Engineers compute in situ mechanical properties using real-time compressional and shear wave data from logging-while-drilling (LWD) sonic tools. Acquiring the acoustic waves to generate these mechanical properties is important in oilfield applications, as these properties can be used to drill with greater efficiency and with better safety margins. They are also used to design hydraulic fracture stimulation programs.
While using wireline logging tools for sonic data acquisition is common, data are difficult to obtain when wells are highly deviated or horizontal. LWD sonic tools, first introduced in the mid-1990s, are better suited to acquire data in these wells. However, until recently, LWD tools were unable to deliver shear wave data in all formations. This was especially true for soft formations where mechanical properties are crucial for developing drilling programs. A recent article in Oilfield Review, “Sonic Logging While Drilling—Shear Answers,” describes a new LWD tool that uses quadrupole sonic modes to provide shear data in formations where earlier tools could not operate.
A recent case study from West Africa demonstrates how engineers have been able to extract shear data in soft formations using the new quadrupole sonic technique. These data, along with compressional data, are then used to optimize drilling practices and monitor real-time pore pressure while drilling. In addition, an example from a horizontal shale well explains how completions programs can be optimized when engineers have access to geomechanical formation properties computed from sonic data.
Read the full article by visiting the Oilfield Review Web site.
Alford J, Blyth M, Tollefsen E, Crowe J, Rodriquez-Herrera A, Loreto J, Mohammed S and Pistre V: “Sonic Logging While Drilling—Shear Answers,” Oilfield Review 24, no. 2 (Spring 2012): 4–15.