| 摘要 |
Methods and systems for imaging-while-drilling and look-ahead imaging of a geological formation using a borehole devices measuring multi-component vector and/or tensor logging data. An electromagnetic field transmitter generates an electromagnetic field. Electromagnetic receivers measure the response from the geological formation around the borehole and ahead of the device at various receiving positions. A central processing unit may compute a migration field by simulating the replacement of the receivers with conceptual transmitters, calculate an integrated sensitivity of the recorded electromagnetic field data, compute a reference field, and calculate a cross power spectra of the reference and the migration fields or cross correlation functions between the reference and the migration fields. A spatial weighting of the cross power spectra or cross correlation functions produces a numerical reconstruction of directional images and look-ahead images of the conductivity distribution around the borehole and/or ahead of the device located within the borehole. |
