Quantifying Proved Undeveloped Reserves in the Woodford Shale: A Seamless Integration of Statistical, Empirical, and Analytical Techniques

摘要

Although not all analytical, empirical, and statistical techniques are applicable at all stages of field maturity, their concurrent and consistent application was indispensable in justifying the Woodford as a World-Class Tier 2 Resource play (SPEE Criteria 2010) and added multiple Proved-Undeveloped (PUD) locations in 2011 that were not direct offsets. Introduction of the ―Modernized SEC Rules" greatly expanded the scope of tools available for evaluating and justifying PUD locations more than one offset away from the existing producers. Shale Plays - with their monumental extent, number of wellbores, drilling activity, and in-place volumes - provide a quintessential laboratory to test application of advanced statistical approaches, in conjunction with analytical and empirical protocols for the play evaluation. The starting point for the PUD evaluation was the protocol advocated in the recently published SPEE Monograph 3. The employment of statistics required the development of a large dataset of projected EURs, which was generated using an in- house decline curve analysis protocol and validated using an empirical model. Analytical correlations were also employed to achieve the sample size dictated by uncertainty analysis of the data. Then, this synthesized dataset was benchmarked against G&G parameters to determine if the entire area met the SEC definition of ―analogous formation." Finally, advanced statistical techniques were applied to define the ―Reliable Technology Area" (RTA) in the play and the Proved volume. The resulting statistics for the RTA established using this protocol were found to be remarkably consistent and reproducible, thus meeting the SEC's definition of ―Reliable Technology." The resulting Proved area was further refined using PVT data and economics. The scope of this paper is limited to the elucidation of the successful application of this integrated Technique to the Anadarko-Woodford. Additional results would likely be presented in future papers as this methodology appears to be highly transferable to other resource plays.