A new generation crossed-dipole acoustic-logging tool acquires data that can be utilized to calculate shear anisotropy. This new tool, the WaveSonic™ tool, was designed using a systems approach so that tool functions such as transmitted pulse shape, center frequency, amplitude and duration are programmable from the surface. Additionally, the tool design is robust enough to allow drillpipe conveyance if well conditions warrant. It can also be combined with other logging tools and is "double-ended", allowing it to be located at any position in the logging tool-string. Shear data can be collected in orthogonal X-Y directions and oriented by a navigational package using data from a four or six-arm caliper device run with the WaveSonic tool. From these measurements, shear slowness anisotropy can be determined, as well as the direction of the fast shear slowness. These slowness values provide input to a model that calculates maximum and minimum principal stresses and their orientations. Information about principal stresses can be instrumental in optimizing completion and stimulation design. In cases where natural fracture information is desired, crossed dipole data can be used to help detect and orient such fracture systems. Introduction The WaveSonic crossed dipole sonic tool is an entirely new wireline sonic tool design.1 The design engineers and scientists were given the luxury of designing the tool "from the ground up", without being required to incorporate legacy features from other tool platforms. The key mechanical design requirement was physical strength, so that the crossed dipole sonic tool could be positioned anywhere in the tool string, allowing extremely "heavy" tools, such as new generation pump-through formation test tools and nuclear magnetic resonance tools, to run in combination below (or above) this tool. The WaveSonic tool is the first acoustic waveform wireline logging tool designed robustly enough to allow drillpipe-conveyed logging operations, where necessary. The WaveSonic tool is composed of the following components: transmitter with associated control electronics, isolator, receiver array and main electronics. All tool functionality is controlled by a surface computer, thus eliminating the necessity to pull out of the hole to change logging parameters. One of the key features of this tool is the ability to control the frequency of the crossed dipole source, allowing flexural shear wave transmission in reservoir rocks having a broad range of shear slowness values. Dipole transmitters are of the "Bender Bar" variety. The "X" and "Y" dipole sources are mounted orthogonally at the same position of the tool, ensuring maximum utilization of all received waveforms for post-processing analysis. The receiver array consists of 8 receiver "rings" spaced 0.5 feet apart. Each receiver ring is comprised of four independent receivers that are matched for frequency response and oriented in the directions of the "X" and "Y" transmitters. Detailed shear anisotropy analysis necessitates matching of frequency responses of receivers over a broad band of frequencies. The tool transmitters (monopole, and X- and Y-dipole) are fired sequentially, and all 32 waveforms associated with each transmitter firing are digitized and sent uphole - real-time - for every 0.5 feet of log. The logging speed for crossed dipole acquisition is 30 ft/min (1800 ft/hour).

fax 01-972-952-9435. AbstractWith the increase in deepwater exploration and production and the advances in logging-while-drilling formation evaluation (along with the high rig costs) the wireline formation evaluation is often limited to only one drill pipe conveyed logging run. A new monopole and crossed dipole acoustic logging tool was designed for the drill pipe conveyed environment. The robust mechanical design does not limit this sonic tool to the bottom of the tool string. NMR and pump-through formation testing tools can be located in the logging string below this tool on drill pipeconveyed logging, or e-line conveyed logging.This tool was designed utilizing a systems approach and most of the functions of the tool are surface programmable. For example, the pulse shape, duration, amplitude, and frequency of the on-depth crossed dipole bender bar sources is programmable. Likewise, the level of the monopole output signal is also surface selectable. The digitization of the 96 waveforms of data per depth sample is programmable for number of samples, sampling interval and waveform compression. With 96 waveforms per depth sample, a logging speed of approximately 1800 ft/hr (30 ft/min) can be achieved with a quad-combo logging suite acquiring sonic data at two samples per foot.Case histories from a variety of formations demonstrate the tool's capability to obtain monopole P wave data, monopole refracted shear data, crossed dipole flexural wave slowness, and anisotropy.The following representative formations are included in the case histories: • near-zero porosity carbonate with refracted shear wave slowness and flexural wave slowness of less than 100 µsec/ft • poro-plastic Gulf Coast sandstones and shales with flexural wave travel times exceeding 700 µsec/ft • formations with natural fractures that are detectable by the cross dipole flexural wave slowness and confirmed with open hole image data • a shale section with approximately 650 psi of stress anisotropy About the Authors Calvin Kessler, is the Business Development,

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fax 01-972-952-9435. AbstractWith the increase in deepwater exploration and production and the advances in logging-while-drilling formation evaluation (along with the high rig costs) the wireline formation evaluation is often limited to only one drill pipe conveyed logging run. A new monopole and crossed dipole acoustic logging tool was designed for the drill pipe conveyed environment. The robust mechanical design does not limit this sonic tool to the bottom of the tool string. NMR and pump-through formation testing tools can be located in the logging string below this tool on drill pipeconveyed logging, or e-line conveyed logging.This tool was designed utilizing a systems approach and most of the functions of the tool are surface programmable. For example, the pulse shape, duration, amplitude, and frequency of the on-depth crossed dipole bender bar sources is programmable. Likewise, the level of the monopole output signal is also surface selectable. The digitization of the 96 waveforms of data per depth sample is programmable for number of samples, sampling interval and waveform compression. With 96 waveforms per depth sample, a logging speed of approximately 1800 ft/hr (30 ft/min) can be achieved with a quad-combo logging suite acquiring sonic data at two samples per foot.Case histories from a variety of formations demonstrate the tool's capability to obtain monopole P wave data, monopole refracted shear data, crossed dipole flexural wave slowness, and anisotropy.The following representative formations are included in the case histories: • near-zero porosity carbonate with refracted shear wave slowness and flexural wave slowness of less than 100 µsec/ft • poro-plastic Gulf Coast sandstones and shales with flexural wave travel times exceeding 700 µsec/ft • formations with natural fractures that are detectable by the cross dipole flexural wave slowness and confirmed with open hole image data • a shale section with approximately 650 psi of stress anisotropy About the Authors Calvin Kessler, is the Business Development,

No abstract