A Case Study on Formation Evaluation of Horizontal Wells in the Tight Gas Nikanassin Group of the Western Canada Sedimentary Basin Using Drill Cuttings

Abstract

AbstractThe use of drill cuttings has evolved recently from qualitative to quantitative evaluations due to the possibility of measuring porosity and permeability from drill cuttings in the laboratory with a good level of certainty. One of the advances has been the implementation of complete quantitative formation evaluation for vertical wells from drill cuttings only in the absence of well logs.This paper uses the same methodology in the case of a horizontal well. The case study is demonstrated with the use of sixty five (65) drill cuttings samples collected over 760 meters of a horizontal well drilled through the Monteith formation, Nikanassin group of the western Canada sedimentary basin (WCSB).Starting with only drill cuttings measurements of porosity and permeability in the laboratory, the method allows a successive approach for determination of several parameters of interest including pore throat aperture radius, water saturation, porosity exponent (m), true formation resistivity, Knudsen number, capillary pressure, construction of Pickett plots, and the estimation of geomechanical properties such as Young Modulus, Poisson’s ratio and brittleness index throughout the horizontal length of the well.And for those cases where there is close to no data at all in the Nikanassin formation, empirical correlations have been developed for estimating Poisson’s ratio, static Young Modulus and brittleness index with the use of only porosity from drill cuttings. The correlation coefficient (R2) in this case is 0.99.It is concluded that drill cuttings provide a useful direct source of information for quantitative formation evaluation of horizontal wells particularly in those cases where core and log data are scarce.