Day 3 Wed, March 20, 2019最新文献

{"title":"AccuPipePred: A Framework for the Accurate and Early Detection of Stuck Pipe for Real-Time Drilling Operations","authors":"A. Magana-Mora, S. Gharbi, Abrar A. Alshaikh, A. Al-Yami","doi":"10.2118/194980-MS","DOIUrl":"https://doi.org/10.2118/194980-MS","url":null,"abstract":"\u0000 Thorough preplanning and best drilling practices are effective in reducing stuck pipe incidents, data analytics offer additional insight into further reducing the significant non-productive time (NTP) that results from this unplanned event. The severity of the stuck pipe problem may stop the drilling operations for a short time, or in more difficult cases, the drill string has to be cut and the borehole is sidetracked or plugged and abandoned. Consequently, detecting the early signs of this problem, in order to take the right actions, may considerably or entirely reduce the risk of a stuck pipe.\u0000 Although computational models have been proposed for the early detection of the stuck pipe incidents, the models are derived from a reduced set of wells with stuck pipe incidents, which may result in under-trained models that predict a large number of false positive alarms. A sufficient amount of data or wells that statistically represent the parameters surrounding stuck pipe incidents under different circumstances is required in order to derive a generalizable and accurate prediction model. For this, we first derived a framework to automatically and systematically extract relevant data from the historical data. As such, our framework searches through the historical data and localizes the surface drilling and rheology parameters surrounding the stuck pipe incidents. Moreover, we performed feature selection by selecting the top-ranked parameters from the analysis of variance, which measures the capability of the drilling and rheology parameters to discriminate between stuck pipe incidents and normal drilling conditions, such as, weight on bit, revolutions per minute, among others.\u0000 Using the relevant features selected by the analysis of variance, we derived a robust and fast classification model based on random forests that is able to accurately detect stuck pipe incidents. The implemented framework, which includes the automated data extraction module, the analysis of variance for feature selection, and prediction, is designed to be implemented in the real-time drilling portal as an aid to the drilling engineers and the rig crew in order to minimize or avoid the NTP due to a stuck pipe.","PeriodicalId":11321,"journal":{"name":"Day 3 Wed, March 20, 2019","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85530667","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":"Challenges with Mega-Projects Implementation: Risk Strategies and Opportunities for Growth","authors":"I. Akimova","doi":"10.2118/194926-MS","DOIUrl":"https://doi.org/10.2118/194926-MS","url":null,"abstract":"\u0000 Russia always plays an important role on iternational energy markets as one of the major oil and gas producers and exporters since the country entered international enrgy market in the middle of the last century. And this role will remain stable at least till the year 2040 according to current forecasts. BP estimates, that Russia will cover around 5% of the global energy demand by the year 2040. Though, Russia has around 17,4% of world gas reserves (OPEC's estimates its even more – around 24,6% due to the different methodology) and only around 6% in world oil reserves, Russia contributes 17,3% to world gas production and 12,2% to world oil production in 2018, according to BP's Statistical Review of World Energy. Developing of enormous gas and oil reserves was extraordinary challenging for the country due to harsh climate conditions, lack of infrastructure, unsufficient financing and need to develop not only fields but the whole remote areas of the country. Though the country was widely ctitised for its dominancy on the European gas market, in this paper it will be outline that developing of the European gas market was of mutual interest of Russia and European Union and both counterpart became beneficiary of it. This paper focuses on challengies with developing enormous gas reserves as Russia has several mega giant gas fields and its experience can be usefull in developing other mega projects around the world.","PeriodicalId":11321,"journal":{"name":"Day 3 Wed, March 20, 2019","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86064535","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":"Sour Fluids Management Using Non-chemical H2S Scavenger","authors":"P. Dhulipala, Jagrut Jani, M. Wyatt, J. Leidensdorf, Soma Chakraborty","doi":"10.2118/194990-MS","DOIUrl":"https://doi.org/10.2118/194990-MS","url":null,"abstract":"\u0000 The objective of this study was to develop and apply a non-chemical based environmentally preferable hydrogen sulfide scavenger that addresses secondary issues caused by current chemical scavengers like triazine and glyoxal and to confirm its ability to mitigate sulfide in different applications. Recombinant DNA and protein expression technologies were exploited to develop this novel H2S scavenger.\u0000 This non-chemical scavenger (NCS) is generated by cloning the cDNA sequence from a thermophilic organism and expression of the encoded protein in suitable vector. Non-chemical based formulation was developed and blended in a pilot plant. The efficacy of the scavenger was evaluated in sour brine, crude oil and mixed production fluids from different sources. Sulfide concentrations before and after reactions in headspace were measured by using Dräger gas detection tubes (ASTM D5705). Corrosion testing was performed using kettle tests. Field assessment of the scavenger was carried out by treating sour oil at the Bakken oil field as per the field testing plan.\u0000 In this study, H2S mitigation was addressed using a novel non-chemical scavenger generated from thermophilic bacteria from lab scale to pilot scale. Functional studies conducted by treatment of soured brine and oil revealed 72% and 90% reduction in H2S concentration respectively. The scavenger showed a 75% reduction of sulfide in simulated mixed production samples containing 30:70 ratio of brine and oil. Limited testing of this scavenger in field showed reduction of headspace sulfide from 400 ppm to 2 ppm. In addition, the field data showed less than 0.5% BS&W. The scavenger also showed no significant increase in corrosion during the scavenging reaction.\u0000 These studies confirm that this novel non-chemical scavenger can be successfully used to mitigate H2S in various systems without causing adverse effects that were seen with chemical scavengers. A non-chemical scavenger has several advantages such as meeting environmental regulations, reducing, or eliminating secondary effects like solids formation, corrosion, scaling, and health hazards that are associated with current chemical scavengers.","PeriodicalId":11321,"journal":{"name":"Day 3 Wed, March 20, 2019","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86305774","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":"First Worldwide Application of HP/HT Water Swellable Packers Eliminates Deployment Risks and Improves MSF Efficiency in Tight Gas Reservoirs","authors":"R. Arias, Pablo Guizada, Khalid Mohanna, A. Desai","doi":"10.2118/194865-MS","DOIUrl":"https://doi.org/10.2118/194865-MS","url":null,"abstract":"\u0000 This paper presents the first-time application of high pressure/high temperature (HP/HT) water swellable packers worldwide for multistage fracturing completions. This technology eliminates deployment risks associated with premature swelling in high temperature oil-based muds (OBM) and improves efficiency of fracturing operations in tight gas reservoirs.\u0000 The overall deployment method of this technology is similar to traditional open-hole multistage fracturing technologies that are industry standard. The main difference being that the isolation packer used is an HP/HT water swell packer that uses water/brine as the swelling medium as opposed to hydrocarbon. The technology comprises of an innovative compound that is capable of holding high differential pressure at high reservoir temperatures and maintaining permanent isolation in a relatively compact element length. The elastomer compound completed an extended qualification process to ensure fulfilling deployment and fracturing completion requirements in a specific well candidate.\u0000 The outcome was an overall successful deployment and stimulation operation of multi stage completion with HPHT water swell packer technology. Water swell packer provided the ability to deploy the lower completion in high temperature/OBM environment with a significant increase of swelling factor delay and its compact length reduces stiffness in the BHA to further decrease the deployment risk. In addition, this technology provided an optimization technique for open-hole multi-stage stimulation by circulating out the drilling mud and leaving completion brine in the wellbore and annular space. Through a complete diagnostic process, it was confirmed that the water swellable packers successfully isolated each stage of the stimulation treatment.\u0000 Prior to the first worldwide installation of an innovative elastomer compound, unique testing was conducted in the laboratory and in field tests to qualify the compound technology with special focus on the acid stimulation treatments domain. The elastomer compound was made of special fillers to chemically retain water in the elastomer matrix and eliminate any reverse osmosis problem present in traditional water-swellable compounds.","PeriodicalId":11321,"journal":{"name":"Day 3 Wed, March 20, 2019","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90880227","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 Effects of Initial Roughness and Mechanical Property of Fracture Surface on Acid Fracture Conductivity in Tight Dolomite Reservoir","authors":"J. Lai, Jianchun Guo, Chi Chen, Kaidi Wu, Huiyun Ma, Changlin Zhou, Shibin Wang, Jichuan Ren, Z. Wang","doi":"10.2118/194780-MS","DOIUrl":"https://doi.org/10.2118/194780-MS","url":null,"abstract":"\u0000 As the most commonly used technology to exploit tight dolomite reservoirs, acid fracturing usually begins with injecting pad fluid to create rough-surface fractures, followed by pumping acid to form non-uniform etching on fracture surfaces. Thus, the etching pattern and acid fracture conductivity depend largely on initial character of rough-surface fractures. In this work, experiments were conducted to examine the effects of initial roughness and mechanical property of fracture surface on acid fracture conductivity.\u0000 Eight artificially split core samples were collected from tight dolomite outcrops and classified into three categories based on the surface topography and splitting force curve. Rough fracture surfaces were scanned utilizing the 3D laser scanner. Then, dynamic acid etching tests were conducted, varying the acid flow rate and acid-rock contact time. Besides, the roughness of fracture surfaces were measured utilizing the 3D laser scanner again. After that, acid fracture conductivity was determined. The effects of acid flow rate, acid-rock contact time, fracture surface topography and mechanical property on acid etching and acid fracture conductivity were discussed.\u0000 The experimental results demonstrated that the initial fracture surface topography and acid flow rate jointly controlled the acid etching pattern and the resulting acid fracture surface topography. The orientation of the fractures distributed on the fracture surface had significant effects on the acid fracture conductivity. Dissolved mass increased with longer acid-rock contact time. Longer acid-rock contact time brought higher acid fracture conductivity under low closure stress, while shorter contact time sustained higher acid fracture conductivity under high closure stress. Higher maximum splitting force referred to higher mechanical property, and more breaking stages referred to more microfractures developed. Rock samples with higher maximum splitting force and only one breaking stage exhibited higher acid fracture conductivity.\u0000 This paper provides a systematic method to study the effects of initial roughness and mechanical property of fracture surfaces on acid fracture conductivity. Compared with the results based on smooth-surface fracture, the experimental results based on rough-surface fracture can guide acid fracturing design and optimization in a more accurate way. Accordingly, a cost-effective stimulation outcome can be expected.","PeriodicalId":11321,"journal":{"name":"Day 3 Wed, March 20, 2019","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84449485","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":"Reservoir Depletion-Induced Proppant Embedment and Dynamic Fracture Closure","authors":"Jian Huang, R. Safari, Oswaldo Perez, F. Fragachán","doi":"10.2118/195135-MS","DOIUrl":"https://doi.org/10.2118/195135-MS","url":null,"abstract":"\u0000 An optimized stimulation design not only achieves high productivity during early times, but also necessitates maintaining conductive flow paths during the life of a well. Because of proppant settling and bridging, proppants are not uniformly distributed within developed fracture networks. Moreover, no fractures retain original conductivity during long term depletion, due to proppant embedment and crushing. This paper introduces a model that analytically predicts the proppant deformation and fracture closure behavior, and forecasts production performance.\u0000 This model is based on contact mechanics to simulate the mechanical interaction between the proppant pack and formation rock. The fracture aperture can be calculated and updated by taking into account the proppant concentration, non-uniform proppant distribution and in-situ stress conditions. The proppant pack permeability is analytically modelled according to its mechanical properties (size and density) and effective normal stress acting on the fracture surface. In this way, the fracture conductive variation caused by reservoir depletion can be quantified and imported into a reservoir model to forecast production.\u0000 This paper presents a new analytical model to describe dynamic fracture closure and its impact on production performance, which varies significantly with the proppant mechanical properties, proppant concentration, proppant distribution, stress condition and formation types. Under different conditions, conductivity evolution of propped fractures can be obtained from the presented model and matched well with multiple experimental tests. Sensitivity of proppant properties, reservoir attributes, and operational parameters are discussed in this study. Production results from these sensitivity analyses can be used to compare and contrast different design scenarios.\u0000 This model enables an efficient and reliable prediction of the fracture dynamic closure behavior and identification of controlling parameters to mitigate premature fracture closure. This model honors heterogeneous proppant distribution and related fracture closure, and hence captures more realistic reservoir performance. By integrating stress-dependent fracture conductivity and production analysis in this model, an operational guideline can be provided to maximize the productivity of fractured formations.","PeriodicalId":11321,"journal":{"name":"Day 3 Wed, March 20, 2019","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87183744","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":"Application of High Performance Asynchronous Acoustic Wave Equation Stencil Solver into a Land Survey","authors":"Rached Abdelkhalak, Kadir Akbudak, V. Etienne, H. Ltaief, T. Tonellot, D. Keyes","doi":"10.2118/194722-MS","DOIUrl":"https://doi.org/10.2118/194722-MS","url":null,"abstract":"\u0000 This paper describes the application of high performance asynchronous stencil computations for 3D acoustic modeling on a synthetic land survey. Using the Finite-Difference Time-Domain (FDTD) method, a parallel Multicore Wavefront Diamond-tiling (MWD) stencil kernel (Malas et al. 2015, Malas et al. 2017) drives the high performance execution using temporal blocking to maximize data locality, while reducing the expensive horizontal data movement. As absorbing boundary conditions, we use Convolutional Perfectly Matched Layer (CPML), which have to be redesigned to not interrupt the asynchronous execution flow engendered by the MWD stencil kernel for the inner-domain points. The main idea consists in weakening the data dependencies by moving the CPML computations into the inner-computational loop of the MWD stencil kernel (Akbudak et al. 2019). In addition to handling the absorbing boundary conditions, applying the asynchronous MWD with CPML kernels to a realistic land survey requires the extraction of the wavefield value at each receiver position. We revisit the default extraction process and make it also compliant with the overall asynchrony of the 3D acoustic modeling. We report performance improvement up to 24% against the standard spatial blocking algorithm on Intel multicore chips using the synthetic land survey, which is representative of an area of interest in Saudi Arabia. While these results concur with previous performance campaign assessment, we can actually produce and assess the resulting 3D shot gather accuracy. To our knowledge, this is the first time the effectiveness of asynchronous MWD stencil kernel with CPML absorbing boundary conditions is demonstrated in an industrial seismic application.","PeriodicalId":11321,"journal":{"name":"Day 3 Wed, March 20, 2019","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87711692","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":"First Rigless Water Shutoff and Reservoir Cross-Flow Leak Mitigation Performed in the United Arab Emirates on a Horizontal Extended Reach Well, Enabling Improved Reservoir Management","authors":"A. Wills, J. Wheatley, Rajes Sau, Jose Jimenez, J. Ulloa","doi":"10.2118/195017-MS","DOIUrl":"https://doi.org/10.2118/195017-MS","url":null,"abstract":"\u0000 The latest developments in well construction rely on advanced drilling and completion technologies to withstand increased wellbore deviation, tortuosity, and complex geometry challenges necessary to access reservoirs, which can create challenges to cement placement between reservoir zones. Hence, well integrity and reservoir management concerns can arise given the possibility for multiple reservoirs to communicate, resulting in undesired crossflow and water production because of poor cement isolation.\u0000 Poor cement placement behind casings, ineffective zonal isolation, and well integrity issues have been traditionally addressed using workover or drilling rigs to remove production tubing and perform either a remedial cement squeeze or zonal abandonment for subsequent sidetrack. However, this generally entails production deferral, capital-intensive rig rates, the potential risks of pulling and running production tubing, which often translates in formation damage from killing the well, large wellsite footprint requirements, and higher logistic demands for rig support equipment.\u0000 This paper describes the systematic process used to identify, diagnose, design, and execute a successful inter-reservoir crossflow mitigation operation in a naturally fractured carbonate formation in Abu Dhabi using a cost-effective solution with rigless coiled tubing-deployed technologies and a hydrocarbon-based microfine cement slurry that activates upon contact with water. The results enabled the operator to restore reservoir integrity, improve reservoir management, and enhance water sweep.\u0000 Post-operation reservoir evaluation validated the successful use of the technology for rigless zonal isolation using coiled tubing (CT) for the first time in the United Arab Emirates, providing significant cost benefits and new best practices to reduce the water cut and restore wellbore integrity.","PeriodicalId":11321,"journal":{"name":"Day 3 Wed, March 20, 2019","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76552940","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":"Deep Learning Method for Latent Space Analysis","authors":"B. Wallet, T. Ha","doi":"10.2118/194889-MS","DOIUrl":"https://doi.org/10.2118/194889-MS","url":null,"abstract":"\u0000 Seismic attributes are a well-established method for highlighting subtle features buried in seismic data in order to improve interpretability and suitability for quantitative analysis. Seismic attributes are a critical enabling technology in such areas thin bed analysis, 3D geobody extraction, and seismic geomorphology. When it comes to seismic attributes, we often suffer from an \"abundance of riches\" as the high dimensionality of seismic attributes may cause great difficulty in accomplishing even simple tasks. Spectral decomposition, for instance, typically produces 10's and sometimes 100's of attributes. However, when it comes to visualization, for instance, we are limited to visualizing three or at most four attributes simultaneously.\u0000 My co-authors and I first proposed the use of latent space analysis to reduce the dimensionality of seismic attributes in 2009. At the time, we focused upon the use of non-linear methods such as self-organizing maps (SOM) and generative topological maps (GTM). Since then, many other researchers have significantly expanded the list of unsupervised methods as well as supervised learning. Additionally, latent space methods have been adopted in a number of commercial interpretation and visualization software packages.\u0000 In this paper, we introduce a novel deep learning-based approach to latent space analysis. This method is superior in that it is able to remove redundant information and focus upon capturing essential information rather than just focusing upon probability density functions or clusters in a high dimensional space. Furthermore, our method provides a quantitative way to assess the fit of the latent space to the original data.\u0000 We apply our method to a seismic data set from the Canterbury Basin, New Zealand. We examine the goodness of fit of our model by comparing the input data to what can be reproduced from the reduced dimensional data. We provide an interpretation based upon our method.","PeriodicalId":11321,"journal":{"name":"Day 3 Wed, March 20, 2019","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89884233","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":"Robust Tomographic Full Waveform Inversion using Adaptive Amplitude Estimation","authors":"A. Almomin","doi":"10.2118/195066-MS","DOIUrl":"https://doi.org/10.2118/195066-MS","url":null,"abstract":"\u0000 I examine the basis of slow convergence of tomographic full waveform inversion (TFWI) and discover that the reason behind it is the unbalanced effects of amplitudes and phase in the design of the regularization term. This imbalance results in a strong reliance of the kinematic updates on the amplitude fitting, slowing down the convergence. To mitigate the problem I propose two modifications to the tomographic inversion. First, by modifying the regularization term to focus more on the phase information, and second, simultaneously updating the source function for modeling. The adjustments reduce the gradient artifacts and allow for explicit control over the amplitudes and phases of the residuals.\u0000 Tomographic full waveform inversion (Symes, 2008; Sun and Symes, 2012; Biondi and Almomin, 2012) is an innovative inversion technique that preserves all the advantages and benefits of full waveform inversion (FWI) while at the same time bypassing its strict initial model requirement and cycle-skipping challenges. To reach this objective, TFWI alters FWI by merging its classical form with a modified form of wave-equation migration-velocity analysis (WEMVA). This combination displays itself as an extension of the velocity model through virtual axes (Biondi and Almomin, 2013).\u0000 The modeling operator is able to match the observed data by extending the velocity model with the proper axis, no matter what the accuracy of the initial model is, by using kinematic information from the extended axis with disregard to the occurrence of cycle skipping. The inversion is set up to extract all the essential information from the virtual axes and smoothly fold them back into their original, nonextended form of the model. The kinematic and dynamic information of the data were successfully inverted with exceptional robustness and precision.\u0000 Even though cycle-skipping is not an issue with TFWI, this method creates its own challenges, which are; its high computational cost and the big number of iterations that it needs (Almomin and Biondi, 2013). The conventional FWI uses only a single frequency per iteration to match the phase (Pratt, 1999; Shin and Ha, 2008). Not using amplitudes reduces the accuracy of the solution because it prevents the simultaneous inversion of scales. Modifying the gradient calculation is another method that is used to reduce some \"kinematic\" artifacts (Fei and Williamson, 2010; Shen and Symes, 2015). These methods are appropriate for image-domain velocity analysis methods, such as WEMVA. The explicit calculations of the nonlinear modeling operator and residuals in the data space prevents it from being applied in TFWI.\u0000 Two adjustments to TFWI are proposed to reduce the slow convergence and allow for more control of the ratio between amplitude and phase. These adjustments are consistent in the framework of TFWI and allow for an accurate calculation of the gradient in the data space. The adjustments were tested and resulted in a reduction in the kinem","PeriodicalId":11321,"journal":{"name":"Day 3 Wed, March 20, 2019","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75325369","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}