Keywords: 
• formation pressure /
• seismic wave velocity /
• prediction /
• monitoring

Abstract: While drilling pore pressure prediction is a technique to correct the model and its result of prior drilling seismic prediction using the results of while drilling pore pressure prediction, then to predict again the pore pressure of virgin formation before the bit based on the corrected newly model in order to improve the accuracy of pore pressure prediction. A field pilot of this technique was done in well Chong 002 in westsouth Tarim. The seismic lay-er velocity data of this well block was collected first and then processed for formation pres-sure predictlon. Durlng operation, dc exponent method and rock strength technique were uti-lized for while drilling pore pressure monitoring. At 3500m,an inversion correction was ap-plied to the seismic prediction model on the basis of monitor result and then, correction ap-plied once more based on the corrected result. Drilling practice proves that the average error of newly predicted result is 12%, 18% less than the average error of 30% in previous predic-tion, resulting in a smooth drilling and drilling completion ahead of schedule in well Chong 002.