A case history of time-lapse 3D seismic surveys at Cold Lake, Alberta, Canada

Geophysics ◽  
2006 ◽  
Vol 71 (4) ◽  
pp. B93-B99 ◽  
Author(s):  
J. Helen Isaac ◽  
Don C. Lawton
Keyword(s):  
Oil Recovery ◽  
Time Lapse ◽  
Steam Injection ◽  
Production Cycle ◽  
3D Seismic ◽  
Data Set ◽  
Seismic Surveys ◽  
History Of ◽  
Interval Velocities ◽  
Cold Lake

Time-lapse 3D seismic surveys were acquired across a bitumen field at Cold Lake, Alberta, Canada, during a production cycle (1990) and a steam-injection cycle (1992) of a thermal-enhanced oil recovery (EOR) program. We observed changes in interval traveltime and amplitude distributions between the processed surveys. We interpret the increased traveltimes observed over most of the injection survey to be a result of lowered interval velocities in the reservoir, caused primarily by higher temperature and lower effective pressure. Reflection-strength variations within the reservoir are present in each data set and change spatially between the surveys. In general, we interpret the amplitude anomalies seen only on the production survey to be caused by local free gas and the amplitude anomalies seen only on the injection survey, which are close to the perforation depths, to be caused by thin, vertically restricted steamed zones.

A case history of experimental time-lapse 3C 2D seismic reflection data for reservoir monitoring at Cold Lake, Alberta, Canada

2014 ◽  
Vol 2 (2) ◽  
pp. SE47-SE54
Author(s):  
J. Helen Isaac ◽  
Don C. Lawton
Keyword(s):  
Seismic Reflection ◽  
Time Lapse ◽  
Steam Injection ◽  
Converted Wave ◽  
Injection Wells ◽  
Seismic Reflection Data ◽  
Experimental Time ◽  
Reflection Data ◽  
History Of ◽  
Cold Lake

We processed, interpreted, and analyzed experimental time-lapse converted-wave 2D-seismic reflection data that were acquired across a bitumen field undergoing cyclical steam injection and production at Cold Lake, Alberta, Canada. The purpose was to assess whether multicomponent-seismic data could be used to detect lateral and/or temporal changes caused by steam injection into the reservoir. We interpreted horizons on PP and PS sections that bracket the reservoir, and calculated [Formula: see text] over this interval. Away from the steam injection wells, [Formula: see text] values average [Formula: see text] during steaming and production and are close to the theoretically predicted value of 2.21 for a cold reservoir. Near the wells, [Formula: see text] is lower during steam injection than during production, averaging [Formula: see text], and the lowest values are observed close to the injection wells. We attributed the changes in [Formula: see text] to changes in the reservoir caused by the injection of steam.

Time-lapse seismic signal analysis for enhanced oil recovery at Cranfield CO2 sequestration site, Cranfield field, Mississippi

2013 ◽  
Vol 1 (2) ◽  
pp. T157-T166 ◽  
Author(s):  
Julie Ditkof ◽  
Eva Caspari ◽  
Roman Pevzner ◽  
Milovan Urosevic ◽  
Timothy A. Meckel ◽  
...  
Keyword(s):  
Oil Recovery ◽  
Time Lapse ◽  
Seismic Signal ◽  
Injection Well ◽  
Saturation Curve ◽  
Seismic Surveys ◽  
Seismic Amplitude ◽  
The Difference ◽  
Seismic Volumes ◽  
4D Seismic

The Cranfield field in southwest Mississippi has been under continuous [Formula: see text] injection by Denbury Onshore LLC since 2008. Two 3D seismic surveys were collected in 2007 and 2010. An initial 4D seismic response was characterized after three years of injection, where more than three million tons of [Formula: see text] remain in the subsurface. This interpretation showed coherent seismic amplitude anomalies in some areas that received large amounts of [Formula: see text] but not in others. To understand these effects better, we performed Gassmann substitution modeling at two wells: the 31F-2 observation well and the 28-1 injection well. We aimed to predict a postinjection saturation curve and acoustic impedance (AI) change through the reservoir. Seismic volumes were cross-equalized, well ties to seismic were performed, and AI inversions were subsequently carried out. Inversion results showed that the change in AI is higher than Gassmann substitution predicted for the 28-1 injection well. The time-lapse AI difference predicted by the inversion is similar in magnitude to the difference inferred from a time delay along a marker horizon below the reservoir.

Time-lapse acoustic impedance variations during CO2 injection in Weyburn oilfield, Canada

Geophysics ◽  
2019 ◽  
Vol 85 (1) ◽  
pp. M1-M13 ◽  
Author(s):  
Yichuan Wang ◽  
Igor B. Morozov
Keyword(s):  
Oil Recovery ◽  
Seismic Data ◽  
Acoustic Impedance ◽  
Time Lapse ◽  
Time Shift ◽  
Co2 Injection ◽  
Inversion Method ◽  
Data Sets ◽  
Storage Site ◽  
Data Set

For seismic monitoring injected fluids during enhanced oil recovery or geologic [Formula: see text] sequestration, it is useful to measure time-lapse (TL) variations of acoustic impedance (AI). AI gives direct connections to the mechanical and fluid-related properties of the reservoir or [Formula: see text] storage site; however, evaluation of its subtle TL variations is complicated by the low-frequency and scaling uncertainties of this attribute. We have developed three enhancements of TL AI analysis to resolve these issues. First, following waveform calibration (cross-equalization) of the monitor seismic data sets to the baseline one, the reflectivity difference was evaluated from the attributes measured during the calibration. Second, a robust approach to AI inversion was applied to the baseline data set, based on calibration of the records by using the well-log data and spatially variant stacking and interval velocities derived during seismic data processing. This inversion method is straightforward and does not require subjective selections of parameterization and regularization schemes. Unlike joint or statistical inverse approaches, this method does not require prior models and produces accurate fitting of the observed reflectivity. Third, the TL AI difference is obtained directly from the baseline AI and reflectivity difference but without the uncertainty-prone subtraction of AI volumes from different seismic vintages. The above approaches are applied to TL data sets from the Weyburn [Formula: see text] sequestration project in southern Saskatchewan, Canada. High-quality baseline and TL AI-difference volumes are obtained. TL variations within the reservoir zone are observed in the calibration time-shift, reflectivity-difference, and AI-difference images, which are interpreted as being related to the [Formula: see text] injection.

THE DIRKALA SOUTH OIL DISCOVERY: FOCUSSING ON COST-EFFICIENT RESERVOIR DELINEATION

1995 ◽  
Vol 35 (1) ◽  
pp. 65
Author(s):  
S.I. Mackie ◽  
C.M. Gumley
Keyword(s):  
Production Performance ◽  
Seismic Survey ◽  
3D Seismic ◽  
Seismic Attribute ◽  
Data Set ◽  
Seismic Surveys ◽  
Seismic Modelling ◽  
Attribute Analysis ◽  
Cost Efficient ◽  
The Cost

The Dirkala Field is located in the southern Murta Block of PEL's 5 and 6 in the southern Cooper and Eromanga Basins. Excellent oil produc­tion from a single reservoir sandstone in the Juras­sic Birkhead Formation in Dirkala-1 had indicated a potentially larger resource than could be mapped volumetrically. The hypothesis that the resource was stratigraphically trapped led to the need to define the fluvial sand reservoir seismically and thereby prepare for future development.A small (16 km2) 3D seismic survey was acquired over the area in December 1992. The project was designed not only to evaluate the limits of the Birkhead sand but also to evaluate the cost effi­ciency of recording such small 3D surveys in the basin.Interpretation of the data set integrated with seismic modelling and seismic attribute analysis delineated a thin Birkhead fluvial channel sand reservoir. Geological pay mapping matched volu­metric estimates from production performance data. Structural mapping showed Dirkala-1 to be opti­mally placed and that no further development drill­ing was justifiable.Seismic characteristics comparable with those of the Dirkala-1 Birkhead reservoir were noted in another area of the survey beyond field limits. This led to the proposal to drill an exploration well, Dirkala South-1, which discovered a new oil pool in the Birkhead Formation. A post-well audit of the pre-drill modelling confirmed that the seismic response could be used to determine the presence of the Birkhead channel sand reservoir.The acquisition of the Dirkala-3D seismic survey demonstrated the feasibility of conducting small 3D seismic surveys to identify subtle stratigraphically trapped Eromanga Basin accumulations at lower cost and risk than appraisal/development drilling based on 2D seismic data.

Time-lapse velocity analysis — Application to onshore continuous reservoir monitoring

Geophysics ◽  
2018 ◽  
Vol 83 (3) ◽  
pp. B105-B117 ◽  
Author(s):  
Julien Cotton ◽  
Hervé Chauris ◽  
Eric Forgues ◽  
Paul Hardouin
Keyword(s):  
Heavy Oil ◽  
Reservoir Characterization ◽  
Real Data ◽  
Time Lapse ◽  
Velocity Model ◽  
Steam Injection ◽  
Calendar Time ◽  
Data Set ◽  
Time Migration ◽  
Velocity Changes

In 4D seismic, the velocity model used for imaging and reservoir characterization can change as production from the reservoir progresses. This is particularly true for heavy oil reservoirs stimulated by steam injection. In the context of sparse and low-fold seismic acquisitions, conventional migration velocity analyses can be inadequate because of a poorly and irregularly sampled offset dimension. We update the velocity model in the context of daily acquisitions with buried sources and receivers. The main objective is to demonstrate that subtle time-lapse effects can be detected over the calendar time on onshore sparse acquisitions. We develop a modified version of the conventional prestack time migration to detect velocity changes obtained after crosscorrelation of the base and monitor surveys. This technique is applied on a heavy oil real data set from the Netherlands and reveals how the steam diffuses over time within the reservoir.

Seismic reflection amplitude versus angle variations over a thermally enhanced oil recovery site

Geophysics ◽  
1991 ◽  
Vol 56 (2) ◽  
pp. 292-301 ◽  
Author(s):  
C. Tsingas ◽  
E. R. Kanasewich
Keyword(s):  
Enhanced Oil Recovery ◽  
Oil Recovery ◽  
Seismic Reflection ◽  
Amplitude Ratio ◽  
Steam Injection ◽  
Angle Of Incidence ◽  
Seismic Experiment ◽  
New Type ◽  
Cold Lake ◽  
Amplitude Versus

In recent years it has become increasingly important to develop a capability for monitoring enhanced oil recovery (EOR) processes as they are occurring within any reservoir. An amplitude‐versus‐angle (AVA) analysis over a steam injection location showed encouraging results and established that seismic reflection methods, when well designed and carefully processed, can be used to map the invaded steam zones in steam stimulation EOR operations. The results are imaged on a new type of display called ARPA (amplitude‐ratio for partial angle), which illustrates reflection zones with low or high Poisson’s ratio or equivalently high or low gas saturation with a CMP stack section plotted as the background. A seismic experiment consisting of three reflection lines was carried out by Esso Resources in February, 1984 over a steam injection site near Cold Lake, Alberta. Analysis of the field data showed that large variations in reflected scattered energy were a function of angle of incidence in areas affected by the steam zone.

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