A New Generation Crossed Dipole Logging Tool: Design and Case Histories

Abstract

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,

Application of Dipole Sonic To Evaluate Hydraulic Fracturing

“…In addition to the compressional and shear travel time processing, the anisotropy is evaluated using the signal induced by the X transmitter in the Y receivers. [14][15][16][17][18] Anisotropy and Stress Direction. The compressional waveform, X-Y shear waveforms, and the anisotropy for well P-7 are presented in Figure 11.…”

Case Histories - Combining Crossed Dipole Sonic Anisotropy and Oriented Perforating To Optimize Hydraulic Fracturing In the Burgos Basin - Reynosa Mexico

“…1,2,3,4,5,6,7,8,9,10 The candidate selection process evaluates the net-to-gross sand thickness ratio, reservoir pressure, and permeability for each zone. The net-to-gross ratio provides information on productive and non-productive fracture height, which is needed for inflow analysis.…”

Application of Dipole Array Acoustic Logging in the Evaluation of Shale Gas Reservoirs

“…In order to perform cross-dipole logging, the receiver array is designed to be arranged in a vertical or parallel position with respect to the dipole transmitter array direction. This type of logging tool not only measures the P-wave, S-wave, and Stoneley wave of the formation, but also applies inversion of the formation anisotropy through the cross-dipole measurement data [15][16][17][18].…”