An experimental investigation of cryogenic treatments effects on porosity, permeability, and mechanical properties of Marcellus downhole core samples (original) (raw)
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Gases, 2021
The technique of cryogenic treatments requires injecting extremely cold fluids such as liquid nitrogen (LN2) into formations to create fractures in addition to connecting pre-existing fracture networks. This study investigated the effects of implementing and pressurizing cryogenic treatment on the physical (porosity and permeability) and mechanical properties (Young’s modulus, Poisson’s ratio, and bulk compressibility) of the Marcellus shale samples. Ten Marcellus core samples were inserted in a core holder and heated to 66 °C using an oven. Then, LN2 (−177 °C) was injected into the samples at approximately 0.14 MPa. Nitrogen was used to pressurize nine samples at injection pressures of 1.38, 2.76, and 4.14 MPa while the tenth core sample was not pressurized. Using a cryogenic pressure transducer and a T-type thermocouple, the pressure and temperature of the core holder were monitored and recorded during the test. The core samples were scanned using a computed tomography (CT) scanne...
Laboratory-determined permeability of cores from the Kola Superdeep Well, USSR
Geophysical Research Letters, 1991
We have conducted constant flow-rate permeability measurements on three core samples taken from the 12-kmdeep well on the Kola Peninsula, USSR. All cores are from !1.4-12.0 km depth. Pore pressures, P,, used in these permeability measurements ranged from • 12 -117 MPa. Measurements were performed at effective confining pressures (Pelf = Pe -Pp) ranging from 10 to 400 MPa. The resulting permeabflifies varied from approximately 2.5 x 10 -17 m 2 (25 gDa) at a Peff of !0 MPa to 1 x 10 -22 m 2 (0.1 nDa) at a Peff of 300 MPa. The unusual sensitivity of permeability to Pelf exhibited by these samples is most likely the result of severe stress-relief crack damage that occurred during coring and sample retrieval. This strong pressure dependence underscores the importance of measuring permeability at in situ pressures to obtain meaning•l bounds on in situ matfix perme. abilities in this well. In an attempt to infer closure pressure of these stress-relief cracks, and provide estimates of in situ Peff, we have analyzed the pressure dependence of permeability, resistivity and crack porosity. By applying an equivalentchannel-model analysis, these data appear consistent wkh either an in situ pore pressure exceeding the hydroshat by as much as 100 MPa or a hydrostatic Pp and sub-lithostatic in situ vertical stress. In either case, if this closure pressure accurately reflects the in situ confining pressure, then an upper bound on in situ matrix permeabilities would be 1 x !0 -20 to 2 x 10 -19 m 2 for the samples studied. Geophys. Res., 83, 5849-5856, 1978.
Effects of lithology and depth on the permeability of core samples from the Kola and KTB drill holes
International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, 1994
Permeability measurements were conducted on intact core samples from the Kola drill hole in Russia and the KTB drill hole in Germany. Samples included granodiorite gneisses, basalts and amphibolites from depths up to 11 km. The tests were intended to determine the pressure sensitivity of permeability and to compare the effects of stress relief and thermal microcracking on the matrix permeability of different rock types and similar samples from different depths. The pore pressure Pp was fixed at the estimated in situ pressure assuming a normal hydrostatic gradient; the confining pressure-Pc was varied to produce effective pressures (-Pe-Pc-Pp) of 5 to 300 MPa. The permeability of the basaltic samples was the lowest and most sensitive to pressure, ranging from 10-2ø to 10-23m 2 as effective pressure increased from 5 to only 60 MPa. In contrast, the granodiorite gneiss samples were more permeable and less sensitive to pressure, with permeability values ranging from 10-l? to 10-22 rn 2 as effective pressures increased to 300 MPa. Amphibolites displayed intermectiate behavior. There was an abundance of microfractures in the quartz-rich rocks, but a relative paucity of cracks in the mafic rocks, suggesting that the observed differences in permeability are based on rock type and depth, and that stress relief/thermal-cracking damage is correlated with quartz content. By applying the equivalent channel model of Walsh g•cl Brace [1984] to the permeability data of the quartz-rich samples, we can estimate the closure pressure of the stress-relief cracks and thereby place bounds on the in situ effective pressure. This method may be useful for drill holes where the fluid pressure is not well constrained, such as at the Kola well. However, the use of crack closure to estimate in situ pressure was not appropriate for the basalt and amphibolite samples, because they are relatively crack-free in situ and remain so even after core retrieval. As a result, their permeability is near or below the measurable lower limit of our apparatus at the estimated in situ pressures of the rocks. ET AL.' PERMEABILITY OF KOLA AND KTB CORE SAMPLES 7269 ..
The Effects of Thermal Alterations on Formation Permeability and Porosity
Petroleum Science and Technology, 2008
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Geotechnique, 1991
The characteristic changes in mechanical behaviour occurring in clays as the temperature is reduced to 77 K have been compared with the molecular mobility and freezing behaviour of the contained water: conventional techniques are used, together with the novel application to clays of dynamic mechanical-therm0 analysis (DMA). There is now substantial evidence linking the low-temperature dilation of clays primarily with the loosely bound freezable water component as defined by differential scanning calorimetry; however, dilation is a complex process, and before an acceptable engineering model can be derived which will predict the performance of soils under conditions appropriate to cryogenic storage of liquefied gases, it will be necessary to develop a sound understanding of this phenomenon. A transition in the stress-strain behaviour of clays from ductile to brittle behaviour occurs at approximately 173 K; this transition has been shown to coincide with the loss in mobility of water observed by nuclear magnetic resonance techniques. It is clear that non-freezable water in clays contains sufficient mobility above 173 K to act as a lubricant between the laminae and allow some ductility. It is only below 173 K that clays become fracture-sensitive.
2006
This paper provides a comparative discussion of coupledhydromechanical processes in three different geological formations:crystalline rock, plastic clay, and indurated clay. First, the importantprocesses and associated property characteristics in the three rock typesare discussed. Then, one particular hydromechanical coupling is broughtup for detailed consideration, that of pore pressure changes in nearbyrock during tunnel excavation. Three field experiments in the three rocktypes are presented and their results are discussed. It is shown that themain physical processes are common to all three rock types, but with verydifferent time constants. The different issues raised by these cases arepointed out, and the transferable lessons learned are identified. Suchcross fertilization and simultaneous understanding of coupled processesin three very different rock types help to greatly enhance confidence inthe state of science in this field.
Deep Boreholes Seals Subjected to High P, T conditions – Preliminary Experimental Studies
2017
The objective of this planned experimental work is to evaluate physio-chemical processes for 'seal' components and materials relevant to deep borehole disposal. These evaluations will encompass multi-laboratory efforts for the development of seals concepts and application of Thermal-Mechanical-Chemical (TMC) modeling work to assess barrier material interactions with subsurface fluids, their stability at high temperatures, and the implications of these processes to the evaluation of thermal limits. Deep borehole experimental work will constrain the Pressure, Temperature (P, T) conditions which "seal" material will experience in deep borehole crystalline rock repositories. The rocks of interest to this study include the silicic (granitic gneiss) end members. The experiments will systematically add components to capture discrete changes in both water and EBS component chemistries.
Hole liquids and gaskets for the ISTUK deep ice core drill
Memoirs of National Institute of Polar Research Special Issue, 1994
Deep boreholes in polar ice sheets haye to be fi11ed with a liquid in order to prevent hole closure due to the overburden pressure of the ice. In Greenland, at ice temperatures of-32eC, the lirnit for open hole dri11ing is 400 m. In Antarctica, a depth of 900 m has been obtained in an open hole. All dri11ing to deeper depths needs to be perforrned in a liquid, The berehole liquid should have a density close to that of {ce, be non-toxic, availab]e in quantities at reasonable cost, compatible with the rnaterials in the dri11, non-aggressive to jce, and have a low viscosity to allew rapid drill rnovement in the borehele. In practice, ne liquid has been availab]e that can fu1fi11 all the requirements. In the past, ethanollwater mixture, DFAIGIycol, DFAXTCE, JET-AltPCE, DFAIFI13, n-buty1 acetate, and D601Fl 13 have been used, All liquids have their own advantages and disadvantage$, and the use ofall have involved severe compromises.