Showing papers by "Sonatrach published in 2019"

Predicting solubility of CO2 in brine by advanced machine learning systems: Application to carbon capture and sequestration

Abstract: Carbon dioxide (CO2) capture and sequestration in saline aquifers have turned into a key focus as it becomes an effective way to reduce CO2 in the atmosphere. The solubility of CO2 in brine is of vital role in monitoring CO2 sequestration. In this study, based on molality of NaCl, pressure and temperature, modeling of CO2 solubility in brine has been carried out utilizing multilayer perceptron (MLP) and radial basis function neural network (RBFNN). Levenberg-Marquardt (LM) algorithm was implemented to optimize the MLP model, while genetic algorithm (GA), particle swarm optimization (PSO) and artificial bee colony (ABC), were applied to optimize the RBFNN model. To this end, a widespread experimental databank including 570 data sets gathered from literature was considered to implement the proposed models. Graphical and statistical assessment criteria were considered to investigate the performances of these models. The obtained results revealed that all the proposed techniques are in excellent correspondence with experimental data. In addition, the performance analyses showed that RBFNN-ABC model exhibits the higher accuracy in the prediction of CO2 solubility in brine compared with the other proposed smart approaches and the existing well-known models. The RBFNN-ABC model yields a root mean square error (RMSE) value of 0.0289 and an R2 of 0.9967. Finally, the RBFNN-ABC model validity was confirmed and a small number of probable doubtful data was detected.

Review of recent advances in polyethylenimine crosslinked polymer gels used for conformance control applications

Abstract: Several crosslinked polymer gels have been developed over the last 5 decades to address the different technical challenges in oil reservoirs especially conformance control operations. Among these systems, polyethylenimine (PEI) crosslinked polymer gels, which have gained a huge interest thanks to their eco-friendly aspect and thermal stability at extremely high temperatures. They have been largely examined in laboratories and implemented in oilfields since their introduction in the late 1990s. One can find in the literature many reviews on gel systems which have addressed briefly polymer/PEI gels. However, in this article, we are providing a thorough and detailed discussion on these systems and their recent developments. To do so, we are presenting the main polymer/PEI gel systems investigated over the last 2 decades. Then, we are highlighting the recent improvements that aimed to extend their gelation times and final strengths; finally, we are representing some of their successful implementations worldwide.

Modeling Wax Disappearance Temperature Using Advanced Intelligent Frameworks

Abstract: The deposition of wax is one of the most potential problems that disturbs the flow assurance during production processes of hydrocarbon fluids. In this study, wax disappearance temperature (WDT) th...

Gas Hydrate Crystallization in Thin Glass Capillaries: Roles of Supercooling and Wettability.

Abstract: We designed and implemented an experimental methodology to investigate gas hydrate formation and growth around a water–guest meniscus in a thin glass capillary, thus mimicking pore-scale processes ...

Magnetic field impact on nanofluid convective flow in a vented trapezoidal cavity using Buongiorno's mathematical model

Abstract: Numerical study for the effect of an external magnetic field on the mixed convection of Al2 O3 –water Newtonian nanofluid in a right-angle vented trapezoidal cavity was performed using the finite volume method. The non-homogeneous Buongiorno model is applied for numerical description of the dynamic phenomena inside the cavity. The nanofluid, with low temperature and high concentration, enters the cavity through the upper open border, and is evacuated through opening placed at the right end of the bottom wall. The cavity is heated from the inclined wall, while the remainder walls are adiabatic and impermeable to both the base fluid and nanoparticles. After validation of the model, the analysis was carried out for a wide range of Hartmann number (0 ≼ Ha ≼ 100) and nanoparticles volume fraction (0 ≼ ϕ 0 ≼ 0.06). The flow behavior as well as the temperature and nanoparticles distribution shows a particular sensitivity to the variations of both the Hartmann number and the nanofluid concentration. The domination of conduction mechanism at high Hartmann numbers reflects the significant effect of Brownian diffusion which tends to uniform the distribution of nanoparticles in the domain. The average Nusselt number which increases with the nanoparticles addition, depends strongly on the Hartmann number. Finally, a correlation predicting the average Nusselt number within such geometry as a function of the considered parameters is proposed.

A Comprehensive Study on Crude Methanolic Extract of Daphne gnidium L. as Effective Corrosion Inhibitors of Mild Steel Induced by SRB Consortium

Abstract: The aim of the present work is the evaluation of effect of methanolic extract obtained from Daphne gnidium against biocorrosion caused by sulphate-reducing bacteria (SRB). Herein, the study of the influence of SRB consortium has been realized on the biological and electrochemical properties of the carbon steel API5LX60 immersed in water sample obtained from an Algerian oil field separator. The monitoring of the treatment effects on the SRB performance using kits test and weight loss methods showed a positive effect of the methanolic extract of D. gnidium as a corrosion inhibitor at a concentration of 0.8 g/L. In the other hand, the weight loss test has generated an efficiency rate of 95.99% at a concentration of 1.6 g/L. A linear polarization resistance approved these results, and they have given a yield of 91.14% with a polarization resistance value of 28.9 kΩ cm2 at a concentration of 0.25 g/L.

Experimental design methodology as a tool to optimize the adsorption of new surfactant on the Algerian rock reservoir: cEOR applications

Abstract: In this research work, a new surfactant called surf EOR ASP 5100 used in the SWCTT (single well chemical tracer test) in the Algerian oilfield and sodium dodecyl sulfate (SDS) were used for static adsorption tests. The Algerian rock reservoir has been characterized by different techniques such as SEM, XRD, XRF, BET analysis. The equilibrium was successfully verified by Langmuir isotherm and second-order ( $R^2>95\%$ models for all concentrations and temperatures to predict the adsorption process. Furthermore, the adsorption process was found to be exothermic ( $\Delta G^{\circ}<0$ . To quantify the minimal adsorbed quantity, a full factorial design of 23 (8 experiments) was applied to analyze the individual effects and interactions of operational parameters using variance analysis (ANOVA), desirability method and response surface methodology. The optimal conditions obtained are as follows: the Qe value was 2.3291mg/g for the SDS surfactant at a concentration of 200ppm and temperature of $ 25 {}^{\circ}$ C, and Qe was 3.894513mg/g for EOR ASP 5100 for the concentration of 200ppm and temperature of $ 80 {}^{\circ}$ C.

Parametric Study of COD Reduction from Textile Processing Wastewater Using Adsorption on Cypress Cone-Based Activated Carbon: An Analysis of a Doehlert Response Surface Design

Abstract: In this study, the performance of a cypress cone-based activated carbon was tested for the COD reduction from industrial textile wastewater. These cypress cones were locally collected after maturation. The Doehlert response surface design was used to simulate and optimize the decrease in COD in treated wastewater. The dominant parameters for COD removal in the effluent were the temperature, the amount of adsorbent and the pH of the initial solution. The obtained model fit the experimental results with high precision (R2 > 0.93) and low Fisher probability ( temperature > initial pH. Under the optimal conditions predicted by the regression, a maximum COD reduction could be obtained with a temperature of 319 K at pH 12 and an activated carbon concentration of 1.144 g L−1 after 1 h treatment. Meanwhile, the designed adsorbent realized the decrease in colour (80.4%), COD (19%) and turbidity (67.1%) of wastewater. It could be concluded that cypress cone-based activated carbon is promising in the treatment of textile wastewater. The increase in COD removal rate through hybridization of processes is being considered for future research.

Numerical study of semi-elliptical cracks in the critical position of pipe elbow

Abstract: Pipelines are considered as a major tool to transport hydrocarbons due to its important role in transporting fluids taking into account the operating conditions. Despite the importance of the elbow which considered as a critical part in the pipelines, the repeated failures and defects became a dangerous and enormously costly issue. In this numerical study, the Fluid-Structure Interaction (FSI) analysis was carried out using Ansys software. This work is divided into four main parts: the first part focused on studying and comparing the effect of bending radius of pipe elbow on the maximum of Von-Mises stress values for each radius with the yield stress of the steel of the pipe. The second part focused on the creation of a semi-elliptical crack for different locations along the elbow angles to show the critical position compared to the stress intensity factors. In the third part, the semi-elliptical crack angle orientation was studied at the critical position to estimate the critical angle. In the last part, the failure assessment diagram (FAD) was used to show the critical crack depth ratios at a critical position and a critical angle.

Influence of the Clay Content and Type of Algerian Sandstone Rock Samples on Water-Oil Relative Permeabilities

Abstract: The objective of this work is to study the effect of certain factors on oil–water relative permeability curves following a considerable drop in the production of certain oil wells at the Hassi Messaoud field in southern Algeria. In the present study, oil–water relative permeability experiments and irreducible water (Swᵢ) and residual oil (Sₒᵣ) saturations have been investigated. The effect of the clay particle content in the samples (such as illite and kaolinite) on oil recovery is investigated. Indeed, other factors, such as injected pressure, wettability alteration, and petrophysical properties, of the reservoir rock interact with each other and, particularly, in the presence of injected Albian water. Results of the waterflooding experiments show that oil recovery (IOP) increases with increasing clay content, namely, kaolinite and illite type; this IOP is clearly higher for plugs containing more kaolinite than illite. The tested samples have water-wetting behavior, showing a decrease in Sₒᵣ and an increase in Swᵢ, and are characterized by a strong presence of clays, 70% kaolinite and 30% illite, with a breakthrough from about 40 to 50%.

A Data-Driven Evaluation of Hydraulic Fracturing Performance in Hassi Messaoud Field, Algeria

Abstract: Hydraulic fracturing is a well-known production enhancement technique that achieves increased production rates when properly planned, performed and followed up after execution. Throughout the life of Hassi-Messaoud field operating companies have aggressively used this technique. The results of those jobs vary significantly from well to well and from one zone to another. In addition, the reporting of these results is scattered across several databases and servers of both operator and service companies in operational records and reports This work focuses on structuring and mining the data of the almost 500 fractured wells in this field, to get a clear understanding of the major parameters affecting hydraulic fracturing in a field like Hassi Messaoud. Almost 80% of engineers’ time is consumed in gathering the data from the many sources before using the data to produce the answers. To reduce this time spent on gathering the data, the first step was to define the variables to be included in the dataframe. This was then followed by creating a workflow to set a battery of routines in R language to extract the information and generate this dataframe from the different repositories. Once the data was structured, it was clear what questions should be asked of the data (calculated variables), how to ask these questions (correlations, evolutions, distributions), and what to expect from future inputs (unsupervised or supervised machine-learning techniques). From the almost 500 fractured wells in the field, 78% were successful with a range of post-job gains between 100 and 3800 BOPD. The most successful periods were 1993 – 1998 and 2000-2006 in Zones 15, 9, 25, and 8. Among the most representative zones, operational success (highest immediate post-job gains) is 30% and technical success (fracs that have sustained production through time) is 45%. Out of 105 re-frac jobs, 60% were operationally successful with gains between 14 and 1500 BOPD, 30% of them sustained through time. Since 2002, ten multi-stage frac attempts on horizontal wells have not yielded the desired results due to high field geological and reservoir complexities. This study briefly discusses the technologies and screening criteria to deal with such complexities. Another important conclusion is that successful jobs in this field are time independent, i.e. fluid distribution and reservoir characterization are important factors in successful frac operations, but they are not as determinant as job design and execution parameters. A map with the distribution of the best candidates for a frac/re-frac/multi-stage frac is also presented after applying machine learning techniques. Lessons learned from, and best practices for, hydraulic fracturing in a mature tight sandstone reservoir and analysis reproducibility are presented from the both long and data-rich history. Task automation and data management habits across the involved staff are the most immediate and effective tangible benefits with the available resources that can be extended to the petroleum engineering community.

Characterization of natural sand proppant used in hydraulic fracturing fluids

Abstract: Natural sand was the first material introduced as a proppant to hydraulic fracturing operations to keep induced rock fractures both open and conductive. It has remained the most commonly us...

Solar Wastewater Treatment: Advantages and Efficiency for Reuse in Agriculture and Industry

Abstract: Algeria wastewater treatment sector uses weakly sustainable processes as natural lagooning and sand filters. The mainly processes use activated sewage sludge process and aerated lagoons. However these lasts induce high electricity consumption especially due to the daily continuous use of aeration propellers for the biologic treatment. The first part of study evaluated the yearly electricity consumption of an activated sewage sludge process to establish an exhaustive diagnostic of wastewater treatment, energy and environmental nexus. Obtained results showed that the used treatment consumed yearly 1.12 GWh of electricity and emitted 15.91 103 t CO 2 -eq of Greenhouse Gas emission (GHG). The biological treatment was the intensive-energy part of the process with 78% of electricity consumption. To decrease the negative impacts of the mentioned nexus, the second part of the study proposes Solar Wastewater Treatment (SOWAT) as a new sustainable and easy solar wastewater treatment. It uses one step treatment: the evaporation/condensation process performed in solar still. Comparatively to the conventional treatment, the sustainable process recorded similar efficiency treatment for municipal wastewater. Better yet, it allowed the wastewater disinfection that is not planned in the studied treatment plant. SOWAT is also applied successfully to treat real textile wastewater rejected from Algerian Textiles Company. Results recorded a significant removal of pollution. Treatment results both of real municipal and textile wastewater are conform to standards which allowed their reuse respectively in agriculture and industry.

A knowledge-based model for managing the ontology evolution: case study of maintenance in SONATRACH:

Abstract: The challenges of the development of a suitable ontology scheme in decision-making environment should be taken in conjunction with the exploitation of more recent technologies. It is expected that ...

Nanostructured Membranes for Water Purification

Abstract: Membrane based processes enjoy numerous industrial applications and have greatly enhanced our capabilities to restructure production processes, protect the environment and public health, and provide new technologies for water purification. The scope of membrane technology is still extending, stimulated by the developments of novel membrane materials and membranes with better properties, as well as by the decrease of capital and operation costs. Recent advances in nanomaterials empower next-generation multifunctional membrane processes with exceptional catalytic, adsorptive, optical and/or antibacterial abilities that enhance treatment cost-efficiency. This chapter reviews emerging opportunities and sustainable approaches for the design of nanostructured membranes for water purification. Potential development and implementation barriers are discussed along with research needs to overcome them for enhancing water purification.

Risk assessment for a steam generator (1050 G1) Skikda refinery Algeria, using HAZOP and RQA methods

Abstract: Similar to other petrochemical plants, different accidents may occur in the refineries and this is due to the treatment of dangerous products in high temperatures. These accidents may lead in some cases to disasters that cause the die of persons similar to that happened in Skikda in 2004 in a LPG plant which cause the die of twenty seven persons, the origin of this accident is an explosion of a steam generator. To avoid such accident in Skikda Refinery steam generators, a HAZOP risk assessment method was chosen to identify the various possible deviations of the system, their causes and consequences on humans, facilities and the environment. A quantification of major risks at the 1050G1 steam generator was performed with the Phast software to estimate the distance effects and consequences of such accidents and to implement suitable means of prevention and mitigation.

Breaking New Grounds and Records for Unconventional Reservoirs Characterization Using the New Formation Testing and Sampling Technology

Abstract: An exploration deep well crossing two reservoirs with different quality and properties, having an objective of: Fluid identification and sampling in extremely tight section (∼0.02mD/cP mobility) as well as in another section that is suspected to be depleted with very high overbalance exceeding legacy tools, knowing the hydrostatic pressure being ∼9500psia. Wireline formation tester was run using single probe, leading to 65% of tight stations, the rest were valid but with very low mobility. This exposes the tool to an increasing pressure differential exceeding its physical limit and leading to damaging it. This makes any further analysis impossible. The toolstring was upgraded with latest technology of WFT, that is a merge between probe based and dual packer modules. This new technology was designed with extreme environments in mind, that allows sampling in all mobility range from extreme tight to very high with its capability of holding up to 8000psia differential pressure. In the job described here, some of the tested reservoir sections were differentially depleted, something unknown to customer as this was an exploration environment. Since this information were not know even after the completion of the first and second run, a third run was carried out with the objective of re-investigating the same depths performed by the single probe, but this time 3D Radial Probe was used instead. This gave the advantage of taking the pressure down to almost 0 psia. The potential hydrocarbon zone which was bypassed (seen dry with single probe) was then tested with 3D radial probe giving a reservoir pressure of 2864psia with a mobility of ∼300mD/cP where gas condensate was identified and captured. Now for the extreme tight reservoir section, in combination with high hydrostatic, the mechanical limitation of traditional tools remains the same making sampling and/or fluid ID impossible. An attempt was made using the 3D radial probe, and despite the extreme low mobility ∼0.02mD/cP, an identification of the reservoir fluid (water) was successfully completed without any issue. The use of 3D Radial Probe technology gave a completely different picture from what was expected, enabled the completion of all objectives and made the impossible (with conventional technology) possibly and easily achievable. This resulted in changing the well strategies accordingly and complete the well successfully. The new technology made the testing of unconventional reservoirs a reality.

Chemical Prevention of Asphaltene Flocculation in Oil Production System

Abstract: The change of pressure, temperature or chemical composition of crude oil during oil production constitute the factors that may destabilize the heaviest fraction of crude oil presented in asphaltenes leading to many problems in the production system including the alteration of reservoir rock wettability, permeability reduction, plugging of tubing and production aerial facilities which generate a high production cost because of loss in the well productivity and the need of corrective measures. In this work, a crude oil sample was taken from an Algerian oil field to study the efficiency of two commercial inhibitors. The flocculation onset point of asphaltenes was measured by a solid detection system which is based on the light transmittance of flocculated particles when n-heptane is added. The effectiveness of two inhibitors was evaluated by the solid detection system at different concentration to select the best inhibitor, however, the best additive should provide a good performance at low concentration. Meanwhile, the effect of thermodynamic conditions has been also established in this work, however, the operator conditions of pressure and temperature have affected the efficiency of the added inhibitor on the flocculation of asphaltenes.

Multidisciplinary Approach for Unconventional Reservoirs Characterisation by Integrating Wireline Openhole Logging Techniques – Electric and Sonic to Formation Testing

Abstract: This paper has an objective of identifying the nature of formation fluid from an extreme tight fractured reservoir. A good understanding of petrophysical properties of the reservoir rock as well as the fluid it contains constitutes a real challenge for tight reservoirs, that are the most common unconventional sources of hydrocarbons. The front-line characterization mean is the Wireline logging which comes directly after drilling the well or while drilling, knowing that for low to extreme low porosity-permeability reservoirs any attempt of conventional well testing will not bring any added value not rather than a confirmation of reservoir tightness. A tailored workflow was adopted to design the most appropriate formation testing module, select the best depths for fluid sampling, and distinguish hydrocarbon from water bearing intervals. This workflow involves ultra-sonic and Electric Borehole Images in combination with Sonic Scanner for natural fractures detection, localization and characterization, integrating Dielectric recording and processing for petrophysical evaluation, then Formation Testing was carried out for fluid identification and sampling. The use of borehole electric and sonic imager coupled with advanced sonic acquisition helped not only to identify the natural fractures depths, but also the nature of these fractures. This integration was used for selecting the sampling station. Successful fluid sampling was carried out in 4 different depths (2 gas and 2 water), then a dielectric measurement was integrated to map the continuity of the water zone and narrow the uncertainty on fluid contact. This novel multidisciplinary approach that was adopted, integrates answer products from different domains to enable the interpreter, (the reservoir engineer, the geologist, and the Petrophysicist) to better understand and characterize the reservoir, toward a good reserve’s evaluation and appropriate development plan.