PORT CAMPBELL REVIEWED: METHANE AND CHAMPAGNE

1995 ◽  
Vol 35 (1) ◽  
pp. 418 ◽  
Author(s):  
J.D. Foster ◽  
A.J. Hodgson

Gas fields in the Port Campbell Embayment cur­rently supply all the natural gas markets (non-LPG) in western Victoria as well as commercial quanti­ties of carbon dioxide (C02) to industrial markets. Initial discoveries made between 1979 and 1981 were brought on-stream in 1986 with production from the North Paaratte field. Another substantial discovery was made in 1988, the Iona gas field, followed by the Boggy Creek C02 field in 1991, then the My lor and Langley fields in 1994. Discovery of Mylor marked the first recovery of oil from the Late Cretaceous Waarre Formation. Extensive 2D seis­mic data sets have been recorded in the region since 1979, and the first 3D seismic survey in the Otway Basin was carried out in 1993 extending beyond the area of the initial discoveries. No data on the fields have been published for nearly a decade and little detail about the structural and stratigraphic geol­ogy of the Late Cretaceous in the area has been documented. Summaries of the fields are presented incorporating many insights gained from interpre­tation of the 3D seismic data and its verification by the 'rotary lie detector'.

2006 ◽  
Vol 46 (1) ◽  
pp. 101 ◽  
Author(s):  
K.J. Bennett ◽  
M.R. Bussell

The newly acquired 3,590 km2 Demeter 3D high resolution seismic survey covers most of the North West Shelf Venture (NWSV) area; a prolific hydrocarbon province with ultimate recoverable reserves of greater than 30 Tcf gas and 1.5 billion bbls of oil and natural gas liquids. The exploration and development of this area has evolved in parallel with the advent of new technologies, maturing into the present phase of revitalised development and exploration based on the Demeter 3D.The NWSV is entering a period of growing gas market demand and infrastructure expansion, combined with a more diverse and mature supply portfolio of offshore fields. A sequence of satellite fields will require optimised development over the next 5–10 years, with a large number of wells to be drilled.The NWSV area is acknowledged to be a complex seismic environment that, until recently, was imaged by a patchwork of eight vintage (1981–98) 3D seismic surveys, each acquired with different parameters. With most of the clearly defined structural highs drilled, exploration success in recent years has been modest. This is due primarily to severe seismic multiple contamination masking the more subtle and deeper exploration prospects. The poor quality and low resolution of vintage seismic data has also impeded reservoir characterisation and sub-surface modelling. These sub-surface uncertainties, together with the large planned expenditure associated with forthcoming development, justified the need for the Demeter leading edge 3D seismic acquisition and processing techniques to underpin field development planning and reserves evaluations.The objective of the Demeter 3D survey was to re-image the NWSV area with a single acquisition and processing sequence to reduce multiple contamination and improve imaging of intra-reservoir architecture. Single source (133 nominal fold), shallow solid streamer acquisition combined with five stages of demultiple and detailed velocity analysis are considered key components of Demeter.The final Demeter volumes were delivered early 2005 and already some benefits of the higher resolution data have been realised, exemplified in the following:Successful drilling of development wells on the Wanaea, Lambert and Hermes oil fields and identification of further opportunities on Wanaea-Cossack and Lambert- Hermes;Dramatic improvements in seismic data quality observed at the giant Perseus gas field helping define seven development well locations;Considerably improved definition of fluvial channel architecture in the south of the Goodwyn gas field allowing for improved well placement and understanding of reservoir distribution;Identification of new exploration prospects and reevaluation of the existing prospect portfolio. Although the Demeter data set has given significant bandwidth needed for this revitalised phase of exploration and development, there remain areas that still suffer from poor seismic imaging, providing challenges for the future application of new technologies.


2003 ◽  
Vol 20 (1) ◽  
pp. 749-759 ◽  
Author(s):  
David E. Lawton ◽  
Paul P. Roberson

abstractThe Johnston Field is a dry gas accumulation located within blocks 43/26a and 43/27a of the UK Southern North Sea. The discovery well was drilled in 1990 and after the drilling of one appraisal well in 1991, a development plan was submitted and approved in 1993. Initially two development wells were drilled from a four slot sub-sea template, with commercial production commencing in October 1994. A further horizontal development well was added to the field in 1997.The field has a structural trap, fault bounded to the SW and dip-closed to the north, east and south. This field geometry has been established using high quality 3D seismic data, enhanced by seismic attribute analysis. The sandstone reservoir interval consists of the Early Permian, Lower Leman Sandstone Formation of the Upper Rotliegend Group. This reservoir consists of a series of interbedded aeolian dune, fluvial, and clastic sabkha lithofacies. The quality of the reservoir is variable and is principally controlled by the distribution of the various lithofacies. The top seal and fault bounding side seal are provided by the overlying clay stone of the Silverpit Shale Formation and the evaporite dominated Zechstein Supergroup.The field has been developed using a phased development plan, with the acquisition of a 3D seismic survey allowing for the optimized drilling of a high deliverability horizontal well.Current mapped gas initially-in-place estimates for the field are between 360 and 403 BCF, with an estimated recovery factor of between 60 and 75%.


2002 ◽  
Vol 42 (1) ◽  
pp. 83
Author(s):  
P. Fink ◽  
M. Adamson ◽  
F. Jamal ◽  
C. Stark

The Patricia and Baleen offshore gas fields are located in the northeastern part of the Gippsland Basin in southeast Australia. Although discovered by two exploration wells almost a quarter of a century ago, the two gas fields only recently have again become the focus of appraisal and subsequent development activity through OMV’s acquisition of Cultus in 1999.After the drilling of a successful appraisal well in late 1999, a high resolution 3D seismic survey was acquired in early 2000. No further data acquisition will be undertaken. Special emphasis was therefore put on maximising the value of the 3D dataset by integrating the PreSTM (Pre. Stack Time Migration) seismic and several Elastic Impedance attributes with all other available subsurface data prior to building a sophisticated stochastic reservoir model for simulation.This paper describes how the integration of leading edge seismic technology with unconventional geological modelling was used to overcome a number of major challenges in order to build a coherent static reservoir model and constrain resource uncertainty given the limited amount of wireline and core data:A large proportion of the gas fields is strongly affected by seismic tuning which would introduce significant uncertainties on GRV and GWC estimations from seismic, if not accounted for properly. Likewise all seismic and to a somewhat lesser extent basic inversion based attributes used for reservoir property determination are strongly affected by this geophysical artefact: These challenges (and seismic pitfalls) were met by inverting the conventional 3D seismic for Pand S- wave impedances and generating a set of Elastic Impedance Cubes, difference cubes and LRM Cubes (standing for the elastic constants Lambda (λ), Rho (ρ) and Mhu (μ)), defining petroacoustic properties of the reservoir rocks. These cubes were tested for mathematical dependency and used for the conditioning of the facies and porosity models.The glauconitic Gurnard reservoir contains a high fraction of conductive minerals and is almost completely bioturbated. Conventional saturation estimations based on wireline-logs and conventional sequence stratigraphic facies description did not deliver a reliable picture: Instead a facies model based on ichnofabric analysis was built and constrained with data available at the three well locations. Saturation height functions were applied separately for each facies type. The Rho-Lambda (ρλ) cube was used to condition facies distribution away from the wells.More specifically, the results presented in the paper are:Elastic Impedance inversion provided vertical seismic resolution in the order of 4 m to 10 m, thereby allowing a more accurate seismic estimation of GRV and the GWC. Lamesf Constants were extracted from seismic in order to classify lithology.A realistic facies model was built utilizing the Rho- Lambda (ρλ) cube combined with ichnofabric analysis tied to permeability and water saturation distributions.Elastic Impedance Difference cubes were successfully calculated to eliminate tuning even further and condition the stochastic porosity model.Connected volume maps were used to optimise the production well pathsThe GIIP upside volume has been upgraded compared to that based on an earlier simplistic geological reservoir model used for simulation. A more realistic P10/P90 reserves range is now supported by a number of deterministic and stochastic reservoir models.


2018 ◽  
Vol 156 (07) ◽  
pp. 1265-1284
Author(s):  
EVA VAN DER VOET ◽  
LEONORA HEIJNEN ◽  
JOHN J. G. REIJMER

AbstractIn contrast to the Norwegian and Danish sectors, where significant hydrocarbon reserves were found in chalk reservoirs, limited studies exist analysing the chalk evolution in the Dutch part of the North Sea. To provide a better understanding of this evolution, a tectono-sedimentary study of the Late Cretaceous to Early Palaeogene Chalk Group in the northern Dutch North Sea was performed, facilitated by a relatively new 3D seismic survey. Integrating seismic and biostratigraphic well data, seven chronostratigraphic units were mapped, allowing a reconstruction of intra-chalk geological events.The southwestward thickening of the Turonian sequence is interpreted to result from tilting, and the absence of Coniacian and Santonian sediments in the western part of the study area is probably the result of non-deposition. Seismic truncations show evidence of a widespread inversion phase, the timing of which differs between the structural elements. It started at the end of the Campanian followed by a second pulse during the Maastrichtian, a new finding not reported before. After subsidence during the Maastrichtian and Danian, renewed inversion and erosion occurred at the end of the Danian. Halokinesis processes resulted in thickness variations of chalk units of different ages.In summary, variations in sedimentation patterns in the northern Dutch North Sea relate to the Sub-Hercynian inversion phase during the Campanian and Maastrichtian, the Laramide inversion phase at the end of the Danian, and halokinesis processes. Additionally, the Late Cretaceous sea floor was characterized by erosion through contour bottom currents at different scales and resedimentation by slope failures.


1983 ◽  
Vol 23 (1) ◽  
pp. 164
Author(s):  
M. David Agostini

The North Rankin gas field discovered in 1971, has been evaluated by a series of appraisal wells and refinement of this is underway through the use of a 3D seismic survey. Extensive production testing on two wells was used to establish reservoir fluid characteristics, inflow performance and to predict reservoir behaviour.The North Rankin 'A' platform has been constructed of a standard steel jacket design. Components of the structure were built in Japan, Singapore, Geraldton, Jervoise Bay and Adelaide. Provision exists for 34 wells to be drilled from the structure to exploit the southern end of the North Rankin field.Simultaneous drilling and producing activities are planned, requiring well survey and deviation control techniques that will provide a high level of confidence. Wells will be completed using 7 inch tubing, fire resistant christmas trees, and are designed to be produced at about 87 MMSCFD on a continuous basis. Process equipment on this platform is designed to handle 1200 MMSCFD and is intended primarily to dry the gas and condensate and to transfer gas and liquid to shore in a two phase 40 inch pipeline. The maintenance of offshore equipment is being planned to maximise the ratio between planned and unplanned work.The commencement of drilling activities is planned for mid 1983, with commissioning of process equipment occurring in the second quarter of 198 The North Rankin 'A' platform will initially supply the WA market at some 400 MMSCFD offshore gas rate, requiring 7 wells. The start of LNG exports is planned for April 1987. The intial gas for this will be derived from the North Rankin 'A' platform.


2015 ◽  
Vol 55 (1) ◽  
pp. 15 ◽  
Author(s):  
Cliff C. Ford ◽  
James K. Dirstein ◽  
Alistair John Stanley

Waveform data from pre-interpretation processing is used in nine Late Triassic interpretation case studies from an area extending more than 30,000 km2 across the Exmouth Plateau, Kangaroo Trough and Rankin Trend on the North West Shelf of Australia. Events selected from a database of automatically generated surfaces extracted from six large open-file 3D marine surveys (~16,000 km2) are used to analyse reservoirs, seals, and pore fluid within the Brigadier and Mungaroo formations in this peer-reviewed paper. Today, geoscience teams are challenged with vast data sets such as the archived versions of more than 125 Carnarvon Basin 3D seismic surveys. Pre-interpretation processing delivers a database of numerous seismic events that cannot be effectively managed using traditional interpretation workstations. With, however, a 3D viewer to query, edit and merge the results, geoscience teams are able to review many large surveys and the surfaces in their interpretation workflows. At the 2013 WABS Conference in Perth, WA, two papers offered models for the Late Triassic gas reservoirs. These models represent many years of synthesis and integration of data by teams of geoscientists from two of the major operators on the North West Shelf. Validation and corroboration of the proposed models was gained by using selected pre-interpretation surfaces. Stacking patterns, waveform fitness, amplitude and two-way time surfaces from these spatial databases revealed geological insights about the formations, such as their complexity of structure, extent of reservoirs, and continuity of seals, along with a better understanding about the trapping and charge systems of the fields.


2020 ◽  
Author(s):  
Benjamin Bellwald ◽  
Sverre Planke ◽  
Sunil Vadakkepuliyambatta ◽  
Stefan Buenz ◽  
Christine Batchelor ◽  
...  

<p>Sediments deposited by marine-based ice sheets are dominantly fine-grained glacial muds, which are commonly known for their sealing properties for migrating fluids. However, the Peon and Aviat hydrocarbon discoveries in the North Sea show that coarse-grained glacial sands can occur over large areas in formerly glaciated continental shelves. In this study, we use conventional and high-resolution 2D and 3D seismic data combined with well information to present new models for large-scale fluid accumulations within the shallow subsurface of the Norwegian Continental Shelf. The data include 48,000 km<sup>2</sup> of high-quality 3D seismic data and 150 km<sup>2</sup> of high-resolution P-Cable 3D seismic data, with a vertical resolution of 2 m and a horizontal resolution of 6 to 10 m in these data sets. We conducted horizon picking, gridding and attribute extractions as well as seismic geomorphological interpretation, and integrated the results obtained from the seismic interpretation with existing well data.</p><p>The thicknesses of the Quaternary deposits vary from hundreds of meters of subglacial till in the Northern North Sea to several kilometers of glacigenic sediments in the North Sea Fan. Gas-charged, sandy accumulations are characterized by phase-reserved reflections with anomalously high amplitudes in the seismic data as well as density and velocity decreases in the well data. Extensive (>10 km<sup>2</sup>) Quaternary sand accumulations within this package include (i) glacial sands in an ice-marginal outwash fan, sealed by stiff glacial tills deposited by repeated glaciations (the Peon discovery in the Northern North Sea), (ii) sandy channel-levee systems sealed by fine-grained mud within sequences of glacigenic debris flows, formed during shelf-edge glaciations, (iii) fine-grained glacimarine sands of contouritic origin sealed by gas hydrates, and (iv) remobilized oozes above large evacuation craters and sealed by megaslides and glacial muds. The development of the Fennoscandian Ice Sheet resulted in a rich variety of depositional environments with frequently changing types and patterns of glacial sedimentation. Extensive new 3D seismic data sets are crucial to correctly interpret glacial processes and to analyze the grain sizes of the related deposits. Furthermore, these data sets allow the identification of localized extensive fluid accumulations within the Quaternary succession and distinguish stratigraphic levels favorable for fluid accumulations from layers acting as fluid barriers.</p>


2009 ◽  
Vol 12 (03) ◽  
pp. 408-418 ◽  
Author(s):  
Adrian White ◽  
Brett McIntyre ◽  
David Castillo ◽  
Julie Trotta ◽  
Marian Magee ◽  
...  

Summary A post-mortem analysis of the Gnu-1 well was conducted to help us to understand drilling experiences in the context of the pore-pressure and stress profiles. The post-mortem involved a review of the drilling experiences and an analysis of CAST image data, wireline-log data, and the logging-while-drilling (LWD) logs. This information was used to refine and verify a geomechanical model (in-situ stress, pore pressure, and rock-mechanical properties) in the vicinity of the Gnu-1 well. Of prime concern was the verification of the predrill pore-pressure prediction previously undertaken using 3D-seismic-velocity data and offset-well data. Wellbore-failure and natural-fracture analyses were integral parts of the post-mortem. Wellbore breakouts seen in the image data allowed the pore pressure in the 8.5-in. hole section of Well Gnu-1 to be constrained. Modeling using image data collected in the Athol formation indicates that the pore pressure does not increase as rapidly as was estimated in the predrill study. Pore pressures in the North Rankin formation and below were consistent with the predrill study. The geomechanical model was able to explain the losses seen in the Athol formation in Well Gnu-1 when using the mud weights experienced by the open hole at the time of drilling. Introduction The Gnu prospect is situated in the northern portion of Block WA-209-P in the Dampier subbasin, Australian northwest shelf (Fig. 1). The prospect is located within the Reindeer gas field. A number of offset wells exist in the region, the closest wells being Well Reindeer-1 (approximately 1.5 km to the northeast) and Well Caribou-1 (2 km to the southeast). Well Gnu-1 was designed as an exploration well. The anticipated overburden stratigraphy at the location of Well Gnu-1 consists of Tertiary and Upper Cretaceous carbonates, marls and siltstones that overlie Cretaceous claystones, siltstones and minor sandstones, and greensands. The primary aim was to drill vertically to intersect the Muderongia australis glauconitic sandstone and then to build angle and continue drilling a deviated hole through the main Reindeer field gas appraisal within the Legendre formation and into the North Rankin, Brigadier, and Mungaroo formations.


1992 ◽  
Vol 32 (1) ◽  
pp. 56
Author(s):  
Adrian Williams ◽  
Dave Macey

Since start-up of Harriet oil production in early 1986, the TL/1 joint venturers have attempted to find a use for the oil-associated gas as well as other gas from neighbouring small gas fields. Initially, supplies from the North West Shelf Project were well in excess of local demand and acted as a damper on new development projects. With time, however, gas reserves in the Harriet area were augmented through new discoveries and the State's demand grew steadily until, in mid 1990, a new project could be justified. In December 1990, an agreement was reached with the State Energy Commission of Western Australia (SECWA) for the supply of 140 PJ (123 BCF) of gas over a ten year period, with an option for a further 65 PJ (57 BCF). First gas supplies are planned for June 1992.The project is based on the supply of Harriet solution gas as well as free gas from the Campbell, Sinbad and Rosette fields. Bambra is a potential future addition but is not required initially for the contract.The project involves small offshore platforms at Campbell and Sinbad, a wet gas pipeline from these platforms to Varanus Island, a facility on the Island to dry the gas and boost the pressure, and a transmission line to SECWA's system, approximately 100 km distant.The transmission pipeline has considerable reserve capacity over the initial contract flowrate of 30 to 60 TJ/day (26 to 52 MMCFGD) and provides a basis for further small gas projects utilising either flare gas from new oil developments or new gas field developments.


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