bluuebunny/crossref_metadata_2025 huggingface dataset:
UNDERSTANDING AUSTRALIA’S PETROLEUM RESOURCES, FUTURE PRODUCTION TRENDS AND THE ROLE OF THE FRONTIERS
Authors: Powell T.G.
Published: August 2017

Relative to its needs over the last 30 years, Australia has enjoyed a high level of self-sufficiency. Whilst the overall remaining reserves of oil have been relatively constant, reserves of condensate have grown substantially as major reserves of natural gas have been added to Australia’s resource inventory. Oil and condensate reserves stand at 3.43 billion barrels (505 GL), of which 50% is condensate in gas fields. Australia’s undiscovered oil potential in its major offshore hydrocarbon producing basins has been upgraded to an indicative 5 billion barrels (800 GL) at the average expectation, following evaluation of the assessment results for Australia in the authoritative worldwide assessment of undiscovered potential by the US Geological Survey.Current reserves, however, are insufficient to sustain present levels of production in the medium term. Estimates of future production of oil and condensate suggest that at the mean expectation, production rates will drop by around 33% by 2005 and 50% by 2010, largely as a result of a decline in oil production. This forecast includes production from fields that have not yet been discovered. Condensate production will continue to grow, but the rate of growth is constrained by gas production rates and overall by the development timetable for the major gas fields.The rate of discovery of new oil fields is insufficient to replace the oil reserves that are being produced. If Australia is to maximise the opportunity to maintain production at similar levels to the recent past, it is probable that exploration effort will have to diversify to the frontier basins to locate a new oil province whilst continuing to explore the full potential of the known hydrocarbon-bearing basins. Australia still has a remarkable number of basins which have received little or no exploration. Whilst there is no substitute for a discovery to stimulate exploration in poorly known areas, demonstrating that petroleum has been generated and migrated is the key to attracting continued exploration interest.
NUMERICAL MODELLING OF OVERPRESSURE GENERATION IN THE BARROW SUB-BASIN, NORTHWEST AUSTRALIA
Authors: Bekele E.B. , Johnson M.D. , Higgs W.G.
Published: August 2017

A numerical basin modelling approach was used to investigate the hydrodynamics and development of overpressures in a Jurassic Prospect in the Greater Gorgon area of the Barrow Sub-basin. Abnormally large fluid pressures have been encountered by numerous exploratory wells in the Carnarvon Basin; however, the mechanisms responsible for overpressuring were uncertain. To better evaluate the risk of encountering overpressures while drilling Jurassic targets in the area, quantitative basin modelling was conducted. Groundwater flow, heat transfer, and hydrocarbon generation were simulated along two geologic cross-sections. Model results for the fluid pressure history of the Jurassic Prospect were constrained by hydrodynamic data from specific wells in the region. A series of modelling experiments was used to determine the relative significance of compaction disequilibrium, tectonic uplift, organic maturation and permeability on overpressure generation. Results indicate that compaction disequilibrium and the permeability of shale layers are the dominant controls on overpressures, while organic maturation does not contribute a significant amount to the pressure anomaly. Quantitative basin modelling applied to pressure prediction provides critical insight needed prior to drilling and well construction.
4D-READY SEISMIC WITH Q-MARINE
Authors: Brice T. , Larsen L. , Morice S. , Svendsun M.
Published: August 2017

A new concept for acquiring calibrated towed streamer seismic data is introduced through a new acquisition and processing system called ‘Q-Marine’. The specification of the new system has been defined by rigorous analysis of the factors that limit the sensitivity of seismic data in 4D studies and imaging. New sensor and streamer technology, new source technology and advances in positioning techniques and data processing have addressed these limitations.Sensitivity analysis revealed that the most significant perturbations to the seismic signal are swell noise and sensor sensitivity variations. Conventional analog groups of hydrophones are designed to suppress swell noise however a new technique for data-adaptive coherent noise attenuation delivers even greater noise suppression for densely spatially sampled single-sensor data.Although modern source controllers provide accurate airgun firing control, the signature of an airgun array may vary from shot to shot. This can be due to factors such as changes in the array geometry, air pressure variations, depth variations and wave action. A method for estimating the far-field signature of a source array is the Notional Source Method (proprietary to Schlumberger) which has been steadily refined since its first disclosure. A recent development compensates for variation in source array geometry by monitoring the position and azimuth of each subarray using GPS receivers mounted on the floats.New calibrated positioning and streamer control systems are part of the new acquisition system. Active vertical and lateral streamer control is achieved using steerable birds and positioning uncertainty is reduced through an in-built fully braced acoustic ranging system.Calibrated marine seismic data are achieved through quantifying the source output, the sensor responses and positioning uncertainty. The consequential improvements in seismic fidelity result in better imaging and more reliable 4D analysis.
BASS STRAIT GAS TO NEW SOUTH WALES—THE COMMERCIALISATION OF THE EASTERN GAS PIPELINE
Authors: Biggs D.A.J.
Published: August 2017

The Eastern Gas Pipeline is an 18-inch diameter pipeline running from Longford in Victoria to Horsley Park in Sydney, New South Wales—a distance of some 795 kms (Fig. 1).While the construction of the pipeline in approximately 12 months is a considerable achievement, it took more than six years to establish the regulatory and market fundamentals to allow construction to commence. The commercialisation of the Eastern Gas Pipeline took place during a period in which the Australian gas industry was subject to much regulatory and market reform. The project provided some impetus for that reform, particularly in NSW.The pipeline was the first interstate gas pipeline to be committed under the National Gas Pipeline Access Code. It also represented the means by which significant quantities of Bass Strait gas could be supplied to the NSW gas market for the first time.This paper discusses the variety of commercial and regulatory issues that needed to be resolved to allow the Eastern Gas Pipeline to become a reality.
MANAGEMENT OF UNCERTAINTY AND RISK IN OFFSHORE PETROLEUM DEVELOPMENT
Authors: Behrenbruch P.
Published: August 2017

Uncertainty in petroleum development projects is most often associated with petroleum reserves. It is the limited amount of subsurface data typically available during the time of development planning that creates this situation. Risks are associated not only with reservoir uncertainty but also with wells and production facilities. Risks for offshore projects, as compared to those onshore, are further compounded by very large capital expenditures and less flexibility in catering for subsurface surprises, or remedial action in case of engineering blunders.These concepts are illustrated using case histories of successful and failed projects. Lessons learned from these and other projects are then summarised and processes for uncertainty and risk management are outlined. Risk and uncertainty cover a wide range of issues, and relate to geoscience, reservoir engineering, well technology, facilities engineering, operations, and project planning and evaluation.
THE USE OF SEISMIC MODELLING WHEN DESIGNING ONSHORE 3D AND 4D SURVEYS
Authors: Egan M.S. , Baaren P. van
Published: August 2017

There are many parameters to consider when designing acquisition geometries for onshore 3D and 4D seismic surveys. Plots of attributes, such as fold and offset distribution, are necessary in the design process but they are not always sufficient. For instance, they fail to predict the bandwidth and signal-to-noise ratios associated with various candidate designs. Properly crafted synthetic seismograms, however, can be used to yield these predictions. Downhole and surface seismic measurements are needed to drive this. The downhole measurements— primarily well logs—are used to create stratified earth models for input to ray trace calculations and reflectivity modelling. The surface seismic measurements-including finely sampled noise tests-are needed to derive intraarray statics distributions, ambient noise distributions, ground roll characterisations and other descriptions. These empower modelling routines to contaminate and perturb the synthetic signal in prospect-specific fashions. Results from Middle East studies typically show that survey designs that are best suited for addressing one particular issue might not be best for addressing others. Incorporation of digital group forming algorithms within the modelling process allows prediction of results that would be obtained from new high channel-count, singlesensor systems.
EXTRACTING SUB-SURFACE INFORMATION FROM LONG OFFSET P-WAVE DATA—A CHEAPER ALTERNATIVE TO MULTICOMPONENT OBC FOR EXPLORATION?
Authors: Williams R.G. , Roberts G. , Hawkins K.
Published: August 2017

Seismic energy that has been mode converted from pwave to s-wave in the sub-surface may be recorded by multi-component surveys to obtain information about the elastic properties of the earth. Since the energy converted to s-wave is missing from the p-wave an alternative to recording OBC multi-component data is to examine p-wave data for the missing energy. Since pwave velocities are generally faster than s-wave velocities, then for a given reflection point the converted s-wave signal reaches the surface at a shorter offset than the equivalent p-wave information. Thus, it is necessary to record longer offsets for p-wave data than for multicomponent data in order to measure the same information.A non-linear, wide-angle (including post critical) AVO inversion has been developed that allows relative changes in p-wave velocities, s-wave velocities and density to be extracted from long offset p-wave data. To extract amplitudes at long offsets for this inversion it is necessary to image the data correctly, including correcting for higher order moveout and possibly anisotropy if it is present.The higher order moveout may itself be inverted to yield additional information about the anisotropy of the sub-surface.
OFFSHORE PETROLEUM EXPLORATION IN AUSTRALIA ACREAGE BIDDING SYSTEMS: WORK BIDDING OR CASH BIDDING?
Authors: Thompson A.G. , Lok V.W.C.
Published: August 2017

The design and efficiency of offshore petroleum acreage bidding systems bear directly on the risk and cost for participants investing in exploration and development projects offshore Australia.Companies, financiers and investors who are interested in investing in petroleum exploration and development activities will find a mixed regime of State and Federal legislation governs such activities in Australia.While the concept of the work program bidding system appears to be sound, the administration of it by the Joint Authorities and Designated Authorities and delegated officers potentially creates many uncertainties for permittees.The approval process is generally a costly and time consuming one under the work program bidding system and its administrative cost diverts funds that otherwise may have been directed to exploration activities.Work program permits are also susceptible to uncertainty and dispute as to whether or not the required work program has been met. Issues of proper or improper exercise of discretionary powers can arise, particularly when wide statutory discretionary powers are in practice circumscribed by Administrative Guidelines.The existence of statutory and administrative discretion requires, in the interests of natural justice, that there be appropriate avenues of appeal for aggrieved permittees. All of the foregoing regulation and cost is removed with cash bid permits. Cash bid permits not only reduce costs for Government but also for industry.The authors are of the view that offering permits by way of the cash bidding system should be reintroduced, with modifications to ensure its efficiency.
DO BUSINESS ETHICS REALLY MATTER?
Authors: Lagan A.
Published: August 2017

There are few people today who would dare to say that business and ethics are incompatible forces. This was not the case so very long ago. Despite this shift, the recent spate of spectacular business collapses would seem to suggest that there is still a lag between the values being espoused by today’s business leaders, and the resources allocated to ensuring the ethical imperative is embedded in day-to-day decision-making.This paper seeks to present an overview of where the business ethics debate sits today and how this relates to the current state of ethical play in the oil and gas industry. It reviews the major forces pushing ethics up the corporate agenda and seeks to build the business case for why attention to business ethics will improve overall organisational performance. It does this by reviewing the new business philosophies of sustainability and corporate social responsibility (CSR) and argues that these new business doctrines can be seen as essentially applied ethical practices and present the greatest opportunity to date for embedding the ethical imperative in organisational life.The author argues that historically it has been the oil and gas industries that have been the first to recognise the interdependence of business ethics and organisational performance and that it is these industries have now moved into stage two phase of sustainability development where they are focussing their efforts on embedding the ethical perspective into their day-to-day performance management systems.
PROCESS-KNOWLEDGE MANAGEMENT AND ITS APPLICATION FOR DRILLING IN GAS HYDRATE ENVIRONMENTS
Authors: Prassl W.F. , Peden J.M. , Wong K.W.
Published: August 2017

Understanding both the potential benefits and mitigation of risk based on the application of the latest technologies and procedures are essential to the success of any venture within the petroleum industry. To allow this, a process-knowledge management system has been formulated in order to capture the available knowledge, verify its impact, enable reasoning and informed decision-making. Such a system allows exploitation of explicit and tacit process-knowledge, so that information from multiple field experts, company best practice policies and latest technological findings can be gathered and applied. To handle embedded uncertainties according to their nature, type-2 fuzzy set theory is used. The system is realised via individual reasoning blocks that establish a coherent reasoning lattice. The two apparent benefits of this approach are that it:allows easy adaptation and upgrading of the system’s knowledge; andprovides sensitivity for selection of particular reasoning blocks, depending on the current scenario and conditions.A prototype has been constructed, therefore, to investigate potential gas hydrate related drilling problems. Its main purpose is to enhance well planning and aid the execution of drilling plans, so that safe working conditions as well as economic and technically successful project outcomes can be achieved. The commercial impact of using such a system will:lead to a potential increase in well-site security as well as an overall reduction of well costs; andinitiate developments of process-knowledge management systems for similar domains.
CERTAINTY IN UNCERTAIN TIMES: CONSIDERING FORCE MAJEURE
Authors: Dharmananda S.K. , Kingsbury N.A.
Published: August 2017

Force majeure clauses are particularly relevant to at least two types of oil and gas agreements: operating agreements and long-term contracts. Each type of contract is characteristically exposed to calamitous events that can take many years to manifest. However, force majeure clauses in each type of contract need to reflect the commercial realities and bargain represented by each type of contract.This paper considers whether the types of force majeure clauses that are used in the Australian oil and gas industry would adequately excuse a party relying on them from performing their obligations under a contract in light of some very real 21st century concerns. The beginning of the 21st century has seen remarkable technological development and the creation of a global village where an isolated event in one part of the world can have a significant effect on the entire world. Therefore, the increased likelihood of a terrorist attack against significant infrastructure (eg. an offshore oil rig or gas pipeline) and the emergence of natural phenomena, particularly widespread viral outbreaks such as the SARS virus can have a devastating effect on industry globally, as is being seen in the airline industry. There is some doubt whether standard contract clauses will automatically treat such circumstances as force majeure events.The paper suggests that certain drafting conventions ought to be adopted to address 21st century concerns, and particularly to provide practical solutions for these issues.
JOHN BROOKES GAS FIELD DEVELOPMENT
Authors: McDiarmid A.J. , Bingaman P.T. , Bingham S.T. , Kirk-Burnnand B. , Gilbert D.P. , Kurylowicz L.E. , Sigsworth I.
Published: August 2017

The John Brookes gas field was discovered by the drilling of John Brookes–1 in October 1998 and appraisal drilling was completed in 2003. The field is located about 40 km northwest of Barrow Island on the North West Shelf, offshore West Australia. The John Brookes structure is a large (>90 km2) anticline with >100 m closure mapped at the base of the regional seal. Recoverable sales gas in the John Brookes reservoir is about 1 Tcf.Joint venture approval to fast track the development was gained in January 2004 with a target of first gas production in June 2005. The short development time frame required parallel workflows and use of a flexible/low cost development approach proven by Apache in the area.The John Brookes development is sized for off-take rates up to 240 TJ/d of sales gas with the development costing A$229 million. The initial development will consist of three production wells tied into an unmanned, minimal facility wellhead platform. The platform will be connected to the existing East Spar gas processing facilities on Varanus Island by an 18-inch multi-phase trunkline. Increasing the output of the existing East Spar facility and installation of a new gas sweetening facility are required. From Varanus Island, the gas will be exported to the mainland by existing sales gas pipelines. Condensate will be exported from Varanus Island by tanker.
REASSESSING POTENTIAL ORIGINS OF SYNTHETIC APERTURE RADAR (SAR) SLICKS FROM THE TIMOR SEA REGION OF THE NORTH WEST SHELF ON THE BASIS OF FIELD AND ANCILLARY DATA
Authors: Jones A.T. , Logan G.A. , Kennard J.M. , Rollet N.
Published: August 2017

The Timor Sea region of the North West Shelf is one of natural hydrocarbon accumulation and seepage, which has been investigated by integrated remote sensing studies in the past 10 years. One of the primary tools incorporated in these studies has been Synthetic Aperture Radar (SAR). During a recent Geoscience Australia marine survey to the Yampi Shelf area, active hydrocarbon seepage was directly observed in the form of gas plumes rising from the sea-floor. Active seepage was not observed in areas associated with dense clusters of elongated to irregularshaped features in the SAR data, which have previously been interpreted as natural hydrocarbon seepage slicks. These slicks, and another dense cluster of slicks across the Browse–Bonaparte Basin Transition Zone, are reassessed in the context of alternative formational processes.Mapping of bathymetric channels directly beneath the SAR slicks using multi-beam swath bathymetry and measurement of tidal currents using an acoustic doppler current profiler indicates that tidal current flows may have contributed to slick formation over the Yampi Shelf headland. In contrast, coral spawning may have contributed to the formation of annular to crescent-shaped SAR slicks associated with submerged reefs and shoals over the nearby transition zone. Subsequent to identifying potential alternative origins for these two types of SAR features, the remaining slicks across the area were re-categorised on the basis of their size and shape in the context of ancillary hydrographic and environmental data. An alternative nonseepage origin was established for most of the 381 SAR slicks previously identified as being related to natural hydrocarbon seepage. This may necessitate a significant downgrading of the extent and frequency of active hydrocarbon (particularly oil) seepage in the region.
AUSTRALIAN MEGASURVEYS—THE KEY TO NEW DISCOVERIES IN MATURING AREAS?
Authors: Edwards H. , Crosby J. , David N. , Loader C. , Westlake S.
Published: August 2017

In a maturing province such as the North West Shelf, it is time-critical to find remaining hydrocarbon resources as well as to develop small finds before existing big field installations and their associated infrastructure are decommissioned. Finding the remaining smaller fields with subtle geophysical expression is a challenge, and a thorough understanding of the petroleum geology is essential. To achieve this, the subsurface structure and depositional systems must be understood in a regional as well as a local context.To date, exploration companies’ regional models have been based on a mixture of 2D and 3D seismic of varying vintages, orientations, and quality. Consequently they have been incomplete and lacking detail. To address this problem, PGS initiated the MegaSurvey Project, merging a number of 3D surveys into large, consistent 3D data sets. For the first time, the regional picture and prospect-size detail are both available from a single dataset.Two MegaSurveys for the North West Shelf are now available; the Vulcan Sub-Basin MegaSurvey (VMS) and the Carnarvon MegaSurvey (CMS).The MegaSurvey seismic data and consistent horizon interpretation (tied to released well control) enables asset- focussed oil companies to concentrate on the more detailed search-for-the-subtle-trap to find, understand, and develop remaining reserves. Interpretation of the first MegaSurvey (Vulcan Sub-Basin) was completed in 2004 and work is focussed on the Carnarvon MegaSurvey, the interpretation of which will be completed in March 2005.The PGS 3D MegaSurveys allow visualisation of the subsurface both on a scale and resolution that has hitherto been unavailable. They provide an essential new tool to help fully unlock the remaining potential of the North West Shelf.
THE EAST COAST BASIN OF NEW ZEALAND, AN EMERGING PETROLEUM PROVINCE
Authors: Uruski C.I. , Field B.D. , Funnell R.
Published: August 2017

More than 300 oil and gas seeps are known in the onshore East Coast Basin of North Island, New Zealand. Spectacular geological structures have been explored by more than 40 wells, only three of which have been offshore. Results are tantalising, with 70% of wells yielding oil or gas shows. Westech’s two gas discoveries onshore at Kauhauroa and Tuhara in northern Hawkes Bay remain un-developed at present.Strong gas shows were encountered in both open-file wells drilled offshore and elevated gas readings were recorded in the recent Tawatawa–1 well, but reservoir quality was poor.Nevertheless, good reservoir facies are abundant in the East Coast Basin. A wide range of Miocene and Pliocene sands and limestones, with porosities of 20% and above are known from outcrop and wells. But, modern, good quality seismic data are essential to allow sequence stratigraphic interpretation and a reasonable likelihood of predicting the distribution of reservoir facies. As part of its program to stimulate exploration in New Zealand, the NZ government is commissioning a new 4,000 km, highquality 2D seismic data set with the intention of making it freely available to interested exploration companies by mid-2005.The very thick sedimentary succession, the presence of direct hydrocarbon indicators on seismic data, the strong gas shows in wells drilled offshore and the reasonable expectation of oil generation and expulsion into numerous large structures with good reservoir facies combine to make the offshore East Coast Basin an attractive exploration venue.
NEW EQUITY RAISING METHODS FOR LISTED COMPANIES: JUMBOS AND RAPIDS—OPTIMISED RIGHTS OFFERS AND PLACEMENTS
Authors: Philips J.D. , Mathewson V.E.
Published: August 2017

Traditional methods of equity capital raising by listed companies may not always be the best way to meet the needs of both the companies and shareholders1. The timetable for a rights issue (being a pro rata offer to all shareholders to subscribe for shares) may be too long to fund an acquisition or project. A placement (being an offer to institutional investors for a certain number of shares), while giving a company certainty and a shorter timeframe, excludes the company's shareholders from participation in the capital raising.Innovative new capital raising structures have been developed. Two of these are known as the jumbo and the RAPIDs™ structures.Broadly, they both combine aspects of a rights offer and a placement. The rights offer is split into two stages; the first stage involves offering institutional investors on the company's share register their component of the rights offer, which can be done in a short timeframe. This institutional component of the rights offer is combined with a placement to other institutional investors through a bookbuild. The retail component of the rights offer is then conducted on the Australian Stock Exchange Limited's (ASX) normal (longer) timetable. The offer structures enable funds raised from the institutional rights offer and placement to be received quickly, while still enabling retail shareholders to participate in the offer and avoid dilution.
DEEPWATER AND FRONTIER EXPLORATION IN AUSTRALIA—HISTORICAL PERSPECTIVES, PRESENT ENVIRONMENT AND LIKELY FUTURE TRENDS
Authors: Walker T.R.
Published: August 2017

Australian deepwater (>500 m) basinal areas are generally extensions of known shallow-water basins, filled with non-marine to marginal marine sedimentary facies. True deepwater sedimentary facies are found in very few of these basins. In Australia, the transition to deep water is often associated with the edge of thick, prograding Tertiary carbonates, which have buried the inboard sediments and promoted recent hydrocarbon generation.Of ~1,040 offshore exploration wells, only 61 have been drilled in deep water, and only one in depths greater than 1,500 m. Most deepwater exploration drilling has occurred on the greater North West Shelf. About 9.4 billion boe of recoverable deepwater resources have been discovered since 1979, of which 94% is gas and 6% liquids. Elsewhere in Australia, deepwater drilling has been sporadic, with only seven wells drilled on the entire southern margin, and none on the southwestern or eastern margins, due to perceptions of limited prospectivity or limited accessibility. The northern basins of Australia lie predominantly in shallow water.An unprecedented amount of deepwater exploration activity will occur in the next three years, with more than 17,500 km of 2D, 14,300 km2 of 3D, and 36 wells committed. Secondary term (variable) commitments comprise a further 5,200 km of 2D, 1,200 km2 of 3D and 24 wells. The challenges for exploration of Australia’s frontier deepwater provinces include identifying new petroleum systems capable of hosting large fields, and working in harsh, remote and high-cost operating environments. Government-sponsored initiatives should encourage future uptake of the frontier areas.
HYDROCARBON ENTRAPMENT IN TRIASSIC TO LATE JURASSIC RESERVOIRS IN THE TIMOR SEA, AUSTRALIA—NEW INSIGHTS
Authors: Ellis G.
Published: August 2017

Abundant oil-filled fluid inclusions at quartz overgrowth/detrital quartz boundaries and in fractures cutting quartz grains are often used as the primary evidence of palaeo-oil columns in Triassic to Late Jurassic reservoirs in numerous wells in the Timor Sea. Based on fluid inclusion analysis of sandstone reservoirs in present oil columns, a Grains containing Oil Inclusions (GOI) value of 5% has been used as a threshold with values >5% indicating palaeo-oil columns. However, values Other indications of palaeo-oil columns are evident below and/or within GOI-defined palaeo-oil columns: good to excellent direct and cut fluorescence on cuttings and/or core, elevated resistivity and reservoir diagenesis. In the case of oil shows these hydrocarbon indications have been discounted as indicating focussed oil migration below a palaeo-oil–water contact rather than indicating a palaeo-oil column.While GOI provides valuable data to support the interpretations of palaeo-oil columns, it provides a picture at one instance in the hydrocarbon entrapment history and therefore should not be used in isolation. Other hydrocarbon indications are equally valid evidence of oil entrapment at one or more different times in the hydrocarbon entrapment history, and should be used with GOI data to provide a comprehensive picture of the evolution of a hydrocarbon trap. Case histories from wells Crux–1, in the northern Browse Basin, and Oliver–1 and Eclipse–2, in the Vulcan Sub-basin of the Timor Sea, illustrate how an integrated picture of hydrocarbon entrapment history can be developed and demonstrate that structures in the Timor Sea have undergone more than one phase of oil entrapment and leakage, with each oil phase potentially from a different oil source.
THE ROLE OF AMPLITUDE VERSUS OFFSET TECHNOLOGY IN PROMOTING OFFSHORE PETROLEUM EXPLORATION IN AUSTRALIA
Authors: Williamson P. E. , Kroh F.
Published: August 2017

Amplitude versus offset (AVO) technology has proved itself useful in petroleum exploration in various parts of the world, particularly for gas exploration. To determine if modern AVO compliant processing could identify potential anomalies for exploration of open acreage offshore Australia, Geoscience Australia reprocessed parts of four publicly available long cable lines. These lines cover two 2006 acreage release areas on the Exmouth Plateau and in the Browse Basin on the North West Shelf. An earlier study has also been done on two publicly available long cable lines from Geoscience Australia’s Bremer Basin study and cover areas from the 2005 frontier acreage release on the southern margin. The preliminary results from these three reprocessing efforts produced AVO anomalies and were made publicly available to assist companies interested in assessing the acreage. The results of the studies and associated data are available from Geoscience Australia at the cost of transfer.The AVO data from the Exmouth Plateau show AVO anomalies including one that appears to be at the Jurassic level of the reservoir in the Jansz/Io supergiant gas field in adjacent acreage to the north. The AVO data from the Caswell Sub-basin of the Browse Basin show an AVO anomaly at or near the stratigraphic zone of the Brecknock South–1 gas discovery to the north. The geological settings of strata possibly relating to two AVO anomalies in the undrilled Bremer Basin are in the Early Cretaceous section, where lacustrine sandstones are known to occur. The AVO anomalies from the three studies are kilometres in length along the seismic lines.These preliminary results from Geoscience Australiaand other AVO work that has been carried out by industry show promise that AVO compliant processing has value—particularly for gas exploration offshore Australia—and that publicly available long-cable data can be suitable for AVO analysis.
DOWNHOLE SEPARATION TECHNOLOGY—PAST, PRESENT AND FUTURE
Authors: Gao C. , Rivero M. , Nakagawa E. , Sanchez G.
Published: August 2017

In the 1990s, a new water management tool, downhole separation technology, was developed. It separates oil and gas from produced water inside the wellbore and injects the produced water into the disposal zone. Based on the different fluid the separators handle, they are categorised as downhole oil-water separators (DOWS) and downhole gas-water separators (DGWS). Two types of separators have been used: hydrocyclone and gravity separators. The authors reviewed the previous 59 DOWS installations and 62 DGWS installations worldwide, and discovered that only about 60% achieved success. Some major issues—including high costs, low reliability and low longevity—have slowed down its industrial adoption. Based on the field experiences, a good candidate well must have a high-quality disposal zone with sustainable permeability. To improve the performance of downhole separation tools, it is crucial to better understand the behaviour of the separator under downhole conditions and the behaviour of the injection zone under the invasion of various impurities in the produced water.
RESPONDING TO THE THREAT OF A COST OF CARBON
Authors: Maimone L. , Curtin R.
Published: August 2017

Climate change is an emerging issue with the potential to have a significant impact on the energy sector and, more specifically, the oil and gas industry. Pressures from public opinion and the introduction of climate change policy and regulations could affect the competitiveness of the industry. Conversely, incentives and subsidies for renewable energy or other lower carbon energy sources could present a potential opportunity for companies looking to diversify their asset portfolios.Australia has implemented a range of mandatory and voluntary schemes that encourage the reduction of greenhouse gas emissions. There is still, however, uncertainty as to if and how a cost of carbon may be regulated in the future.
CHANGES TO GAS ACCESS LEGISLATION—POLICY RATIONALE AND IMPLICATIONS FOR INDUSTRY
Authors: Carkeet M.L.
Published: August 2017

The introduction of a national gas access regime has coincided with a rapid expansion in the Australian market for gas transportation services. The threat of regulation and the approach of regulators, however, have influenced both the configuration of pipelines and the nature of transportation contracts. The recent introduction of reforms to the National Third Party Access Regime for Natural Gas Pipelines (Gas Access Regime), and to part IIIA of the Trade Practices Act 1974 (Cth), has the effect of introducing part but not all of the reforms recommended by the Council of Australian Governments’ Independent Review of Energy Market Directions, and the Productivity Commission’s Review of the Gas Access Regime. The principal amendments, relating to the insertion of an objects clause and the introduction of regulatory holidays for certain greenfield projects are also likely to influence the configuration of pipelines and the nature of pipeline contracts. These amendments are precursors to a major restatement of National Gas Access legislation that will, if enacted, have the effect of creating greater uniformity between the National Electricity Law and the regulatory environment that will apply to gas, but, will also open up the opportunity for pipeline owners and operators to submit to a lighter form of regulation.
CONDEEP® MonoFloater—spread-moored turretless FPSO platform
Authors: Næss Jacqueline , Haug Nora , Munkeby Jan
Published: August 2017

The CONDEEP® MonoFloater is an innovative concrete floating platform with a cylindrical hull capable of supporting large topsides. Its design allows for topside weights in excess of 30,000 tonnes. Storage space inside the hull is in excess of 1 million barrels with options for direct offloading to cargo tankers. The CONDEEP® MonoFloater is anchored in a conventional spread mooring so a high number of risers can be accommodated as no turret limitations apply. The CONDEEP® MonoFloater is designed for operation in harsh environments and water depths in excess of 250 m with a potential concrete design life of over 70 years.
The challenges of seismic acquisition in a remote and sensitive marine environment: Scott Reef, Western Australia
Authors: Taylor Mark , Fitzgerald Nick , Fitzpatrick Jeremy , Weiss Ralph
Published: August 2017

Woodside Energy Ltd, as operator of the Browse LNG Development, recently acquired two seismic surveys at Scott Reef, Western Australia. The surveys were important steps towards acquiring full seismic coverage over the Torosa gas field, part of which underlies Scott Reef
The Maxima 3D marine seismic survey, conducted in late 2007, was a conventional towed streamer survey. This was followed in May 2008 by the Gigas 2D transition zone survey in the shallow waters of north Scott Reef, and Woodside’s first experience with ocean bottom cable (OBC) seismic technology. Each survey presented unique challenges during the planning, regulatory approval and acquisition stages.
Scott Reef comprises two coral atolls located on the outer continental shelf of northwest Australia, approximately 400 km north of Broome. The only permanently emergent land is a small sand cay (Sandy Islet, Fig. 1), although the reef crests of both atolls are exposed at low tide.
Outside the reefs the seafloor drops away rapidly, with water depths of about 350 m to the east, increasing to more than 1,000 m to the west. South Scott Reef lagoon is open to the north, with water depths increasing to about 50 m before deepening abruptly into the channel between the two reefs.
North Scott Reef lagoon is shallower—generally less than 25 m—and is connected to the ocean by two narrow channels. Semi-diurnal tides with a range of up to 4.6 m produce strong tidal currents in and near these channels. Small, steep-sided coral heads, or bombies, are common throughout the lagoons, especially in water less than 25 m deep.
Tectonostratigraphic development and hydrocarbon reservoir quality on a convergent margin: East Coast, North Island, New Zealand
Authors: Field Brad , Baur Jan , Bland Kyle , Browne Greg , Griffin Angela , Ilg Brad , Juniper Zoe , Lawrence Mark , Marrett Randall , Mildren Scott , Milner Michael , Morgans Hugh , Roncaglia Lucia , Uruski Chris , Zhu Hai
Published: August 2017

Hydrocarbon exploration on the East Coast of the North Island has not yet yielded significant commercial reserves, even though the elements of a working petroleum system are all present (Field et al, 1997).
Exploration has focussed on the shallow, Neogene part of the succession, built up during plate margin convergence over the last ∼24 million years.
Convergent margins are generally characterised by low-total organic carbon (TOC) source rocks and poor clastic reservoir quality due to poor sorting and labile grains.
However, the obliquely-convergent Hikurangi subduction margin of the East Coast has high TOC source rocks that pre-date the subduction phase, and its reservoir potential, though variable, has several aspects in its favour, namely: deep-water rocks of high porosity and permeability; preservation of pore space by overpressure; the presence of fractured reservoirs and hybrid reservoirs, where low clastic permeability is enhanced by fractures.
The East Coast North Island is a Neogene oblique subduction margin, with Neogene shelf and slope basins that developed on Late Cretaceous-Paleogene passive margin marine successions.
The main hydrocarbon source rocks are Late Cretaceous and Paleocene and the main reservoir potential is in the Neogene (Field et al, 2005). Miocene mudstones with good seal potential are common, as is significant over-pressuring.
Neogene deformation controlled basin development and accommodation space and strongly-influenced lateral facies development and fractured reservoirs. Early to Middle Miocene thrusting was followed by later Neogene extension (e.g. Barnes et al 2002), with a return to thrusting in the Pliocene. Local wells have flow-tested gas shows.
GEOPHYSICAL EXPLORATION IN TORRES STRAIT
Authors: Vind E. W. , Harwood C. R.
Published: August 2017

Torres Strait is the narrow waterway on the Continental Shelf which connects the Arafura Sea to the Coral Sea and separates the Cape York Peninsula from South-western Papua. Within Torres Strait and the Arafura Sea the marine seismic survey area specifically discussed here covers the north-western part of Authority to Prospect 104P held by Marathon Petroleum Australia Ltd. Except for a few small islands this area is covered by a shallow tropical sea not more than 160 feet deep which is studded with coral reefs.Four regional structural features influence the area. These are the Cape York-Oriomo Ridge to the east, the Carpentaria Basin to the south and the Morehead and Papuan Basins to the north. These features are indicated by regional geology and have been confirmed by the combined interpretations of reconnaissance geophysical surveys conducted by various exploration organisations during the past 30 years.The A.T.P. 104P (West) Marine Seismic Survey, consisting of 618 miles of subsurface coverage, was carried out for Marathon between November 8 and November 28, 1964.Several operational problems prevented completion of the survey as originally planned. Shallow water and reefing prevented shooting in the north-east portion of the proposed area.Shooting 300 per cent subsurface coverage commenced in the south-eastern part of the survey area, but, due to shallow basement at less than one second, multiple coverage was not feasible. Production shooting which gave 100 per cent subsurface coverage on the short spreads was continued throughout the remainder of the survey.Two reflection horizons and a resultant isochron were mapped in the area. A "deep" reflector is interpreted as originating from granitic basement, while a "shallow" reflector is tentatively correlated with a horizon in the Cretaceous section.The "shallow" horizon mapped is essentially conformable with the "deep" horizon. Both show a regional west dip with thinning of section to the east. Some north and south components of the regional west dip are established. The resultant isochron comparisons based on this work appear too limited in scope to establish any definite local structural control of deposition.
PRE-JURASSIC IN NORTH CENTRAL QUEENSLAND
Authors: Lindner A. W.
Published: August 2017

Sedimentary rock sequences of early, middle and late Palaeozoic to Triassic age are present in north-central Queensland. Their distribution beneath the Jurassic-Cretaceous Great Artesian Basin sequence and degree of deformation are matters of some importance in the search for petroleum. Identification of the pre-Jurassic structural basins, which contain these sequences, is assisted by data from exploration drilling, geophysical surveys and water bores.The pattern which emerges, while obscure for the lower Palaeozoic, suggests that by the middle Palaeozoic the more active sedimentation and tectonism in the Tasman geosynclinal zone was confined to a region near the present coastline. Between this position of the geosyncline and the stabilised Pre-cambrian block to the west, middle and then upper Palaeozoic sequences were deposited in intracratonic basins. The basins overlapped westwards on to a low-grade metamorphic sequence, which may be the age counterpart of the stable shelf Cambrian-Ordovician sequence of the Georgina Basin.The middle Palaeozoic sequence, ranging from Middle Devonian to Lower Carboniferous, is present in the Drummond Basin, as well as in several small structural remnants further north, east of the Georgetown Inlier. The Upper Carboniferous to Triassic sequence is preserved in the Galilee Basin. The sequences in these basins are distinguished by an interval of folding, igneous intrusions and erosion during the Carboniferous.Several exploratory tests have been drilled in the middle and upper Palaeozoic basins and have indicated a prospective association of sandstone and shale in the two sequences. An oil show from the upper Palaeozoic in Lake Galilee 1 and the gas discovery and oil shows at Gilmore, in the Devonian of the Adavale Basin, are promising and encourage further exploration in the Galilee and Drummond Basins.
THE STRATIGRAPHY OF THE PERMIAN OF THE NORTHERN PERTH BASIN, WESTERN AUSTRALIA
Authors: Johnstone M. H. , Willmott S. P.
Published: August 2017

The Perth Basin is a narrow, deep graben flanking the lower 400 miles of the west coast of Western Australia. It attains a maximum width of 60 miles and may contain more than 40,000 feet of sediments.Permian rocks crop out around the northern margin of the basin, between the Greenough Precambrian Inlier on the west and the Darling Fault on the east. Bores near the northern margin of the basin and down the west coast for some 120 miles south of Geraldton have encountered Permian rocks. Because of the limited nature of the outcrop, most of our information concerning variations of stratigraphy within the Permian comes from these bores.As in other basins in Australia, the Permian sedimentation in the Perth Basin started with a cycle of intense glaciation. Two units were deposited: the lower one is a submarine tillite consisting of boulders set in a sandstone and siltstone matrix; the upper unit is a fossiliferous marine shale. The thickest development of these units is adjacent to the eastern boundary fault of the basin. They thin rapidly to the west by sedimentary onlap on to the Beagle Ridge.The glacial cycle is followed by a continual cycle in which coal measures predominate. This unit shows a remarkable constancy of thickness, indicating very stable tectonic conditions during its deposition.The coal measures are followed by a monotonous marine siltstone unit which completes the Lower Permian (Artinskian) sequence in this basin.After a hiatus in which both tectonism (faulting and tilting) and erosion occurred, a series of estuarine lakes developed in uppermost Permian times, and the Wagina Sandstone was deposited. These rather restricted lakes were then followed by the more widespread Lower Triassic transgression in which the Kockatea Shale blankets most of the Permian.Significant signs of oil are seen in several of the Permian units-oil in the Coal Measures, oil and gas in the overlying marine strafes, and oil and gas associated with the Wagina Sandstone. Thus the Permian ranks as one of the best potential source and reservoir sequences for hydrocarbons in the Perth Basin.