Realize the benefits of real-time multipole sonic data for advanced risk mitigation, cement evaluation, formation evaluation, and completion design.
To optimize gas production from the Raudhatain Field’s tight carbonate reservoirs, Kuwait Oil Company (KOC) was preparing for a multistage, horizontal well completion. As part of its completions process, the operator needed to evaluate cement bond quality and ensure the integrity of the 75/8-in liner in the zone of interest before drilling out the shoe.
The inclination angle of the 7 5/8-in liner reached up to 90°—preventing conventional wireline logging tools from reaching the desired depth. In previous high-deviation wells, KOC acquired the cement bond log by using drillpipe to move the required wireline logging tools. While necessary to ensure the success of the planned completion, pipe-conveyed logging operations add time and costs to the project.
Schlumberger proposed using the cement evaluation component of the SonicScope multipole sonic-while-drilling service, which verifies cement quality without the additional runs and rig time of conventional cement bond logging tools. The SonicScope service uses both the amplitude of the casing arrival and its attenuation rate across the receiver array to derive a quantitative bond index (QBI) measurement equivalent to a conventional cement bond log.
KOC ran the SonicScope service for a total of 500 ft within the 75/8-in liner, successfully acquiring the high-quality waveform from monopole high frequency needed to compute the QBI. By conducting cement evaluation while drilling, the operator eliminated the need for a separate cement bond log run. As a result, KOC cut wireline costs and 4 days of rig time, saving USD 340,000.