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Marine seismic acquisitions record both primary and multiple wavefields. In a typical processing sequence, multiple energy is removed from the data before migration. However, there may be valuable information contained in the multiple wavefield. To discover this hidden information, reverse time migration of multiples (RTMM) was proposed. We evaluated the advantages of RTMM through three different real data processing projects and identified three key advantages. Additionally, we present a synthetic study of two types of crosstalk noise that hinder the full potential of RTMM as well as propose corresponding practical strategies to handle them.

The heterogeneity in geological properties of carbonate rocks makes their acoustical behaviour more difficult to model and predict than siliciclastics. This uncertainty in prediction normally is attributed to their pore structure complexity and heterogeneity. Pore structure in carbonate is a result of the place they are deposited combining with subsequent post-depositional processes to form the final carbonate rock. Carbonates can form in different depositional environments and subsequently can undergo into various diagenesis regimes. This combination along with their chemically active mineralogy makes them susceptible for complex and heterogeneous pore structures. This study investigates variation of carbonates depositional environment on their velocity behavior. It, furthermore, uses this information to quantify a more comprehensive pore model for carbonate rocks. This geology dependent workflow is tested on a number of carbonate core-plugs from two exploration wells with ultrasonic measurements. The results confirm application of this workflow for defining a more comprehensive pore model compared with the routine approach using only Wyllie time average by defining maximum two pore types. This study uses another reference curve from depositional environment in addition to the routine approach to derive a more general (geology oriented) pore aspect ratio spectrum.

It has been well documented that the pre-stack seismic attributes can be an efficient tool for hydrocarbon exploration and pore fluid detection using techniques like Amplitude Versus Offset (AVO) analysis. These studies mainly focus on siliciclastics rather than carbonates as fluid effects in carbonate rocks can be masked by their complex pore structure. These fluid detection seismic attributes usually reside on a linear background model for P- and S-velocities of the water-saturated rocks, and any deviation from this trend is assigned to the possible pore fluid changes. This means that fake (or even missed) fluid effects can be detected in carbonate rocks if the fluid detection seismic attributes, which designed for siliciclastics, are used. This can mainly be related to the nonlinearity of background model in carbonates due to their varying pore structure. In this study, both well logs and seismic data from a carbonate sequence are used to show that the correlation between P- and S-velocities in water-saturated carbonates becomes more linear when considering P-velocity squared versus the product of the P- and S-velocities. Furthermore, this linear version is used for detecting the fluid anomalies, and being compared with other various fluid factors to highlight the gas saturated interval. The modified fluid attribute displays the gas-saturation brighter than the alternatives, although, in this case, all the studied indicators perform well and consistently.

This article highlights some important outcomes from an integrated study in the Anadarko Basin. Newly generated data is presented and discussed across the study area. The main aspects discussed here focus on 1) basin evolution, which has played an important role in source maturity and hydrocarbon generation. 2) Source rock characterization, including source rock properties and quantification of the hydrocarbon content performed with a newly developed pyrolysis method and 3) reservoir characterization based on the integration of regional information and data generated from seismic reservoir characterization. These aspects are discussed to assess their implications on hydrocarbon distribution within unconventional resources from Woodford and Mississippian section. In the last section of this article, we propose a play assessment workflow that could be applied to address uncertainties associated with these plays. This workflow comprises 1) a regional or basin-scale evaluation based on 3D petroleum system modelling (3D PSM) and 2) a more detailed evaluation based on the integration of seismic reservoir characterization into petroleum systems modeling on a local scale.

FWI velocity models do not necessarily ensure an optimal flattening of common image gathers (CIG). A fundamental reason for this is that mid to high wavenumbers are brought into the model by the reflection amplitudes, which are only partly explained by changes in velocity. A residual low wavenumber update of the model is then frequently done with the consequence that the positioning of small-scale events in the model may no more be consistent with the migrated image. In this paper we first highlight and illustrate the above mentioned pitfalls. We then propose an innovative workflow based on FWI-guided tomography.

Summary of the evolution based processing and imaging of the Montrose/Arbroath fields of the Central North Sea, with a focus on new demultiple technology in the form of wave equation deconvolution, Ghost Wavefield Elimination using legacy NFH recordings, joint reflection/refraction tomography followed by Q-FWI and reservoir focused QC based on collaboration with Repsol Sinopec.