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Results
ABSTRACT TomoSeis Inc. (a division of Core Laboratories) acquired a crosswell seismic survey for Numac Energy Inc. in the Crystal Viking Oil Pool, in Alberta Canada, about 180 miles (300 km) northwest of Calgary. The goal of the survey was to delineate a high porosity sand (as described in Reinson et al 1988, fine to medium grained sandstone) within the incised valley system of the Viking Formation for horizontal development drilling. Two crosswell profiles were acquired, modeled, processed and interpreted to help design the trajectory of a planned horizontal well. The well was drilled and confirmed the interpretations.
- Geology > Geological Subdiscipline > Economic Geology > Petroleum Geology (0.50)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Sandstone (0.35)
- North America > Canada > Saskatchewan > Western Canada Sedimentary Basin > Alberta Basin > Viking Formation (0.99)
- North America > Canada > Alberta > Western Canada Sedimentary Basin > Alberta Basin > Viking Formation (0.99)
- North America > Canada > Alberta > Western Canada Sedimentary Basin > Alberta Basin > Redwater Viking Field > Viking Formation (0.99)
- (2 more...)
- Well Drilling > Drilling Operations > Directional drilling (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Seismic processing and interpretation (1.00)
- Reservoir Description and Dynamics > Formation Evaluation & Management (1.00)
ABSTRACT Drill-bit seismic data can provide valuable information about reflector characteristics above or below the drill bit. In this paper, an interferometric migration method is developed and applied to synthetic data and Union Pacific Resources Corporation (UPRC) drill-bit data. UPRC data are recorded on the earth’s free surface while a tricone drill bit and down hole motor were used to drill along a horizontal trajectory at a depth of 9188 ft in the Austin Chalk formation. Crosscorrelograms were migrated based on the primary-ghost imaging condition. The merit of interferometric or crosscorrelogram migration is that both drill-bit position and pilot signal do not need to be known and is applicable to deviated wells.
- Well Drilling > Drill Bits (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Seismic processing and interpretation (1.00)
ABSTRACT Drilling-related problems cost the oil industry large amounts of money. Drill-bit seismic data can be used to detect drilling hazzards in sections drilled with rollercone bits and at relatively small water depths. An interesting alternative is VSP data acquired while drilling. Using a drill string equipped with receivers and a repeatable surface source, zero-offset and offset VSP data can be used to put the drill bit on the surface seismic section, and to compute the distance to reflectors ahead of the bit. Walkaway data have a potential both for structural imaging and for detection of overpressured sediments ahead of the bit. We discuss some potential application of VSP while drilling data. The applications are illustrated with simple numerical examples.
- Well Drilling (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Near-well and vertical seismic profiles (1.00)
ABSTRACT Mud filtrate invasion can occur in many types of permeable hydrocarbon bearing formations. It often causes sonic logs to be too fast and density logs to be too high because these logs are sampling mostly water saturated rock. Uncorrected, it can cause substantial errors in well ties to seismic. The problem can be easily detected with multiple depth resistivity logs and then can be corrected using careful application of Biot-Gassmann fluid substitution.
- North America > United States > Texas (0.17)
- Europe > Norway (0.16)
- Geophysics > Seismic Surveying > Seismic Processing (1.00)
- Geophysics > Borehole Geophysics (1.00)
- Geophysics > Seismic Surveying > Seismic Interpretation > Well Tie (0.35)
- Well Drilling > Formation Damage (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Seismic processing and interpretation (1.00)
- Reservoir Description and Dynamics > Formation Evaluation & Management > Open hole/cased hole log analysis (1.00)
The cracks in a porous matrix which is subjected to a change in the applied stress or fluid pressure will undergo a distortion related to their orientation relative to the principal directions of the applied stress. Both the crack distribution and the fluid-flow properties of the aggregate will be altered as a consequence of a change in either the applied stress or fluid pressure, resulting in a change in the effective elastic parameters of the material. An effective medium theory, based on the method of smoothing and incorporating a transfer of fluid between connected cracks via non-compliant pores, is used to derive an expression for the effective elastic parameters of the material, to first order in crack density. This expression involves a dependence on both the applied stress and the fluid pressure, and is used to determine the effects on the anisotropy of the effective medium of the applied stress and fluid pressure. A biaxial compressive stress is applied to an isotropic crack distribution to determine the anisotropy of the (transversely isotropic) effective medium as a function of differential pressure. As a result of competing processes, the theory predicts that there is a pressure at which the anisotropy reaches a maximum value before the properties of the effective medium decay, under increasing stress, to those of the uncracked matrix.
- Europe > United Kingdom (0.29)
- North America > United States > Texas (0.17)
- Well Drilling (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Seismic processing and interpretation (1.00)
Summary The ability to identify discoveries associated with non-bright pay has been somewhat elusive. Large structural discoveries are a thing of the past and with the maturing of many of the world’s known producing fields, amplitude discoveries are also becoming harder to find. The ability to identify pay found in non-bright zones could play a crucial role in future exploration scenarios. It will be shown that by using rock property contrast volumes that these areas of non-bright pay can be identified. It will also be shown that using these rock property contrast volumes may highlight potential horizons of bypassed pay in areas of known production associated with bright amplitudes.
- Reservoir Description and Dynamics > Reservoir Characterization > Seismic processing and interpretation (0.98)
- Well Drilling > Wellbore Design > Rock properties (0.83)
- Reservoir Description and Dynamics > Reservoir Characterization > Reservoir geomechanics (0.83)
Summary Seismic-while-drilling (SWD) services efficiently support drilling decisions. They use the vibrations produced by the drill-bit during perforation as a downhole seismic source. The seismic signal is recorded by sensors on the surface and it is processed in order to obtain/update an image of the subsurface around the borehole. To improve the characterization of the source, some sensors have been experimentally installed also downhole, on the drill pipes in close proximity to the bit: data logged downhole have been able to give better quality information. Currently, the main drawback of downhole equipments is the absence of a high bit-rate telemetry system to enable real-time activities. This problem may be solved by employing either an off-line solution, with limited memory capacity up to few hundreds of Mbytes; or an on-line solution with telemetry at a very low bit-rate (few bits/s).
- Well Drilling > Drilling Operations (1.00)
- Well Completion (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Seismic processing and interpretation (1.00)
- Well Drilling > Drill Bits (0.91)