Drilling Cutting Analysis and Geo-Algorithm Conversion to Petrophysics

Abstract

The distributed properties analysis in petrophysics is based on the individual components properties and widely applied. This method of using kLab mineralogical and reservoir parameters components measured on drill cuttings will be explained. The method includes several analytical and petrographic analyses of cutting in the lab. The output of data is tabulated and presented in an LAS file. The kGeo-Algorithm accepts the kLab output parameters and calculates the required output to be exported into petrophysical software. Formation evaluation of matrix density RhoM presented in demo case study.

Where the RhoM is a sum of components densities distributed by their mass quantities: RhoM = q1*RhoQtz + q2*RhoCaCO₃ + q3*RhoCaMg(CO₃)² + q4*RhoClay +q5*RhoPyr + … qi*RhoXXX, where q1 + q2 + q3 + … + qi = 1.

High resolution cutting sampling produce additional information on matrix density. Using the cuttings RhoM and inversion principals we convert the discreet data to curve matching formation properties measured by open-hole logs. The reservoir porosity calculated using this method will significantly defer from a straight line matrix density method commonly applied.

Case study of component sonic DTC measured from cuttings is correlated to sonic DTC: DTCcut = q1*DTC_Qtz + q2*DTC_LS + q3*DTC_DOL + q4*DTC_Clay + q5*DTC_Pyr + … + qi*DTS_IthMnrl, and DTClog = k * DTCcut; and DTScut = q1*DTS_Qtz + q2*DTS_LS +q3*DTS_DOL + q4*DTS_Clay + q5*DTS_Pyr + qi*DTS_IthMnrl, and DTSlog=k1*DTScut; where k and k1 are compaction coefficients and where the q1 + q2 + q3 + … + qi = 1.

Using the DTC and DTS the elastics properties of Young's modulus, Poisson's ratio and brittleness can be calculated.

We will demonstrate the advantage of adding kLab analysis, obtained from drill cuttings, and kGeo_Algorithm for Petrophysical formation evaluation. These techniques are successfully used in Texas and abroad. Sweet spots and frackability are defined.

AAPG Datapages/Search and Discovery Article #90219 © 2015 GCAGS, Houston, Texas, September 20-22, 2015