Petroleum Geo-Services (United Kingdom)

• Experimental determination of physicochemical properties of DPA. • Modeling and simulation of thermophysical properties of DPA solution. • Modeling and simulation of EOR performances of DPA/polymer injection. Sustainable oil recovery has become imperative due to environmental and economic concerns. It has also necessitated exploration of plant-based injectants for enhanced chemical oil recovery (CEOR). Date palm ash (DPA) is a waste product from combustion of palm fibers and shells. In this research, injection of DPA solution for CEOR has been proposed due to its high alkalinity. For this purpose, a series of studies including experimental determination of physico-chemical properties as well as thermodynamic modeling and simulation of thermophysical properties have been employed to characterize DPA solutions. Subsequently, numerical modeling and simulation of EOR performance considering DPA-polymer injection was conducted as proof of concept. Experimental results show that DPA contains different elements including Ca, K, Mg, Al, Na, P, S, Cl, and Si, as well as transition metals such as Mn, Fe, Cu, and Zn, typical of wood biomass ash. In addition, an alkaline medium (pH: 10 - 13) was obtained from 0.1 - 10 % wt/wt. DPA solution. The thermodynamic simulation and analysis show that the hypothetical DPA solution is characterized by the presence of basic cations (Ca 2+ , K + , Mg 2+ , and Na + ), hydroxides (CaOH + and MgOH + ), and carbonates (CO 3 2- and HCO 3 - ). Furthermore, pertinent thermophysical properties including osmotic pressure (39.04 - 4469.8 kPa), ionic strength (0.0148 - 1.194 mol/kgw), heat capacity (75.21 - 157.21 kJ/kgmole), and conductivity (1.42 - 125.21 mS/cm) were calculated for the solution. Similarly, the viscosity, density, and molecular weight of the DPA solution (0.1 - 10 % wt/wt.) were found to range between 0.891 to 1.047 cP, 0.9998 to 1.08 g/cm 3 , and 18.03 to 19.6 g/mol, respectively. Ultimately, the EOR simulation showed that DPA solution could be applied for alkaline assisted polymer flooding to mitigate polymer adsorption and improve oil recovery with overall performance similar to those observed using synthetic caustic (NaOH) injection.

A 3D Ultra High Resolution Seismic (UHRS) survey was initiated in the summer of 2023, offshore USA. The survey, utilizing a P-Cable system, covers an expansive area very efficiently. The near-surface stratigraphy, ranging from the Miocene to the Holocene, provides a geological context challenging for effective site characterization.The processing workflows for 3D UHRS data, although sharing similarities with conventional seismic processing sequences, require enhancement due to significant scale differences. High-Performance Computing (HPC) resources are vital for processing the high-density and small-samplingrate 3D UHRS data. Key steps include achieving a broadband wavelet via data-driven deghosting and designature techniques. Accurate statics computation addresses challenges arising from sea state variations, ensuring clear and sharp reflections. The demultiple step, utilizing methods like convolutional 3D Surface Related Multiple Elimination (SRME) and 3D wave-equation multiple modeling, effectively removes unwanted reverberations, providing a cleaner seismic dataset.While the acquisition and processing are ongoing, preliminary post-stack time migration results provide a continuous 3D volume with high vertical and spatial resolution. The 3D aspect provides an invaluable platform for interpretation, small features detection, shallow geohazard investigation, and quantitative analysis.

Environmental impact mitigation is one of the grand challenges for industries globally. Volatile organic compounds (VOCs) are solvents whose emissions are potentially toxic to human health and ecosystems yet indispensable for the manufacturing of life-saving medicine. Adsorption with activated carbon columns is an established countermeasure for end-of-pipe emission control, whose efficiency, however, is impeded by irregular bed saturation due to the complex nature of its inputs. This work presents the application of a validated nonisothermal adsorption model to examine multicomponent trace mixtures of acetone-toluene and benzene-toluene on activated carbon. Our results indicate preferential adsorption of toluene over both acetone and benzene for all concentrations examined, which is in agreement with experimental data. Moreover, moderate temperature variations and pressure drops are revealed. Finally, Glueckauf's hodograph theory is employed for maximum outlet concentration prediction and compared with simulation results and experimental data, thus providing valuable insights into nonisothermal VOC abatement, which paves the way for industrial operation optimization.

Abstract Seismic fluid indicators are highly accurate when calibrated, but when the data is scarce, an interpreter must choose between different indicators. We investigate the data from multiple basins to understand the most effective fluid indicators for use. Unlike previous studies, the data comprises a large, equal, and statistically meaningful number of hydrocarbon and brine sands from different basins. We show that Poisson’s ratio-LambdaRho templates can be used to separate different facies in synthetic and real data and can be used as a useful crossplot interpretation tool. We develop a fluid indicator, as LambdaRho Poisson’s ratio multiplication (λρ)σ, which is highly sensitive to saturation and can be potentially used as a fizz-gas discriminator. We compare the sensitivity of different fluid indicators to hydrocarbon saturation by using Bhattacharyya distance, which provides a quantitative metric for how well different indicators separate hydrocarbon and brine sands, and it is a nonparametric measure unlike other fluid indicator scores developed in similar studies. Absolute properties derived from seismic by inversion are rarely available in regional studies, whereas relative elastic properties can be easily obtained and used. Following the concepts of elastic reflectivity vectors and geometry of intercept-gradient crossplots, we show how the reflectivity of different fluid indicators can be approximated from amplitude variation with offset (AVO) parameters at various chi (χ) angles, enabling an interpreter to use them even when inversion products are not available. Finally, we compare the effectiveness of relative elastic parameters on different AVO classes and show that no single attribute works best across all classes but for general screening purposes fluid factor and R((λρ)σ) can be good choices. The findings of this study can help better characterization of fluids in exploration, appraisal, and development of hydrocarbons, and in other areas where monitoring produced and injected fluids is important like 4D seismic or carbon capture storage.

Summary In the autumn of 2023, a 3D Ultra-High-Resolution Seismic (UHRS) survey using a P-Cable system was initiated for a major offshore wind developer. The survey efficiently covered a large area and provided detailed near-surface stratigraphy. Enhanced processing workflows, requiring significant High-Performance Computing (HPC) resources, were developed to handle the high-density and high-frequency data. Key steps included data-driven deghosting, complex designature techniques, and 3D wave-equation multiple modelling. Post-stack time migration resulted in a high-resolution 3D volume, aiding in geological interpretation, small feature detection, and potential future quantitative analysis. This study underscores the potential of 3D UHRS data to decrease offshore wind farm development by removing the need for additional survey campaigns.

Summary We introduce a method using Fourier neural operators to rapidly generate a high-quality starting model for FWI or joint inversion. Instead of directly moving from field shot gathers to velocity, we migrate the data to produce angle gathers. Our approach leverages the simplicity of mapping within the model space and the reduced variety of data features in migrated angle gathers, making it easier to train a neural network. This gather-based migration velocity analysis is valuable for quickly estimating a starting velocity, leading to fewer FWI iterations in finalizing the velocity model. We showcase a successful inference derived from 3D, full azimuth field data collected offshore Brazil using ocean-bottom nodes. A few iterations of low-frequency RTM were sufficient to go from a featurelessly smooth model to one which had the 3D structure of the salt mostly defined, and shallow and deep sediments approximately corrected. In complex settings (e.g., salt), this could be a valuable tool for rapidly generating a model suitable for input to FWI.

Summary This abstract proposes a novel deghosting solution for Ultra-High-Resolution (UHR) seismic data. The solution addresses the problem of the non-stationarity of the receiver ghost period which is caused by variations in the sea-state. This problem is more visible when the streamers are towed at a shallow depth which is often the case for UHR surveys. For this reason, most of the proposed solutions in the literature track the period of the ghost and then remove it by Wiener filtering. However, this is done trace-by-trace, and it is clearly sub-optimal because of the 3D nature of the ghost. Moreover, the Wiener deconvolution filter has a limited ability to control the amount of spectral boosting at the different orders of the notch frequency and this increases the potential risk for ringing artefacts in the output. The proposed solution solves these issues by tracking and deconvolving the ghost in the (τ-p) domain which is more physically correct. Deconvolution of the ghost operator is done via re-weighted iterative least squares which offers a better management of the ringing artefacts. The proposed deghosting solution has been validated on UHR dataset and was found to be effective and robust in removing the receiver ghost.

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Abstract Modern broadband seismic data provides new regional insight into the underexplored deep-water offshore basin geometry of the Pase Sub-basin, from its basin segmentation with intra-basinal highs grabens to the development and prospectivity of syn-post-rift clastic reservoir sections proven in the prolific onshore area. The high degree of basin segmentation in the NW Sub-basin has led to the development of local depocenters in grabens with accumulation of thick clastic sections and potential for reservoirs sands. The clastic input and accumulation in the sub-basins were controlled by the intra basinal highs acting in periods as structural barriers disconnecting the grabens or as clastic input providers through erosion.