Correction: An investigation of trace elements’ behavior during chemical preparation of ultramafic matrix rock samples using bomb digestion for analysis by ICP-MS

Correction for ‘An investigation of trace elements’ behavior during chemical preparation of ultramafic matrix rock samples using bomb digestion for analysis by ICP-MS’ by Olga Ilyinichna Okina et al., J. Anal. At. Spectrom., 2020, 35, 2627–2638, DOI: 10.1039/D0JA00255K.

MICROPOROSITY CHANGES WITH ACIDIZING EFFECT IN SANDSTONES (KIZILDERE FORMATION-HATAY/S-TURKEY)

This study aims to determine the field and petrographic properties of sandstones observed in Arsuz-İskenderun (Hatay) region and micro-size porosity changes in acidizing stages. The fine-grained sandstones of the Aktepe formation have more quartz grains than the other components and the binding material is matrix. Rock fragments that consist of fossil shells, limestone and igneous fragments are observed relatively to quartz and feldspar grains in the Kızıldere formation sandstones. The first step of reservoir rock acidizing is HCl acidizing and the process is experimentally provided by capillarity experiment. HCl with dilution rates of 7.5% - 15% - 30% was absorbed into the samples at room temperature and after 100 minutes, effective distances were observed as 0.6-0.8-1.1 cm and dissolved rock amounts as 32.82-34.02-35.54 g, respectively. In acidizing process, the average porosity analysed with Micro-CT is 39.6% of acidified samples with 15% diluted acid and non-acidified samples, equivalent results were obtained with porosity values measured by well logs. There is an increase in the porosity of about 16% with acidizing. Pores were bonded together by acidizing and pore size increase about 20%. The change in the pore throat by acidizing is 105%. Calculation of porosity of rocks by Micro-CT and image processing methods can be performed faster compared to the other methods.

APPLICATION OF SEISMIC DILATOMETER FOR CEMENTATION ANALYSIS IN RESIDUAL GNEISS SOIL

Residual soils have different properties and behavior from sedimentary soils. Aspects related to the processes of origin and formation directly impact these geotechnical particularities. One of the characteristic properties of this material is cementation. Cementation is an additional resistance that occurs in the solid skeleton due to weathering actions on these materials. In a residual soil profile, different cementation levels occur between the grains, these differences are due to different types of matrix rock, decomposition mechanisms involved in the process and anthropic actions. This article evaluated changes in the degree of cementation in residual soil horizons using the Marchetti Seismic Dilatometer (SDMT). The research was carried out in a residual gneiss soil in the State of Santa Catarina. The evaluation of the cementation degree was based on the relationships obtained with the Go (shear modulus with small strain) and other field geotechnical indices. The results show that the interpretation of the correlations from the results obtained by the SPT (Standardized Penetration Test), CPT (Cone Penetration Test) and SDMT tests allow the identification of layer boundaries with different degrees of cementation in residual gneiss soils. . In the present work, the limits between the saprolitic and the lateritic layers were identified and, finally, it was concluded that the studied residual soil presents a low level of cementation between the particles.

Field Performances, Effective Times, and Economic Assessments of Polymer Gel Treatments in Controlling Excessive Water Production From Mature Oil Fields

Polymer bulk gels have been widely applied to mitigate excessive water production from mature oil fields by correcting the reservoir permeability heterogeneity. This paper reviews water responses, effective times, and economic assessments of injection-well gel treatments based on 61 field projects. Eight parameters were evaluated per the reservoir type using the descriptive analysis, stacked histograms, and scatterplots. Results show that water production generally continues to increase after the treatment for undeveloped conformance problems. Contrarily, it typically decreases after the reactive gel treatments target developed conformance issues. For the developed problems, gel treatments do not always mitigate the water production where the water cut may stabilize or increase by 17% in 22% of instances. In addition, they often do reduce water production but not dramatically to really low levels where the water cut stays above 70% and reduces by only 10% in most cases. Gel treatments are economically appraised based only on the oil production response, and both water responses (injection and production) are not considered in the evaluation. They have a typical payout time of 9.2 months, cost of incremental oil barrel of 2 $/barrel, and effective time of 1.9 years. In addition, they have better water responses and economics in carbonates than in sandstones and in unconsolidated and naturally fractured reservoirs than in matrix-rock formations. The current review strongly warns reservoir engineers that gel treatments are not superior in alleviating the water production and candidates should be nominated based on this fact to achieve favorable economics and avoid treatment failures.

Denitrification potential and occurrence of reactive minerals in the fractured carbonate aquifer of the Upper Muschelkalk, SW-Germany

<p>Fractured or karstified carbonate rocks constitute major drinking water resources all over the world. Nitrate is one of the major threads for drinking water suppliers in regions with intensive agrucultural use. Field scale observations in the Upper Muschelkalk aquifer in the area “Oberes Gäu”, SW-Germany, suggest that denitrification due to oxidation of Fe<sup>(II)</sup> or sulfide-bearing minerals might be a relevant attentuation process at least in cases of extended mean residence times (> 5-40 years).</p><p>To identify reactive minerals within the rock matrix rock samples have been taken from major facies types within the Upper Muschelkalk from outcrops, drillings and carbonate quarries. Samples have been analysed in polished thin sections using transmitted & reflected light microscopy as well as electron microscopy including energy-dispersive elemental analysis.</p><p>Reactive Fe<sup>(II)</sup> and sulfide-bearing minearls are pyrite and marcasite as well as saddle dolomites (Fe-bearing dolomites). Concentrations of these minerals depend on facies types and amount to several weight percent iron. Porosities range from very low values (<1 %) up to 25 %.</p><p>In combination with a hydrogeological characterization, these investigations allowed to delineate reactive zones within the fractured aquifer. Denitrification within these reactive zones depends on the amount and dissolution of these minerals as well as effective diffusion in the pore space.</p>

An investigation of trace elements' behavior during chemical preparation of ultramafic matrix rock samples using bomb digestion for analysis by ICP-MS

A chemical treatment scheme providing complete dissolution of a 300 mg test portion of ultramafic rocks with various MgO contents is proposed.

Nanoparticles as Fluid Loss Control Additives for Hydraulic Fracturing of Tight and Ultra-Tight Hydrocarbon-Bearing Formations

Injection of polymeric solutions, either as slick water or cross-linked fluids, in order to propagate a fracture and distribute proppants and keep the fracture open is a common practice in hydraulic fracturing of unconventional tight and ultra-tight formations. In addition to propagation of a main fracture, polymeric fluids will be invading the already existing network of micro-fractures and extending the network connected to the main fracture. Fluid loss into the matrix rock and micro-fractures is inevitable, so is the use of a comparable fluid loss additive to reduce the filtrate volume. Different classes of nanoparticles have been used by several researchers to carry different agents including surfactants and enzymes for hydraulic fracturing purposes. Nano-sized pores and micro-sized fractures in tight and ultra-tight formations require a nano to micro-sized fluid loss additive to improve propagation of the hydraulic fractures by efficiently reducing the fluid loss. In this study, application of silica and polyelectrolyte complex (PEC) nanoparticles as fluid loss additives for three sets of core plugs with permeability values within the 10−5 −10−4 mD, 0.01–0.1 mD and 1–40 mD range was investigated. The nano-sized material used in this study significantly reduced the fluid loss volume for the cores with permeability values below 0.1 mD when mixed only with 2% KCl or with low concentrations of guar polymer prepared in 2% KCl. Combination of the fluid loss additive application with chemical carrying application makes these nanoparticle systems a suitable package for hydraulic fracturing of tight and ultra-tight formations.

CSD correction as a tool for estimating 3d block size distribution.

For the headrace Moglicë-Grabovë, part of Devoll Hydropower Project in Albania, two different techniques of tunnelling are planned: DS TBM for the Flysch series starting in Moglicë and Drill & Blast for the Ophiolite section, starting in Grabovë. A major question concerning the tunnelling seems to find the point where DS-TBM excavation from the Moglicë side should stop to “wait” for the Drill&Blast excavation from the Shemsit access tunnel side. Assumed that the so called “block in matrix” rock mass is very unfavourable, respectively disqualifying for TBM excavation. These mixtures of hard blocks embedded in weaker and finer matrix that are very difficult to characterize, frequently challenge the engineering geologists with the characterization, design and construction problems associated with them. Evaluating Block Size Distribution in the BiM rock zone of this project area has been only the first step in characterizing all the geological and geotechnical parameters of the rock mass which will influence a decision that has major economic consequences. CSDCorrections 1.39 is the program used to convert the two dimensional data gathered from thin sections, outcrops, photographs etc. to true three dimensional crystal size distributions (CSD).