Acoustic logging is also used for determination of cement bond in cased wells. Acoustic signals propagated in steel casing are observed to have large amplitude in free uncemented casing. See our cement bond log notes for logging tips, simultaneous gamma ray sie cement bond logging for how that is accomplished, and paul knights care and feeding of sie cement bond tools for maintenance tips. Cement bond logs drilling engineering netwas group oil. Cbl logging tool is run on electric wire line cable after cementing job is done. Case studies in evaluation of cement with wireline logs in a deep. Cement evaluation cement bond log cbl services accurate cement evaluation in any downhole environment halliburtons cement bond log tools reveal the e. Crains petrophysical handbook cement integrity logs. Cement bond logs cbl andor cement evaluation logs are usually conducted to evaluate the quality of the cement bond behind a cemented casing or liner before a well test or production operation. The fundamental principle is that the acoustic signal will be more attenuated in the presence of cement than if the casing were uncemented. Interestingly, at least epa region v seems to recognize that cement bond logs can only be used as substitute records of cementation. Logging services are faced with the task of minimizing. A bond is a type of investment that represents a loan between a borrower and a lender. The important curves are the attenuation and compressive strength values.
Private information, yield volatility, and interaction between groups of investors. Interpretation products have moved from consulting a nomograph to colourful displays that provide clearer representations of anticipated cement placement in the. The newer versions, called cement evaluation logs, along with. Bond note meaning in the cambridge english dictionary.
Acoustic signals propagated in steel casing are observed. This webpage version is the ed intellectual property of the author. The bond transcript contains those documents which were considered necessary by the parties to the transaction. Spgr interpretation geological time scale posted in a logarithmic log scale. There are no coupons attached for the owner to submit for payment of. By logging on you are accepting the terms and conditions outlined in the policy. Amplitude is normally presented on a scale of 0 to 100 percent amplitude. Cement integrity logs are run to determine the quality of the cement bond to. Cement bond log interpretation and evaluation casing. No cement bond is represented by 100 percent amplitude.
Crains petrophysical handbook cement integrity logs cbl. So, if good pipe bond but bad formation bond is suspected, the best interpretation can be made by combining the cement evaluation log with the cement bondvariable density log. The cement bond log clearly indicates top of cement, free pipe, and gives an indication of well cemented pipe. Proper cement placement between the well casing and the formation is essential. A practical approach to the interpretation of cement bond. The log is typically obtained from one of a variety of sonictype tools. Unfortunately, the cement bond log is perhaps the most misunderstood log used in drilling operations. The term of cbl is particularly refer to amplitude measurement of acoustic wave. The sonic tool uses a transducer to transmit an acoustic wave through the well fluid, steel pipe, cement sheath and surrounding formation. Cement bond log interpretation confidence interval. Cement evaluation a risky business glen benge benge consulting spe 170712. Interestingly, at least epa region v seems to recognize that cement bond logs can only be. The examples in this section are taken from cement bond log interpretation of. Cement bond log measurements and mechanical integrity evaluations are critical concerning well integrity and more particularly casing integrity.
Understanding bond documents 120 issuer cannot locate its bound volume, you may suggest that the issuer obtain it from its counsel or bond counsel. Pdf issues with cement bond and cement evaluation logscase. Cement evaluation objectives is the material behind the pipe a solid or liquid solids cant be fixed is there isolation in the annulus where is the cement toc cement evaluation. This interpretation is made more convenient with the use of a nomograph. In the process of drilling and completing a well, cement is injected through the wellbore and rises up the annulus between the steel casing and the formation. We specialise in the cement bond log interpretation based on cased hole wireline tools. Cement bond logs were run as early as 1958 with early sonic logs and the temperature log was used to find cement top beginning in 1933. Cement bond loga study of cement and casing variables onepetro. Cement bond loga study of cement and casing variables authors g. Always crosscheck your bond log with open hole logs to see that you have adequate bonding through the proper intervals. Wireline services log interpretation chart book weatherford products and services are subject to the companys standard terms and conditions, available on request or at for more information contact an authorized weatherford representative. The worm holes are almost impossible to squeeze and this well may leak gas to surface through the annulus for life, because the bond is poor everywhere above the gas. The variabledensity log is commonly used as an adjunct to the cementbond log, and offers better insights into its interpretation. Crains petrophysical handbook cement integrity logs cmt.
Arash dahi taleghani, associate professor of petroleum engineering at penn state university, will discuss this important measurement tool during topcorps webinar, cement bond log and its interpretation, on tuesday, may 21st from 1 to 2 pm et. A cement bond log documents the evaluation of the integrity of cement work performed on an oil well. This log shows good bond over the oil and water zones, but poor cement over the gas zone, probably due to percolation of gas into the cement during the curing process. The results of the experimental and theoretical study have provided means of quantitative interpretation of the cement bond log. Cement bond log analysis is vital to ensure well integrity isnt compromised. Cement bond log cbl has confirmed good cement bond, running of cbl was delayed due to requirement to drill out excess cement within the casing which has now completed. Bond log theory and interpretation slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. Therefore, due diligence and care should be taken in interpreting cement bond and cement evaluation logs to prevent costly mistakes. It is basically a variety of acoustic logging tools running. Introduction to cement bond logs february fact sheet 2017 cement bond log tools cbls have evolved over the years as technology and telecommunications have advanced. Acceptable use of ict policy for students or staff. A construction bond is triggered when the principal defaults on the obligation guaranteed by the bond and the obligee follows the proper claim procedure. Cement bond logs are used to detect the presence or absence of external cement behind casing. If you continue browsing the site, you agree to the use of cookies on this website.
Unless noted otherwise, trademarks and service marks herein are the property of. In the process of drilling and completing a well, cement is injected through the wellbore and rises up the annulus between the steel casing and the formation a sonic tool is typically run on wireline by a service company that detects the bond of the cement to the casing and formation via a. Cement bond log interpretation confidence interval casing. Cement bond log cbl logging services halliburton fliphtml5. The obligee cannot merely suspect a principal is in default of its obligations and leave it to the surety to make a determination. Log interpretation includes cblvdl, sector bond logs, usit, urs, and cast. Cement bond log, or in short cbl, is a basic method to evaluate cement quality in the annulus.
Qualitative interpretation of the cementtoformation interface. From the 1950s basic single transmitter and dual receiver design with analog communication and zero reprocessing capability, industry has moved to broadband transmitters. Our support for your well are in the areas of casing integrity. Experimental and theoretical studies of casingborne signals have provided data on the attenuation effect, compressive strength and shear modulus for different types of cement. Most of the cementingrelated problems encountered can be diagnosed by use of the cbl. Spe back to basics bond log theory and interpretation. Cement integrity logs are run to determine the quality of the cement bond to the production casing, and to evaluate cement fillup between the casing and the reservoir rock. Cement bond log interpretation and evaluation casing integrity. This amplitude is maximum in unsupported pipe and minimum in wellcemented casing. A cement bond log cannot be required as an external mit under any circumstances, not even under regfixs 40 cfr 146. Two kinds of cementbondlog cbl tools are run as part of a standard cementevaluation program. Bond online is available to all customers regardless of where they live.
Cement bond log interpretation free download as pdf file. The variabledensity log is commonly used as an adjunct to the cement bond log, and offers better insights into its interpretation. Do not copy or distribute in any form without explicit permission. Examples of good cement bond and free pipe and what things to look for. Archdrill is an independent consulting company providing thirdparty interpretation.
Logs and logging tools offered by the service companies may be different, and the interpretation may depend heavily on a knowledge of the particular tools characteristics. This article is based on crains analyzing cement integrity by e. The purpose here is to dispel some of the myths created by misguided interpretation practices. The cement bond log cbl gives a continous measurement of the amplitude of sound pulses from a transmitter to receiver. Cement bond logging cbl is an important part of a wellcompletion program and is also recommended for most workover programs. With a vast array of maturities, yields and credit quality available, investing in corporate bonds has the potential to provide higher yields than government bonds and diversification benefits for investors. Cement bond loga study of cement and casing variables. A log that uses the variations in amplitude of an acoustic signal traveling down the casing wall between a transmitter and receiver to determine the quality of cement bond on the exterior casing wall.
There are no coupons attached for the owner to submit for payment of interest. Oct 20, 2015 bond log theory and interpretation slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. You may login with either your assigned username or your email address. These data resulted in the establishment of a definite relationship between the cement compressive strength and the cement bond log reading.
Acoustic logs do not measure cement quality directly, rather, this value is inferred from the degree of acoustic coupling of the cement to the casing and to the formation. Clay type program determines clay type by using spectral gamma ray log this program shows how litology is determined with a density neutron log. A representation of the integrity of the cement job, especially whether the cement is adhering solidly to the outside of the casing. However, successful interpretation of a cbl depends on certain minimum requirements. An introduction to bond basics investment industry association of canada the information contained in this publication is for general information purposes only and is not intended by the investment industry association of canada as investment advice or a recommendation on the appropriateness of bond investing. Tool response depends on the acoustic impedance of the cement. For detailed analysis of the wave propagation, we use a. This type of log is most often referred to as a cement bond log cbl. If the bond log shows adequate bond through an interval where the geology allows fluid to move permeable andor fractured zones, fluids may move around perfectly bonded cement by traveling through the formation. Properly run and interpreted, cement bond logs cbl provide highly reliable estimates of well integrity and zone isolation. Some corporate bonds are issued as certificates, with the owners name printed on them. Think of it as similar to getting a personal loan from a bank except in this. Cost effective alternative to cased hole bond logging. The scbt evaluates the cement bond quality and integrity to both pipe and formation by providing the measurements of the cement bond amplitude cbl through the near receiver 3ft crystal, and variable density log vdl through the far receiver 5ft crystal.
Full waveform capture using open hole sonic tool with rig rental costs rising and attempts to minimize costs, the need for fast, efficient and accurate log acquisition is becoming more prevalent. So, if good pipe bond but bad formation bond is suspected, the best interpretation can be made by combining the cement evaluation log with the cement bond variable density log. Feb 17, 2016 cement bond log cbl what is it used for. Pdf issues with cement bond and cement evaluation logs. In general terms, a high signal amplitude indicates poor cement bond. Cement bond log how is cement bond log abbreviated. Convertible bond, whose holder has the right to convert it into shares in accordance with the agreed terms of the bond within a certain period, combines the common features of the bond and stock. The obligee must make the determination and a declaration i. After government bonds, the corporate bond market is the largest section of the global bond universe.
Cement bond vdl logs crains petrophysical handbook. This new measurement combined with conventional cement bond log data and. An introduction to bond basics investment industry association of canada bond basics what is a bond. Understanding acoustic methods for cement bond logging.
Knowledge of the well completion and the inherent physical restraints placed on the log measurements is needed to evaluate the log properly. At distances of three and five feet from the transmitter are receivers, which measure the refracted acoustic wave. If the fluid changes between two points, the travel times may drift, causing difficulty in interpretation and quality control. The effectiveness of these tools and their evaluations often are challenged, and they are not regarded as a replacement for reservoir interzonalcommunication tests performed between producing reservoirs.
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