This page contains a Flash digital edition of a book.
Seismic Survey


Sean Ottewell looks at a new seismic survey technique which enhances palaeochannel mapping, oil sands and regolith characterisation.


Sean Ottewell examina una nueva técnica de encuesta sísmica que mejora el proyección del paleocanal, las arenas petrolíferas y la caracterización de regolita.


Sean Ottewell untersucht eine neue Technik für seismischen Aufschluss, die die Kartierung von Paläokanälen sowie die Charakterisierung von Ölsanden und Regolith verbessert.


Enhanced definition of near-surface layers


I


mprovements to near-surface resolution and depth of exploration are continuous goals for exploration customers engaged in geological mapping and mineral exploration.


Previously, customers were forced to choose a system which had been optimally tuned to achieve one of these goals while sacrificing some capability in the other. Now CGG has launched


MULTIPULSE, an innovative new near-surface and deep-penetrating electromagnetic (EM) survey technique which increases resolution and bandwidth. Te proprietary MULTIPULSE technology combines the benefits of the trusted CGG airborne time-domain EM products HELITEM, GEOTEM, MEGATEM and TEMPEST, by offering both a high-power pulse (half-sine wave) for depth of exploration, and a lower- power pulse (square wave) for near- surface resolution; both within one cycle, providing the value of two exploration techniques in one pass (Fig. 1). MULTIPULSE technology can be applied on either CGG fixed-wing or helicopter time-domain systems, offering customers a cost-effective option for regional projects and a premium option providing maximum spatial resolution. Exploration customers can expect to benefit from the enhanced definition of


near-surface layers such as palaeochannel mapping, oil sands and regolith characterisation for engineering or agricultural applications as well as in mineral exploration for low-conductivity targets such as porphyry deposits, sedimentary exhalative deposits (SEDEX), volcanic-associated massive sulphide (VMS) and Mississippi valley type (MVT) deposits. In addition, better mapping of the weakly conductive alteration haloes around many deposit types can be obtained. In other developments the company has successfully completed a second BroadSeis multi-client survey offshore Norway. Te survey covers a 2300km2 area in the Barents Sea. Fast-track processing deliverables will be available by the end of 2013 and final processing products by August 2014. Tis second BroadSeis 3D survey is located in the south eastern part of the Barents Sea adjacent to the recent eastward extension of Norwegian territory as a result of the border agreement between Norway and Russia. New data is required to assess the petroleum potential in this region. Te Barents Sea BroadSeis survey


follows on from CGG’s recent first BroadSeis multi-client survey offshore Norway which targeted the Halten


Fig. 1. Top section: square wave (TEMPEST) – near-surface resolution. Middle section: half-sine (GEOTEM) – greater depth of exploration. Bottom section: MULTIPULSE – combining the near-surface and deeper information without compromising resolution.


Image courtesy of CGG. www.engineerlive.com 79


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68  |  Page 69  |  Page 70  |  Page 71  |  Page 72  |  Page 73  |  Page 74  |  Page 75  |  Page 76  |  Page 77  |  Page 78  |  Page 79  |  Page 80  |  Page 81  |  Page 82  |  Page 83  |  Page 84