Paulo Tarso Luiz Menezes

Petrobras is launching a multidisciplinary carbon capture and storage project at the Barra do Furado Fieldlab, onshore Campos Basin, to test geophysical methods for monitoring the CO2 plume in a deep saline aquifer. Planned activities include advanced 3D seismic and electromagnetic data acquisitions. However, gravity measurements are not part of the current strategy. From 2028 to 2031, approximately 0.36 million tonnes (Mt) of supercritical CO2 will be injected into a reservoir with an average thickness of 130 m at a depth of 1200 m. As part of our objectives at the monitoring site, we conducted a feasibility study using flow simulators to model gravity variations during the CO2 injection. Our results indicate that after two years of injection, the gravitational response exceeded the 1 µGal threshold, demonstrating the effectiveness of 4D surface gravity measurements for monitoring subsurface fluid dynamics. Based on these findings, it is recommended that Petrobras incorporate gravimetry into its current data-acquisition plan to enhance data collection and improve CO2 management strategies at the study site. Upon request, Petrobras will provide the academic community with the 4D density model and related data presented in this paper.

Recent advances in applied geophysics have greatly enhanced our ability to accurately image and understand the Earth’s physical characteristics and geological processes

Imaging subsalt layers is challenging in the BM-C-33 block in the Campos Basin’s ultradeep waters. This block is important because it has three significant gas and condensate discoveries in the presalt carbonate and volcanic reservoirs—Seat, Gávea, and Pão de Açucar. Understanding basement morphology is essential to better define the petroleum system in the area. To that end, we performed a 2D gravity modeling exercise along a northwest–southeast section using seismic interpretation as input to reduce the ambiguity of the modeling exercise. To achieve this, we fixed the main sedimentary horizons and their densities (calculated via well-log information) to better estimate the top of the basement morphology. This interpretation strategy better delineated the presalt sedimentary section and the complex structural framework with two asymmetric grabens bounded by a prominent horst, interpreted as a migration focusing high in the BM-C-33 area. In addition, our findings show that obtaining clear images remains challenging even after extensive processing of the seismic data set. We suggest that seismic node acquisition with ultralong offsets and multiazimuthal illumination and then carefully processing the data is required to accurately reveal the area’s prerift section and basement morphology under study.

Open-source geophysical datasets and synthetic earth models are becoming increasingly common in geosciences as they are required to study various geologic problems. There are published examples from several projects covering all geophysical methods at different scales and for diverse goals such as stratigraphy (Huber, 2019;Menezes, 2021), petroleum exploration (Fehler, 2009 To take part in the Resource Identification Initiative, please use the corresponding catalog number and RRID in your current manuscript. For more information about the project and for steps on how to search for an RRID, please click here.

The Parecis Basin, one of Brazil’s most extensive intracratonic basins, holds significant potential for hydrocarbon exploration. Despite its vast size, Parecis has yet to be extensively explored, with only five wildcat wells drilled. So far, no commercial discoveries have been announced. Regional studies have suggested Paleozoic sedimentation, while recent analyses have revealed a Neoproterozoic infill. Its tectonic model is still a matter of debate, and to date, no detailed structural map for the whole basin has been published. The present work proposes a new detailed structural map of the Parecis Basin based on a four-step interpretation workflow integrating seismic and gravimetric data. The first step includes converting the public 2D seismic lines to the depth domain. The second step is estimating the residual Bouguer anomaly, where the computed residual anomalies should relate to the basin’s tectonic features. The third step comprises the 2D forward modeling of the gravimetric anomalies using the 2D seismic interpretation as a constraint. The final step compiled all the interpreted features into our new structural map. This map reveals the top of the basement, forming a complex framework of horsts and grabens. Normal faults define the main structural style in the basin. Further, we could recognize thick, high-density bodies embedded in the crystalline basement. These bodies consist of Orosian–Calimian (1.8–1.6 Ga) mafic and ultramafic rocks, which may be a potential source for hydrogen exploration in the basin. Subsequent geophysical and geochemical surveys will assess the hydrogen potential in the area.

The Parecis Basin is one of the largest intracratonic basins in Brazil. Despite its considerable size, the basin has yet to be extensively explored, with only five wildcat wells drilled for hydrocarbons. So far, no commercial discoveries have been announced. Regional studies have suggested Paleozoic sedimentation, while recent studies indicate a Neoproterozoic fill. However, no tectonic model accurately describes the basin’s development, and no detailed structural map for the entire basin has been published. The present work presents a new detailed structural map of the Parecis Basin based on a four-step interpretation workflow integrating seismic and gravimetric data. The first step includes converting the public 2D seismic lines to the depth domain. The second step is estimating the residual Bouguer anomaly, where the computed residual anomalies should relate to the basin’s tectonic features. The third step comprises the 2D forward modeling of the gravimetric anomalies using the 2D seismic interpretation as a constraint. The final step compiled all the interpreted features into our new structural map. This map reveals the top of the basement, forming a complex framework of horsts and grabens. Normal faults define the main structural style in the basin. Further, we could recognize thick, high-density bodies embedded in the crystalline basement. These bodies consist of Orosian-Calimian (1.8-1.6 Ga) mafic and ultramafic rocks, which may be a potential source for hydrogen exploration in the basin. Subsequent geophysical and geochemical surveys will assess the hydrogen potential in the area.

Discriminating geological discontinuities is important for reservoir management because they influence storage capacity and fluid flow. Structural heterogeneities, such as faults and fractures, significantly impact the compartmentalization of the reservoir’s facies and affect the flow of hydrocarbons. These structures can act as the pore space for fluid storage, flow-control conduits, or barriers that allow the accumulation of exploitable volumes of oil and gas. Understanding these structures’ spatial and temporal development can significantly impact hydrocarbon exploration. Reservoir characterization is a critical process in the oil and gas industry that aims to comprehensively understand reservoir rocks and their fluid content and distribution. It is a multidisciplinary approach that combines geological, geophysical, and engineering datasets through statistical and deterministic mathematical models. Seismic datasets play a crucial role in reservoir characterization. Interpreters can use seismic data processing and imaging to interpret geological horizons and map faults, building complex geological models. Seismic inversion is also employed to estimate acoustic impedance and other petrophysical properties. Faults and fractures mapping are highly relevant themes in reservoir characterization. Identifying subtle faults and fractures is essential in specifying hydrocarbon migration paths and identifying bypassed oil accumulations. However, traditional seismic amplitude data interpretation should consider these structures more. In this study, we apply a high-resolution fault mapping workflow to map the subtle faults system at the Marlim field in the offshore portion of the Campos Basin. As an outcome, we imaged two separate fault trends inside and outside the Marlim reservoir.

Since its inception, applied geophysics methods have been crucial in the oil and gas exploration industry

We present a seafloor 4D gravity feasibility analysis for monitoring deep-water hydrocarbon reservoirs. To perform the study, we have simulated the gravity effect due to different density and pore pressure distributions derived from a realistic model of a turbiditic oil field in Campos Basin, offshore Brazil. These reservoirs are analogs of several other passive-margin turbiditic systems located around the world. We considered four reservoir scenarios including and not including seafloor subsidence. Our results indicate that the gravity responses are higher than the feasible value of 3 μGal 12 years following the base survey. The area of maximum gravity anomaly corresponds to where we suppose hydrocarbon extraction occurs. A maximum seafloor subsidence of 0.6 cm was estimated, resulting in no detectable gravity effects. Our results endorse the 4D seafloor gravity acquisition as a beneficial tool for monitoring deep-water passive-margin turbiditic reservoirs.