Seismic surveys at an artificially created field-test cavern within a salt pillar

2020 ◽  
Author(s):  
Heike Richter ◽  
Rüdiger Giese ◽  
Axel Zirkler ◽  
Bettina Strauch
Keyword(s):  
Field Test ◽  
Seismic Data ◽  
Field Experiments ◽  
Experimental Simulation ◽  
Seismic Survey ◽  
Baseline Survey ◽  
Multiphase System ◽  
Rock Interaction ◽  
Seismic Surveys ◽  
Salt Rocks

<p>Salt rocks serve as host rock for technical caverns due to their impermeability but their can also be influenced by fluid migration due to geological fracture zones. Seismic methods can be used to monitor cavernous structures in the transition zone between cavity and undisturbed salt rocks. Around an artificially created cavity (field-test cavern) in a salt pillar with a volume of approximately 100 litre, travel time tomography was utilized to image structures related to caverns and fluid-storage. Seismic surveys were performed at different stages of an experimental simulation of gas-water-rock interaction in the field-test cavern aiming for a better understanding of the multiphase system in the cavern-near area. The baseline survey (1) was carried out using 8 three-component piezo-electrical sensor rods and a seismic vibrator source at the surface of the salt pillar, first without an installed field-test cavern. After drilling and installing the field-test cavern, seismic cross-hole measurements were performed after producing partial vacuum in the test cavern (2) and infill of gas (3) and water (4). To finalize the field experiments the last seismic survey (5) was again conducted at the surface of the salt pillar as a repeat measurement to the baseline survey. The seismic monitoring of the salt pillar was carried out in a frequency range of 100 Hz to 14000 Hz allowing a spatial resolution in the cm-range. This was followed by pre-processing of the seismic data sets to apply the picked travel times in a tomography program. On the basis of the tomography results and reflection seismic data we want to assess the potential enlargement of the field-test cavern due to water-infill and to image the differences between unaffected salt rocks, cavernous structures and developing transition zones.</p>

Discrimination between pressure and fluid saturation changes from time‐lapse seismic data

Geophysics ◽  
2001 ◽  
Vol 66 (3) ◽  
pp. 836-844 ◽  
Author(s):  
Martin Landrø
Keyword(s):  
Seismic Data ◽  
Time Lapse ◽  
Seismic Survey ◽  
Baseline Survey ◽  
Water Contact ◽  
Data Set ◽  
Seismic Surveys ◽  
Fluid Saturation ◽  
Oil Water ◽  
Pressure Changes

Explicit expressions for computing saturation‐ and pressure‐related changes from time‐lapse seismic data have been derived and tested on a real time‐lapse seismic data set. Necessary input is near‐and far‐offset stacks for the baseline seismic survey and the repeat survey. The method has been tested successfully in a segment where pressure measurements in two wells verify a pore‐pressure increase of 5 to 6 MPa between the baseline survey and the monitor survey. Estimated pressure changes using the proposed relationships fit very well with observations. Between the baseline and monitor seismic surveys, 27% of the estimated recoverable hydrocarbon reserves were produced from this segment. The estimated saturation changes also agree well with observed changes, apart from some areas in the water zone that are mapped as being exposed to saturation changes (which is unlikely). Saturation changes in other segments close to the original oil‐water contact and the top reservoir interface are also estimated and confirmed by observations in various wells.

WARROON GAS DISCOVERY SUPPORTS EXPLORATION OF ANTICLINES

1981 ◽  
Vol 21 (1) ◽  
pp. 85
Author(s):  
B. R. BROWN
Keyword(s):  
Seismic Data ◽  
Acoustic Impedance ◽  
Gas Condensate ◽  
Seismic Survey ◽  
Seismic Surveys

Warroon, a small gas condensate discovery in the western Surat Shelf, was mapped as a faulted anticline from seismic data shot in April 1979. The discovery well was drilled in August 1979 on the then highest known point of the mapped closure. The well flowed up to 8 MMcf/D from about 2.4 m (eight feet) of Showgrounds Sandstone over the gross interval 2 048 to 2 060 m (6 720 to 6 760 ft). Subsequently, two small seismic surveys comprising 62 km and including experimental shooting and acoustic impedance processing have been shot over the anticline. A step-out will be considered in the 1981 drilling program.The discovery of gas and condensate in Warroon, and in the Glen Fosslyn discovery in an adjacent permit, optimistically suggests that the prospective area of the Wunger Ridge may be extended. A major seismic survey comprising over 450 km of 12-fold 96 channel recording was shot in the Spring of 1980. The interpretation of the data could lead to proposals to drill a number of wildcats on structures similar in appearance to Warroon.

Innovative high trace density design with broadband seismic data acquisition in the Cooper–Eromanga Basins, Australia

2018 ◽  
Vol 58 (2) ◽  
pp. 773
Author(s):  
John Archer ◽  
Milos Delic ◽  
Frank Nicholson
Keyword(s):  
Seismic Data ◽  
Survey Design ◽  
New Technology ◽  
Time Frame ◽  
Seismic Survey ◽  
Baseline Survey ◽  
3D Seismic ◽  
Seismic Data Acquisition ◽  
Trace Density ◽  
Cooper Basin

Through a combination of innovative survey design, new technology and the introduction of novel operational techniques, the trace density of a 3D seismic survey in the Cooper Basin was increased from a baseline of 140 000 to 1 600 000 traces km–2, the bandwidth of the data was extended from four to six octaves, and the dataset was acquired in substantially the same time-frame and for the same cost as the baseline survey.

A comparative study of multi-scaled high-resolution seismic surveys in shallow marine environments: examples from three sites, offshore Korea

2020 ◽  
Author(s):  
Young Jun Kim ◽  
Snons Cheong ◽  
Deniz Cukur ◽  
Dong-Geun Yoo
Keyword(s):  
High Resolution ◽  
Data Processing ◽  
Seismic Data ◽  
Single Channel ◽  
Seismic Source ◽  
Seismic Survey ◽  
Minimum Length ◽  
Seismic Surveys ◽  
Air Gun ◽  
Target Depth

<p>In marine seismic surveys, various acquisition systems are used depending on the survey purpose, target depth, survey environment, and conditions. A 3D survey of oil and/or gas exploration, for instance, require large-capacity air-gun arrays and six or more streamers with a minimum length of 6 km. In contrast, a high-resolution seismic survey for the shallow-water geological research and engineering needs a small capacity source such as air-gun, sparker, and boomer, deployed with a single-channel or multi-channel (24-channel) streamers. The main purpose of our seismic survey was to investigate the Quaternary geology and stratigraphy of offshore, Korea. Because the Quaternary is the most recent geological period, our target depth was very shallow at about 50 m below the sea-bottom. We used a high-frequency seismic source including a sparker of 2,000 J capacity or a 60 in<sup>3</sup> mini GI-gun and an eight-channel streamer with a 3.125 m group interval or a single-channel streamer that included 96 elements. To compare the resolution of seismic data according to the seismic source, a boomer or sparker systems were used with the single-channel streamer on a small survey ship. The seismic data processing was performed at the Korea Institute of Geoscience and Mineral Resources (KIGAM) with ProMAX, and the data processing and resolution of each survey were compared based on their acquisition systems.</p>

SHELL'S OFFSHORE VENTURE, IN SOUTH AUSTRALIA

1978 ◽  
Vol 18 (1) ◽  
pp. 44
Author(s):  
R. K. Whyte
Keyword(s):  
Deep Water ◽  
Seismic Data ◽  
South Australia ◽  
Field Work ◽  
Seismic Survey ◽  
Total Expenditure ◽  
Aeromagnetic Survey ◽  
Well Drilling ◽  
Seismic Surveys ◽  
Geological Information

Offshore South Australia permit O.E.L. 38 was granted to Shell Development (Aust.) Pty. Ltd. on 1st January 1966. An aeromagnetic survey of 10,300 km, three seismic surveys totalling 10,300 km and five man months of coastal field work were carried out before the permit was reissued at the end of 1968 as three separate permits SA-5, SA-6 and SA-7 under the newly enacted joint offshore legislation. At that time Shell also secured two adjoining deep Water permits SA-10 and SA-11.In the period 1969-70 two seismic surveys totalling some 11,750 km were shot. Given geophysical results, a six well drilling programme was planned to commence early 1972. Two dry wells, Platypus-1 and Echidna-1 were drilled in early 1972 in SA-6 and SA-7, with Platypus-1 providing some geological encouragement.Several more prospects were found in SA-6 and SA-7 by the 1973 and 1974 seismic surveys, but these were so small that further work could not be economically justified. SA-6 and SA-7 were surrendered in late 1975 without further wells being drilled. Potoroo-1 was drilled in early 1975 in SA-5. It severely downgraded the prospectivity of that permit, leading to early relinquishment later in 1975, but provided vital geological information relevant to permits SA-10 and SA-11 where drilling was due to commence in 1978. A detail seismic survey in the latter two permits was shot in 1976. Prior to 1976, the main incentive for exploration of the deepwater play had been the apparent presence of a very large anticlinal trend in the central part of SA-10. Interpretation of the 1976 survey showed this trend to be non-prospective, and as a result SA-10 and SA-11 were relinquished in April, 1977. This ended a venture in which three wells were drilled and 24,546 km of seismic data recorded for a total expenditure of $15,837,000.

Modeling velocity changes associated with a miscible flood in the Prudhoe Bay Field

Geophysics ◽  
1997 ◽  
Vol 62 (5) ◽  
pp. 1442-1455
Author(s):  
Robert J. Withers ◽  
Michael L. Batzle
Keyword(s):  
Seismic Data ◽  
Baseline Survey ◽  
Time Varying ◽  
Seismic Surveys ◽  
Recovery Processes ◽  
Fluid Saturation ◽  
Fluid Velocities ◽  
Gassmann’S Equation ◽  
Velocity Changes ◽  
Prudhoe Bay

The Prudhoe Bay Field, Alaska, is produced by a number of recovery processes. A miscible gas (MI) injection pilot was studied to see if repeated seismic surveys could detect the progress of the MI gas. Gassmann's equation was used on the injection, producing and monitor wells where a detailed reservoir simulation was available. Time‐varying saturations of the three fluid phases and the pressure were used to calculate the expected velocity of the reservoir at different stages of the injection. The differences between the modeled velocities at two extremes of gas saturation after the water‐after‐gas (WAG) range up to 500 ft/s (150 m/s). It was concluded that it have been possible to detect the fluid saturation had a baseline survey been collected early in the field's development. Unfortunately, initial production introduced 2% gas into the fluid, muting later attempts to map changes in saturation that varied from between 30% and 60%. Additionally, the use of a WAG process further complicated the gas mapping by both increasing and decreasing the reservoir fluid velocities. Collecting new seismic data over this pilot was not recommended. The modeling exercise highlighted a number of issues that are important in monitoring other reservoirs. Amongst these are the timing of data collection and the weakness of the petrophysical models caused by the numerous assumptions that are required in the absence of field observations. It was demostrated that modeling exercises can both save unnecessary field expenses and provide considerable insight in reservoir behavior.

Seismic solutions utilizing existing in-mine infrastructure for mineral exploration: A case study from Maseve platinum mine, South Africa

2022 ◽  
Vol 41 (1) ◽  
pp. 54-61
Author(s):  
Moyagabo K. Rapetsoa ◽  
Musa S. D. Manzi ◽  
Mpofana Sihoyiya ◽  
Michael Westgate ◽  
Phumlani Kubeka ◽  
...  
Keyword(s):  
South Africa ◽  
Seismic Data ◽  
Mineral Exploration ◽  
Ground Surface ◽  
Seismic Survey ◽  
Noisy Environment ◽  
Borehole Data ◽  
Passive Seismic ◽  
Below Ground

We demonstrate the application of seismic methods using in-mine infrastructure such as exploration tunnels to image platinum deposits and geologic structures using different acquisition configurations. In 2020, seismic experiments were conducted underground at the Maseve platinum mine in the Bushveld Complex of South Africa. These seismic experiments were part of the Advanced Orebody Knowledge project titled “Developing technologies that will be used to obtain information ahead of the mine face.” In these experiments, we recorded active and passive seismic data using surface nodal arrays and an in-mine seismic land streamer. We focus on analyzing only the in-mine active seismic portion of the survey. The tunnel seismic survey consisted of seven 2D profiles in exploration tunnels, located approximately 550 m below ground surface and a few meters above known platinum deposits. A careful data-processing approach was adopted to enhance high-quality reflections and suppress infrastructure-generated noise. Despite challenges presented by the in-mine noisy environment, we successfully imaged the platinum deposits with the aid of borehole data and geologic models. The results open opportunities to adapt surface-based geophysical instruments to address challenging in-mine environments for mineral exploration.

scholarly journals Time-Lapse Seismic Monitoring of Onshore Reservoirs in Niger Delta, Field ‘K’ as a Case Study

2017 ◽  
Vol 1 (1) ◽  
pp. 23-27 ◽  
Author(s):  
A. Ogbamikhumi ◽  
T. Tralagba ◽  
E. E. Osagiede
Keyword(s):  
Seismic Data ◽  
Acoustic Impedance ◽  
Niger Delta ◽  
Rock Physics ◽  
Time Lapse ◽  
Seismic Survey ◽  
Impedance Change ◽  
Data Set ◽  
Reservoir Fluid ◽  
4D Seismic

Field ‘K’ is a mature field in the coastal swamp onshore Niger delta, which has been producing since 1960. As a huge producing field with some potential for further sustainable production, field monitoring is therefore important in the identification of areas of unproduced hydrocarbon. This can be achieved by comparing production data with the corresponding changes in acoustic impedance observed in the maps generated from base survey (initial 3D seismic) and monitor seismic survey (4D seismic) across the field. This will enable the 4D seismic data set to be used for mapping reservoir details such as advancing water front and un-swept zones. The availability of good quality onshore time-lapse seismic data for Field ‘K’ acquired in 1987 and 2002 provided the opportunity to evaluate the effect of changes in reservoir fluid saturations on time-lapse amplitudes. Rock physics modelling and fluid substitution studies on well logs were carried out, and acoustic impedance change in the reservoir was estimated to be in the range of 0.25% to about 8%. Changes in reservoir fluid saturations were confirmed with time-lapse amplitudes within the crest area of the reservoir structure where reservoir porosity is 0.25%. In this paper, we demonstrated the use of repeat Seismic to delineate swept zones and areas hit with water override in a producing onshore reservoir.

3D baseline seismics at Ketzin, Germany: The C O2 SINK project

Geophysics ◽  
2007 ◽  
Vol 72 (5) ◽  
pp. B121-B132 ◽  
Author(s):  
Christopher Juhlin ◽  
Rüdiger Giese ◽  
Kim Zinck-Jørgensen ◽  
Calin Cosma ◽  
Hesam Kazemeini ◽  
...  
Keyword(s):  
Injection Site ◽  
Seismic Survey ◽  
Depth Interval ◽  
Storage Site ◽  
Borehole Data ◽  
Seismic Surveys ◽  
Drilling Operations ◽  
Heterogeneous Formation ◽  
Gas Chimneys ◽  
East West

A 3D 25-fold seismic survey with a bin size of 12 by [Formula: see text] and about [Formula: see text] of subsurface coverage was acquired in 2005 near a former natural gas storage site west of Berlin, as part of the five-year EU funded [Formula: see text] project. Main objectives of the seismic survey were to verify earlier geologic interpretations of structure based on vintage 2D seismic and borehole data and to map, if possible, the reservoir pathways in which the [Formula: see text] will be injected at [Formula: see text] depth, as well as providing a baseline for future seismic surveys and planning of drilling operations. The uppermost [Formula: see text] are well imaged and show an anticlinal structure with an east-west striking central graben on its top that extendsdown to the target horizon. About [Formula: see text] of throwis seen on the bounding faults. No faults are imaged near the planned drill sites. Remnant gas, cushion and residual gas, is present near the top of the anticline in the depth interval of about [Formula: see text] and has a clear seismic signature; both higher amplitudes in the reservoir horizons and velocity pulldown are observed. Amplitude mapping of these remnant gas horizons shows that they do not extend as far south as the injection site, which is located on the southern flank of the anticline. Amplitude anomalies, gas chimneys along an east-west striking fault, show that the stored or remnant gas either has been or is presently migrating out of the reservoir formations. Summed amplitude mapping of the planned injection horizon indicates that this lithologically heterogeneous formation may be more porous at the injection site.

DEMETER HIGH RESOLUTION 3D SEISMIC SURVEY—REVITALISED DEVELOPMENT AND EXPLORATION ON THE NORTH WEST SHELF, AUSTRALIA

2006 ◽  
Vol 46 (1) ◽  
pp. 101 ◽  
Author(s):  
K.J. Bennett ◽  
M.R. Bussell
Keyword(s):  
High Resolution ◽  
Seismic Data ◽  
New Technologies ◽  
Seismic Survey ◽  
Future Application ◽  
3D Seismic ◽  
Gas Field ◽  
North West ◽  
The North ◽  
Exploration And Development

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.

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