating upwards during reactivation. The two fault systems are soft-linked within Cretaceous claystones, only locally linking to form through-going faults. Hydrocarbon leakage pathways are most likely located at these points where critically stressed parts of Jurassic faults link up with Tertiary faults. The position of these linkage zones in relation to structural closure is key to understanding the distribution of preserved and breached columns that have been observed to date.The integration of 3D seismic fault plane mapping with in-situ stress analysis from borehole image and pressure test data provides a valuable tool for the evaluation of trap integrity, potential hydrocarbon leak paths and a more accurate risk assessment of exploration prospects.
CONTROLS ON SEASPRAY GROUP SONIC VELOCITIES IN THE GIPPSLAND BASIN—A MULTI-DISCIPLINARY APPROACH TO THE CANYON SEISMIC VELOCITY PROBLEM
Authors: Holdgate G.R. , Wallace M.W. , Gallagher J. Daniels S.J. , Keene J.B. , Smith A.J.
Published: August 2017

Seaspray Group carbonate sediments of Oligocene to Recent age overlie the main hydrocarbon producing Upper Cretaceous to Eocene Latrobe Group in the offshore Gippsland Basin. Their sonic complexity creates major difficulties for hydrocarbon exploration. Carbonate facies are divisible into three subgroups based on seismic character, sonic logs, velocity profiles, carbonate content, petrologic character and age. The oldest unit is the Angler Subgroup that consists of carbonate pelagic marls (CaC03 70%) with interbedded clastic-rich units.Zones of high velocity (>3,000m/s) are restricted to the deeply buried parts of the Albacore Subgroup, at TWT's greater than 0.8 seconds. The characteristics of this high velocity facies are: a composition of fine grained bioclast-rich packstones and wackestones with less than 10% silt sized quartz; the carbonate content exceeds 60%; the intervals are prone to cementation and are stylolitised; they are diachronous (i.e. cut across seismic boundaries); velocities progressively increase with depth; highest velocities occur where the unit is thickest towards the centre of the basin; velocity increases laterally with steepness of angle on downlap surfaces due to coarser grain sizes and inferred greater initial porosity; and velocities increase with stratigraphic age in the Albacore Subgroup. Regardless of burial depth the Angler and Hapuku Subgroups contain no significantly high velocity zones.An empirical relationship derived from this data set provides a basis for re-interpreting average velocity to the top of the Latrobe Group in areas underlying high velocity canyon-fill sediments.
THE 3-C ACOUSTIC PROCESS—A NEW APPROACH TO PREDICTING ACOUSTIC WAVE PERFORMANCE IN SEDIMENTS
Authors: Wiltshire M.J. , Huggard L.M.
Published: August 2017

Acoustic wave performance modelling is of considerable interest to seismic interpreters. Conventional interpretative models employ continuous density log data to compute theoretical acoustic data. Their dependence on high quality density log data limits the application of these techniques to areas where good logs have been acquired. Such techniques are therefore commonly used in field studies, but are generally not used in exploration.This paper details a newly developed method of predicting acoustic compression wave performance, based on sequence compaction theory, elastic wave theory and established petrophysical relationships. This allows extension of the existing density log based p-wave velocity prediction methods into areas where log data are minimal and log quality is marginal.Applications of the technique include:improvements to the quality of acquired sonic data;improved velocity control, resulting in better quality synthetic seismograms and more precise control of time-depth conversion; andimproved seismic attribute mapping, offering possibilities of better drilling target selection.With application of the technique, many wells can now be used in which poor log data quality or absence of key logs previously prevented their use as well-to-seismic control points in basin modelling. The technique can be allied to MWD resistivity logging technology to allow continuous computation of acoustic properties and realtime correlation of drilling data to seismic. This results in better location of casing and logging points, and the design of more efficient logging programs, with benefits to both drilling safety and economics.The technique allows improvement in the quality of acquired data and acquisition economics, better utilisation of old data, and better engineering and geologic management practices in current exploration drilling. It has considerable potential for overcoming sonic log acquisition problems associated with poorly compacted rocks, and has application in many areas of sequence and basin studies.
TECHNICAL CHALLENGES IN THE DEVELOPMENT OF UNCONVENTIONAL GAS RESOURCES IN AUSTRALIA
Authors: Johnson R.L. , Jr  , Hopkins C.W. , Zuber M.D.
Published: August 2017

Unconventional gas resources, defined as low- permeability sandstone, coal seam and naturally- fractured shale gas reservoirs, represent a huge potential resource for future natural gas supply in Australia and around the world. Because low individual well-production rates are often the norm, unconventional reservoir development may involve the drilling of hundreds of wells to make the economics attractive. Thus, careful planning, sound development strategies and cost control are critical for project success.Virtually all unconventional gas resources must be stimulated to be economic; stimulation costs are often the most significant amount of the total well expenditure. Thus, a cost-effective method for reservoir characterisation and fracture treatment optimisation is required. Because of marginal economics, techniques used to analyse the process and results are often oversimplified; this can lead to confusing or inadequate descriptions of the complex behavior of a hydraulically-fractured, low- permeability reservoir and in some cases bad development decisions. Detailed data collection programs and fracture treatment optimisation strategies are essential to adequately address the technical issues involved in unconventional reservoir development.Besides the technical challenges associated with unconventional gas development, good forethought is necessary as to the planning and execution of the overall project. The development scenarios for coal seam and low-permeability sandstone gas resources are highly statistical and succeed or fail based on the average performance of the group of wells within the project. Following proven guidelines and methods during development while integrating key technologies into the planning and optimisation process are essential for success in unconventional reservoir development.
LOW COST FLOATING PRODUCTION FACILITY CONCEPTS FORTROPICAL WATERS
Authors: Rathie L.C. , Hogan G.F. , Paton M.J.
Published: August 2017

A number of floating production facility concepts can be readily applied to the development of small and marginal oilfields in moderately deep tropical waters. These concepts can be used to extend the lives of existing mature fields. They can be deployed for a significant cost reduction compared with a conventional full field development provided that boundary limits for application of the concepts are not exceeded.Simple, standardised, reliable and proven equipment should be utilised that may be deployed in innovative ways. Wherever possible, existing equipment should be used and rented where this is economical.Marginal field projects should be managed and operated by small organisations competent in these activities to minimise overheads and maximise flexibility.An inter-field transfer approach (Ocean Truck) offers many options for developing a number of such projects as part of an area development strategy.Cooperation between operators, both as partners in a particular project and in different projects where the same facilities can be used sequentially or in parallel, can be an effective means to control costs and ensure that small oil accumulations are developed.
RESERVOIR GEOMECHANICS APPLIED TO DRILLING AND COMPLETION PROGRAMS IN CHALLENGING FORMATIONS: NORTHWEST SHELF, TIMOR SEA, NORTH SEA AND COLOMBIA
Authors: Castillo D.A. , Moos D.
Published: August 2017

It has become increasingly clear to the oil and gas community that earth stresses at depth in sedimentary basins have a profound effect on wellbore stability. Drilling problems frequently occur due to severe mechanical instabilities at the borehole wall where stress amplification has exceeded the strength of the rock. This is because the rock surrounding the hole must support the stress previously supported by the material removed in the drilling process. Drilling problems associated with lost circulation often occur where the borehole has intersected critically-stressed natural fractures that are inherently prone to high fracture permeability. In order to design a drilling and completion program that eliminates or minimises these mechanical instabilities in the borehole, it is essential to understand the interaction between the stress field, pore pressure, natural fractures, rock strength, mud weight, and borehole trajectory.In some cases wellbore performance can be maximised by selecting an optimal trajectory through the reservoir that can be drilled near balanced or under-balanced to minimise the formation damaging effects of mud infiltration, while other trajectories may require more aggressive drilling parameters. In these situations a well-constrained stress field is essential for determining the appropriate mud window to control compressive failure leading to the development of wellbore breakouts and, at the same time, prevent catastrophic tensile failure leading to formation breakdown or fluid losses through natural fractures.This paper serves to illustrate how a well-constrained geomechanical model can be used to address a suite of drilling and completion problems. Case studies reviewed include; wellbore stability and completion practices in extended reach wells (North West Shelf), wellbore stability in vertical and deviated wells (North Sea); drilling and completions in complex geological environments associated with steeply-dipping bedded shales (Colombia), and lost circulation in highly fractured regions (Timor Sea).
ASSET KNOWLEDGE INTEGRITY MANAGEMENT (ASSET INTEGRITY MANAGEMENT FORTHETHIRD MILLENNIUM)
Authors: Clarke M. , Woolley K.J.
Published: August 2017

This paper presents a framework for introducing effective knowledge transfer across departments and disciplines at all stages of a project lifecycle, with the aim of improving the process of asset integrity in the Third Millennium.The tools of building a learning organisation are presented as a starting point for promoting a knowledge management culture that recognises that most of the valuable information resides with the people and needs a mechanism for capture.All too often, vital information remains with key people on the job because they simply do not have a means to transfer that knowledge into a system.Asset integrity knowledge management provides a framework to identify the key stages in the life cycle of an asset and how to share and capture knowledge at all stages to lead to significant benefits in managing asset integrity.
MAKING ALLIANCES WORK
Authors: Morton S.
Published: August 2017

Alliances. Partnerships. Joint ventures. Interdepartmental initiatives. Co-ops. Cross cultural projects. Call them what you will, a new wave of networked endeavours has swept through today's business environment, with companies and organisations collaborating now as never before. This collaboration occurs not only between non-competitive, similar business entities and legally-bound business associates, but between competitors and corporate 'odd couples' as well.Whether matters concern an alliance between companies of differing industries, a partnership with former competitors, or a quantum leap in internal collaboration, alliances can yield remarkable, measurable, profitable and heretofore impossible performance results. Success, however, calls for new ways of thinking and working. The environment within an organisation must foster openness, a willingness to develop new behaviours, set new precedents, create new possibilities and break new ground.In many cases, however, the preconceived notions of the alliance members about what is required for a sound alliance keep the venture from realising its hoped-for success. To build a successful alliance and sustain it through difficulties, challenges and conflict, the preconceived notions and common misconceptions surrounding alliances must be explored and alternative views generated.
FRONTIERS AND CHALLENGES FOR INSURERS AND BROKERS
Authors: Henderson S.J.L.
Published: August 2017

A worsening industry claims experience generated principally by a number of significant offshore construction losses, an increase in attritional losses from wells, and a firming of the reinsurance market has forced insurance brokers and underwriters to re-evaluate the largely conventional range of products and services which it has been providing to the energy exploration and production sector for decades.Challenges posed by advances in technology, environmental pressures, the new geographical frontiers and the inevitable convergence of the insurance and capital markets has committed the energy insurance industry to a course of product innovation and cooperation with new providers of risk treatment products.At the same time the industry must ensure that tried and tested products, which have evolved in line with innovations in the exploration field and which remain relevant, are retained and modified to ensure their continuing relevance and efficiency.The energy insurance market, once generally perceived to be conventional and slow to change, has recognised the needs of its clients and the need to generate dynamic change in parallel with the industry it serves.
IF QUANTIFIED RISK ASSESSMENT ISTHE ANSWER, ARE WE ASKING THE WRONG QUESTION?
Authors: Sullivan R.
Published: August 2017

Regulatory bodies in Australia are taking an increasing interest in quantified risk assessment for assessing the significance of risks to worker safety and the environment associated with oil and gas exploration and production. In principle, quantified risk assessment (QRA) provides an objective, independent assessment of the risks associated with a particular activity or development, thereby enabling risk management decisions to be better informed. However, there are significant uncertainties associated with QRA which limit its potential to contribute to decision making.This article considers the limitations of QRA in decision making and proposes a policy framework within which safety and environmental risks can be assessed and decisions made. The proposed framework considers issues such as uncertainty in QRA, risk communication, the role of regulatory bodies and the need for credibility in the QRA process. The role of QRA is seen as assisting in clarifying the implications of various courses of action for decisionmakers, assisting in making decisions on safety issues and bringing a structured and analytical approach to assessments.
AN INVESTIGATION OF BENTHIC SEDIMENT CHARACTERISTICS INTHEVICINITY OFTHE COSSACK PIONEER FPSO, NORTHWEST SHELF
Authors: Colman J.G. , West N.F.
Published: August 2017

Routine discharges from the Cossack Pioneer floating production storage and offloading facility (FPSO) on the North West Shelf include produced formation water (PFW) from the Wanaea-Cossack and Lambert-Hermes oil fields. PFW is the highest volume discharge from the FPSO and contains a variety of naturally occurring materials from the formation, including residual volatile and non-volatile hydrocarbons not removed by the separation process, trace metals, naturally occurring radioactive materials (NORMs) and process chemicals carried over from the production stream.In May 1999, a total of 22 sediment samples were collected at the Cossack Pioneer location, using a remotely operated vehicle (ROV) deployed from a support vessel. Sampling stations were located along four transects, aligned along and perpendicular to the prevailing current direction. The objective of this survey was to investigate the physical and chemical characteristics of benthic sediments in the vicinity of the Cossack Pioneer to determine whether there have been any significant inputs of trace metals, hydrocarbons and NORMs into benthic sediments as a consequence of PFW discharge from the facility.Trace metal concentrations were low in all the samples analysed, with levels at all sites generally below those detected at the control site, approximately 16 km from the Cossack Pioneer location. Low concentrations of TPH were detected in all of the samples, apart from the sample collected at the control site. These TPH levels were solely composed of a series of high molecular weight alkanes (C27−C34 n-alkanes) the distribution of which is not consistent with those commonly observed in crude oils, distilled petroleum fractions or synthetic oil- based drilling fluids. Concentrations of NORMs were also generally below those detected at the control site and were comparable with levels measured in uncontaminated sediments in the Gulf of Mexico.Overall, the concentrations of trace metals, TPH and NORMs measured in sediments adjacent to the Cossack Pioneer location did not indicate any significant anthropogenic input resulting from PFW discharge, and were below levels that have been shown to cause adverse biological effects in marine sediments.