Bond Log Theory and Interpretation. April 16th, Variable Density Log ( VDL). • Examples of good . Single CBL 3′ amplitude can not identify channeling. 23 May A standard CBL (Cement Bond Logging) tool uses sound energy to determine how well bonded the Below is the explanation of bonded pipe. Cement Bond Log Interpretation – Free download as PDF File .pdf), Text File .txt ) or SBT is a combination of CBL/VDL and pad sonic devices that provides a.
|Published (Last):||20 November 2010|
|PDF File Size:||3.39 Mb|
|ePub File Size:||12.13 Mb|
|Price:||Free* [*Free Regsitration Required]|
Modern acoustic cement-evaluation bond devices are comprised of monopole axisymmetric transmitters one or more and receivers two or more.
Track 2 contains the acoustic attenuation logs for the six pads. This provides good acoustic coupling and most interprstation the cbl vdl interpretation energy is transmitted to the formation, resulting in cbl vdl interpretation weak to no casing signals and little amplitude until the arrival of the strong formation signal. Days, weeks and as Gary and Matteo said even a month.
As with openhole tools, cement-bond tools require centralization to ensure accurate measurements. Measurements from these devices are influenced by the same factors as openhole televiewer devices. Proper cement placement between the well casing and the formation is cbl vdl interpretation Table 1  .
Just a quick remark, now that I am reading again my previous comment …. Eventually, cbl vdl interpretation devices using dual transmitters and dual receivers were introduced in the s, and today most commercial devices use multiple transmitters and receivers in a variety of arrangements to provide compensated measurements.
This condition is indicated by the lack of later-arriving formation energy. Whenever possible, amplitude data should be used in conjunction with the other measurements presented interpretatlon the log e.
If the cement is tested at a BHCT that is higher than the BHST where you are cbl vdl interpretation expect a very long time for any significant compressive strength development. Maybe distinct permeable zones in cbl vdl interpretation thin-bed formation? The cement log would quickly change from good to bad; it would stay bad in front of the problem zone and then quickly changing back to good in the next formation.
Quick Cement Log Interpretation Guide
Depending on the timing in cbl vdl interpretation the signals are evaluated. Theoretically this micro-annulus would be either dry or wet. The result is that little energy is transferred to the annular fluid and virtually none is transferred dvl the formation.
To support the casing shear bond To prevent fluid from leaking to the surface For isolating producing zones from water-bearing zones hydraulic bond Acoustic logs provide the primary means for evaluating the mechanical integrity and quality of the cement bond. Cbl vdl interpretation you should be worry about, if the log is not answering important questions:. Cbl vdl interpretation, the analysis would become more of niterpretation educated guess than an objective fact-based report.
Quick Cement Log Interpretation Guide | Better Well Cementing for ALL
The VDL should be examined to ensure that the formation arrival is impacting the amplitude curve. Basically, interprehation cement liquid phase filtrates into the permeable formation or b formation fluids invade the cement during the transition liquid to solid stage.
There is poor cement condition between Cbl vdl interpretation and X depth units. In these situations, users are advised to consult with the logging service company regarding the cbl vdl interpretation calibrations. Floating gates remain open, but recording is only triggered by an amplitude value greater than a designated threshold value.
Cement bond logs
It may lead to unnecessary squeeze operation. From what you say I cbl vdl interpretation suspect contamination on the way down: Back in the simple days of only 8 well centralized receivers on ultrasonic logs these were identified as secondary reflections. The resulting waveform is comprised of a casing signal and a formation signal; the casing signal arrives first, followed by the interpretatipn signal.
Comments one of factors that could misled your cement bond is If we run CBL too early cbl vdl interpretation cement is set, we may see poor cbl vdl interpretation. The bonding between cement and formation is investigated through a CBL-type receiver array for wave-train presentation Fig. And for practical purposes I would agree, however certain situations can blur that interpretatino It would affect the CBL with amplitude values ranging 10 to 30 mV, but lower than free-pipe value.
They operate on the principle that acoustic amplitude is rapidly attenuated in good interprettation bond but not in partial bond or free pipe. If we see that in average or, better, circumferentially then we infer that isolation in likely there… But, if we do not see sufficient cement then isolation cannot be verified by cbl vdl interpretation But by interpretation, if we are lucky enough.
This map can indicate the presence of channels and their orientations. That may cbl vdl interpretation what you are referring to with your 0. By analyzing the entire waveform, an acoustic-impedance map of the cement can be constructed. Contaminated cement is common cause when no bottom plug is present, e. The cement-evaluation presentation includes casing ovality and tool eccentricity in Track 1.
On a variable-density log, free pipe and fluid arrivals if present are easily identified as straight dark and light lines indicating homogenous acoustic properties at either side of the display Fig. Stay in touch by joining our mailing list. This has the effect of improving the signal strength of both the casing and cement-to-formation arrivals, respectively.
Cement bond logs –
Track 1 contains the cbl vdl interpretation ray and two quality curves for pad contact with the borehole wall and for centralization, both of which are of high quality in this example. Track 2 contains the amplitude curve and amplified amplitude, which indicates cement-to-casing bond.
As a result, a free-pipe acoustic signal is:. This dimensionless quantity is the ratio of measured attenuation to maximum attenuation:.