RECENT DEVELOPMENTS IN BOREHOLE SEISMIC SURVEYS, OFFSHORE NORTHERN AUSTRALIA

1991 ◽  
Vol 31 (1) ◽  
pp. 250
Author(s):  
A. Sutherland ◽  
P.M. Smith
Keyword(s):  
Shear Wave ◽  
Seismic Data ◽  
Seismic Energy ◽  
Hard Water ◽  
Main Body ◽  
Northern Australia ◽  
Seismic Surveys ◽  
Sensor Module ◽  
Borehole Seismic

Offshore northern Australia has long been recognised as a region where the quality of seismic data is frequently adversely affected by several factors which include the following.The presence of a hard water bottom.The presence of carbonate units in the Eocene and Paleocene which are highly reflective and reduce the amount of seismic energy which penetrates to the deeper target horizons. These also produce interbedded multiples which are difficult to remove from the seismic data.Complex shallow faulting which causes ray path distortion and disperses the seismic energy.The confidence with which well data can be tied to the poor quality seismic data through well velocity surveys is further reduced by the complicated deeper faulting associated with the structures drilled and the low acoustic impedance contrast at the target horizon.Borehole seismic surveys provide the most reliable link between the subsurface intersected by a well and seismic data. The recent introduction of a new borehole seismic tool has improved the quality of Vertical Seismic Profiles (VSPs) acquired. This tool has three component geophones mounted in a sensor module which is isolated from the main body of the tool by springs which minimise the effect of source-generated noise.This reduction in sensitivity to the source-generated noise has allowed the introduction of more powerful source arrays to improve the signal to noise ratio. The use of source arrays has increased the bandwidth of the seismic impulse and decreased the effect of the bubble pulse.The quality of the horizontal component VSP data recorded using the new tool has also improved significantly and this has increased the possibility of detecting mode converted reflected and transmitted shear wave energy and the more accurate measurement of shear wave velocities.

The use of an active drill bit for inverse VSP measurements

1989 ◽  
Vol 20 (2) ◽  
pp. 343 ◽  
Author(s):  
J.W. Rector III ◽  
B.P. Marion ◽  
R.A. Hardage
Keyword(s):  
Seismic Energy ◽  
Seismic Source ◽  
Drilling Process ◽  
Drill Bit ◽  
Seismic Surveys ◽  
Reference Trace ◽  
Vsp Data ◽  
Sensor Signals ◽  
Borehole Seismic ◽  
Reference Sensor

Vertical Seismic Profiling (VSP) is often used to provide high resolution seismic images near a wellbore. A new borehole seismic technique, the TOMEX� survey (Rector, et al., 1988), uses the vibrations produced by a drill bit as a downhole seismic energy source to produce inverse VSP data. No downhole instrumentation is required to acquire the data, and the data recording does not interfere with or delay the drilling process. Hence, there is no loss of rig time in performing the survey. These characteristics offer a method to acquire SWD (seismic-while-drilling) borehole seismic surveys. In addition, 3-D imaging around a well can be obtained at significant savings compared to conventional offset VSP imaging. The continuous signals generated by the bit during drilling are monitored with a reference sensor attached to the top of the drillstring, and the reference sensor signals are crosscorrelated with signals from surface-positioned geophones to produce inverse VSP data. Deconvolution and time shifts are then performed to remove the effects of recording the source reference trace at a location that is a considerable distance from the source. Results from tests demonstrate that these processed drill-bit source data are virtually identical to conventional forward VSP data. In using the drill bit as a downhole seismic source for inverse VSP, many of the limitations of conventional VSP are overcome. Several applications for VSP that were previously considered to be prohibitively expensive are now feasible. Furthermore, this seismic-while-drilling technique offers the potential for the explorationist to make real-time drilling decisions at the well site.

3D interpolation of irregular data with a POCS algorithm

Geophysics ◽  
2006 ◽  
Vol 71 (6) ◽  
pp. E91-E97 ◽  
Author(s):  
Ray Abma ◽  
Nurul Kabir
Keyword(s):  
Seismic Data ◽  
Convex Sets ◽  
Fourier Transforms ◽  
Higher Dimensions ◽  
Seismic Surveys ◽  
Projection Onto Convex Sets ◽  
Irregular Data ◽  
Restoration Method ◽  
The Cost

Seismic surveys generally have irregular areas where data cannot be acquired. These data should often be interpolated. A projection onto convex sets (POCS) algorithm using Fourier transforms allows interpolation of irregularly populated grids of seismic data with a simple iterative method that produces high-quality results. The original 2D image restoration method, the Gerchberg-Saxton algorithm, is extended easily to higher dimensions, and the 3D version of the process used here produces much better interpolations than typical 2D methods. The only parameter that makes a substantial difference in the results is the number of iterations used, and this number can be overestimated without degrading the quality of the results. This simplicity is a significant advantage because it relieves the user of extensive parameter testing. Although the cost of the algorithm is several times the cost of typical 2D methods, the method is easily parallelized and still completely practical.

A workflow to skeletonize faults and stratigraphic features

Geophysics ◽  
2017 ◽  
Vol 82 (4) ◽  
pp. O57-O70 ◽  
Author(s):  
Jie Qi ◽  
Gabriel Machado ◽  
Kurt Marfurt
Keyword(s):  
Seismic Data ◽  
Fault Plane ◽  
Random Noise ◽  
Principal Component ◽  
Component Structure ◽  
Seismic Surveys ◽  
Seismic Amplitude ◽  
Amplitude Data ◽  
Seismic Reflectors

Improving the accuracy and completeness of subtle discontinuities in noisy seismic data is useful for mapping faults, fractures, unconformities, and stratigraphic edges. We have developed a workflow to improve the quality of coherence attributes. First, we apply principal component structure-oriented filtering to reject random noise and sharpen the lateral edges of seismic amplitude data. Next, we compute eigenstructure coherence, which highlights the stratigraphic and structural discontinuities. We apply a Laplacian of a Gaussian filter to the coherence attribute that sharpens the steeply dipping faults, attenuates the stratigraphic features parallel to the seismic reflectors, and skeletonizes the unconformity features subparallel to the reflectors. Finally, we skeletonize the filtered coherence attribute along with the fault plane. The filtered and skeletonized seismic coherence attribute highlights the geologic discontinuities more clearly and precisely. These discontinuous features can be color coded by their dipping orientation or as a suite of independent, azimuthally limited volumes, providing the interpreter a means of isolating fault sets that are either problematic or especially productive. We validate the effectiveness of our workflow by applying it to seismic surveys acquired from the Gulf of Mexico, USA, and the Great South Basin, New Zealand. The skeletonized result rejects noise and enhances discontinuities seen in the vertical and lateral directions. The corendering of the “fault” azimuth and the fault-dip magnitude exhibits the strengths of the discontinuities and their orientation. Finally, we compared our workflow with the results generated from the swarm intelligence and found our method to be better at tracking short faults and stratigraphic discontinuities.

Combining Wireline and LWD Borehole Seismic Data for Drilling HPHT Well: A Novel Approach

2009 ◽  
Author(s):  
Teck Kean Lim ◽  
Aqil Ahmed ◽  
Muhammad Antonia Gibrata ◽  
Gunawan Taslim
Keyword(s):  
Seismic Data ◽  
Novel Approach ◽  
Borehole Seismic

scholarly journals Deep insights into urinary tract infections and effective natural remedies

2021 ◽  
Vol 27 (1) ◽  
Author(s):  
Bibi Sedigheh Fazly Bazzaz ◽  
Sareh Darvishi Fork ◽  
Reza Ahmadi ◽  
Bahman Khameneh
Keyword(s):  
Urinary Tract ◽  
Herbal Medicines ◽  
Main Body ◽  
Antibiotic Resistant ◽  
Duration Of Symptoms ◽  
Development Of Resistance ◽  
Natural Remedies ◽  
Tract Infections ◽  
Time Limitations

Abstract Background Urinary tract infection (UTI) is a common occurrence in females, during pregnancy, and in peri- and postmenopausal women. UTIs are associated with significant morbidity and mortality, and they affect the quality of life of the affected patients. Antibiotic therapy is an effective approach and reduces the duration of symptoms. Development of resistance, adverse effects of antibiotics, and other associated problems lead to establishing the research framework to find out the alternative approaches in controlling UTIs. Natural approaches have been extensively used for the management of various diseases to improve symptoms and also improve general health. Main body Different databases were employed to identify studies reporting on natural options including herbal medicines, vitamins, trace elementals, sugars, and probiotics without time limitations. Conclusion Herbal medicines can be effective at the first sign of the infection and also for short-term prophylaxis. Using vitamins, trace elementals, and/or sugars is an effective approach in preventing UTIs, and a combination of them with other antibacterial agents shows positive results. Probiotics have great potential for the threat of antibiotic over-usage and the prevalence of antibiotic-resistant microorganisms. This study may be of use in developing the efficient formulation of treatment of UTI.

scholarly journals A guide to do randomized controlled trials in the field of otolaryngology

2021 ◽  
Vol 37 (1) ◽  
Author(s):  
Sameh M. Zamzam ◽  
Mosaad Abdel-Aziz ◽  
Ahmed Atef ◽  
Usama Abdel-Naseer ◽  
Mostafa Hamoda ◽  
...  
Keyword(s):  
Randomized Controlled Trials ◽  
Study Groups ◽  
Controlled Trials ◽  
Main Body ◽  
Main Research ◽  
Randomized Controlled ◽  
New Treatment ◽  
Meta Analyses ◽  
Based Medicine

Abstract Background Randomized controlled trials (RCTs) are prospective comparative studies in which study groups are allocated randomly to intervention or serve as controls. RCT is the mainstay to achieve evidence in the literature in clinical research. A RCT is the main research design to study the effect of an intervention and the only way to confirm the value of a new treatment. Main body RCT also gives the way to generate meta-analyses and systematic reviews giving a stronger evidence for clinical practice. Evidence-based medicine (EBM) is crucial for safe, effective, and standardized patient care. Although there is an agreement on the importance of performing RCT, it can be challenging to do it efficiently including different aspects like study design, funding, randomization, blinding, follow-up, data analysis, statistics, generalization of results, and reporting of quality of the studies. Conclusion In this article, we gave a comprehensive review for RCT in otolaryngology discussing their importance, advantages, and drawbacks, types, steps, challenges, reporting their quality and their prevalence in the literature.

scholarly journals Importance of immunoglobulin therapy for COVID-19 patients with lymphocytopenia

2021 ◽  
Vol 45 (1) ◽  
Author(s):  
Heba K. Nabih
Keyword(s):  
Passive Immunization ◽  
Immunoglobulin Therapy ◽  
World Health ◽  
Clinical Feature ◽  
Main Body ◽  
Plasma Therapy ◽  
Rapid Spread ◽  
The World ◽  
Health Organization

Abstract Background The global coronavirus disease 2019 (COVID-19) was announced as pandemic by the World Health Organization (WHO). With the increased number of infected and dead victims daily all over the world, it becomes necessary to stop or overcome its rapid spread. Main body Although the production of vaccine or even specified effective anti-virus may take about six months to a year, intravenous immunoglobulin (IVIg) may be clinically used as a safe treatment to save and improve the quality of life of patients with a variety of immunodeficiency diseases such as lymphocytopenia, which is a common clinical feature in COVID-19. Conclusion Through the current review, it was concluded that this passive immunization may promote the immunity to better fight against the virus, so the survival of the patients could be kept longer. The efficacy of immunotherapy with IVIg would be greater if the immune IgG antibodies were collected from convalescent plasma therapy.

Effects of oil‐water saturation on shear‐wave splitting in multicomponent seismic data

2007 ◽  
Author(s):  
Zhongping Qian ◽  
Xiang‐Yang Li ◽  
Mark Chapman ◽  
Yonggang Zhang ◽  
Yanguang Wang
Keyword(s):  
Shear Wave ◽  
Seismic Data ◽  
Water Saturation ◽  
Shear Wave Splitting ◽  
Multicomponent Seismic ◽  
Wave Splitting ◽  
Oil Water

scholarly journals Marginal mandibular nerve — a wandering enigma and ways to tackle it

2021 ◽  
Vol 37 (1) ◽  
Author(s):  
Adarsh Kudva ◽  
Kiruthika Babu ◽  
Mehul Saha ◽  
Smriti Puri ◽  
Lakshmi Pandey ◽  
...  
Keyword(s):  
Head And Neck ◽  
Neck Surgery ◽  
Mandibular Nerve ◽  
Surgical Approaches ◽  
Main Body ◽  
Branching Pattern ◽  
Marginal Mandibular Nerve ◽  
Critical Measure ◽  
Quality Of Surgery

Abstract Background This study aims to propose surgical approaches intended to localize and preserve the marginal mandibular nerve (MMN) during routinely performed head and neck surgical procedures. Main body of abstract Preservation of the functional integrity of the MMN is a critical measure in the success of orofacial surgeries involving the submandibular triangle. This study systematically reviews the anatomical description of the nerve including origin, course relative to fascial planes, relation to the parotid gland and facial pedicle, branching pattern and anastomosis of nerve and consolidate the findings of several significant studies to determine the “surgically safe” approaches to avoid iatrogenic injury to MMN. Short conclusion The systematic approaches described in this study have helped the authors precisely determine which particular MMN preserving approach to be adopted for each aspect of head and neck surgery. This has definitely enhanced the quality of surgery performed and the postoperative satisfaction of the patients.

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