Bojan Brodic

Delineating structures controlling sandstone‐hosted base‐metal deposits using high‐resolution multicomponent seismic and radio‐magnetotelluric methods: a case study from Northern Sweden

Over the past few decades seismic methods have increasingly been used for the exploration of mineral, geothermal, and groundwater resources. Nevertheless, there have only been a few cases demonstrating the advantages of multicomponent seismic data for these purposes. To illustrate some of the benefits of three-component data, a test seismic survey, using 60 digital three-component sensors spaced between 2 m and 4 m and assembled in a 160 m-long prototype landstreamer, was carried out over shallow basement structures underlying mineralized horizons and over a magnetic lineament of unknown origin. Two different types of seismic sources, i.e., explosives and a sledgehammer, were used to survey an approximately 4 km-long seismic profile. Radio-magnetotelluric measurements were also carried out to provide constraints on the interpretation of the seismic data over a portion of the profile where explosive sources were used. Good quality seismic data were recorded on all three components, particularly when explosives were used as the seismic source. The vertical component data from the explosive sources image the top of the crystalline basement and its undulated/faulted surface at a depth of about 50 m–60 m. Supported by the radiomagnetotelluric results, however, shallower reflections are observed in the horizontal component data, one of them steeply dipping and associated with the magnetic lineament. The vertical component sledgehammer data also clearly image the crystalline basement and its undulations, but significant shear-wave signals are not present on the horizontal components. This study demonstrates that multicomponent seismic data can particularly be useful for providing information on shallow structures and in aiding mineral exploration where structural control on the mineralization is expected.

Delineating fracture zones using surface-tunnel-surface seismic data, P-S and S-P mode conversions

A surface-tunnel-surface seismic experiment was conducted at the Aspo Hard Rock Laboratoryto study the seismic response of major fracture systems intersecting the tunnel. A newly developedthree-com ...

Reducing the risk of hydrocarbon exploration and lithology characterization — using a neural network approach in the West Delta Deep Marine Concession Area, Offshore Nile Delta, Egypt

There are many approaches and concepts for the exploration and development of hydrocarbon reservoirs. In this study, we develop both a lithology classification and a gas chimney prediction workflow. We classify the entire seismic volume into its most likely facies domains and transform the seismic cube into a gas chimney probability cube. Both these approaches utilize a neural network algorithm, which we find is an efficient method to integrate the multiple input attributes required to extract the target log, or to isolate target features from the seismic background data. A combination of a set of seismic attributes (obtained from multilinear regression) with the nonlinearity of the artificial neural network technique is used to develop effective workflows to classify and explore the reservoirs. Analysis of the results helps to quantify the chance of success of the exploration prospects and also, in conjunction with the petroleum system of the prospects, leads to a reduced risk of the hydrocarbon exploration and development wells.It is estimated that urban life will be the norm for around 60% of the world’s population by 2040, leading to a more centralized distribution of people and making the city as the main place of resi ...

Bedrock and Fracture Zone Delineation UsingDifferent Near-surface Seismic Sources

To delineate the bedrock surface and a fracture zone intersected by a well at c. 50 m depth, a seismic survey wasconducted using four different near-surface seismic sources. These were a 5-kg sledg ...