Carbonates are infamous for their complex intrinsic heterogeneity, exaggerated due to stratification and layered geology. Characterization and correlation of this heterogeneity with recovery mechanisms becomes critical pertaining to Lower Cretaceous reservoir ‘A’ with over 4 decades of production/injection history. Hence, it is pertinent to systematically reduce the uncertainties associated with reservoir characterization by delineating high permeability streaks, permeability-contrasts, links between geological and petrophysical facies and their impact on field scale production/injection strategies. Emphasis was put on capturing downhole dynamic Kv/Kh profile across sub layers of the reservoir ‘A’, to enable assignment of representative values into reservoir simulation model with associated reservoir zonation. Vertical interference testing (VIT) was designed in a crestal location well with a history of near-by waterflooding, integrating simulator-based outputs with petrophysical and borehole image logs of an offset. Drawdown-buildup cycle was performed across source probe or packer, while simultaneous monitoring of pressure at observation probe. To reduce uncertainty and incorporate statistical sense into the data, multiple cycles of drawdown-buildup were conducted for vertical connectivity evaluation. In total, eleven VIT tests conducted with formation tester tool utilizing dual-straddle-packer and two-probe modules were interpreted implementing a systematic approach considering vertical communication as a function of geological facies and textural aspects from borehole images, geological information on fractures/faults, and surfaces. Interpretation involves identification of flow-units based on available logs, followed by identification of flow regimes (spherical/radial) to history-match data for estimation of horizontal and vertical permeabilities of each layer. Resultant analysis yielded insights on anisotropy by validating vertical communication through stylolite and across dense layers. Integration of VIT analysis results (Kh,Kv,Kv/Kh) with petrophysical logs led to the establishment of water flood advancement mechanism in this observation well at the crestal location of field. This establishes a critical link between integrated geological, textural and facies analysis in context of sedimentology, layering and rock quantified fabric permeability indicators visible on high vertical and horizontal resolution borehole image. Thereby, allowing derivation of scalable answer products and workflows. Subsequently, explaining water flood mechanism and enabling updating of simulation model for enhanced reservoir characterization. Furthermore, this also allows for field development augmentation and injection strategy optimization through linking of dynamic results to reservoir description of two major sub-layers of this giant carbonate field. Integration and analysis of key insights on vertical communication and carbonate anisotropy with major geological/petrophysical features aided in characterizing 3D static and dynamic models. This would allow improved trajectory planning of future wells, leading to improvement in recovery efficiency through guided injection strategy. Additionally, proactive data aggregation and insightful interpretation to help accelerate realization of value from field development strategy was highlighted.

This work is done in the context of a giant carbonate reservoir with 40 years of production/injection history. In this reservoir, the key heterogeneities that impact the production mechanisms (high permeability streaks, permeability contrast, intra dense and dual sub-zones of varying maturity) are well characterized, through major field reviews. However, in the recent years, unexpected high water saturation were encountered while drilling infill horizontal drains. An integrated multi-scale investigation was conducted to understand the potential mechanism of water movement within the lower sub-zone through an assimilation and interpretation of data and multi-disciplinary understanding. This work resulted in further optimization of remaining infill wells and the field development strategy. The observed high water saturation signatures were investigated through integration and analysis of multi-disciplinary data, using data acquired in infill wells during the last three (3) years. First, the studied wells were categorized primarily based on their water cut, water saturation encountered and then mapped along with their data. Second, the different scenarios of possible water movement were developed chronologically. Third, a multi-scale integrated analysis (well level to reservoir level) and subsequent mapping was captured on a montage. The developed scenarios were validated with recent surveillance, monitoring data and corroborated with geological/geophysical understanding. This comprehensive approach and results were corroborated with blind tests in terms of the dynamic behavior of the water. Faults and their characteristics were identified as a key element affecting this local dynamic behavior. Saturation logs showed high water saturation but were inconclusive on whether this water is mobile or not. This required integration with dynamic flow data from production logging and well tests. The dynamic data was integrated with the seismic and geological findings to ascertain whether the water presence is due to poor rock type, water migration through faults or water movement in the matrix. The findings were mapped and led to re-consider the well placements and expectations from infill wells while crossing faults. This enhancement of the reservoir understanding resulted in mitigation of risks in future producers which subsequently impacted the reservoir development strategy. This multi-scale analysis over the reservoir provided an insight into the source of the unexpected high water saturation in the undrained lower sub-zones of the reservoir. Thus, revising the understanding of the field development strategy, well placement and related contingencies.

ADNOC's limestone reservoirs suffer from the phenomena of injection water traveling preferentially at the top of the reservoir placing injection water above oil held there by capillary forces. Horizontal wells placed below areas of water override, cause the water above to slump unpredictably, increasing water cut and eventually killing the horizontal. Ultra Deep Directional Electromagnetic (EM) Logging While Drilling (LWD) tools provide the measurements to identify and map these water zones, improving reservoir management and design optimal well placement. 1D & 2D EM inversion modeling was conducted on two of ADNOC's largest oil producing reservoirs to evaluate the ability of an Ultra Deep Directional EM LWD Resistivity tool to identify water slumping in the presence of formation bed resistivity contrasts and predict depths of reliable detection (DOD) under various well trajectory scenarios. The inversion was run using depth of inversions up to 150 ft, the maximum expected vertical distance of tool to injection water. Modeling provided an optimized tool configuration (frequency, transmitter-receiver spacing's) to meet objectives. The inversion results further provided guidance for Geosteering, Geomapping and Geostopping decisions. The inversion results in these reservoirs indicated that the Ultra Deep resistivity tool has a DOD of 50-150 ft to pick reservoir tops and water slumping or non-uniform waterfront boundaries. The real-time inversion will optimize landing and drilling long horizontal section to increase net pay for production and even through sub-seismic faults, measuring changes in the reservoir fluid distribution, reduce drilling risk and exceed well production life. This information will aid in updating static model with water flood areas, reservoir tops, faults and structure, designing better infill well spacing and trajectories within bypass oil regions, designing proactive and not reactive smart well completions to delay or reduce water production and ultimately extended plateau and improve ultimate recovery factor. Furthermore, it will aid resistivity mapping of underlying or overlying reservoirs for future development plans. The encouraging results of this study confirmed to move forward with a field trial in these challenging reservoirs for better reservoir and fluid characterization and its management.

Reservoir characterisation in laminated sand shale reservoir has always been a very challenging task. The presence of conductive shales between the resistive hydrocarbon bearing sand reduces its resistivity drastically. It happens as the current flows through them as resistors in parallel. Therefore, the classical shaly sand interpretation grossly underestimates the hydrocarbon potential of laminated reservoir. Over the years many techniques have been developed to solve this problem. The development of latest resistivity tools like triaxial resistivity has also helped in addressing this problem. The introduction of these tools has helped upto a great extent to unlock the reservoir potential. However, the technology is very costly and sometimes may not be possible to run due the limited extent of the reservoirs. In those cases, it is important to find some alternate approach to addres the problem of low resistivity by using conventional logging tools. The current study deals with the case history from the East coast deep water field in India. The field has many drilled wells where the latest resistivity tools have been run. Petrophysical interpretations are done using this resistivity anisotropy data and are available for validation with the new technique. The latest approach uses the conventional resistivity data. The critical part in the study is the type and distribution of the shale within the reservoir. If we can find out the same then using this information true resistivity can be inverted. The approach has been tried on several wells across the different fields and has given good results. The results from the resistivity anisotropy data and the new technique are comparable. Thus a very cost effective method of predicting true resistivity has been developed, which ultimately gives realistic hydrocarbon saturation in the laminated sand shale sequences.

The COVID-19 pandemic, sometimes referred to as the coronavirus pandemic, is an ongoing worldwide illness outbreak brought on by the coronavirus 2 that causes severe acute respiratory syndrome (SARS-CoV-2). The outbreak's impact on the world's health, economy, and people's lives was unparalleled. Frontline employees are under extreme and unprecedented pressure from reporting to work during this epidemic, endangering their physical, emotional, and social well-being. Long-term exposure to severe stress can have a number of negative effects on frontline employees' emotional and mental health. This essay's goal is to examine the difficulties experienced by front-line personnel (doctors, nurses, and community health workers) during COVID 19 in several international locations. Only peer-reviewed articles about the difficulties experienced by front-line personnel during the COVID 19 outbreak were examined in the literature study. This study examines the psycho-social wellbeing and health of front-line medical personnel throughout the epidemic. Employers and organisations must understand the difficulties this essential workforce faces during pandemics and provide the right kind of assistance.