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Journal of Applied Mathematics
Volume 2014, Article ID 905079, 19 pages
Research Article

Reservoir Characterization during Underbalanced Drilling of Horizontal Wells Based on Real-Time Data Monitoring

1State Key Laboratory of Oil and Gas Reservoir Geology and Exploration, School of Petroleum Engineering, Southwest Petroleum University, Chengdu, Sichuan 610500, China
2Engineering Supervision Center, SINOPEC Southwest Oil & Gas Company, Deyang, Sichuan 618000, China

Received 4 April 2014; Accepted 15 July 2014; Published 17 August 2014

Academic Editor: Vijay Gupta

Copyright © 2014 Gao Li et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


In this work, a methodology for characterizing reservoir pore pressure and permeability during underbalanced drilling of horizontal wells was presented. The methodology utilizes a transient multiphase wellbore flow model that is extended with a transient well influx analytical model during underbalanced drilling of horizontal wells. The effects of the density behavior of drilling fluid and wellbore heat transfer are considered in our wellbore flow model. Based on Kneissl’s methodology, an improved method with a different testing procedure was used to estimate the reservoir pore pressure by introducing fluctuations in the bottom hole pressure. To acquire timely basic data for reservoir characterization, a dedicated fully automated control real-time data monitoring system was established. The methodology is applied to a realistic case, and the results indicate that the estimated reservoir pore pressure and permeability fit well to the truth values from well test after drilling. The results also show that the real-time data monitoring system is operational and can provide accurate and complete data set in real time for reservoir characterization. The methodology can handle reservoir characterization during underbalanced drilling of horizontal wells.