Technical papers

Field Trial Design and Analyses of Production Data From a Tight Gas Reservoir: Detailed Production Comparisons From the Pinedale Anticline (SPE 106151, CARBO authored)


Carefully designed trial examined the results from 446 frac treatments, concluding with over 99.9% confidence that proppant selection affects production in this 2 microdarcy formation.  20/40 CarboProp provided 70% higher production rates than a broadly-sieved ceramic.


Field trials of new methodologies, products or technologies are considered to be an effective way to gauge the true value of such innovations.  However it is difficult and expensive to conduct a rigorous field trial, especially in tight, multi-layered reservoirs, and proper design and analyses are critical to accurately interpret the results.  In multi-layered reservoirs the production from individual frac stages must often be evaluated with production logs - this additional expense accentuates the need to carefully design the field trial and thoroughly analyze the resulting data to extract as much value as possible.  This paper will provide a detailed comparison of well productivity in the Pinedale Anticline as a function of proppant type and subinterval.  Well production has been normalized by many parameters, including reservoir kh, kh∆P, kh*(Pr2-Pf2), Φh, and also compared by well location to determine the degree to which those techniques provide similar conclusions.  In addition to describing how these field results influence proppant selection in the Pinedale Anticline, this paper will describe many aspects of field trial planning, as well as the proper handling of data to assist in the design of future trials.

This paper will review the following topics:

  • Design of the field trial
  • Efforts to minimize variables
  • Well selection to promote valid offset comparisons
  • Data handling techniques to minimize bias
  • Production logging of wells – calibration and timing
  • Detailed comparison of production data, normalized with six methods to determine whether consistent conclusions can be reached
  • Statistical analyses to determine whether statistically significant conclusions can be drawn with a high degree of confidence

The results of this study will also be compared to other published field trials to examine well populations, data consistency, and to assess whether studies in similar reservoirs carry similar findings.  This paper will summarize the conclusions that are consistent between numerous tight gas field studies in the region, and highlight changes to fracture treatments which have consistently improved well productivity and profitability in these reservoirs.

Author(s): M.C. Vincent, SPE, SPE, CARBO Ceramics Inc.; Paul Huckabee, Shell E&P Co.; and Michael Conway, Stim-Lab Inc.

Paper Number: SPE 106151



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