Measurements, predictions and results of geometrical repeatability in 4D seismic acquisition

2007 ◽  
Author(s):  
Ole E. Naess
Keyword(s):  
Seismic Acquisition ◽  
4D Seismic

Semiquantitative 4D seismic interpretation integrated with reservoir simulation: Application to the Norne field

2018 ◽  
Vol 6 (3) ◽  
pp. T601-T611
Author(s):  
Juliana Maia Carvalho dos Santos ◽  
Alessandra Davolio ◽  
Denis Jose Schiozer ◽  
Colin MacBeth
Keyword(s):  
Simulation Model ◽  
Reservoir Simulation ◽  
History Matching ◽  
Time Lapse ◽  
Seismic Signal ◽  
Seismic Interpretation ◽  
Production Forecast ◽  
Seismic Acquisition ◽  
Reservoir Simulation Model ◽  
4D Seismic

Time-lapse (or 4D) seismic attributes are extensively used as inputs to history matching workflows. However, this integration can potentially bring problems if performed incorrectly. Some of the uncertainties regarding seismic acquisition, processing, and interpretation can be inadvertently incorporated into the reservoir simulation model yielding an erroneous production forecast. Very often, the information provided by 4D seismic can be noisy or ambiguous. For this reason, it is necessary to estimate the level of confidence on the data prior to its transfer to the simulation model process. The methodology presented in this paper aims to diagnose which information from 4D seismic that we are confident enough to include in the model. Two passes of seismic interpretation are proposed: the first, intended to understand the character and quality of the seismic data and, the second, to compare the simulation-to-seismic synthetic response with the observed seismic signal. The methodology is applied to the Norne field benchmark case in which we find several examples of inconsistencies between the synthetic and real responses and we evaluate whether these are caused by a simulation model inaccuracy or by uncertainties in the actual observed seismic. After a careful qualitative and semiquantitative analysis, the confidence level of the interpretation is determined. Simulation model updates can be suggested according to the outcome from this analysis. The main contribution of this work is to introduce a diagnostic step that classifies the seismic interpretation reliability considering the uncertainties inherent in these data. The results indicate that a medium to high interpretation confidence can be achieved even for poorly repeated data.

4D seismic interpretation in a Nigerian deepwater field

2015 ◽  
Vol 3 (2) ◽  
pp. SP11-SP19 ◽  
Author(s):  
Oghogho Effiom ◽  
Robert Maskall ◽  
Edwin Quadt ◽  
Kazeem A. Lawal ◽  
Raphael Afolabi ◽  
...  
Keyword(s):  
Management Practices ◽  
Time Lapse ◽  
Seismic Interpretation ◽  
Lessons Learned ◽  
Water Flooding ◽  
Reservoir Architecture ◽  
Depositional Settings ◽  
Seismic Acquisition ◽  
Net To Gross ◽  
4D Seismic

To improve the management of a Nigerian deep water field, two vintages of 4D data have been acquired since field start up in 2005. The first Nigerian 4D seismic (monitor-I) in water depths greater than 1000 m was taken in this field in 2008, and the second monitor (monitor-II) was acquired in 2012. Compared to monitor-I, better geometric repeatability was achieved in monitor-II as the lessons learned from monitor-I were incorporated to achieve better results. The final normalized root mean square of monitor-II fast-track volume was 12% compared to 25% for monitor-I. The improved quality is attributed to improvements in the acquisition methodology and prediction of the effects of currents. Seismic interpretation of the field revealed two distinct turbidite depositional settings: (1) An unconfined amalgamated lobe system with low relief, high net-to-gross reservoir sands that exhibit fairly homogeneous water flooding patterns on 4D and (2) an erosional canyon setting, filled with meander belts having a more complex 3D connectivity within and between the channels resulting in a challenging 4D interpretation. The time lapse data were instrumental for better understanding the reservoir architecture, enabling improved wells and reservoir management practices, the identification of infill opportunities, and more mature subsurface models. We evaluated the seismic acquisition and the 4D interpretation of the deepwater 4D seismic data, highlighting the merits of a multidisciplinary collaborative understanding to time-lapse seismic. At present, the value of information of the 4D monitor-II is conservatively estimated at 101 million United States dollars, equivalent to the cost of a well in this deepwater operating environment.

Fit for purpose 4D seismic acquisition-Petronius 2012 experience and lessons learned.

2013 ◽  
Author(s):  
Baraka D. Kinabo ◽  
Heather Bedle ◽  
Bernard Regel ◽  
Hugo Hidalgo ◽  
George Chou ◽  
...  
Keyword(s):  
Lessons Learned ◽  
Seismic Acquisition ◽  
Fit For Purpose ◽  
4D Seismic

Multiwell 3D distributed acoustic sensing vertical seismic profile imaging with engineered fibers: CO2CRC Otway Project case study

Geophysics ◽  
2021 ◽  
Vol 86 (6) ◽  
pp. D241-D248 ◽  
Author(s):  
Alexey Yurikov ◽  
Konstantin Tertyshnikov ◽  
Roman Isaenkov ◽  
Evgenii Sidenko ◽  
Sinem Yavuz ◽  
...  
Keyword(s):  
Low Cost ◽  
Optimal Solution ◽  
Time Lapse ◽  
Local Area ◽  
Seismic Profile ◽  
Enhanced Backscattering ◽  
Seismic Acquisition ◽  
Vsp Data ◽  
4D Seismic

The 4D surface seismic monitoring is a standard method for reservoir surveillance during the production of hydrocarbons or CO2 injection. However, land 4D seismic acquisition campaigns are often associated with high cost and disruptions to industrial operation or agricultural activities in the area of acquisition. An alternative technique for time-lapse monitoring of the subsurface is the 3D vertical seismic profiling (VSP), which becomes particularly attractive when used with distributed acoustic fiber-optic sensors (DAS) installed in wells. The advantages of 3D DAS VSP include its relatively low cost, minimal footprint on the local area during acquisition, and superior spatial resolution compared to the resolution of geophones. The potential of this technique is explored by processing and analyzing multiwell 3D DAS VSP data acquired at the CO2CRC Otway Project site in Victoria, Australia. The DAS data were recorded using an engineered fiber with enhanced backscattering cemented behind the casing of five wells. The data from each well are processed individually using the same processing flow and then migrated using a 3D migration code tailored to DAS data. Having DAS along the full extent of multiple wells ensures adequate seismic coverage of the area of CO2 injection. The migrated images provide detailed information about the subsurface up to 700 m away from a well and up to 2 km depth. The images are consistent with previously acquired geophone VSP and surface seismic data. The quality of the 3D DAS VSP imaging is comparable or superior to the quality of conventional imaging using geophone data. Therefore, 3D DAS VSP is a demonstrably optimal solution for reservoir monitoring.

4D PLANNING AND EXECUTION STRATEGIES FOR AUSTRALIAN RESERVOIR MONITORING PROJECTS

2006 ◽  
Vol 46 (1) ◽  
pp. 67
Author(s):  
A.S. Long ◽  
M. Widmaier ◽  
M.A. Schonewille
Keyword(s):  
Time Lapse ◽  
Seismic Signal ◽  
Reservoir Simulations ◽  
Reservoir Models ◽  
Processing Strategies ◽  
Reservoir Monitoring ◽  
Seismic Acquisition ◽  
4D Seismic ◽  
Interactive Visualisation ◽  
Time Acquisition

Time-lapse (4D) reservoir monitoring is in its infancy in Australia, but is on the verge of becoming a mainstream pursuit. We describe the 4D seismic acquisition and processing strategies that have been developed and proven elsewhere in the world, and customise those strategies for Australasian applications.We demonstrate how a multidisciplinary pursuit of real-time acquisition and processing Quality Control (QC) is an integral component of any 4D project. The acquisition and processing geophysicists must be able to understand all the factors contributing to the 4D seismic signal as they happen. Such an understanding can only arise through rigorous project QC and management using interactive visualisation technology. In turn, the production geologists and reservoir engineers will then receive 4D seismic products that can be robustly and confidently used for the construction of accurate reservoir models and the pursuit of reliable reservoir simulations and forecasts.

Unlocking 4D seismic technology to maximize recovery from the pre-salt Rotliegend gas fields of the Southern North Sea

2017 ◽  
Vol 8 (1) ◽  
pp. 465-471 ◽  
Author(s):  
Jonathan Brain ◽  
Thomas Lassaigne ◽  
Mathieu Darnet ◽  
Peter Van Loevezijn
Keyword(s):  
Travel Time ◽  
North Sea ◽  
Field Tests ◽  
Time Lapse ◽  
Gas Production ◽  
Southern North Sea ◽  
Before And After ◽  
Seismic Acquisition ◽  
Uncertain Time ◽  
4D Seismic

AbstractThe Southern North Sea is a mature gas basin, producing mainly from faulted Permian Rotliegend sandstones. Identifying infill well opportunities in un-depleted or partially depleted blocks in these fields is challenging, particularly if the sealing capacity of faults within a field is uncertain. Time-lapse (4D) seismic monitoring provides an opportunity to identify depleted reservoir blocks by measuring differences in travel time across the producing interval between seismic surveys acquired before and after gas production. 4D seismic field tests were initially performed by Nederlandse Aardolie Maatschappij (NAM) and Shell in 2001. However, the observed travel-time differences proved to be smaller than predicted and any possible signals were too noisy to confidently detect depletion. Since then, advances in seismic acquisition and processing technology have improved the accuracy of 4D measurements and enabled the effective mapping of 4D related gas depletion signals. 4D seismic has now been deployed over a number of fields in the Southern North Sea, and a portfolio of infill opportunities has been identified. In 2015, the first 4D targeted infill well was successfully drilled into a block with limited depletion. This technology represents a breakthrough for operators seeking to maximize hydrocarbon recovery and extend field life in the Rotliegend play of the Southern North Sea.

4D seismic acquisition feasibility and technology study in the SY region

2010 ◽  
Author(s):  
Wang Dan ◽  
Liu Bing ◽  
Sun Xiuying ◽  
Yang Dawei ◽  
Gao Jun
Keyword(s):  
Technology Study ◽  
Seismic Acquisition ◽  
4D Seismic

4D Seismic Detectability in a Brazilian Pre-Salt Carbonate Field

2021 ◽  
Author(s):  
Cyril Agut ◽  
Tom Blanchard ◽  
Ya-Hui Yin ◽  
Adeoye Adeyemi
Keyword(s):  
Dynamic Interactions ◽  
Pvt Data ◽  
Flow Units ◽  
Water Alternating Gas ◽  
Reservoir Flow ◽  
Full Complement ◽  
Seismic Acquisition ◽  
Dynamic Simulation Model ◽  
Gassmann Fluid Substitution ◽  
4D Seismic

Abstract This paper is dedicated to a pre-salt carbonate field located within the Santos Basin, Brazil, comprising thick Aptian reservoirs interspersed with igneous rocks. One of the main challenges for reservoir management is the surface constraint on the gas, as all of the produced gas will have to be reinjected and can be miscible with the in-situ hydrocarbons. The recovery mechanism selected is mainly WAG (water alternating gas) injection, with both producers and injectors equipped with intelligent completions using Inflow Control Valves (ICVs). A 4D seismic monitoring survey is planned to delineate gas and water fronts in reservoir flow units about 10m thick, providing critical information to help piloting a planned 6-month WAG cycle for improved recovery. Seismic imaging is challenging in this case and 4D signal is expected to be weak (±2% dIp/Ip). We propose here, a methodology, based on a 1-D Gassmann fluid substitution model at wells (only limited reservoir fluid PVT data available) to rapidly answer the following pertinent questions as posed by the asset team in charge of the field: From a phenomenological stand-point and neglecting some possible processing, imaging and acquisition challenges, will 4D data (post 4D inversion) detect a gas streak from an injector to a producer? What is the 4D seismic detection limit based on reservoir thickness? What kind of seismic acquisition will assure this detectability? Under the assumptions made in this work, this methodology shows that a permanent system of acquisition seems to be a fit-for-purpose technology for detectability. Further work is however recommended using full complement of a 3D static and dynamic simulation model coupled with a complete fluid PVT model in order to assess more complex 3D dynamic interactions between the injectors and producers.

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