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METHODS OF ANALYZING THE GEOCHEMICAL AND MICROSTRUCTURAL DEVELOPMENT OF SHALES DURING ARTIFICIAL THERMAL MATURATION

IP.com Disclosure Number: IPCOM000225695D
Publication Date: 2013-Feb-26

Publishing Venue

The IP.com Prior Art Database

Abstract

This subject disclosure describes methods for simulating and measuring the geochemical and microstructural development of shales during thermal maturation. The natural thermochemical maturation process is simulated on immature core or outcrop shale samples using a high pressure pyrolysis procedure, with attendant changes in (a) abundance and isotopic composition of gas, oil, residual organic matter, and mineralogy measured by gas chromatography, gas chromatography-isotope ratio mass spectrometry, combustion elemental analysis, and infrared spectroscopy respectively, and (b) microstructural surface area and pore volume measured by isotherm gas sorption analysis. When monitored over several time points, this integrated data provide a framework for both quantitatively predicting and mechanistically describing the evolution of shale reservoir quality across maturity gradients in a formation of interest.

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METHODS OF ANALYZING THE GEOCHEMICAL AND MICROSTRUCTURAL DEVELOPMENT OF SHALES DURING ARTIFICIAL THERMAL MATURATION

                         FIELD
[0001]
This disclosed subject matter is generally related to the field of shale formation evaluation, with more specific applications in interpreting core and drill cuttings analysis in both the laboratory and at the well site, as well as basin model (e.g. PetroMod) predictions of high reservoir quality areas.

BACKGROUND


[0002]Driven by the explosion of unconventional reservoir development in the United States over the past few years, renewed study of source rock microstructure has underscored the importance of organic matter (OM) maturity and distribution in regulating petroleum storage and flow therein (Javadpour et al., 2007; Bustin and Bustin, 2008; Javadpour, 2009; Loucks et al., 2009; Wang and Reed, 2009; Loucks et al., 2010; Takahashi and Kovscek, 2010; Curtis et al., 2011a,b). For example, a series of groundbreaking investigations have suggested that the development of a very high surface area (As), oil-wet nanopore network in kerogen during thermochemical maturation provides the primary storage and flow medium for the co-generated petroleum inventory in shale formations (O'Brien et al., 1994, 2002; Loucks et al., 2009; Wang and Reed, 2009; Javadpour, 2009; Curtis et al., 2010; Loucks et al., 2010; Sondergeld et al., 2010; Shabro et al., 2011). The complex mineral matrix with which it is intermixed also likely exerts control on kerogen and petroleum dynamics by regulating initial OM distribution (fabric) during rock deposition and diagenesis, catalyzing subsequent - 1 -


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hydrocarbon cracking reactions, and hosting a more hydrophilic mesopore counterpart to the kerogen nanopore system (Passey et al., 2010). Quantitative models describing the catagenic co-evolution of the organic-mineral fabric with matrix structure remain ill constrained at the meso-to nanoscales, however, hampering efforts to predict unconventional reservoir quality from log strings, core and cuttings measurements, or model simulations at the macroscale.

SUMMARY


[0003]This subject disclosure describes methods for simulating and measuring the geochemical and microstructural development of shales during thermal maturation. The natural thermochemical maturation process is simulated on immature core or outcrop shale samples using a high pressure pyrolysis procedure, with attendant changes in (a) abundance and isotopic composition of gas, oil, residual organic matter, and mineralogy measured by gas chromatography, gas chromatography-isotope ratio mass spectrometry, combustion elemental analysis, and infrared spectroscopy respectively, and (b) microstructural surface area and pore volume measured by isotherm gas sorption analysis. When monitored over several time points, this integrated data provide a framework for both quantitatively predicting and mechanistically describing the evolution of shale reservoir quality across ma...