Henry C. Bland

Analyzing the effectiveness of receiver arrays for multicomponent seismic exploration

This paper uses an experimental seismic line recorded with three‐component (3C) receivers to develop a case history demonstrating very little benefit from receiver arrays as compared to point receivers. Two common array designs are tested; they are detrimental to the P‐S wavefield and provide little additional benefit for P‐P data. The seismic data are a 3C 2‐D line recorded at closely spaced (2 m) point receivers over the Blackfoot oil field, Alberta. The 3C receiver arrays are constructed by summing five (one group interval) and ten (two group intervals) point receivers. The shorter array emphasizes signal preservation while the longer array places priority on noise rejection. The effectiveness of the arrays versus the single geophones is compared in both the t−x and f−k domains of common source gathers. The quality of poststack data is also compared by analyzing the f−x spectra for signal bandwidth on both the vertical receiver component (P‐P) and radial receiver component (P‐S) structure stacks produc...

3-D depth migration: Parallel processing and migration movies

The advantages of parallel processors are shown by Figure 1 (taken from Kalantzis, 1994), which illustrates scalar, vector, parallel, and vector/parallel processes for putting out a fire with buckets of water. In scalar mode, a single processor performs the operation (one bucket carrier). In vector mode, the task is performed by a series of simultaneous operations on a vector or array of elements (the bucket brigade). In parallel mode, a number of processors perform similar tasks (several bucket carriers running in parallel). The vector/parallel operation has several lines of bucket brigades operating at once. Obviously, the latter would perform the fastest.

Passive Seismic Event Classification Techniques Applied to Heavy Oil Production from Cold Lake, Alberta

Passive seismic monitoring listens for small earthquakes (microseisms) that occur when there are stress changes in a reservoir (Maxwell and Urbancic, 2001). The CREWES Project at the University of Calgary is involved in passive seismic research with Imperial Oil Ltd. regarding reservoir monitoring at Cold Lake, Alberta, where more than 120,000 barrels of bitumen are produced each day (Imperial Oil Ltd., 2006).

Design of a Low Power, Wireless, Passive Seismic Monitoring Instrument

Rural and remote passive seismic monitoring sites are often challenged by the lack of power and communication utilities. Sites without power lines require costly on-site generation (from diesel, gasoline, propane) or self-sustaining power sources (solar, wind). In all cases, electrical power is a key component in the capital and operating cost of surface-based monitoring systems. An instrument was designed for environmental and oilfield passive seismic monitoring with very low power consumption. The device was designed to use either a wired or wireless network link for data communication. Designed for sample rates up to 4 KHz, the instrument is ideally suited for connection to seismic-band sensors such as geophones or accelerometers. A low-noise, high-gain, programmable gain preamplifier provides the necessary amplification for the A/D converter. Several of these instruments have been installed at two remote sites using wireless data transmission. Running on solar power alone, the instruments have operated very successfully over the past two years. Reliability and the availability of remote diagnostic facilities are found to be key components in a successful remote passive seismic monitoring program.

Analysis of the Effectiveness of 3-C Receiver Arrays For Converted Wave Imaging

During November 1997 the CREWES Project at the University of Calgary recorded a 3C-2D seismic survey at the Blackfoot field east of Calgary. This survey consisted of recording dynamite shots into a combination of conventional 20 m and high-resolution 2 m receiver intervals. We used this high-resolution data to examine two alternative approaches to array design by simulating 3-C receiver arrays via convolution in the t-x domain. The effectiveness of each approach was then evaluated by analyzing the response in both the t-x and f-k domains. The post-stack effect was also compared by analyzing the f-x response of both the final P-P and P-S structure stacks produced using these two array design philosophies.

Land vertical cable acquisition and analysis: Results from the Blackfoot high-resolution 3-C seismic survey

During November 1997, the CREWES Project at the University of Calgary acquired a high-resolution 3C-2D seismic survey at the Blackfoot field located east of Calgary. To test the feasibility of vertical cable acquisition in a land environment, a 48-channel hydrophone cable was deployed in a 100 m cased and water-filled hole located in the centre of the profile. The additional hydrophone channels were patched into the surface recording spread which allowed for the simultaneous recording of all 151 dynamite shots into the surface geophones and the vertical cable. Initial results of a VSPCDP stack of the entire hydrophone data revealed a continuity of reflectors across the section and good correlation with the surface seismic results. An average of the VSPCDP stacked traces near the hydrophone cable spliced between the surface seismic section demonstrated the ability to obtain reliable images from the hydrophone cable data.