Shear sonic log.

Shear sonic log Sometimes the logs in the different files are similar, but often slight differences existed between the various sonic logs for a well. ) Industry-leading quadrupole shear inversion for accurate shear data in both real time and memory in slow formations Shear validated against wireline out to 960 us/ft From top: SonicScope 900, SonicScope 825, SonicScope 675, SonicScope 475 services. The best known elastic constants are the bulk modulus of compressibility, shear modulus, Young's Modulus (elastic modulus), and Poisson's Ratio. Mengetahui proses dan melakukan clustering pada dataset conventional well log untuk melakukan identifikasi Badhole. If “local” trends are not available then care should be taken when choosing an “analogue” dataset to make such a comparison. Before the invention of the Dipole Sonic Log, older wells did not measure these essential parameters. 40 to 250 µs/ft (130 to 820 µs /m) Measurement range - shear slowness. 1 View in Scopus Google Scholar Dec 1, 2020 · The approach allows an extension of the range of applicability of full-wave sonic logging to determination of shear wave velocity profiles in formations with low compressional wave velocities. Conventional methods for predicting rely on empirical relationships and rock-physics models, which often fall short in Typically, shear sonic travel time (DTS) in conjunction with compressional sonic travel time (DTS) and bulk density are the key factors used in estimating rock mechanical properties. What are the advantages of CET, SBT, USI? 3. Since the S-wave is practically insensitive to fluid effect, there must be no influence of the invaded zone and it wouldn’t be necessary the knowledge of fluid parameters to calculate S-wave porosity. Trends were identified in sands and shales and were matched with semi-empirical correlations based on the Gassmann formalism. The sonic transit time can be used to compute porosity by using the appropriate transform and to estimate fracture porosity in carbonate rocks. , 2006). During the last decade important advances have been made in sonic logging. 1. It is virtually impossible to provide a complete collection of "standard" curve mnemonics. Rock-physics-guided machine learning for shear sonic log prediction. 1524 m. This is slower than the P-wave, but usually has a higher amplitude. Example of log reconstruction in a shaly sand sequence (Dunvegan). Jan 1, 2015 · Primary evaluation where openhole logging is not possible Resistivity Logging . Mengetahui proses dan melakukan prediksi Shear Sonic Log pada dataset conventional well log. Apr 1, 2021 · When laboratory measurement of shear sonic acoustic travel time (shear sonic velocity or V s) is time-consuming and expensive, V s is typically determined from empirical correlations developed using wireline logs (Anemangely et al. Aug 20, 2019 · The main goal of this work was to estimate carbonate porosity from sonic log S-wave slownessmeasurement, practically insensitive to fluid effect. 8, log track 1 from the right) had the best match with the measured Vs from the dipole sonic log (Fig. Although empirical and conventional machine learning (ML) have been used for shear sonic slowness estimates, both approaches suffer from multiple fundamental problems. Aug 5, 2019 · Abstract. Over the past few years new developments in the field of sonic logging have made the evaluation of shale anisotropy more accurate (Pistre et al. Obtain the elastic wave velocity log, V(z), from the sonic log using Eq. However, these two logs are often missing or incomplete in many oil and gas wells. Nov 14, 2019 · This means that the logging is done through the bare rock sides of the formation. Original density and sonic are shown in black, modeled logs are in colour. 4 m) Enhanced = 0. These estimates of rock mechanical properties provide us with valuable insights on subsurface characterization. 5, the measured and ANN predicted shear wave sonic transit times are plotted versus depth. Jan 1, 1984 · The measurement of the first wave arrival relates only to those waves refracted at the critical angle as these are the fastest. Realistic filtrate properties need to be understood and applied. They can be counted by hundreds or even thousands, and growing. SHEAR TRAVELTIME FROM COMPRESSIONAL DATA A shortcut that cam be used is to determine a multiplier (Vp/Vs) based on the graph at the right: Abstract Shear wave velocity (VS) data from sedimentary rock sequences is a prerequisite for implementing most mathematical models of petroleum engineering geomechanics. GEOPHYSICS. So It must be remembered that the sonic log gives a one-way travel time, and the seismic Nov 1, 2018 · On the right-hand side of Fig. 397 ft in terms of MAE, and 8. On the full wave or array sonic log, we can measure travel time and attenuation of the compressional, shear, and Stoneley wave energies, instead of merely the compressional energy as on conventional sonic logs. 8, the measured shear sonic transit log is plotted against the depth profile of the wells used for the case study from 6000 to 800 ft. The introduction, a few years ago, of shear dipole sonic logs gave the industry the possibility to record high-quality shear and compressional slownesses in soft formations. Wireline sonic logging tools use acoustic sources and receivers to measure formation properties. Post sonic log prediction, lithology determination is performed with the help of an unsupervised ML algorithm, k-means clustering. 5 Acronyms Sep 1, 2021 · Determination of formation shear attenuation from dipole sonic log data Geophysics , 84 ( 3 ) ( 2019 ) , pp. The seismic data are Aug 1, 2021 · Compressional and shear sonic traveltime logs (DTC and DTS, respectively) are crucial for subsurface characterization and seismic-well tie. The arrival of this pulse is detected at Sep 21, 2021 · The well logging technique is used to determine the petrophysical properties like porosity, permeability and fluid saturations of subsurface formations. Sonic logging data are useful in a variety of applications, including seismic correlation, rock mechanics and wellbore stability, pore pressure prediction, sourceless porosity estimation, gas detection, and stress and fracture characterization. , one compressional, one or two dipole shear, and one tube Jun 10, 2021 · Shear sonic logs, however, are not often measured compared with other well logs. (2) The amplitude at the receiver of the first or second wave in the signal train, either on arrival of the compressional wave or the shear wave. extends the application of sonic logging comparing with common acoustic logging method, for example, composite of P-wave and S-wave data, we can discern lithol-ogy,fluid type, to calculate poisson ratio, and using Stoneley wave, we can identify fracture, estimate permeability, and to achieve formation mechanical stress Oct 11, 2023 · Request PDF | Rock Physics guided machine learning for shear sonic log prediction | Shear wave velocity (Vs) is a vital parameter for various petrophysical, geophysical, and geomechanical the world, including the Permian Basin in the United States, the cur-rent study area. (Slowness is the reciprocal of velocity and corresponds to the interval transit time measured by standard sonic tools. 1 January 2024. The dipole sonic imager (DSI) is a multiconfigurable tool that can emulate a BHC sonic, a standard monopole array tool, or an array dipole tool. 7 ft (200 mm) Accuracy. Sep 29, 2020 · The Shear Log Modelling module is intended to help users generate a calibrated shear sonic log for wells in which only a compressional sonic log was measured, as is often the case. (1985) have demonstrated a relationship between shear (Vs) and P-wave velocity (V P). Compressional (P-wave), shear (S-wave) slowness, fast shear azimuth. , 2000). The tool provides high quality waveforms and slowness measurements with 3. Aug 1, 2021 · Having the potential of demonstrating shear sonic log prediction in hydrocarbon-bearing zones, which cannot be precisely predicted by the Greenberg-Castagna method that only works in brine-saturated rocks, this approach will provide improved accuracy, where shear sonic logs are missing and need to be predicted for geomechanics, rock physics Jan 28, 2014 · The document summarizes acoustic logging, which uses sonic tools to measure the speed of sound waves through rock formations. We would like to show you a description here but the site won’t allow us. Nevertheless, obtaining shear sonic log is frequently challenging because of its high economic, time, and operating costs. (1995) extended the work of Castagna et al Apr 1, 2021 · The wireline log data such as gamma-ray, formation bulk density, neutron porosity, acoustic compressional, and shear sonic velocities are considerably changed with formation depth due to the complex behavior and heterogeneity of shaly sand sedimentary rocks. 298% for AAPE, on average for the 10 training wells (Wells d1 to d10). , natural gamma ray, P-wave velocity, density, and resistivity) that can be readily obtained from standard logging suites. 748 ft in terms of RMSE, 1. In addition,it can be used to compute a “pseudodensity” log over sections where this log has not been recorded or the response was not satisfactory. Shear slowness is more difficult to measure with monopoles and requires coherence processing of waveforms from a receiver array. Standard sonic logs may not record flushed zone properties. If weuse the DTC log as the independent variablein Log quality generally is not as good where the wall of the hole is rough, or where rocks are soft. Used for determining porosity, lithology, and formation velocity. Dec 1, 2022 · This study proposes a data-driven approach to generating the synthetic shear sonic log (DTS) using five types of wireline logs (GR, RHOB, NPHI, RT, and DTC) that are commonly accessible in hydrocarbon production fields or exploration sites. Feb 19, 2021 · Real-time open-hole wireline sonic logging data processing becomes a nontrivial task to accurately, automatically, and efficiently evaluate the compressional and shear slowness of a borehole rock formation when human interaction is not possible and the signal processing time is limited to the elapsed time between different transmitter excitations. Dipole shear sonic logs offer many display options. GeoConvention | Geoscience Conference Compressional and Shear Sonic Log Determination Using Data-Driven Machine Learning Techniques. For certain reasons, most of the wells in the Lower Indus Basin (LIB) lack DTS logs, which are modeled using conventional techniques based on empirical relations and rock physics modeling. The method could be used to obtain shear wave velocity profiles where compressional wave velocity is as low as slightly larger than the mud-wave speed. Similar to the dipole shear sonic log, the array sonic log with a monopole source measures compressional, Stoneley, and wave velocities which are used to estimated shear wave velocities. Data from the Sonic Scanner platform is acquired and ready for solutions through integrated Techlog™ wellbore software platform workflows for Aug 1, 2022 · Shear sonic log (DTS) availability is vital for litho-fluid discrimination within reservoirs, which is critical for field development and production. The document provides an overview of sonic logging, which measures the velocity of sound waves in rock. The approach allows an extension of the range of applicability of full-wave sonic logging to determination of shear wave velocity profiles in formations with low compressional wave velocities. This tool combines monopole and dipole sonic acquisition capabilities for the reliable acoustic measurement of compressional, shear, and Stoneley slownesses with space resolution of 0. 3. As for the sonic log, shear waves will split when passing through an anisotropic formation, shear waves will split during propagation, and the azimuth of fast shear waves is consistent with the orientation of in-situ stress. The post-acquisition processing and inversion provides an alternative to determine the properties of drilled formations. Generating Vs from Vp sonic logs David G. To address real-time sonic data Aug 1, 2017 · Dipole shear sonic imager (DSI) log offers valuable data for geophysical, petrophysical and geomechanical studies of the hydrocarbon bearing intervals. To determine if such differences Jan 1, 2019 · Upon analyzing the outputs from the six Vs scenarios generated, we observed that in the Montney interval, the Vs SH estimated log (Fig. - Applications include determining porosity, identifying lithology, improving correlation, and estimating secondary pore space. Logging speed. Full waveform acoustic logging tools are similar to conventional acoustic logging tools. We provide an example from the benchmark dataset where a complete shear sonic log is predicted and compared with both the original shear sonic log and the outcome of a This page is a summary of: Rock Physics guided machine learning for shear sonic log prediction, Geophysics, October 2023, Society of Exploration Geophysicists, DOI: 10. On the other hand, the shear sonic log prediction was 15. 2. (1985). 312 ft in terms of MAE, and 2. We can group together as acoustic logs those that involve recording a parameter linked with the transmission of sound waves in the formation. Dipole sources generate flexural waves that can better Dec 21, 1998 · Log analysts at ODP Logging Services carry out the processing, mostly using Schlumberger GeoQuest’s "GeoFrame" software package. the prediction of missing logs and will produce shear sonic logs pre-diction accurately from essential logs. Our sonic log gives slowness (reciprocal velocity) measurements at regular depths (10cm intervals) through the subsurface. 1. Borehole engineering logging surveys are performed to accurately acquire rock properties, structural stress-strain relationships, fracture statistics, and other in-situ properties for major tunneling and engineering projects. However, the conventional way of log evaluation is very expensive and tiresome. Journal article Published. Sep 7, 2022 · The proposed approach shows more consistency and accuracy in shear sonic log prediction along the entire Wolfcamp section. Aug 12, 2022 · Shear sonic log (DTS) availability is vital for litho-fluid discrimination within reservoirs, which is critical for field development and production. 05 m); and (3) the receiver is commonly an array consisting of four to twelve phones. Mar 1, 2004 · In this paper, we present sonic data acquired in the AIG 10 well using a dipole sonic logging tool between depths 711 m and 1004 m (depths are hereafter understood as meters below blow out preventer). Jun 16, 2017 · Derivate the formula of interval transit time for sonic logging, and how to eliminate the borehole effect? 3. What are the principle and applications of CBL and VDL? 3. Dipole Sonic Logging: Employs dipole sources to generate shear waves, providing shear wave velocity in soft Jul 18, 2015 · Abstract. Jan 1, 2015 · The dipole shear sonic log has reduced the need for this calculation, as it sees shear waves better than older array sonic logs. These are the most important two waves. Publication. Conventional methods for predicting rely on empirical relationships and rock-physics models, which often fall short in Aug 12, 2022 · 1 Department of Earth Sciences, Quaid-I-Azam University, Islamabad, Pakistan; 2 LMK Resources (Private) Limited, Islamabad, Pakistan; Shear sonic log (DTS) availability is vital for litho-fluid discrimination within reservoirs, which is critical for field development and production. 35 (left) and larger than 0. -Feb. Furthermore, advanced frequency domain Jun 1, 2022 · Ojala (2009) established an experimental method to generate a pseudo sonic log in a mudstone formation in the North Sea. Figure 9. The next wave, usually, to arrive is the transverse or shear wave (S-wave). Dec 1, 2012 · Full waveform analysis of sonic log considers the analysis of all the whole wavefields that are recorded: P, S wave and guided waves. Fig. Compressional slowness is measured using a monopole source and provides porosity and seismic velocity indications. 9W, Palisades, NY 10964 FMS/DSI-2 Tool String The TAP tool is a 2. Jun 10, 2021 · Shear sonic logs, however, are not often measured compared with other well logs. This is the significant limitation of the (Mineral) Monopole Full Waveform Sonic tool. - Sonic tools emit These are a typical suspension logging method, an integrated logging system and Crosshole shear logging. 1190/geo2018-0006. The blue curve indicates true shear sonic slowness, whereas the orange curve is the ML-predicted shear sonic slowness curve. The interest of the shear interval transit time measurement is shown by Pickett. d1 to d10), the compressional sonic log prediction was 1. Cased Hole Dipole Shear Sonic Log. 6. Each logging company assigns its own mnemonics, and each interpreter usually assigns its own mnemonics, with versions and initials. We provide reliable, high-quality acoustic data. New approaches to ML, namely, unsupervised multivariate time series clustering MicroScanner/Dipole Shear Sonic Imager tool string. The module uses the Greenberg and Castagna methodologies for calculating a synthetic shear log that can then be used in other calculations, such as in the We develop a physics-guided machine learning (ML) approach to predict the shear sonic log using various physical parameters (e. This is the sonic amplitude log, which has an important application in cementation evaluation, such as the Cement Bond Log (CBL), Variable density logging (VDL), and Convert the density log in depth to that against two-way time using the TTI information from the sonic log. Conventional methods for predicting V S rely on empirical relationships and rock-physics models, which often fall short in accuracy due to their inability to account for the complex factors influencing the relationship Shear (Vs) and compressional (Vp) sonic logs are important parameters required in reservoir exploration, development, recovery, geothermal operations, and fluid sequestration. Aug 1, 2017 · Dipole shear sonic imager (DSI) log offers valuable data for geophysical, petrophysical and geomechanical studies of the hydrocarbon bearing intervals. Dec 5, 2019 · The most modern type of sonic logs are the dipole shear sonic logs. The main differences are that (1) the source is usually of lower frequency, centered at 5 to 10 kHz rather than at 20 kHZ; (2) the source-receiver spacing is longer, on the order of length::10 ft (3. Tool String Specifications ODP Logging Services, Lamont-Doherty Earth Observatory, Rt. 70 to 900 µs /ft (230 to 2,960 µs /m) Vertical resolution. It discusses the principles of acoustic logging, including measuring interval transit time and classifying compressional and shear waves. Jul 26, 2024 · In the example project, we have multiple wells in a study area where only one well has a shear sonic log, some have compression wave sonic logs, and all have neutron and gamma ray logs. Sonic (Acoustic) Log 3 The sonic log is a porosity log that measures slowness or interval transit time ( 4 ) of a compressional sound wave travelling through the formation along the axis of the borehole. Modes are configured to meet the logging conditions presented by different borehole environments. The monopole source is not able to measure shear wave velocities in slow formations. The operating frequency range for these measurements is typically from 0. Conventional log data (natural gamma radioactivity, resistivity, density, porosity, sonic velocity, magnetic susceptibility logs) are transmitted via Mar 30, 2014 · The direct way to estimate the rock mechanical properties is using dipole sonic log, from which the P-wave velocity and S-wave velocity can be extracted. 57-86 (Data Science and Machine Learning Applications in Subsurface Engineering). Cross-dipole sonic logging is a powerful instrumentation to detect shear wave velocity anisotropy in a formation (Plona et al. D73 - D79 , 10. e. Relationships between compressional and shear wave velocities were established in the classic paper by Castagna et al. 8. The source is operated at low frequencies, usually below 4 kHz. 4 (October 1990): 9-12. / Otchere, Daniel Asante; Gholami, Raoof; Nta, Vanessa et al. 4. There are two types of body waves (compressional and shear) that are commonly used to estimate rock σ v Total vertical stress through the integration of ρ b bulk density log (a change in the slope may suggest gas presence) ν Poisson ratio from shear and compressional sonic logs; G Shear modulus from shear travel time and bulk density logs; E Young modulus from G and Poisson ratio ν ABSTRACT The S-wave velocity is a vital parameter for various petrophysical, geophysical, and geomechanical applications in subsurface characterization. (16). Along with the compressional velocity log, they used a full set of well log data from one well as inputs to train the model that can be used to predict accurately the log This type of sonic log can have both a monopole or dipole source. The dynamic elastic constants can be derived with appropriate equations, using sonic log compressional and shear travel time along with density log data. The shear wave is slower than the compressional, and modern sonic log processing can segregate and record both. Figure 8. This approach is based on supervised machine learning and is implemented in MATLAB. The sonic device consists of one or more ultrasonic transmitters and two or more receivers. 358% for AAPE. 1 DTSC DELT or DTC 2 TTC DELT or DTC 1 AC1 DELT or DTC 1 MSTT DELT or DTC 5 VEL DELT = 3. compression and shear wave velocity, Vp and Vs, (i. Oct 1, 2014 · In this study, sonic Shear and Stoneley velocities were predicted from well log data using intelligent systems including: Fuzzy logic, neural networks, neuro-fuzzy, and support vector regression. ABSTRACT Shear sonic logs are critical for formation evaluation, rock physics, quantitative reservoir characterization, and geomechanical studies. Dipole shear sonic coupled with automated sonic waveform processing for slowness determinations, provides accurate formation compressional and shear slowness measurements in cased wells. What is the difference between Acoustic logging and Dipole shear image logging? 3. Empirical equations, such as Greenberg-Castagna relations, can be used to estimate shear sonic logs, but they only work for brine-saturated rocks (paper SPE 198764). In particular, linear trends for correlating the compressional and shear wave velocities are presented, including the Castagna mudrock line derived from in-situ sonic and seismic measurements. , 2019). Key points: - Sonic logs measure interval transit time, which is inversely related to velocity and depends on lithology, porosity, and fluid. p. (1974) and Rider (1986) presented two density-based equations capable of Shear Sonic Log menggunakan algoritma Boosted Random Forest dan LSTM. However, they are often not acquired in all wells because of cost limitations or borehole problems. VDL indicates Sep 1, 2023 · Several studies attest to the ability of ML algorithms to synthesize or predict sonic logs based on commonly acquired logs such as gamma ray, density, neutron-porosity, resistivity, and spontaneous potential, among others [5]. This cross-plotting method may be extended to compare your data to published global rock property trends. (2019) applied a supervised machine learning model in MATLAB. Mar 21, 2020 · In Fig. For most wells, multiple compressional and shear sonic log files were available. 281 * 1000000 / VEL 3 SHEAR SONIC Jul 17, 2023 · Sonic Logging Principle: Borehole Sonic Logging is based on the principle of measuring the travel time of Compressional (P), Shear (S) and Stoneley waves propagating along a borehole with different radial depths into the formation. more accurate porosity determination from sonic data: The Log Analyst, Jan. What is the application of UBI? 3. 5 confirms a closer match of the measured and ANN predicted values for compressional wave sonic transit time than for shear wave sonic transit time. Oct 14, 2024 · This arrangement is suitable for detecting azimuthal velocity variations in a borehole. 7, Fig. Compressional (Vp), shear (Vs) and Stoneley (Vst) waves are acquired through processing and interpreting the DSI data. Record type. Apr 1, 2019 · The ratio of compressional to shear sonic log has been reported to be more sensitive to lithology and fluid saturation (Bailey, 2012; Domenico, 1984; Eastwood and Castagna, 1983; Hamada, 2004; Han et al. SHEAR TRAVELTIME FROM COMPRESSIONAL DATA A shortcut that cam be used is to determine a multiplier (Vp/Vs) based on the graph at the right:. 6, Fig. Compressional and shear waves are excited along with a dispersive flexural mode of the borehole. Some efforts have been made to use machine learning to generate synthetic logs, and these obtained In other words the repeat log (log B) looks similar to well A except for a few locations, specifically at about 1m (10 sample intervals) at depths of 2, 35, 40, 96, 120 and 137m from the top of the log. It is identical to the interval transit time, which is a basic measurement made by sonic logging tools. Jan 1, 2021 · Shear-sonic versus P-sonic (or V s vs V p): use an edited sonic to guide shear editing. 6 ft (1. Our industry-leading sonic tools and experienced LWD engineers can help you to correlate seismic time-versus-depth measurements, determine porosity, and understand the mechanical state of the rock. Numerous attempts have been made to establish a precise relationship between DTS and other petrophysical data. Aug 1, 2021 · PEF log was utilized to generate sonic logs (compressional and shear velocity) using ANN, recurrent neural networks (RNNs), RF, ensemble method (combination of several models) and LightGBM, where Dec 27, 2023 · Nevertheless, obtaining shear sonic log is frequently challenging because of its high economic, time, and operating costs. Jun 20, 2022 · The results of the shear sonic log prediction on the test data were qualitatively and quantitatively analyzed. For certain reasons, most of the wells in the Dec 1, 2023 · Hence, both the compressional and shear wave travel times have proven to be important tools in every phase of oil and gas exploration and production [2]. You can read the full text: Read Sep 20, 2024 · Type of Sonic Logging: Description: Key Applications: Standard Sonic Logging: Measures the travel time of acoustic waves between a source and receiver in the borehole. After them come Rayleigh waves, Stoneley waves, and mud waves. 4. Shear sonic is the model result as none was recorded in this well. A machine learning approach to shear sonic log prediction is demonstrated. 1 Using “Shear Wave Logging with Dipoles,” Oilfield Review 2, no. inverse of compression and shear transit time DT and DTS from sonic log) as below: ( ) (3 4 ) 2 2 2 2 2 c s s c s dyn V V V V V E (1) 2( ) 2 2 2 2 2 c s c s dyn V V V V (2) The dynamic properties representing log acquired data are converted to the static rock properties in static conditions. Steps of modeling and adopted rock physic models Slowness is the inverse of velocity, which depends on the rock elastic modulus: ρ K G VP 3 4 + = ρ G VS = (1) SST Shear Sonic Tool TAP Temperature-Acceleration-Pressure Tool TLT Temperature Logging Tool UHT-MSM Ultra-High Temperature Multisensor Memory Tool. It is normal. The work of Brie et al. ,1983). Tujuan Tujuan kerja praktik ini adalah sebagai berikut: 1. 3,600 ft/hr (18 m/min) Measurement range - compressional slowness. Pickett (1963), and Castagna et al. Jun 17, 2024 · A specialized type of sonic log is the cement-bond log (CBL) or bond-attenuation log (BAL) that uses the full-waveform to assess how well casing is bonded to the formation. 3, and 3. Shear wave transit times can be inferred by making lithologic assumptions based on Vp/Vs ratios thus with a DTS shear wave log, and that there is no need for a porosity log (since the information of this property is implicit in the modeled slowness values). In this study, a method Jun 15, 2019 · ABSTRACT. Acquire acoustic data while drilling. 7 meter long memory or real-time logging tool ♦Mapping of formation structures ♦Dip determination ♦Correlation of coring and logging depths established. 1190/geo2023-0152. Basic Principle of How Logs Work . The predicted shear sonic log closely matches the measured shear sonic log values. 5. Feb 8, 2021 · These problems may be overcome during data processing but logger’s client might be disappointed to learn that the monopole sonic used in mineral logging cannot measure the shear wave transit time in slow formations. Some efforts have been made to use machine learning to generate synthetic logs, and these obtained Feb 21, 2022 · Using sonic logs from wells in the CONDA field located in the deep offshore Niger delta basin of the Gulf of Guinea, we demonstrate that machine learning algorithms can be used to predict sonic Jun 1, 2014 · The digitized well logs consist of dipole shear sonic imager (DSI), compressional wave sonic log (DTCO), gamma ray log (CGR), density log (ROHZ), effective porosity (PHIT), true formation resistivity log (RT), and caliper logs (HCAL). Qualitatively, in the interest area the predicted data shows a good fit with the Nuclear logging has now largely supplanted sonic logging for porosity determination, although the sonic porosity reflects primary porosity and not total porosity. ABSTRACT The S-wave velocity is a vital parameter for various petrophysical, geophysical, and geomechanical applications in subsurface characterization. This study proposes a novel approach to ABSTRACT Real-time open-hole wireline sonic logging data processing becomes a nontrivial task to accurately, automatically, and efficiently evaluate the compressional and shear slowness of a borehole rock formation when human interaction is not possible and the signal processing time is limited to the elapsed time between different transmitter excitations. We develop a method to estimate the DT and DTS simultaneously from other commonly acquired well logs such as gamma Dec 27, 1992 · Good estimates of formation strength from offset well sonic log data can help in the planning of bit programs and well stimulation procedures. , 54 - 59 The invasion process is complicated and mud filtrate can have a large effect on log derived seismic or reservoir properties. The shear interval transit time can automatically be obtained by using the Schlumberger Long Spacing Sonic tool. Apr 2, 2022 · Compressional (V p) and shear (V s) sonic wave velocities, routinely obtained from seismic surveys and wireline logging, play a first-order role in reservoir evaluation under in-situ conditions. This is followed by a plot of the shear sonic transit log along the same depth in Fig. These logs measure values for compressional, shear, and Stoneley slowness through both monopole and dipole sources. Both compressional and shear waves refract back into the borehole, the shear converting to a compressional wave, to be detected by the receivers in the logging tool. , 2005; Walsh et al. The 3 tracks on the left show the measured gamma ray, caliper, density, and compressional sonic. In a dipole shear sonic tool, a directional (dipole) source and directional receivers are employed. Permeability values were calculated over the entire reservoir length and showed good agreement with NMR permeability values. Schieck and Robert R. This algorithm helps us to define an optimum number of clusters (Mohamed et al Combining new dipole-based technology with the latest monopole developments into one system provides the best method available today for obtaining borehole compressional, shear and Stoneley slownesses (slowness is the reciprocal of velocity and corresponds to the interval transit time measured by standard sonic tools). The shear wave cannot propagate in fluids, as fluids do not behave elastically under shear deformation. 8), thus indicating that for the Montney Formation in our Shear wave splitting and orientation of the fast shear azimuth guide lateral well placement, and Stoneley analysis can indicate and characterize fractures as well as reveal formation mobility. Authors. “Shear Wave Logging with Dipoles,” Oilfield Review 2, no. 7. Jun 1, 2024 · To predict shear sonic log for the Poseidon field in the Browse Basin offshore North West Australia, Bukar et al. A monopole source emits radially while a dipole energy source emits energy in one direction. 5, Fig. Also, Gardner et al. sonic logging. ±-2% Porosity and “pseudodensity” log. 5 to 20 kHz. While the Greenberg-Castagna method is an empirical method that attempts to predict shear velocity log from file was available, the density log was downloaded from NLOG and imported separately. Extracting such data by analyzing finite reservoir rock cores is very costly and limited. It operates in different modes such as upper and lower dipole, crossed dipole, and Stoneley modes. Method The sonic log measured curves Slowness is the inverse of velocity, depending on the rock elastic modulus: ρ G K VP 3 4 + = ρ G VS = (1) Where K is the bulk modulus, G is the shear modulus and ρ is the rock density. g. , 1986; Tatham, 1982). suggested that the transmission of sonic waves through the formation, “sonic well logging” can provide valuable data such as compressional transit time and shear transit time that is used Combining new dipole-based technology with the latest monopole developments into one system provides the best method available today for obtaining borehole compressional, shear and Stoneley slownesses. Therefore, many petrophysical and geophysical workflows include sonic log synthetization or pseudo-log generation based on multivariate regression or rock physics relations Oct 22, 1995 · Abstract. In the language of sonic logging, slowness—the reciprocal of velocity—is most commonly used. Another interesting pattern isthe resolution of output rock properties. Aug 18, 2022 · In the geophysical exploration field, the sonic log (DT) and shear sonic log (DTS) are frequently used as quick and affordable procedures for reservoir evaluation. ABSTRACT Compressional and shear sonic transit time logs (DT and DTS, respectively) provide important petrophysical and geomechanical information for subsurface characterization. Theoretical and experimental results are well documented on P and S-wave velocities and attenuation (Sun et al. 2. Mar 1, 1998 · Sonic logging is becoming a routine way to plan well placement strategies, leading to improvements in reservoir production. Cased-hole logging involves retrieving logging measurements through the well casing, or a metal piping that is inserted into the well. Mar 30, 2014 · The direct way to estimate the rock mechanical properties is using dipole sonic log, from which the P-wave velocity and S-wave velocity can be extracted. If not available, we can use sonic log coupled with one of the methods mentioned in the previous section to predict the shear velocity. In many deep-water wells to save the cost of operations, shear sonic data are not recorded. 5 ft vertical Apr 18, 2025 · Figure 5 shows the correlation between a tube wave amplitude log calculated from digitized acoustic waveform data and fracture aperture or permeability from straddle packer tests (Davison, Keys, and Paillet, 1982). 797 ft in terms of RMSE, 10. Example of shear (DTS) and compressional (DTC) sonic relationships from the reference wells with a VClay cutoff smaller than 0. The goal is to predict shear and compression sonic logs for all wells. This may be due to the fact that ANN input vectors like bulk density The document describes the Dipole Sonic Imager Tool (DSI-2) which combines monopole and crossed-dipole transmitters with an 8-receiver array to obtain borehole compressional, shear and Stoneley slownesses. Since the introduction of the dipole shear This is the sonic log (AC). Acoustic-televiewer log of fracture-producing zone A in a geothermal well, Roosevelt Hot Springs, Utah. Several tool designs are available, but they all generally assess amplitude and attenuation of the waveform to evaluate the strength of the formation bond. CRC Press, 2023. Sonic logging tools emit a sound pulse every second. 1, 2. relied on supervised ML algorithms to predict shear sonic log based on gamma ray, neutron-porosity, bulk density, true resistivity, compressional sonic, computed total Dec 1, 2022 · Under oil-based mud conditions, the induced fractures are difficult to identify due to the compromised image quality. The high cost of sonic dipole advanced wellbore logging service and its implementation in a few wells of a field has placed many Jan 19, 2022 · Tools. These trends can The work adapts to carbonates a methodology to obtain porosity curve from shear slowness (S-wave slowness), measured by sonic logging tool. Aug 5, 2019 · As a result, there has been extensive research regarding the application of artificial intelligence (AI) techniques in well log interpretation [7], shear sonic log prediction [8], and prediction the log data to be used to calibrate and check the seismic data. The sonic log is a porosity log that measures slowness or interval transit time ( 4 ) of a compressional sound wave travelling through the formation along the axis of the borehole. Figure 3 is a composite log including shear and tube wave amplitude, temperature, single point resistance, and VDL. 2 Sonic Log 75. Convert the elastic wave velocity log in depth to that against two-way time using the TTI information from the sonic log. Due to the high acquisition costs, DTS is only accessible in a few wells within an oil/gas field. In petrophysical forma-tion evaluation, the use of sonic data is limited, and hence, sonic data, especially shear sonic, are not considered as critical. Thus, the difference between the two can be a useful indicator of secondary porosity, and both compressional and shear sonic data can be used as gas indicators. As the resolution of the sonic log is about 61cm and that of the seismic technique is IOOcm to 500cm, the sonic data must be averaged for the comparison to be made. This report looks at how sonic shear-wave anisotropy measurements are In this context, it is important to more accurately relate the three or four available sonic slowness measurements from sonic tools, i. , 2000, Tang, 2004, Zhang and Tang, 2000) and in analysis of shear wave isotropy from borehole guided wave (Tang, 2002). Logging passes were done at three different applied borehole fluid pressures (0. We took the sonic log mean as a baseline, and that is because sonic on average increases with depth due to compaction. 0 MPa). Stewart INTRODUCTION The correct identification of primary events on the converted S-wave section in the absence of a VSP or S-wave sonic log may be difficult (Corbin et a1. In many cases, logging-while-drilling (LWD) sonic logs provide a helpful alternative to wireline logs because of hazard avoidance, timeliness Jan 1, 2015 · Well Log Curve Name Alias Table. 3. Dynamic shear modulus values were calculated from Porosity and “pseudodensity” log. Nov 26, 2016 · Three major types of acoustic logging depend on its investigating parameters such as sonic velocity logging, sonic amplitude logging, and sonic frequency logging. The results of this approach were compared to that of an approach based on the Greenberg-Castagna empirical method. The dipole shear sonic log has reduced the need for this calculation, as it sees shear waves better than older array sonic logs. Data sets were acquired and analyzed on Vp/Vs versus Δtc crossplots. 8 Primary evaluation where openhole logging is not possible Resistivity Logging . 35 (right) for formations between Kujung Sonic logging is a well logging tool that provides a formation’s interval transit time, designated as , which is a measure of a how fast elastic seismic compressional and shear waves travel through the formations. Typically, shear sonic travel time (DTS) in conjunction with compressional sonic travel time (DTS) and bulk density are the key factors used in estimating rock mechanical properties. Jun 1, 2022 · Ojala (2009) established an experimental method to generate a pseudo sonic log in a mudstone formation in the North Sea. (1974) and Rider (1986) presented two density-based equations capable of Shear slowness data are crucial data in rock physics analysis and seismic reservoir characterization. Data Science and Machine Learning Applications in Subsurface Engineering. The same workflow can also predict other properties like porosity and permeability. ybjgz avjs chbho zqdn kupt gajmm lkk mzkidr jfanu mrhe