BCGS Technical Talk – January 20, 2016
Speaker: Ross Polutnik, SJ Geophysics Ltd.
Title: Advances in 3DIP Array Design: Characteristics of Customizable Distributed Arrays
Date/Time: Wednesday January 20, 2016 @ 4:30pm
Location: 4th Floor Conference Room, Room 451, 409 Granville St. (UK Building at Granville and Hastings), Vancouver
Advances in 3DIP Array Design: Characteristics of Customizable Distributed Arrays
Syd Visser, Ross Polutnik, SJ Geophysics Ltd., Delta, Canada
Since the early 90’s, SJ Geophysics has been continually developing and experimenting with unconventional IP array designs. Current customized arrays utilized with the Volterra acquisition system make use of cross-line dipoles to improve the azimuthal distribution of the data. A key aspect of any IP survey, the selected array design must meet the survey objectives determined at the start of the project.In the mineral exploration industry, survey design rarely gets the time and attention that it deserves. Rather, surveys are acquired by essentially “shooting in the dark” using last week’s parameters in the hopes that the target of interest will become illuminated and the picture more clear. Unfortunately, this approach simply doesn’t work. A well defined survey objective and a-priori geologic information must be taken into consideration during the survey evaluation and design process in order to get the best results.
All to often the survey objectives are overlooked by the potential client when requesting a survey and replaced with “How deep can I see?” Their hope is to have an answer in 30 seconds. In trying to answer this question for clients, the importance of good array design becomes important.
Simple 2D-inline arrays have evolved into complex customizable arrays such as the diamond array that incorporate dipoles in multiple directions to maximize signal coupling and improve surface resolution. An examination of receiver arrays and how they affect the resulting data collected will be discussed. Data examples from real world surveys will be provided to illustrate the benefits of 3DIP array designs. A key example is the Ootsa Property, owned by Gold Reach Resources. In 2013, SJ Geophysics took the initiative to re-survey the Seel deposit to compare their new 3DIP acquisition equipment and survey methods against an older IP survey acquired using conventional 2DIP and early 3DIP systems. The benefits of advanced 3D array designs is evident in the resulting inversion models.