High-resolution acoustic impedance inversion to characterize turbidites at Marlim Field, Campos Basin, Brazil

Abstract

Seismic inversion is routinely used to determine rock properties, such as acoustic impedance and porosity, from seismic data. Nonuniqueness of the solutions is a major issue. A good strategy to reduce this inherent ambiguity of the inversion procedure is to introduce stratigraphic and structural information a priori to better construct the low-frequency background model. This is particularly relevant when studying heterogeneous deepwater turbidite reservoirs that form prolific, but complex, hydrocarbon plays in the Brazilian offshore basins. We evaluated a high-resolution inversion workflow applied to 3D seismic data at Marlim Field, Campos Basin, to recover acoustic impedance and porosity of the turbidites reservoirs. The Marlim sandstones consist of an Oligocene/Miocene deepwater turbidite system forming a series of amalgamated bodies. The main advantage of our workflow is to incorporate the interpreter’s knowledge about the local stratigraphy to construct an enhanced background model, and then extract a higher resolution image from the seismic data. High-porosity zones were associated to the reservoirs facies; meanwhile, the nonreservoir facies were identified as low-porosity zones.

Marlim R3D: a realistic model for CSEM simulations - phase I: model building

“…We have built an integrated database in an open-source seismic platform and loaded the wells' information (stratigraphic markers and well-log curves), the dip-steering (DS) filtered seismic data and the main stratigraphic horizons interpreted by Nascimento et al (2014). Those authors have shown that the DS filtered data, in which random spurious noises were attenuated, highlight the main reflections related to stratigraphy and therefore they would be more amenable to interpretation.…”

“…To that end, we follow the interpretation of Nascimento et al (2014), that described the reservoir facies with the acoustic impedance lower-equal than 5,700 m/s.g/cm 3 and porosity in the 0.26-0.32% range.…”

“…The Horizon Cube was created using six stratigraphic intervals, bounded by the main horizons mapped by Nascimento et al (2014) The Horizon Cube is shown in Figure 5A, and the Vp cube is shown in Figure 5B. We used a single velocity of 4,500 m/s to the salt sequence (Schön 2015), and a regional velocity trend published by Bulhões et al (2015) to the sediments of the Lagoa Feia Group up to the basement rocks.…”

“…MR3D is based on previous 3D seismic interpretation (Nascimento et al 2014) and constrained by public welllog data and regional geological information.…”

Recognition of Anhydrite Intercalated Salt Deposit from Seismic Dataset Distorted by Noise

“…Inversion of seismic data is widely used in investigation of hydrocarbons to estimate reservoir geometry and petrophysical feature. High resolution pseudoacoustic impedance sections allow detailed lithology-fluid prediction at various stages of the reservoir life cycle [8]. The benefit of the inversion is that the seismic resolution is increased and pseudoacoustic impedance is closely connected to acoustic impedance of layers, so geological interpretation is more comfortable.…”