scholarly journals Permeability evolution of pyrolytically-fractured oil shale under in situ conditions

2018 ◽  
Author(s):  
Fuke Dong ◽  
Zijun Feng ◽  
Dong Yang ◽  
Yangsheng Zhao ◽  
Dereck Elsworth
Keyword(s):  
Oil Shale ◽  
Oil And Gas ◽  
Peak Temperature ◽  
Threshold Temperature ◽  
Stress Effect ◽  
Permeability Evolution ◽  
Triaxial Stresses ◽  
In Situ Conditions ◽  
Oil Shales

In-situ injection of steam for heating of the subsurface is an efficient method for the recovery of oil and gas from oil shale where permeability typically evolves with temperature. We reported measurements on Jimusar oil shales(Xinjiang, China) at different temperatures to 600℃ and under recreated in situ triaxial stresses to obtain permeability evolution with temperature and stress. Permeability of tight oil shales evolves with temperature to a threshold temperature and peak temperature. The threshold temperature was subjected to triaxial stresses. For Jimusar oil shale, the threshold temperature ranges from 200℃ to 250℃ at ground stress of buried depth of 500m and from 350℃ to 400℃ at buried depth of 1000m. The peak temperature was almost not subjected to triaxial stress and the range is from 450℃ to 500℃ for all Jimusar samples. Pyrolysis plays an important role in permeability evolution and fundamentally changes permeability tendency and magnitude. At high temperature permeability exhibits a little reduction due to stress effect but still remains a high level due to pyrolysis. The above results show that oil shale mass can change from tight porous media into highly permeable media and oil & gas can easily flow through oil shale stratum.

scholarly journals Permeability Evolution of Pyrolytically-Fractured Oil Shale under In Situ Conditions

Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 3033 ◽  
Author(s):  
Fuke Dong ◽  
Zijun Feng ◽  
Dong Yang ◽  
Yangsheng Zhao ◽  
Derek Elsworth
Keyword(s):  
Oil Shale ◽  
Oil And Gas ◽  
Gas Production ◽  
Peak Temperature ◽  
Threshold Temperature ◽  
Rapid Rise ◽  
Permeability Evolution ◽  
Triaxial Stresses ◽  
In Situ Conditions

In-situ injection of steam for heating of the subsurface is an efficient method for the recovery of oil and gas from oil shale where permeability typically evolves with temperature. We report measurements on Jimusar oil shales (Xinjiang, China) at stepped temperatures to 600 °C and under recreated in situ triaxial stresses (15 MPa) and recover permeability evolution with temperature and stress. Initial very low permeability evolves with the temperature above an initial threshold temperature at high rate before reaching a plateau in permeability above a peak temperature. The threshold temperature triggering the initial rapid rise in permeability is a function of triaxial stresses. For Jimusar oil shale, this threshold temperature ranges from 200 °C to 250 °C for burial depths of 500 m and from 350 °C to 400 °C for burial depths of 1000 m. This rapid rise in permeability correlates with the vigor of pyrolysis and directly scales with the production rate of pyrolysis-derived gas production. The permeability increases with temperature to a plateau in peak permeability that occurs at a peak-permeability temperature. This peak temperature is insensitive to stress and is in the range 450 °C to 500 °C for all Jimusar samples. Pyrolysis plays an important role in the stage of rapid permeability evolution with this effect stopping once pyrolysis is essentially complete. At these ultimate high temperatures, permeability exhibits little reduction due to stress and remains elevated due to the vigor of the pyrolysis. These results effectively demonstrate that oil shale may be transformed by pyrolysis from a tight porous medium into highly permeable medium and that oil and gas may be readily recovered from it.

scholarly journals Cyclic Subcritical Water Injection into Bazhenov Oil Shale: Geochemical and Petrophysical Properties Evolution Due to Hydrothermal Exposure

Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4570
Author(s):  
Aman Turakhanov ◽  
Albina Tsyshkova ◽  
Elena Mukhina ◽  
Evgeny Popov ◽  
Darya Kalacheva ◽  
...  
Keyword(s):  
Energy Demand ◽  
Oil Shale ◽  
Oil And Gas ◽  
Subcritical Water ◽  
Pore Space ◽  
Water Injection ◽  
Microstructural Properties ◽  
Gas Generation ◽  
Geochemical Parameters

In situ shale or kerogen oil production is a promising approach to developing vast oil shale resources and increasing world energy demand. In this study, cyclic subcritical water injection in oil shale was investigated in laboratory conditions as a method for in situ oil shale retorting. Fifteen non-extracted oil shale samples from Bazhenov Formation in Russia (98 °C and 23.5 MPa reservoir conditions) were hydrothermally treated at 350 °C and in a 25 MPa semi-open system during 50 h in the cyclic regime. The influence of the artificial maturation on geochemical parameters, elastic and microstructural properties was studied. Rock-Eval pyrolysis of non-extracted and extracted oil shale samples before and after hydrothermal exposure and SARA analysis were employed to analyze bitumen and kerogen transformation to mobile hydrocarbons and immobile char. X-ray computed microtomography (XMT) was performed to characterize the microstructural properties of pore space. The results demonstrated significant porosity, specific pore surface area increase, and the appearance of microfractures in organic-rich layers. Acoustic measurements were carried out to estimate the alteration of elastic properties due to hydrothermal treatment. Both Young’s modulus and Poisson’s ratio decreased due to kerogen transformation to heavy oil and bitumen, which remain trapped before further oil and gas generation, and expulsion occurs. Ultimately, a developed kinetic model was applied to match kerogen and bitumen transformation with liquid and gas hydrocarbons production. The nonlinear least-squares optimization problem was solved during the integration of the system of differential equations to match produced hydrocarbons with pyrolysis derived kerogen and bitumen decomposition.

Mechanics of Geological Materials

1985 ◽  
Vol 38 (10) ◽  
pp. 1256-1260 ◽  
Author(s):  
M. M. Carroll
Keyword(s):  
Solid Mechanics ◽  
Oil And Gas ◽  
Rock Fracture ◽  
Energy Resource ◽  
Earthquake Hazard ◽  
Soil Liquefaction ◽  
Failure Behavior ◽  
Geological Materials ◽  
In Situ Conditions

Needed advances in various areas of energy resource recovery, underground construction, earthquake hazard reduction, and conventional and nuclear defense depend critically on the development of improved theories for mechanical and thermal behavior of geological materials. The areas include oil and gas (including off-shore and Arctic production), mining and in situ recovery, geothermal production, nuclear waste isolation, under-ocean tunneling, underground storage, nuclear test containment, and effects of surface explosions. The needed developments, some of which are detailed in earlier National Academy of Science reports, include constitutive theories for inelastic deformation, failure, and post-failure behavior, influence of microstructure and macrostructure, rock fracture (direct breakage, hydraulic fracture explosive fracture), frictional sliding, soil liquefaction, mechanics of ice, determination of in situ conditions, flow through porous media, and thermal effects. Advances in mechanics of geological materials will require adaptation of some established techniques in rheology, metal plasticity, composite materials, mixtures, etc., and also the development of some entirely new ideas and methods. The complicated nature of rocks and soils, the wide ranges of stress, temperature, strain rate, etc., the interactions encountered in geotechnical processes, and the vastly different dimensions and time scales involved, lead to a host of challenging problems in solid mechanics.

ORGANIC MATTER IN OIL SHALES

1980 ◽  
Vol 20 (1) ◽  
pp. 44 ◽  
Author(s):  
A.C. Hutton ◽  
A.J. Kantsler ◽  
A.C. Cook ◽  
D.M. McKirdy
Keyword(s):  
Organic Matter ◽  
Oil Shale ◽  
Large Scale ◽  
Mineral Matter ◽  
Green River ◽  
Fine Grained ◽  
Recovery Cost ◽  
Oil Shales

The Tertiary oil-shale deposits at Rundle in Queensland and of the Green River Formation in the western USA, together with Mesozoic deposits such as those at Julia Creek in Queensland, offer prospects of competitive recovery cost through the use of large-scale mining methods or the use of in situ processing.A framework for the classification of oil shales is proposed, based on the origin and properties of the organic matter. The organic matter in most Palaeozoic oil shales is dominantly large, discretely occurring algal bodies, referred to as alginite A. However, Tertiary oil shales of northeastern Australia are chiefly composed of numerous very thin laminae of organic matter cryptically-interbedded with mineral matter. Because the present maceral nomenclature does not adequately encompass the morphological and optical properties of most organic matter in oil shales, it is proposed to use the term alginite B for finely lamellar alginite, and the term lamosites (laminated oil shales) for oil shales which contain alginite B as their dominant organic constituent. In the Julia Creek oil shale the organic matter is very fine-grained and contains some alginite B but has a higher content of alginite A and accordingly is assigned to a suite of oil shales of mixed origin.Petrological and chemical techniques are both useful in identifying the nature and diversity of organic matter in oil shales and in assessing the environments in which they were formed. Such an understanding is necessary to develop exploration concepts for oil shales.

scholarly journals RISK ANALYSIS OF THE PILLAR STRENGTH IN THE ESTONIA MINE

2015 ◽  
Vol 1 ◽  
pp. 19
Author(s):  
Juri-Rivaldo Pastarus ◽  
Sergei Sabanov ◽  
Jekaterina Shestakova ◽  
Oleg Nikitin
Keyword(s):  
Experimental Data ◽  
Risk Analysis ◽  
Moisture Content ◽  
Bearing Capacity ◽  
Oil Shale ◽  
Volume Density ◽  
Analysis Method ◽  
Strength Parameters ◽  
In Situ Conditions

This paper deals with the risk analysis and assessment of the pillars strength problems in the Estonia oil shale mine. Aim of this investigation was to determine the strength parameters and predict the bearing capacity of the pillars in Estonia mine, mining block No. 3107 Methods were based on theoretical investigation and experimental data of in-situ conditions. It is given the geological description of the mining block and determined the strength parameters, moisture content and volume density of the oil shale and limestone layers. Analysis showed that the used risk analysis method is applicable for Estonian oil shale mines. The results of the risk analysis are of particular interest for practical purposes.

scholarly journals Thermodynamic mechanism evaluate the feasibility of oil shale pyrolysis by topochemical heat

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shuai Zhao ◽  
Xiaoshu Lü ◽  
Youhong Sun ◽  
Jiandong Huang
Keyword(s):  
Transition State ◽  
Oil Shale ◽  
Oil And Gas ◽  
Early Stage ◽  
Oil Production ◽  
Pilot Project ◽  
Main Stage ◽  
Oil Shale Pyrolysis ◽  
Heat Method

AbstractTopochemical heat in-situ pyrolysis of oil shale is achieved by injecting high temperature nitrogen to promote oil shale pyrolysis and release heat, and then injecting air to trigger oil shale combustion in the early stage of oil shale pyrolysis, and then by injecting normal temperature air continuously to promote local oxidation of oil shale in the later stage. In order to verify the oil and gas recovery by topochemical heat method, Jilin University has chosen Fuyu City, Jilin Province, to carry out pilot project of oil shale in-situ pyrolysis by topochemical heat method. Besides, in order to infer the spontaneity, feasibility and difficulty of continuous pyrolysis of oil shale based on topochemical heat, this paper, the mechanism of solid-state pyrolysis and the thermodynamic analysis of transition state of oil shale in Fuyu area are discussed. Because the second stage of oil shale pyrolysis is the main stage of oil production. Therefore, the characteristics of Gibbs free energy, free enthalpy and free entropy of transition state in the main oil production stage of oil shale pyrolysis are obtained by calculation. The results show that in situ pyrolysis of oil shale topochemical heat can be carried out spontaneously and continuously, and the release characteristics of volatiles during pyrolysis of oil shale are described.

Application Prospects in China of Oil Shale In Situ Mining Method and an Improved Method

2014 ◽  
Vol 535 ◽  
pp. 602-605 ◽  
Author(s):  
Gui Jie Zhao ◽  
Chen Chen ◽  
Fang Qian
Keyword(s):  
Alternative Energy ◽  
Oil Shale ◽  
Oil And Gas ◽  
Outlet Channel ◽  
Heat Efficiency ◽  
Initial Stage ◽  
New Energy ◽  
Development And Utilization ◽  
Mining Methods

Oil shale resources is a new energy has a huge potential for development, as the complement and alternative energy of the oil and gas, more and more people pay attention to it. China's oil shale resources are widely distributed and reserves are huge, but current mining methods are still primitive, mainly to direct exploitation, exploitation efficiency is low and ecological damage is serious, it will be replaced by in-situ mining methods in the future. This paper summarizes the research of oil shale in situ mining, aims at the problems of that the conduction of heat efficiency is low and the outlet channel is less which exist in the in-situ mining at the present, and put forward the concept of in-situ broken that is using some methods to make the oil shale change from huge to small block in the initial stage of the in-situmining, further in-situ heating, mining of oil shale，and put forward the method of in-situ noncontact wind breaking oil shale, this method using the crushing wind to break the oil shale, having high feasibility. This paper did in-depth research on the in-situ mining, and it can provide a reference for the development and utilization of oil shale resources.

scholarly journals A Comprehensive Simulation Model of Kerogen Pyrolysis for the In-situ Upgrading of Oil Shales

SPE Journal ◽  
2016 ◽  
Vol 21 (05) ◽  
pp. 1612-1630 ◽  
Author(s):  
K.. Lee ◽  
G. J. Moridis ◽  
C. A. Ehlig-Economides
Keyword(s):  
Oil Shale ◽  
Effective Porosity ◽  
Fractured Media ◽  
Natural Fracture ◽  
Sensitivity Analyses ◽  
Bulk Oil ◽  
System Changes ◽  
Oil Shales ◽  
Kerogen Pyrolysis

Summary Oil shale, which is composed of abundant organic matter called kerogen, is a vast energy source. Pyrolysis of kerogen in oil shales releases recoverable hydrocarbons. Here, we describe the pyrolysis of kerogen with an in-situ upgrading process, which is applicable to the majority of oil shales. The pyrolysis is represented by six kinetic reactions resulting in 10 components and four phases. Expanding the Texas A&M Flow and Transport Simulator (FTSim), which is a variant of the TOUGH + simulator (Moridis 2014), we develop a fully functional capability that describes kerogen pyrolysis and accompanying system changes. The simulator describes the coupled process of mass transport and heat flow through porous and fractured media and includes physical and chemical phenomena of reservoir systems. The simulator involves a total of 15 thermophysical states and all transitions between them and computes a simultaneous solution of 11 mass- and energy-balance equations per element. The simulator solves the equations in a fully implicit manner by solving Jacobian matrix equations with the Newton-Raphson iteration method. To conduct a realistic simulation, we account for geological structure of oil-shale reservoirs and physical properties of bulk-oil shale rocks by considering phases and components in the pores. In addition, we involve interaction between fluids and porous media, diverse equations of state (EOSs) for computation of fluid properties, and numerical modeling of fractured media. We intensively reproduce the field-production data of Shell In-situ Conversion Process (ICP) implemented in the Green River formation by conducting sensitivity analyses for the diverse reservoir parameters, such as initial effective porosity of the matrix, oil-shale grade, and the spacing of the natural-fracture network. We analyze the effect of each reservoir parameter on the hydrocarbon productivity and product selectivity. The simulator provides a powerful tool to quantitatively evaluate production behavior and dynamic-system changes during in-situ upgrading of oil shales and subsequent fluid production by thoroughly describing a reservoir model, phases and components, phase behavior, phase properties, and evolution of porosity and permeability.

Uncertainty Quantification of an Explicitly Coupled Multiphysics Simulation of In-Situ Pyrolysis by Radio Frequency Heating in Oil Shale

SPE Journal ◽  
2020 ◽  
Vol 25 (03) ◽  
pp. 1443-1461
Author(s):  
Travis Ramsay
Keyword(s):  
Radio Frequency ◽  
Uncertainty Quantification ◽  
Oil Shale ◽  
Oil And Gas ◽  
Polynomial Chaos ◽  
Epistemic Uncertainty ◽  
Rf Heating ◽  
Commercial Development ◽  
Mc Simulation

Summary In-situ pyrolysis provides an enhanced oil recovery (EOR) technique for exploiting oil and gas from oil shale by converting in-place solid kerogen into liquid oil and gas. Radio-frequency (RF) heating of the in-place oil shale has previously been proposed as a method by which the electromagnetic energy gets converted to thermal energy, thereby heating in-situ kerogen so that it converts to oil and gas. In order to numerically model the RF heating of the in-situ oil shale, a novel explicitly coupled thermal, phase field, mechanical, and electromagnetic (TPME) framework is devised using the finite element method in a 2D domain. Contemporaneous efforts in the commercial development of oil shale by in-situ pyrolysis have largely focused on pilot methodologies intended to validate specific corporate or esoteric EOR strategies. This work focuses on addressing efficient epistemic uncertainty quantification (UQ) of select thermal, oil shale distribution, electromagnetic, and mechanical characteristics of oil shale in the RF heating process, comparing a spectral methodology to a Monte Carlo (MC) simulation for validation. Attempts were made to parameterize the stochastic simulation models using the characteristic properties of Green River oil shale. The geologic environment being investigated is devised as a kerogen-poor under- and overburden separated by a layer of heterogeneous yet kerogen-rich oil shale in a target formation. The objective of this work is the quantification of plausible oil shale conversion using TPME simulation under parametric uncertainty; this, while considering a referenced conversion timeline of 1.0 × 107 seconds. Nonintrusive polynomial chaos (NIPC) and MC simulation were used to evaluate complex stochastically driven TPME simulations of RF heating. The least angle regression (LAR) method was specifically used to determine a sparse set of polynomial chaos coefficients leading to the determination of summary statistics that describe the TPME results. Given the existing broad use of MC simulation methods for UQ in the oil and gas industry, the combined LAR and NIPC is suggested to provide a distinguishable performance improvement to UQ compared to MC methods.

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