Room temperature synthesis of perylene diimides facilitated by high amic acid solubility

A novel protocol for the synthesis of perylene diimides (PDIs), by reacting perylene dianhydride (PDA) with aliphatic amines is reported. Full conversions were obtained at temperatures between 20 and 60˚C,...

A review of the various treatments of oil-based drilling fluids filter cakes

Treatment of the filter cake layer after drilling is essential for better cement integrity and to retain the original reservoir permeability. Compared to water-based filter cake, oil-based mud filter cake removal is more sophisticated as oil encloses the filter cake’s particles. Therefore, oil-based mud clean-up requires wettability alteration additives (mutual solvents and/or surfactants) for permitting acid/filter cake reaction. With an appropriate acid, microemulsions were reported to be very efficient in cleaning oil-based filter cakes, due to their low interfacial tension and high acid solubility. The objective of this paper is to provide an overview of the different techniques and treatment solutions utilized in oil-based filter cake clean-up. Furthermore, a synopsis of the various treatments for drilling fluids densified with different weighting materials is presented. Subsequently, the research limitations and opportunities have been highlighted for future work. In the light of the review that has been presented in this paper, it's recommended to conduct further investigation on some areas related to filter cake removal. The removal of filter cake formed from weighting materials other than barite, calcium carbonate, ilmenite, and manganese tetroxide needs to be investigated thoroughly. Additionally, the overall efficiency of oil-based mud removal needs to be studied under wide ranges of temperature, salinity, and pH. The utilization of surfactant-free microemulsions in filter cake treatment could also be investigated.

Evaluation of Accuracy and Uncertainty of ISO 13503-2 Proppant Testing

Proppant is one of the key aspects of a successful fracturing treatment and subsequent well production, and its quality is strictly controlled by ISO 13503-2, an international standard for proppant testing. Proppant suppliers, oilfield companies and their clients all around the world rely on the standard measurement procedures and limit values to ensure the quality of a product they produce or use for fracturing operations. ISO 13503-2 prescribes testing procedures; however, the standard does not contain information about uncertainty of final measurements. This information is essential for consistent quality assurance, for resolving inconsistencies between different laboratories, and for comparing properties of different products. An interlaboratory study was organized to evaluate the precision of ISO 13503-2 proppant testing. Four proppant samples were distributed among proppant quality control laboratories all around the world; 17 laboratories participated in the study. The obtained test data were used to calculate repeatability and reproducibility standard deviations (in accordance with ISO 5725-2) and uncertainty of ISO 13503-2 test data (in accordance with ISO 21748). The study showed that most proppant parameters measured using ISO 13503-2 methods yielded high uncertainty. For example, for turbidity and acid solubility values, the uncertainty was up to ±50%. Uncertainty of roundness and sphericity values was ±0.1 since the values are estimated by operator, making the test quite subjective. For crush resistance, the highest uncertainty among tested samples, ±40%, was observed for an HSP 30/50 sample measured at 15,000 psi stress. For absolute density, a systematic difference between values obtained using gas pycnometers from different manufactures was observed; also, the equipment differs by repeatability characteristics. The results of the interlaboratory study allowed estimating the uncertainty of ISO 13503-2 test methods. It was shown that high measurement uncertainty for some critical proppant parameters should be considered for correct interpretation of the obtained test results.

Concentration effect of Sodium Chloride Salt on Benzoic Acid Solubility and Dissociation into Water at 298 K Temperature

In article, we have been reported the study of a concentration effect of sodium chloride (NaCl) salt on benzoic acid solubility and its dissociation in water at 298 K temperature. At this temperature the benzoic acid solubility into water and their dissociation value for six samples in range of 0.00, 0.05, 0.10, 0.30, 0.40 and 0.50 M. Each of these different ionic strength or concentration of sodium chloride is analyzed by titrimetrically against of 0.05 M sodium hydroxide (NaOH) basic solution. The pH of each solution is measured well by using of calibrated pH-meter. Observation reveals that the value of pH of benzoic acid into water at applying temperature is may inversely related with concentration of NaCl. Graphically, the value of ionic strength (I) of that benzoic acid is plotted versus with dissociation constant (Kc) of acid into water at specific 298 K temperature. The value of benzoic acid dissociation constant for given each six concentration of NaCl is found to be -4.169, -4.045, -3.993, -3.885, -3.848 and -3.788, respectively.

BUFFER SOLUTION BEHAVIOUR ON SOLUBILITY AND DISTRIBUTION COEFFICIENT OF BENZOIC ACID BETWEEN TWO IMMISCIBLE LIQUIDS

The two immiscible solvents such as hydrophilic (water) and hydrophobic (benzene) have been reported for study of solubility and distribution of benzoic acid in it. The solubility of benzoic acid in water and in different acidic, neutral, and basic pH benzene-buffer solutions are analyzed by titrimetrically, and concentration of acid in both solvents by acid-base titration method. The shake-flask method are involved for where the partitioning or distribution coefficient of benzoic acid in these two solvents layer at room temperature (25°C). Observation reveals that, the benzoic acid solubility in g/100g for water is being 0.142±0.033 and at different buffer solutions with pH 4.0, 7.0 and 9.0 it being 0.153±0.012, 0.186±0.145 and 0.148±0.708, in respect of partition coefficient of that acid where it for water-benzene solvent as 0.636 and in buffer solutions is being 0.841, 0.624 and 0.589 respectively. In graphically, at different pH buffer solutions the solubility plot of acid in neutral pH (7.0) is higher than other acidic and basic, but it for distribution coefficient of acid in acidic (pH 4.0) medium is higher than both neutral and basic pH (9.0) medium.

Pillar Fracturing Production Enhancement Results for an Unconventional Calcareous Shale in Ecuador

Economical production from low-permeability oil-saturated reservoirs has always been a challenge in a basin known for its mature assets. M2 limestone is a new challenge. To characterize, it was necessary to use the methodology based on shale plays, integrating information from different logs using a proprietary evaluation method. Applying pillar fracturing, creating stable voids between pillars, and hence, infinite-conductivity channels in geomechanically competent candidates resulted in economical production and proved reserves from a low-permeability calcareous shale. Geomechanics, mineralogy, and saturated intervals were addressed by using a combination of rock mechanical properties and mineralogy, carbon/oxygen logs, and X-ray diffraction (XRD) on drilling cuttings. Once the prospective zones in the M2 limestone intervals were selected, a conventional fracturing treatment was designed using a 3-D gridded simulator. The candidate well was evaluated for pillar fracturing by using results from geomechanics and the conventional fracture application. A pumping schedule that included pillar volume, spacer, and tail in stages was then designed. Results from the fracture simulator were loaded in a numerical reservoir simulator, and different development scenarios were evaluated. M2 limestone has shown production potential near areas where volcanic intrusion is present, or indicated hydrocarbon potential by oil shows observed on cuttings and high-gas readings during drilling. The data used for this project was collected during conventional reservoir development but had never been evaluated using an unconventional reservoir approach. XRD analysis and acid solubility tests confirmed that the reservoir does not contain a high-carbonate content nor acid solubility. Diagnostic Fracture Injection Test (DFIT) and minifrac analysis helped to define the size and fracturing technique to be used. Results from this work provided a better understanding of the reservoir; a development plan is needed to improve the investment return for this type of project. Geomechanical evaluation is fundamental to the application and design of pillar fracturing. This fracturing technique was selected because it used 43% less proppant than a conventional job, reduced risk of screen out, and provided higher productivity over a conventional fracturing job. This is the first time that pillar fracturing has been applied in this Ecuadorian reservoir. The production outcome proved reserves of 32°API oil and resulted in the largest fracturing job in Ecuador. Different development scenarios are proposed based on the results from this well. A complete workflow to characterize, design a hydraulic fracture job using proprietary geomechanical candidate selection criteria, and develop an unconventional calcareous shale is presented. The available data are the same as in a conventional reservoir, whereas the evaluation technique, as well as fracture design, is customized to this type of reservoir to attain economical production.

Regulatory properties of vitronectin and its glycosylation in collagen fibril formation and collagen-degrading enzyme cathepsin K activity

Vitronectin (VN) is a glycoprotein found in extracellular matrix and blood. Collagen, a major extracellular matrix component in mammals, is degraded by cathepsin K (CatK), which is essential for bone resorption under acidic conditions. The relationship between VN and cathepsins has been unclear. We discovered that VN promoted collagen fibril formation and inhibited CatK activity, and observed its activation in vitro. VN accelerated collagen fibril formation at neutral pH. Collagen fibers formed with VN were in close contact with each other and appeared as scattered flat masses in scanning electron microscopy images. VN formed collagen fibers with high acid solubility and significantly inhibited CatK; the IC50 was 8.1–16.6 nM and competitive, almost the same as those of human and porcine VNs. VN inhibited the autoprocessing of inactive pro-CatK from active CatK. DeN-glycosylation of VN attenuated the inhibitory effects of CatK and its autoprocessing by VN, but had little effect on acid solubilization of collagen and VN degradation via CatK. CatK inhibition is an attractive treatment approach for osteoporosis and osteoarthritis. These findings suggest that glycosylated VN is a potential biological candidate for CatK inhibition and may help to understand the molecular mechanisms of tissue re-modeling.

Titrimetric Study of Solubility of Solute Benzoic Acid and Their Partition in Water and Benzene Solvents

The solubility and distribution coefficient (K) of solute in solvent is depends on temperature and solute-solvent interaction, where the solute is partitioned between two immiscible solvents phase and dissociated into ionic form. Here, we have reported the titrimetric study for solubility and partition or distribution coefficient of benzoic acid (solute) in aqueous water and in organic benzene which are using as solvents. The benzoic acid solubility (in g/100g of solvent) in water and in benzene solutions have determined by titrimetrically. There is partitioning and concentration of such acid in these solvent phase by shake-flask and acid-base titration method as well. The benzoic acid solubility and their distribution between water and benzene as in different pH buffer solutions have been analyzed at room temperature (25°C) in acidic, neutral and basic (pH 4.0, 7.0 and 9.0) medium, respectively.

Evaluation of Pozzolanic Activity of Metakaolin Chemometric Method According to the UV-VIS-NIR Spectroscopy

It is introduced to use a portable spectrometer along with a calibration model for rapid quality control of metakaolin in situ. Verification of the calibration model for predicting the values of two indicators: total acid solubility and mass loss during calcination, indirectly characterizing the pozzolanic activity of metakaolin.