Diverse Scale Data for Shale Gas Formation Description—Why Is Digital Shale Rock Model Construction Difficult? The Polish Silurian and Ordovician Rocks Case Study

Paulina I Krakowska-Madejska,Jadwiga A Jarzyna

doi:10.3390/min10020108

Abstract

The aim of the study was to show that the petrophysical parameters, characterizing the shale gas formation, obtained from the various scale well logging and laboratory methods, correlated among themselves. Relationships determined on the basis of mesoscale (logs) and microscale outcomes (laboratory experiments on plugs or crumbs) were also recognizable in nanoscale in the computed tomography results. Selected logs (spectral gamma ray, resistivity, density, neutron, geochemical and acoustic logs) and laboratory methods turned out to be effective in rock typing and description of petrophysical parameters. Nanoscale results processing and interpretation was supported by the sophisticated special software poROSE (version 3.18, AGH University of Science and Technology, Kraków, Poland) to determine special parameters, which correlated with the standard laboratory outcomes. Results of the mercury injection porosimetry, together with adsorption/desorption of nitrogen at 77 K and pressure decay permeability, were used as the basal parameters for building a digital model of shale rock and a detailed description of the Silurian and Ordovician shale formation, treated as the hydrocarbon prospective unconventional reservoirs. Including the computed X-ray tomography results in the correlation analyses, gave the platform to extend the standard 2D approach in building the rock model to novel, 3D and more detailed presentations of rock characteristics.

Highlights

The broad discussion on shale gas as a potential source of hydrocarbon production took place in Poland in the first two first decades of the twenty-first century
Many industrial and scientific units were engaged in prospection, completion and exploitation works in order to provide information on the industrial production from the Polish shale gas formations [1,2]
Some of the methods resulted in data redundancy, so, having the limited budget for laboratory experiments, some of the methods can be rejected

Summary

Introduction

The broad discussion on shale gas as a potential source of hydrocarbon production took place in Poland in the first two first decades of the twenty-first century. Many industrial and scientific units were engaged in prospection, completion and exploitation works in order to provide information on the industrial production from the Polish shale gas formations [1,2]. Shale gas deposits belong to unconventional hydrocarbon resources. The most important issue regarding these type of deposits, is porosity volume and pore space structure determination, which allow the understanding of the quantity and location of shale gas resources. Unconventional resources in Poland, mostly tight gas and shale gas, are under careful and detailed considerations regarding cognitive works. There is worldwide interest in prospection of unconventional deposits, because of the necessity to increase energy production and consciousness of geological limitations regarding conventional hydrocarbon deposits

Objectives

Methods

Results

Conclusion