Laserfiche WebLink
Bird Seismic Field Operations <br />The seismic reflection method proposed for this survey involves sound waves reflected from (echoed) from rock layers under the ground <br />surface. <br />The sound waves are generated by a truck mounted 458 pound weight driven by a nitrogen gas spring impacting a thick aluminum plate held <br />on the ground surface by the weight of the vehicle (AF450). The echoing waves are detected by sensitive ground motion sensors called <br />geophones, which in turn are connected by cable to recording instruments where the data is digitized and sent on to the recording truck, <br />displayed and stored. The data is then sent to a processing facility where the data is organized and processed by a qualified geophysicist, <br />resulting in a 2D section of the earth. <br />The following is a description of field operations for 2D seismic reflection exploration. <br />The site is permitted and arrangements are made for survey crew access. The site is scouted and assessed, and parameters are set. A <br />surveyor lays out the geophone location using wire stake flags and a dot of ground marking paint every 110 feet, the points surveyed with GPS <br />or optical survey equipment. <br />The proposed survey consists of 3 or 4 seismic lines a bit under 5 miles in length each. Every 110 feet along the receiver lines will be placed a <br />group of 4 geophones spaced approximately 18 feet apart. The source truck will also move along this line. <br />A pickup truck will drive down the seismic line dropping off cables and sets of geophones as it drives along the lines. Crew members walk <br />along the line planting the geophones by hand and foot, pushing them into the ground. An ATV is used for troubleshooting faulty equipment at <br />times. 4 geophones, connected together by wire, one geophone every few feet are pressed into the ground approximately 3 ", and connected to <br />a seismic cable (an Ethernet network cable) running to a recording instrument "box" every 660 feet, the length of the total array approximately <br />3 3/ miles. A geophone is approximately a 2" square plastic molded sensor with a 3" long metal spike protruding from the bottom. The <br />recording box is a rectangular aluminum box measuring 8" by 4" by 1 % inches, and has a small sealed battery to power it. <br />At a location along this array of cables and equipment the recording trailer is parked and the data recorded on and displayed by a computer <br />when the weight drop source truck is activated. The source truck does its work along the sensor array, timed by radio link with the recording <br />system. The source truck will thump every 110 feet, about 3 — 6 times at that location, and then move to the next station 110 feet away. Then <br />another crew comes along hand picking the geophones, and a pickup truck following along to spool the wire back into the truck. <br />This continues along the entire length of the line. As the source truck moves up every 110 feet, we disconnect a group of geophones from the <br />back part of the line and gain a new one in the front (the forward direction) of the proposed profile. The seismic array "travels" along the entire <br />line. <br />After the survey is complete the crew will pick up the flags and flagging the crew used to mark the line locations <br />The source truck (Digipulse) is environmentally friendly and we have worked in several locations along roads, on county roads (Martin County, <br />Texas April 2005, approved by the county road department head present on the survey site), farm fields, prairie, desert, and other areas with <br />little or no noticeable pad mark left behind. We have also worked on top of high pressure gas lines with no problems (Huntsville Utilities, <br />Huntsville, Alabama). <br />We are estimating a production rate of 2 to 3 miles a day. <br />Bird Seismic Services, Inc., (928) 719 -1848 Cell, (928) 425 -3342 Fax, Kenneth Bernstein, kengbirdseismic.com , PO Box 1062, <br />Globe, Arizona 85502 <br />