The Role of Specific Surface Area and Cation Exchange Capacity in Determining Shale Rock Properties

Josh, Matthew; Bunger, Andrew P.; Kear, James; Sarout, Joël; Dewhurst, D.; Raven, Mark; Piane, Claudio Delle; Esteban, Lionel; Clennell, Michael B.

doi:10.3997/2214-4609.20140014

Cited by 3 publications

(1 citation statement)

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“…In smectite rich intervals, however, CEC as a resistivity decreasing indicator is controversial (cf. Josh et al, 2014;Matsui et al, 2000): because both high resistivity and low resistivity smectite rich zones are found. At shallow depths CEC is linearly correlated with the bound water of smectites .…”

Section: Effect Of Clays On Vp-resistivity Cross-plot Relationshipsmentioning

confidence: 99%

Compaction processes and rock properties in uplifted clay dominated units– the Egersund Basin, Norwegian North Sea

Kalani

Jahren

Mondol

et al. 2015

Marine and Petroleum Geology

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This thesis entitled "Multiscale seal characterization in the North Sea-implications from clay sedimentology, well logs interpretation and seismic analyses" has been submitted to the Department of Geosciences at the University of Oslo in agreement with the requirements for the degree of Philosophiae Doctor (PhD). The PhD research was performed within the multidisciplinary project "Evaluation of the long-term sealing capabilities in the southern Norwegian sector of the North Sea for CO 2 storage purposes" (CO2SEAL) sponsored by the Norwegian Research Council (NFR) and Statoil under the CLIMIT program. CO2SEAL aims primarily to assess the long-term sealing capabilities of shaly seal rock units overlying potential adequate CO 2 storage reservoirs. The presented research largely deals with understanding of sedimentary rocks with an emphasis on fine-grained siliciclastic rocks and the distribution and thickness variation of such rocks. Progressively depleting oil reserves and, on the other hand, more rigid environmental considerations promote the study to have a great

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Section: Effect Of Clays On Vp-resistivity Cross-plot Relationshipsmentioning

confidence: 99%

Compaction processes and rock properties in uplifted clay dominated units– the Egersund Basin, Norwegian North Sea

Kalani

Jahren

Mondol

et al. 2015

Marine and Petroleum Geology

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Broadband electrical properties of clays and shales: Comparative investigations of remolded and preserved samples

Josh

Clennell

2015

GEOPHYSICS

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The dielectric permittivity of mudrocks cannot be determined from the mixing ratios of the constituent minerals and brine and their individual dielectric response. The high-frequency dielectric permittivity is linked (R 2 ¼ 0.77 correlation) to water content, but the relationship is complicated by mineral type and the hydration state. The cation exchange capacity (CEC) and specific surface area (SSA) determine the establishment of a polarizable electrical double layer and give rise to the long range diffusion of ions leading to Maxwell-Wagner polarization. This ultimately determines the dielectric response below 50 MHz. Procedures for SSA analysis based on sorption of 2-ethoxyethanol and CEC analysis based on methylene blue titration, were developed for investigating swelling clays. These were combined with a procedure for preparing remolded paste samples from pulverized rock and drill cuttings to form the basis of this investigation. In a case study of 123 drill cutting samples retrieved from an undisclosed well, dielectric analysis of the remolded samples exhibits R 2 ¼ 0.93 correlation with SSA, R 2 ¼ 0.86 correlation with CEC, and R 2 ¼ 0.81 correlation with clay content. A pseudodielectric log of the remolded drill cuttings exhibited a weak correlation with downhole resistivity, gamma ray, and compressional slowness logs measured by a service company in the shaly sections of the well, but no correlation in the sandy section of the well. This attributed to better preservation of shaly cuttings due to finer microstructure and therefore less alteration during uphole transport and sample preparation.

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Reliability of Formation Cuttings as an Aid in Defining Minerology to Reduce Subsurface Uncertainties

Shah

Ali

Rashid³

2018

Day 3 Thu, March 22, 2018

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In the current climate, of oil price slump, native sampling and data acquisition are deemed uneconomical as oil and gas companies adopt cost rationalization to sustain business models. Exploration and development data which were previously overlooked are now being sought to gain critical. Cuttings, collected during drilling, can provide overburden and reservoir mineralogical data for better understanding of formations as well as a detailed evaluation of seal integrity for a consideration as a potential CO2 storage sites. Through reservoir zonation and well correlation, drill cuttings were selected from respective target zones. Depending on the sample condition, necessary preparations were carried out prior to mineralogical analysis on this cutting samples. Sample age and improper preservation significantly impacted sample condition and some had to be discarded during the screening process. X-ray diffraction (XRD) analysis was carried out on selected samples which yielded semi-qualitative mineralogical data (+/- 5%). The drill cuttings mineralogy data were then cross checked with rock chips from available conventional core and well logs to observe variances and consistency. Samples from four wells in the S field were analyzed to establish the mineralogical data. Variance of mineralogical content was observed between cuttings and rock chip samples, however mineral proportion are comparable, particularly in clay minerals, plagioclase, siderite and pyrite. Similar type of clay minerals were observed in both ditch cutting samples and core chip samples, where the total clay amount in Seal A is higher than in Seal B. Both types of samples have high contents of illite, and mixed layer (illite dominated) and minimal content of the swelling clay, smectite. Overall, results indicated similar mineralogical composition across S field cap rock in seal A and seal B intervals. The study demonstrates the reliability of the ditch cutting samples, with proper selection and preparation, providing more extensive coverage and availability of mineralogical description over extended zones. The mineralogical information is useful for the analysts to discern the facies types and distribution, hence reducing the uncertainties.

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The Role of Specific Surface Area and Cation Exchange Capacity in Determining Shale Rock Properties

Cited by 3 publications

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Compaction processes and rock properties in uplifted clay dominated units– the Egersund Basin, Norwegian North Sea

Compaction processes and rock properties in uplifted clay dominated units– the Egersund Basin, Norwegian North Sea

Broadband electrical properties of clays and shales: Comparative investigations of remolded and preserved samples

Reliability of Formation Cuttings as an Aid in Defining Minerology to Reduce Subsurface Uncertainties

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