A. Salomone, S. Burrafato, G. R. Maccarini, R. Poloni, C. Molaschi, Arve Huse, G. Tangen, Thorsten Regener, Oliver Backhaus, S. Grymalyuk
{"title":"Kick Isolation While Drilling - First Field Test of an Innovative Risk Mitigation Technology","authors":"A. Salomone, S. Burrafato, G. R. Maccarini, R. Poloni, C. Molaschi, Arve Huse, G. Tangen, Thorsten Regener, Oliver Backhaus, S. Grymalyuk","doi":"10.2118/197756-ms","DOIUrl":"https://doi.org/10.2118/197756-ms","url":null,"abstract":"\u0000 Uncertainty in predicting formation integrity as well as pressure regimes poses significant risks to drilling operations. Several technologies can predict downhole environments in terms of formation strength, kick detection etc., but no solution currently exists for kick isolation. This paper presents an innovative well control and risk mitigation technology that is deployed while drilling and the result of a field test offshore Italy.\u0000 The new system is integrated in the bottom hole assembly (BHA), and in case of a kick can shut-in the annulus and the drillstring on demand to confine the influx at the well bottom below the sealing elements. A bypass port that establishes communication with the drillstring and annulus can be opened above the sealing elements to allow adjusting of the mud weight. Downhole pressure above and below the annular seal and inside the string can be monitored in real time. The system is deployed in combination with Wired Drill Pipe to ensure activation and bi-directional communication that is independent of any fluid flow.\u0000 The system was run on top of the directional rotary steerable BHA while drilling an 8½-in. hole section. The field test was conducted after drilling more than 500 m of new formation and 90 hours in hole. Prior to the test, the system was pulled to surface for visual inspection. No irregularities were observed. The system was then run back in open hole, activated according to operating procedures and tested by applying pressure into the annulus. The well was monitored and no leakage was observed concluding a successful test. Finally, the bypass was opened, circulation was re-established, and the system was deactivated and then pulled out of hole.\u0000 This paper describes the technology features and summarizes the first field test results of a new risk mitigation technology for well control situations. This document also shows how deploying new solutions can help E&P operators improve well control through a cost-effective solution and reduce operational risk in case of formation fluid influx into a wellbore.","PeriodicalId":11061,"journal":{"name":"Day 1 Mon, November 11, 2019","volume":"67 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83804210","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Thermoelastic Fracturing on Water Injectors as Part of Injectivity Enhancement in Giant Offshore Carbonate Field. Case Study","authors":"Arlen Sarsekov","doi":"10.2118/197569-ms","DOIUrl":"https://doi.org/10.2118/197569-ms","url":null,"abstract":"\u0000 Water Injection is part of secondary recovery mechanism which aims to increase oil recovery by increasing or maintaining the reservoir pressure and provide additional pressure support.\u0000 Most of the time water injection is controlled under matrix injection below the fracture pressure in order to avoid the creation of fractures and risk of bypass oil. However, there are two different mechanisms of fracture creation in water injection: poroelastic fracturing and thermoelastic fracturing. First one will activate above fracture point, while the second one creates below the original fracture point and most of the time missed in reservoir field development\u0000 Normally fractures can be categorized in 3 groups: –Fractures induced due to increase of injection pressure above pore pressure. (Poroelastic fractures)–Fractures induced due to drilling activities (Overbalance drilling)–Fractures induced due to injection of cold water.\u0000 Fractures which are induced due to difference in temperature between injected fluid and rock fluid called thermoelastic fractures. Thermoelastic fracturing is controlled primarily by the difference in temperature between reservoir rocks and injected fluids. This paper will focus on thermoelastic fractures and its propogation along the formation.\u0000 The analysis performed in a giant offshore carbonate field in Middle East on a well level as well as field level through injection modules.\u0000 This paper will describe the mechanisms of thermoelastic fracturing and methodology to identify this type of fractures in water injectors through several cases studies.","PeriodicalId":11061,"journal":{"name":"Day 1 Mon, November 11, 2019","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90899566","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"The Impact of Dynamic Filtration on Formation Testing in Low Mobility Carbonate Formations. Case Study: Lower Cretaceous Carbonate Reservoir in the UAE","authors":"M. Kuliyev, S. Molua, K. Cig, S. Sepehri","doi":"10.2118/197221-ms","DOIUrl":"https://doi.org/10.2118/197221-ms","url":null,"abstract":"\u0000 Formation pressure and sampling measurements in low mobility formations under dynamic filtration can lead to measurements influenced by continuous mud circulation. Generally, active mud circulation inhibits mud cake growth, promoting filtration and invasion of mud filtrate into the reservoir. The resulting invasion adds its own pressure to the actual formation pressure. This is more pronounced in low mobility formations where pressure or sampling measurements made with mud circulation show higher than expected reservoir pressures and/or extended clean up times as a result of dynamic filtration and invasion.\u0000 We focus on formation pressure acquisition and present data sets where pressure acquisition was done with active mud circulation. The data is then compared with measurements acquired in a pseudo-static and static mud column.\u0000 The measured near wellbore formation pressures acquired with active mud filtration are significantly higher (in some cases, > 400psi) compared to those obtained with a static mud column (assumed to be reading closer to the true formation pressure). The additional pressure is often referred to as supercharging, i.e., the excess pressure superimposed on the original formation pressure by the viscous flow of mud filtrate. The difference depends amongst other factors primarily on the formation mobility and surface pump flow rate during the pressure acquisition. For higher mobilities, there is generally little appreciable difference between active mud circulation and zero mud circulation. Secondary factors like pipe movement, pipe diameter, mud composition and reservoir wettability also influence the degree of the extra pressure measured.\u0000 Best practices for formation testing while drilling in low mobility carbonates are discussed. Lessons are drawn from experience where ignoring such best practices result in questionable data.","PeriodicalId":11061,"journal":{"name":"Day 1 Mon, November 11, 2019","volume":"275 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73550933","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Reducing Pipeline Maintenance Costs, Time, and Resources Through Nonintrusive Diagnostics","authors":"N. Stewart, G. Jack","doi":"10.2118/197262-ms","DOIUrl":"https://doi.org/10.2118/197262-ms","url":null,"abstract":"\u0000 Maintaining pipelines in optimum condition is a costly and time-consuming process for operators, which requires many resources. To help ensure an asset remains in a good operational state, it is necessary to understand its condition to allow it to be maintained in an efficient and cost-effective manner. Current methods for deposit assessment are limited to intrusive methods, theoretical modeling, or external measurement. This paper details a compressive solution to these challenges using pressure wave analysis.\u0000 The method is based on analyzing the signal response generated by a pressure wave transiting the system as it is affected by geometrical changes in the system. By capturing high resolution pressure measurement on an ultrahigh speed logger, the generated pressure wave can be recorded for analysis. Applying acoustic velocity gradient modeling in conjunction with the effect of the of the system and the fluid parameters, the profile of the internal bore of the system can be accurately determined without the use of intrusive or localized external tools.\u0000 Detailed is how the theory behind the method is confirmed by results observed when used during a controlled full-scale field-trial environment in addition to subsequent activities to survey system profiles. A case study is presented, demonstrating that the method allows operators to make decisive asset performance decisions and review deposit buildup in a safe and cost-effective manner without having to stop production. The theoretical method for calculation of acoustic velocity for known system and fluid parameters is shown to be accurate within tolerances compared to the acoustic velocity gained in the field by recording the time of flight between two known points. It is demonstrated that restrictions can be detected to a level of accuracy of plus or minus three millimeters of thickness, verified by comparison with other inspection methods.\u0000 The described is a unique method for determining the internal profile of systems, which can offer significant advantages from traditional bore determination methods. It can provide information in a repeatable and verified level of accuracy without the requirement for expensive and time consuming intrusive intervention, this allows operators the opportunity to target remediation work in the most efficient and cost effective manner, therefore maximizing production uptime and throughput.","PeriodicalId":11061,"journal":{"name":"Day 1 Mon, November 11, 2019","volume":"82 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85858174","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Shbair, L. Saputelli, F. Noordin, V. Bogoslavets, Y. Alblooshi, A. Soufi, Mohammed Hijjawi
{"title":"Unlocking Challenges in Water Injection Development Schemes Utilizing a Novel IRM Automation Workflow for Opportunities Generation","authors":"A. Shbair, L. Saputelli, F. Noordin, V. Bogoslavets, Y. Alblooshi, A. Soufi, Mohammed Hijjawi","doi":"10.2118/197708-ms","DOIUrl":"https://doi.org/10.2118/197708-ms","url":null,"abstract":"\u0000 Water injection is by far the most popular method used in the secondary recovery phase of field development for oil displacement and pressure maintenance. Proactive reservoir management is important to validate the efficiency of the existing water injection schemes and to assess field development strategies to prolong oil production plateau and improve the recovery factor (RF). The main challenges arise in stretching the reservoir target whilst ensuring stabilized or reduced water cut (WCT), minimizing by-passed oil volumes and preventing wells from becoming inactive due to high WCT.\u0000 In order to mitigate premature water flooding issues, mainly two options are available: (1) artificial lift techniques to activate producers suffering early and rapid water breakthrough; and (2) optimized completion designs via preventive or corrective controls. Preventive (i.e. proactive) approach involves segmenting the wellbore using sliding sleeves, influx control equipment, limited-perforated liners, while corrective (i.e. reactive) methods attempt to divert/remedy unwanted water influx via water-shut off (WSO) interventions. None of these alternatives can be fully pursued as full-field development strategies without realizing the technical limitations as well as their economic benefits.\u0000 The objective of this paper is to determine the value of applying subsurface water control strategies in the context of enhancing reservoir management and develop a novel framework to assess potential remediation opportunities. The technical evaluation was supported by a robust Integrated Reservoir Management (IRM) process. This process identified the rig/rigless jobs opportunities to intervene inactive wells due to high WCT and rank all possible mitigation methods in an automated economic manner.\u0000 The findings have also proved the value of installing autonomous inflow control devices (AICDs) to control water production along horizontal sections. In effect, it controlled water slumping without jeopardizing oil production of wells awaiting gas lifting. A case scenario of combined Gas-lift and ICD deployments suggested a net incremental value of $66 million (or 106%). Field test results of the horizontal well's production and WCT were found to be within 10% of the expected planned rates, and the oil gain is expected to further improve by 50% when gas-lift is commenced.","PeriodicalId":11061,"journal":{"name":"Day 1 Mon, November 11, 2019","volume":"7 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88163455","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Kelkouli, John Zaggas, Y. Boudiba, Abderrahmane Akham, Riad Boumahrat, S. Ferraz, Sofiane Bellabiod
{"title":"Breaking New Grounds and Records for Unconventional Reservoirs Characterization Using the New Formation Testing and Sampling Technology","authors":"M. Kelkouli, John Zaggas, Y. Boudiba, Abderrahmane Akham, Riad Boumahrat, S. Ferraz, Sofiane Bellabiod","doi":"10.2118/197281-ms","DOIUrl":"https://doi.org/10.2118/197281-ms","url":null,"abstract":"\u0000 An exploration deep well crossing two reservoirs with different quality and properties, having an objective of: Fluid identification and sampling in extremely tight section (∼0.02mD/cP mobility) as well as in another section that is suspected to be depleted with very high overbalance exceeding legacy tools, knowing the hydrostatic pressure being ∼9500psia.\u0000 Wireline formation tester was run using single probe, leading to 65% of tight stations, the rest were valid but with very low mobility. This exposes the tool to an increasing pressure differential exceeding its physical limit and leading to damaging it. This makes any further analysis impossible. The toolstring was upgraded with latest technology of WFT, that is a merge between probe based and dual packer modules. This new technology was designed with extreme environments in mind, that allows sampling in all mobility range from extreme tight to very high with its capability of holding up to 8000psia differential pressure.\u0000 In the job described here, some of the tested reservoir sections were differentially depleted, something unknown to customer as this was an exploration environment. Since this information were not know even after the completion of the first and second run, a third run was carried out with the objective of re-investigating the same depths performed by the single probe, but this time 3D Radial Probe was used instead. This gave the advantage of taking the pressure down to almost 0 psia. The potential hydrocarbon zone which was bypassed (seen dry with single probe) was then tested with 3D radial probe giving a reservoir pressure of 2864psia with a mobility of ∼300mD/cP where gas condensate was identified and captured. Now for the extreme tight reservoir section, in combination with high hydrostatic, the mechanical limitation of traditional tools remains the same making sampling and/or fluid ID impossible. An attempt was made using the 3D radial probe, and despite the extreme low mobility ∼0.02mD/cP, an identification of the reservoir fluid (water) was successfully completed without any issue.\u0000 The use of 3D Radial Probe technology gave a completely different picture from what was expected, enabled the completion of all objectives and made the impossible (with conventional technology) possibly and easily achievable. This resulted in changing the well strategies accordingly and complete the well successfully. The new technology made the testing of unconventional reservoirs a reality.","PeriodicalId":11061,"journal":{"name":"Day 1 Mon, November 11, 2019","volume":"31 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83950867","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Running Sour Hydrocarbon Assets: Eni's Story of Experience","authors":"L. Scataglini, L. Decarli","doi":"10.2118/197582-ms","DOIUrl":"https://doi.org/10.2118/197582-ms","url":null,"abstract":"\u0000 Eni has more than 40 years' experience on developing and managing sour hydrocarbons Projects. That has allowed to build up in Eni a specific knowhow, which is continuously improving and updating through operational activities on assets with an high concentration of H2S in the process fluids such as Karachaganak and Kashagan in Kazakhstan, COVA in Southern Italy and the more recent Zohr facilities in Egypt.\u0000 The Eni's acquired knowledge in running sour hydrocarbon assets, both offshore and onshore, has been founded on a robust risk based approach. Since the project start, risk assessments such as blowout study, Quantitative Risk Assessment, Emergency Escape Rescue Analysis, etc. results are considered the pillars for the proper design, construction, commissioning, start-up and operations phases. Specifically, SIMOPS/CONOPS methodologies and procedures and their applications in sour operational contexts are defined for managing sour hydrocarbons assets and activities.","PeriodicalId":11061,"journal":{"name":"Day 1 Mon, November 11, 2019","volume":"30 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78697268","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Y. Bashir, A. H. A. Latif, Shiba Rezaei, M. Mahgoub, Syed Yaser Moussavi Alashloo, M. Hermana, D. Ghosh, C. Sum
{"title":"Seismic Diffraction Imaging in Laterally Varying Velocity Media for Frequency Bandwidth Expansion - Application in Carbonate Field Sarawak, Malaysia","authors":"Y. Bashir, A. H. A. Latif, Shiba Rezaei, M. Mahgoub, Syed Yaser Moussavi Alashloo, M. Hermana, D. Ghosh, C. Sum","doi":"10.2118/197656-ms","DOIUrl":"https://doi.org/10.2118/197656-ms","url":null,"abstract":"\u0000 Seismic Imaging for the small-scale feature in complex subsurface geology such as Carbonate is not easy to capture because of propagated wave affected by heterogeneous properties of objects in the subsurface. The principal goal of anisotropic seismic diffraction & reflection imaging is to get a subsurface image of structural features with the greatest sharpness or resolution. In this paper, we have presented a new approach for anisotropic diffraction preservation using offset and angle domain data during the initial data processing. Which leads to the better preservation of diffractions amplitude in laterally varying velocity condition. The plane-wave destruction filter is used with a modified approximation for Diffraction separation as the conventional filtering techniques mixed the diffraction amplitudes when there are a series of diffraction hyperbola. Further, the implementation of the proposed method has proven on carbonate field data from Sarawak Basin for steeply dipping Carbonate Build-up.","PeriodicalId":11061,"journal":{"name":"Day 1 Mon, November 11, 2019","volume":"53 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76154032","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Zainah Salem Al Agbari, M. Chatterjee, P. Hewitt, I. Mohamed, M. Sudarev, E. Latypov, Ahmed Mohamed Al Bairaq, Ammar Al Amri
{"title":"Use Of Tracer Technology to Improve Reservoir Understanding","authors":"Zainah Salem Al Agbari, M. Chatterjee, P. Hewitt, I. Mohamed, M. Sudarev, E. Latypov, Ahmed Mohamed Al Bairaq, Ammar Al Amri","doi":"10.2118/197364-ms","DOIUrl":"https://doi.org/10.2118/197364-ms","url":null,"abstract":"\u0000 Using a tracer as a monitoring technique to measure the migration of the injected fluid in the reservoir is relatively inexpensive method, and it applied in numerous fields throughout the world. The application of tracer can assess the volumetric sweep to quantify the amount of fluid flowing from injectors to producers. It gives an indication of offending injectors. Tracer helps in addressing the communication between different reservoir units. Another objective is delineation of flow barriers to identify the geological features that dominate the flow directionality (i.e. high permeability streaks, faults, fractures, etc) to determine directional permeability trends. The information obtained from tracer can reduce the model uncertainty and provide better tuning for future prediction.\u0000 The tracer data is used to generate not only qualitative information but also a substantial amount of quantitative data. Primarily, chemical tracers should be tested against a number of reservoir formation rocks and found not to adsorb or retard. Tracers are injected in the injectors and the samples are collected from nearby producers. Analysis of tracer concentration versus time curves from individual producing wells enables interwell flow characteristics to be determined so that improvements can be made to optimize sweep effectiveness of the hydrocarbon reserve. A record of base line sampling and analyses from all producers should be conducted. A frequent sampling and analysis are performed to understand the reservoir characteristics and performance.\u0000 After the application of tracer technique, the following results were observed: The first breakthrough was detected after about one year; due to the short distance between the injector and the producer. The second breakthrough was detected after about three years; due to the reservoir characteristic in the producers. An identical patterns of tracer response was seen, indicates almost homogenous reservoir in the tracer injected. This points out towards a similar depositional pattern across the reservoir. Most of tracers are observed downward towards the flank area. Tracer direction was to the least pressure area (flank) due to high offtake. No breakthrough was observed in the attic wells due to high pressure area.\u0000 Tracer technology is inexpensive method used to provide inflow directional information, and it has no impact on the completion design and effectively prove the reservoir characterizations and well performance.","PeriodicalId":11061,"journal":{"name":"Day 1 Mon, November 11, 2019","volume":"110 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79248864","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Cara Smith, P. Vasilyev, A. Glushchenko, D. Zarubov
{"title":"Q-Compensation from Near Surface to Reservoir and Below: Case Study from Onshore Abu Dhabi","authors":"Cara Smith, P. Vasilyev, A. Glushchenko, D. Zarubov","doi":"10.2118/197443-ms","DOIUrl":"https://doi.org/10.2118/197443-ms","url":null,"abstract":"\u0000 Interest in quantitative interpretation (QI) of seismic data in the Abu Dhabi region continues to steadily increase, and the objective of creating inversion-ready seismic data is driving evolution of the surface seismic data processing workflows to focus on more detailed and thorough handling of the amplitude and phase throughout processing (pre-, during, and post-imaging). To achieve close well ties across the survey and to ensure the data is suitable for interpretation purposes, zero-phasing and wavelet stability (along with using well information during earth model building) are key stages in the depth imaging seismic processing workflow. Accurate amplitude with offset and azimuth handling is also required for inversion studies. In this paper, we propose a workflow where a geophysically and geologically credible, 3D variable Q-field is built into the earth model early in the processing flow, allowing a more complete approach to handling the Q-effects of the subsurface without increasing project turnaround time. This case study shows that a data-driven spatially variable Q-field combined with Kirchhoff Pre-Stack Depth migration compensates effectively for both amplitude and phase effects, providing a broadband image with improved event continuity and better handling of noise compared with applying a constant pre-migration Q-compensation (which was previously thought to be suitable for this low-relief region). By calibrating the variable Q-field to available well logs and near surface information, and ensuring that the different geophysical parameters in the earth model are all suitably coupled, an enhanced image is achieved which then requires minimal spectral shaping or residual phase corrections post migration. Ray-based Q-tomography workflows allow iterative 3D updates alongside coupled subsurface properties like anisotropy and velocity, within a high-resolution Earth model suitable for depth imaging. Reliable phase stability, higher resolution, broader useable bandwidth and improved amplitude preservation are key targets of this holistic approach.","PeriodicalId":11061,"journal":{"name":"Day 1 Mon, November 11, 2019","volume":"381 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74261234","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}