Phase Equilibria of Acid-Gas Aqueous Systems (CO2, H2S, CH4, Water) and In-Situ pH Measurements in Application to Top-of-Line Corrosion

SPE Journal ◽  
2021 ◽  
pp. 1-16
Author(s):  
Birol Dindoruk ◽  
Ram R. Ratnakar ◽  
Sanyal Suchismita
Keyword(s):  
Binary Systems ◽  
Measurement Data ◽  
Ph Measurements ◽  
Acid Gas ◽  
Wellbore Integrity ◽  
Fluid Systems ◽  
Data Saturation ◽  
Condensed Water ◽  
Model Subject

Summary We present thermodynamic modeling and pH measurements of fluid systems containing acid-gases (e.g., CO2 and H2S), water, and hydrocarbons—replicating the production and shutdown conditions in sour fields—for the purpose of evaluating top-of-line corrosion (TLC) and wellbore integrity and screening/selection of the proper wellbore materials. In particular: An equation of state (EOS) model using Peng-Robinson EOS in combination with the Huron-Vidal (HV) mixing rule for an aqueous subsystem is developed. In the model, subject EOS parameters are calibrated against existing thermodynamic data (saturation data for pure components and solubility data for binary systems) in literature. New in-situ pH measurement data are presented for a model system corresponding to a sour field. It was found that the wellbore can be subjected to pH levels as low as 2.7 with reservoir fluid containing 12 mol% CO2 and 88 mol% CH4 with downhole flowing conditions of 200 bar and 150°C and wellhead shut-in conditions of 300 bar and 4°C, as observed from the experiments. A modeling workflow is developed to estimate pH of the condensed water as a function of temperature and composition of the aqueous phase. The comparison between prediction and experimental measurement shows a very good match between the two (within pH ±0.1). Such studies (pH measurements and prediction) are not available in the literature but play important roles in material screening and assuring wellbore integrity for sour fields. More importantly, sensitivity analysis can be performed to investigate the effects of various factors (such as reservoir temperature/pressure, shutdown conditions, and compositions or extent of souring) on pH prediction. Furthermore, the methodologies developed through this work can also be extended to reservoir facilities, pipelines, sour gas disposal/handling units, and downstream systems such as water utilities, reactor plants, and refineries. The work can also support regulation/licensing for these sour systems.

Unexpected Keto-enol Tautomerism in the Cyclopyridinophane Class Direct and indirect proofs

2008 ◽  
Vol 59 (10) ◽  
Author(s):  
Paul Ionut Dron ◽  
Neculai Doru Miron ◽  
Gheorghe Surpateanu
Keyword(s):  
Nmr Spectroscopy ◽  
1H Nmr ◽  
Stable Conformer ◽  
Ph Measurements ◽  
Theoretical Methods ◽  
Nmr Data ◽  
Tautomeric Forms ◽  
New Compounds

The paper presents the synthesis of cyclo (bis-paraquat p-phenylene p-phenylene-carbonyl) tetrakis (hexafluorophosphate), named �CETOBOX�, and the closely related structural determinations. This compound exists in three tautomeric forms. These forms were evidentiated by NMR-data (1H-NMR, TOCSY, COSY, NOESY), UV-Vis spectra coupled with pH measurements and by synthesis. As the �CETOBOX� gives �in situ� only the corresponding monoylide, the synthesis of a new fluorescent indolizine cyclophane has been performed by a 3+2 cycloaddition. All structures of the new compounds presented herein have been established by NMR spectroscopy. Also, theoretical methods (MM3, AM1, AM1-COSMO and B88LYPDFT) have been used to determine the most stable conformer structures.

In Situ Stress Measurement and Inversion in Deep Roadway

2013 ◽  
Vol 734-737 ◽  
pp. 759-763 ◽  
Author(s):  
Yong Li ◽  
Yun Yi Zhang ◽  
Ren Jie Gao ◽  
Shuai Tao Xie
Keyword(s):  
Field Measurement ◽  
Stress Measurement ◽  
Measurement Data ◽  
Back Analysis ◽  
In Situ Stress ◽  
Deep Mine ◽  
Accuracy Requirement ◽  
Initial Stress Field ◽  
In Situ Stress Measurement

Jixi mine area is one of the early mined areas in China and it's a typical deep mine. Because of large deformation of underground roadway and dynamic disasters occurred frequently in this mine, five measurement points of in-situ stress in this mine was measured and then analyzed with inversion. Based on these in-situ stress measurement data, numerical model of 3D in-situ stress back analysis was established. According to different stress fields, related analytical samples of neural network were given with FLAC program. Through the determination of hidden layers, hidden nodes and the setting of parameters, the network was optimized and trained. Then according to field measurement of in-situ stress, back analysis of initial stress field was conducted. Compared with field measurement, with accuracy requirement satisfied, it shows that the in-situ stress of rock mass obtained is basically reasonable. Meanwhile, it proves that the measurement of in-situ stress can provide deep mines with effective and rapid means, and also provide reliable data to optimization of deep roadway layout and supporting design.

scholarly journals Estimation of Surface Concentrations of Black Carbon from Long-Term Measurements at Aeronet Sites over Korea

2020 ◽  
Vol 12 (23) ◽  
pp. 3904
Author(s):  
Yongjoo Choi ◽  
Young Sung Ghim ◽  
Ying Zhang ◽  
Seung-Myung Park ◽  
In-ho Song
Keyword(s):  
Black Carbon ◽  
Measurement Data ◽  
Water Soluble ◽  
Mixing Rule ◽  
Range Transport ◽  
Urban Rural ◽  
Fine Mode ◽  
The Difference ◽  
Mlr Model

We estimated fine-mode black carbon (BC) concentrations at the surface using AERONET data from five AERONET sites in Korea, representing urban, rural, and background. We first obtained the columnar BC concentrations by separating the refractive index (RI) for fine-mode aerosols from AERONET data and minimizing the difference between separated RIs and calculated RIs using a mixing rule that can represent a real aerosol mixture (Maxwell Garnett for water-insoluble components and volume average for water-soluble components). Next, we acquired the surface BC concentrations by establishing a multiple linear regression (MLR) between in-situ BC concentrations from co-located or adjacent measurement sites, and columnar BC concentrations, by linearly adding meteorological parameters, month, and land-use type as the independent variables. The columnar BC concentrations estimated from AERONET data using a mixing rule well reproduced site-specific monthly variations of the in-situ measurement data, such as increases due to heating and/or biomass burning and long-range transport associated with prevailing westerlies in the spring and winter, and decreases due to wet scavenging in the summer. The MLR model exhibited a better correlation between measured and predicted BC concentrations than those based on columnar concentrations only, with a correlation coefficient of 0.64. The performance of our MLR model for BC was comparable to that reported in previous studies on the relationship between aerosol optical depth and particulate matter concentration in Korea. This study suggests that the MLR model with properly selected parameters is useful for estimating the surface BC concentration from AERONET data during the daytime, at sites where BC monitoring is not available.

Time-of-flight neutron diffraction studies of clay-fluid interactions under basin conditions

Clay Minerals ◽  
2000 ◽  
Vol 35 (1) ◽  
pp. 283-290 ◽  
Author(s):  
N. T. Skipper ◽  
G. D. Williams ◽  
A. V. C. de Siqueira ◽  
C. Lobban ◽  
A. K. Soper
Keyword(s):  
Neutron Diffraction ◽  
Sedimentary Basin ◽  
Time Of Flight ◽  
Ambient Conditions ◽  
Isotopic Labelling ◽  
Fluid Systems ◽  
High Pressure High Temperature ◽  
Temperature Sample ◽  
Fluid Interactions

AbstractNeutron diffraction experiments can provide an extremely high-resolution structural picture of clay-fluid systems. Here we describe the application of time-of-flight neutron scattering to hydrated clays, including discussion of issues such as isotopic labelling, sample containment, and data analysis. Recent studies of hydrated vermiculites under ambient conditions are used as an example. We then describe a new high-pressure/high-temperature sample environment that is being used to study clay-fluid interactions, in situ under hydrostatic sedimentary basin conditions. This environment enables us to approximate conditions encountered during burial, at depths of up to 10 km.

Acid Stimulation Used in In-Situ Leaching Uranium

2010 ◽  
Author(s):  
Wen-sheng Liao ◽  
Li-min Wang ◽  
Yi-xuan Yao ◽  
Guo-ping Jiang ◽  
Hai-jun Zhao ◽  
...  
Keyword(s):  
Formic Acid ◽  
Injection Rate ◽  
Low Permeability ◽  
Reaction Products ◽  
Treatment Results ◽  
The Core ◽  
Fluid Systems ◽  
Core Permeability ◽  
Significant Production

Acidization was studied on a uranium sandstone deposit in Inner Mongolia with low–permeability and heavy calcium cementation. Acid dissolving test indicates that hydrochloric acid, formic acid and mud acid can easily dissolve formation minerals. With proper volumes and concentrations of acids used, the risk of precipitation of reaction products could be minimized. Core flow acidizing trial shows that the acidic fluid systems of hydrochloride acid, formic acid or acetic acid can significantly improve the core permeability. The average permeability has increased by 763 percent for the above three systems. But mud acid didn’t increase the core permeability; on the contrary, it caused formation damage, and led to lowering permeability. In the pilot test, the injection rate has improved by 118 percent for 6 wells. The acid treatment results indicate that a significant production enhancement of wellfields can be achieved by acid stimulation.

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