Crude Oil Field Research Articles

Asphaltene structure determination: FTIR, NMR, EA, ICP-OES, MS, XRD and computational chemistry considerations

As complex hydrocarbon molecules, petroleum asphaltenes pose significant challenges in the crude oil production, making them the focus of many investigations in the literature. Despite this, fewer studies have examined in-depth the structure of asphaltenes. In fact, when trying to understand and predict the macroscopic properties of asphaltene especially its colloidal behaviors, knowledge of its micro and macro structures as well as its chemical composition is of crucial importance. In the present work, the asphaltene separated from one of the Middle East (Iranian) crude oil field is studied by different spectroscopic and diffraction techniques. Indeed, successful determination of asphaltene structure with monomer molecular formula of C90H50O15 and four repeating units via stepwise procedures for handling X-ray diffraction and NMR laboratory data, along with other techniques including FTIR, EA, ICP-OES, and MS, reflecting crucial complementary information, is presented. To optimize the current asphaltene structure, a computational chemistry method (DFT) is applied, and its results show excellent agreement with experimental data.

Selection of Solvents for the Removal of Asphaltene–Resin–Paraffin Deposits

In this study, we aimed to select the optimal solvents for the removal of asphaltene–resin–paraffin deposits. The effectiveness of various solvents was determined based on the asphaltene–resin–paraffin deposits (ARPDs) of the Zhanaozen (Ozen) crude oil field. These deposits affect the geological, physical, and technological conditions of the oil field, thus influencing its development. According to the results, we found that the most effective composite solvent is a composition comprising a 50% gasoline fraction and a 50% kerosene fraction. This composition showed mass loss of deposits of 97.7% and a dissolving power of 93.5 g/cm3 after 5 h. We confirmed the effectiveness of this composition by the paraffinic type of the deposits, which is explained by the high content of paraffin in the oil from the Zhanaozen field. Aromatic solvents showed a relatively low dissolving power compared with aliphatic solvents, which also confirms the low content of resins and asphaltenes in the ARPD.

Brent Crude Oil Price Forecast Utilizing Deep Neural Network Architectures.

Brent crude oil is considered as one of the most important sources of crude oil pricing in the worldwide market, and it is used to set the price of two-thirds of the traded crude oil supplies in the world. To predict the price of Brent crude oil, LSTM and Bi-LSTM methods are applied, which are the architecture of the recursive neural network. Initially, the database creates the appropriate data for the period January 2015 to March 2021 from Brent crude oil price signals and daily data from a financial market, and then, the modeling process is performed via the use of MATLAB software. Also, about 90% of the data are for training and the remaining for validation and comparison. Using LSTM and Bi-LSTM neural networks, the network architecture has been worked on, and by adding the number of layers and changing the solvers (SGDM, RMSProp, and Adam), the errors of different models are compared with each other. Nonlinear techniques of artificial neural networks and deep learning were used for modeling. Then, the network architecture was worked on and the model error rate was evaluated by comparing different layers and solvents such as SGDM, RMSProp, and Adam. The superiority of SGDM solvent over others was shown, and finally, it can be mentioned as the superior method of modeling of price forecasting in Brent crude oil field. The results show that the model with two layers of LSTM and SGDM solver has less error and better accuracy.

Study the Effect of Corrosion on the Pipes of Oil Well Production

Corrosion costs of the oil industry are billions of dollars in a year. Corrosion affects every aspect ofexploration and production of oil, from offshore rigs to casing and transporting the crude oil torefinery or exporting terminal. This study aims to investigate the effect of sulfur content on thecorrosion of carbon steel and composite material (polyester/fiberglass) pipes used in wellproduction. .In the present work three specimens of pipes from (Al – Nasiriyah oil field, Al – Daura refinery, andcomposite material) are prepared in the center of the training and workshop in university oftechnology with (3, and 5 mm) thickness and (30 mm) diameter which immersed in different typesof Iraqi crude oil field (East – Baghdad, Al – Nasiriyah, and Al – Rumaila field) in different times (0,14, 28, 42, and 56 day). Physical properties (viscosity, density, API grade, specific gravity (sp.gr),sulfur %, sediment %, and water %) of three types of Iraqi crude oil are tested in lab of petroleumtechnology department. Also study specimens of pipes by microscope to knowing the effect ofsulfur % on these specimens. .The results showed that when increasing duration of immersed pipes and sulfur content in crude oilincreased the rate of corrosion, and the composite material pipe gives the best result compared withthe other two specimens pipes used because they didn’t influenced by corrosion when immersed inIraqi crude oil. Also, it was noted that the diffusion coefficient decreased in composite pipecompared with the other pipes.

Assessment of Possibilities to Use Captured Co2 in the Western Black Sea Area

In order to define the offshore solution, the first step was to identify the ports along the Danube which have the necessary infrastructure to facilitate the transport of CO2 by ship to the Black Sea. 17 ports have been identified, from which 11 are only fluvial, 3 are fluvial-maritime, and 3 maritime. The offshore solution considers transporting captured CO2 from the Oltenia region for utilization in the Black Sea. At the current knowledge level, the most favorable region for CO2 geological storage is Histria Depression. This depression comprises five hydrocarbon fields (discovered so far) located on an NW-SE alignment on its northern flank. These fields are: •Lebada Est, discovered in 1980, with oil in Albian and Upper Cretaceous rocks and gases in Eocene deposits; •Lebada Vest, discovered in 1984, with oil in Albian, Upper Cretaceous, and Eocene reservoirs; •Sinoe, discovered in 1988, with oil in Albian reservoirs; •Delta, discovered in 2007, with oil in Albian reservoirs; •Pescarus, discovered in 1999, with oil in Upper Cretaceous (Cenomanian) reservoir. From these fields, only Lebada East and Lebada West can be used for CO2-EOR operations and CO2 storage purposes. These fields already have injection wells that are used for enhanced recovery operations (not involving CO2). The East Lebada deposit was discovered in 1980, following the development and exploitation of the associated oil and gas deposit between July 1984 and January 1991, on three production platforms. Initially, the deposit has produced in May 1987, in its eastern part, in natural mode. Secondary exploitation by water injection began after about 2 months. There are defined 3 deposits, superimposed vertically, cantoned in Albian reservoirs, Upper Cretaceous and Eocene. In the oil field, of the Albian age, East Lebada, two porous-permeable zones were divided, separated by two compact zones. The productive area comprises only the upper porous-permeable range. West Lebada deposit was discovered in 1984 with the 82 Lebada West Probe that produced oil and associated gases from two Albian collectors. The drilling program comprised 9 production wells and 2 injection wells, production starting in April 1993. During the operation, it was found that apart from the two A3 and A4 collectors belonging to Albian, there is another dated collector on top of them. Vraconian, a distinct hydrodynamic unit, characterized as a narrow-band gas field of crude oil. Within the Albian formation, four porous-permeable intervals were separated, characterized by different porosity values. The A3 and A4 layers, the productive ones, are located in the upper part of the Albian and have medium to good porosity and permeability values. The ranges noted A1 and A2 are located in the lower part of the Albian and have very small porosities and permeabilities. The mechanism of the trap is complex with both structural and stratigraphic components. A combination of factors acts in the formation of the A4 layer trap, namely: an erosional truncation to the west, tapering to the north, structural to the east, and facies compaction to the south. On the structure of the Lebada Vest deposit was identified a crude oil field with a primary gas head, enclosed in Eocene detritus rocks. The Eocene reservoir contains two porous-permeable layers E3, E4, with average porosity and good respectively. The closure of the E4 layer trap is made by erosion and erosion truncation in the east and by compaction in the west. The closure of the E3 trap is achieved by erosion and erosion truncation in the East and North and by structural closure and facies change in the West and South. The screen of the two layers E4 and E3 is represented by the Oligocene clays. Within the Black Sea, the major structural unit that accommodates oil reservoirs and potential storage structures and the only structure investigated so far from the CO2 storage perspective are Histria Depression. The oil reservoirs that can be used for injection and utilization of captured CO2 for EOR are Lebada Vest and Lebada Est, Sinoe, Portia, Pescarus, and Delta.

Synergistic Effects between Anionic and Sulfobetaine Surfactants for Stabilization of Foams Tolerant to Crude Oil in Foam Flooding

AbstractIn foam flooding, foams stabilized by conventional surfactants are usually unstable in contacting with crude oil, which behaves as a strong defoaming agent. In this article, synergistic effects between different surfactants were utilized to improve foam stability against crude oil. Targeted to reservoir conditions of Daqing crude oil field, China (45 °C, salinity of 6778 mg L−1, pH = 8–9), foams stabilized by typical anionic surfactants fatty alcohol polyoxyethylene ether sulfate (AES) and sodium dodecyl sulfate (SDS) show low composite foam index (200–500 L s) and low oil tolerance index (0.1–0.2). However, the foam stability can be significantly improved by mixing the anionic surfactant with a sulfobetaine surfactant, which behaves as a foam stabilizer increasing the half‐life of foams, and those with longer alkyl chain behave better. As an example, by mixing AES and SDS with hexadecyl dimethyl hydroxypropyl sulfobetaine (C16HSB) at a molar fraction of 0.2 (referring to total surfactant, not including water), the maximum composite foaming index and oil tolerance index can be increased to 3000/5000 L s and 1.0/4.0, respectively, at a total concentration between 3 and 5 mM. The attractive interaction between the different surfactants in a mixed monolayer as reflected by the negative βs parameter is responsible for the enhancement of the foam stabilization, which resulted in lower interfacial tensions and therefore negative enter (E), spreading (S), and bridging (B) coefficients of the oil. The oil is then emulsified as tiny droplets dispersed in lamellae, giving very stable pseudoemulsion films inhibiting rupture of the bubble films. This made it possible to utilize typical conventional anionic surfactants as foaming agents in foam flooding.

Cold damage from wax deposition in a shallow, low-temperature, and high-wax reservoir in Changchunling Oilfield

Wax deposition is an important factor that influences oil production for high-wax crude oilfield. There are few studies on the formation damage by wax deposition, especially cold damage to the shallow low-temperature reservoir. With laboratory tests conducted on reservoir oil and cores of Changchunling Oilfield, this study aims to experimentally investigate the influence of temperature variations on characteristics of oil–water percolation and cold damage mechanisms, as well as the relative permeability of high-wax reservoirs. Experimental results show that seepage flow of high-wax crude is significantly sensitive to temperature-wax deposition evidently increases, whereas the cold damage such as the pore-throat radius and relative permeability sharply decrease with the decline in formation temperature. The research results can be applied to enhance oil recovery of high-viscosity or high-wax oilfields.

A methodology for synthesis of reduced graphene oxide membranes for desalination of produced water

We present a simple methodology for desalination of produced water generated on crude oil fields, using reduced graphene oxide based membranes. This work was developed in three steps: 1) Synthesis of graphene oxide through Modified Hummers method, 2) A novel method for membrane fabrication through a layer-by-layer thermal-chemical reduction of graphene oxide on a hydrophilic paper and 3) Vacuum filtration of produced water of a Colombian crude oil field. The rGO was characterized by Fourier transform infrared spectroscopy – attenued total reflection, scanning electron microscopy and X-ray diffraction. The efficiencies of adsorption of Na+ and Mg2+cations on produced water were evaluated by determining the percentages of removal for each cation through Atomic Absorption Spectroscopy. Conductivity test was made on produced water in crude oil field to determine the useful life of membranes synthetized. These results confirm that rGO membranes are very efficient for water purification.

Comparison of the inhibitory capacity of vegetable oils, and their nonionic surfactants on Iran crude oil asphaltene precipitation using Quartz crystal microbalance

ABSTRACTAsphaltene deposition is one of the main problems in some oil field production. Using the cheap chemical compounds to control asphaltene precipitation is one of the important tools in crude oil field development. Vegetable oil are natural chemical compounds which can be used as asphaltene stabilizer. In this work, the inhibitory capacity of the vegetable oils, their binary mixtures, and their binary mixtures with nonionic surfactants were studied by Quartz Crystal Microbalances. The results show that the turnip oil, binary mixtures of rosemary oil/sesame oil, sweet almond oil/camomile oil, and olive oil/tritoonX-100 are more efficient than other additives and the percentages of the inhibitory capacity are 87%, 89%, 90, and 90% respectively.

Strontium isotopes as an indicator for groundwater salinity sources in the Kirkuk region, Iraq

The Kirkuk region in northern Iraq hosts some of the largest oil fields in the Middle East. Several anticline structures enabled vertical migration and entrapment of the oil. Frequently, complex fracture systems and faults cut across the Eocene and middle Oligocene reservoirs and the cap rock, the Fatha Formation of Miocene age. Seepage of crude oil and oil field brines are therefore a common observation in the anticline axes and contamination of shallow groundwater resources is a major concern. In this study, 65 water samples were collected in the Kirkuk region to analyze and distinguish mixing processes between shallow groundwater resources, uprising oil field brines, and dissolution of gypsum and halite from the Fatha Formation. Hydrochemical analyses of the water samples included general hydrochemistry, stable water isotopes, as well as strontium concentrations and for 22 of the samples strontium isotopes (87Sr/86Sr). Strontium concentrations increased close to the anticline axes with highest concentrations in the oil field brines (300mg/l). Strontium isotopes proved to be a valuable tool to distinguish mixing processes as isotope signatures of the oil field brines and of waters from the Fatha Formation are significantly different. It could be shown, that mixing of shallow groundwater with oil field brines is occurring close to the major fault zones in the anticlines but high concentrations of strontium in the water samples are mainly due to dissolution from the Fatha Formation.

Microbial diversity and hydrocarbon degrading gene capacity of a crude oil field soil as determined by metagenomics analysis.

Soils contaminated with crude oil are rich sources of enzymes suitable for both degradation of hydrocarbons through bioremediation processes and improvement of crude oil during its refining steps. Due to the long term selection, crude oil fields are unique environments for the identification of microorganisms with the ability to produce these enzymes. In this metagenomic study, based on Hiseq Illumina sequencing of samples obtained from a crude oil field and analysis of data on MG-RAST, Actinomycetales (9.8%) were found to be the dominant microorganisms, followed by Rhizobiales (3.3%). Furthermore, several functional genes were found in this study, mostly belong to Actinobacteria (12.35%), which have a role in the metabolism of aliphatic and aromatic hydrocarbons (2.51%), desulfurization (0.03%), element shortage (5.6%), and resistance to heavy metals (1.1%). This information will be useful for assisting in the application of microorganisms in the removal of hydrocarbon contamination and/or for improving the quality of crude oil. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:638-648, 2016.

Microbial enhanced heavy crude oil recovery through biodegradation using bacterial isolates from an Omani oil field.

BackgroundBiodegradation is a cheap and environmentally friendly process that could breakdown and utilizes heavy crude oil (HCO) resources. Numerous bacteria are able to grow using hydrocarbons as a carbon source; however, bacteria that are able to grow using HCO hydrocarbons are limited. In this study, HCO degrading bacteria were isolated from an Omani heavy crude oil field. They were then identified and assessed for their biodegradation and biotransformation abilities under aerobic and anaerobic conditions.ResultsBacteria were grown in five different minimum salts media. The isolates were identified by MALDI biotyper and 16S rRNA sequencing. The nucleotide sequences were submitted to GenBank (NCBI) database. The bacteria were identified as Bacillus subtilis and B. licheniformis. To assess microbial growth and biodegradation of HCO by well-assay on agar plates, samples were collected at different intervals. The HCO biodegradation and biotransformation were determined using GC-FID, which showed direct correlation of microbial growth with an increased biotransformation of light hydrocarbons (C12 and C14). Among the isolates, B. licheniformis AS5 was the most efficient isolate in biodegradation and biotransformation of the HCO. Therefore, isolate AS5 was used for heavy crude oil recovery experiments, in core flooding experiments using Berea core plugs, where an additional 16 % of oil initially in place was recovered.ConclusionsThis is the first report from Oman for bacteria isolated from an oil field that were able to degrade and transform HCO to lighter components, illustrating the potential use in HCO recovery. The data suggested that biodegradation and biotransformation processes may lead to additional oil recovery from heavy oil fields, if bacteria are grown in suitable medium under optimum growth conditions.

Effects of Operating Pressure on Energy-saving of Water Recycling Utilization with MVR system in Oil Extraction Fields

One of the most effective methods for the extraction of crude oil with high viscosity is injecting high temperature water vapor to the oil well. To save water consumption and achieve zero discharge, it is needed to separate and purify the water, which is mixed with oil, mud and other impurities. In this paper, the mechanical vapor recompression (MVR) system is analyzed and the parameters for analysis are based on a demonstration project on water recycling utilization in the Karamay crude oil field in northwest China. Two kinds of technological processes, high pressure and low pressure processes are proposed by the authors. The recovery work is utilized to decrease power consumption of the compression work and the energy from the high temperature purified water is used to drive an absorption refrigerator. The results show that 680 kJ/kg of energy can be saved in the high pressure process compared to a low-pressure process. For low pressure process, the saving energy is only 420kJ/kg, the material is easily corrosive, and additional 9.8t/h cooling water is needed. Compared the MVR system with TVR one, when the same pressure ratio and mass quantity of condensing water are obtained, the MVR system need use about 80 kW electrical power from compressor and the TVR system need use 3129.5 kW thermal energy from steam.

Wax Deposition in Pores and the Permeability Change for High-wax Crude in a Sandstone Reservoir

Wax deposition in pay zone is an important factor that influences well productivity for high-wax crude oilfield. Taking Hongze oilfield as an example, rheological property of the crude and effective flow permeability at different temperature was measured. Flow pattern and process of wax deposition in porous medium was studied. Experiment results show that seepage flow of high-wax crude is significantly sensitive to temperature. It is non-Darcy flow and there exist threshold pressure gradient when temperature is lower than wax appearance temperature. According to experimental data, seepage flow and deposition patterns were proposed.

THE SULFIDE STRESS CORROSION CRACKING CHARACTERISTICS OF THE PIPE WELD IN THE PETROCHEMICAL PLANT

Sulfide stress corrosion cracking (SSCC) in crude oil field environment including hydrogen sulfide ( H 2 S ) has been recognized as a materials failure mechanism. Welding residual stress generation and metallurgical change by fusion welding process increase the cracking driving force and reduce the resistance of brittle fracture as well as environmental fracture. On the base of this understanding, firstly, we analyzed welding residual stresses of welded ASTM A 106 Gr B steel pipe using in the petrochemical plant. And next, SSCC tests were conducted to assess SSCC resistance of the weld with smooth specimens. From the result, influence of temperature on corrosion rate was sensitive in order of HAZ, base metal and weld metal. Therefore, the most sensitive region in the weld is HAZ, and its corrosion rate increases with the temperature of corrosion environment increase. And failure positions of the most cases among failed specimens were at HAZ of the weld. Low limit (σ SSCC ) of A 106 Gr B steel pipe was assessed as 0.6 σ y (7271.6N)

Assessment of the sulfide stress corrosion cracking characteristics in the multi-pass weld of the A106 Gr B steel pipe

Sulfide stress corrosion cracking (SSCC) in crude oil field environment containing hydrogen sulfide (H2S) has been recognized as a material degradation and damage mechanism. Laboratory data and field experience have demonstrated that extremely low concentration of H2S may be sufficient to lead to SSCC failure of susceptible materials. In some cases, sulfides may act synergistically with chlorides to produce SSCC failures. SSCC mechanism is a form of hydrogen embrittlement that occurs in high strength steels and in localized hard zones in weld of susceptible materials. In the heat-affected zones adjacent to the weld, there are often very narrow hard zones combined with regions of high residual stress that may become embrittled to such an extent by dissolved atomic hydrogen. On the basis of this understanding, SSCC tests were conducted with smooth specimens of the multi-pass welded ASTM A106 Gr B steel pipe used in the oil industries. And SSCC resistance according to the welding processes was evaluated. From the results, the weld by GTAW+FCAW showed the largest resistance against SSCC.

Corrosion behavior of low-alloy steel in the presence of Desulfotomaculum sp.

The objective of this study was to determine the effect of sulfate-reducing Desulfotomaculum sp. bacteria isolated from a crude oil field on the corrosion of low-alloy steel. The corrosion rate and mechanism were determined with the use of Tafel slopes, mass loss method and electrochemical impedance spectroscopy (EIS). The formation of the biofilm and the corrosion products on the steel surface was determined with scanning electron microscopy (SEM) micrographs and energy dispersive X-ray spectra (EDS) analysis. It was observed from the Tafel plots that the corrosion potential exhibited a cathodic shift that verifies an increase in the corrosion rates. The semicircles tended to open at lower frequencies in the Nyquist plots which indicates the rupture of the protective film. The corrosion current density reached its maximum value at the 14th hour after the inoculation and decreased afterwards. This was attributed to the accumulation of corrosion products on the surface.

Bacterial communities in a crude oil gathering and transferring system (China)

Bacterial communities in crude oil and oil field production water samples from an oil gathering and transferring system in Changqing Oil field in China were investigated by 16S rRNA denaturing gradient gel electrophoresis (DGGE) analysis followed by gene cloning and sequencing. DGGE profiles showed that bacterial communities are far more rich in the water samples than that in the crude oil samples, and that bacteria related to Ochrobactrum sp. and Stenotrophomonas sp. were detected in all crude oil and oil field water samples. Bacteria related to Burkholderia sp., Brevundimonas sp., and Propionibacterium sp. were detected in the crude oil samples but not in water samples. Bacteria related to Hippea sp., Acidovorax sp., Arcobacter sp., Pseudomonas sp., Thiomicrospira sp., Brevibacterium sp., Tissierella sp. and Peptostreptococcus sp. were detected in the water samples but not in crude oil samples. Using an archaea-specific primer set, methanogens related to Methanomicrobials and Methanosarcinales were found in water samples but not in crude oil samples. The comparability of the microbial communities in the water and crude oil phase during the period of oil gathering and transferring process was 83.3% and 88.2%, respectively, indicating a stable structure of the microbial communities.

Non-isothermal kinetic analysis and feasibilty study of medium grade crude oil field

In this research, non-isothermal kinetics and feasibility study of medium grade crude oil is studied in the presence of a limestone matrix. Experiments were performed at a heating rate of 10°C min−1, whereas the air flow rate was kept constant at 50 mL min−1 in the temperature range of 20 to 600°C (DSC) and 20 to 900°C (TG). In combustion with air, three distinct reaction regions were identified in all crude oil/limestone mixtures, known as low temperature oxidation (LTO), fuel deposition (FD) and high temperature oxidation (HTO). The activation energy values were in the order of 5–9 kJ mol−1 in LTO region and 189–229 kJ mol−1 in HTO region. It was concluded that the medium grade crude oil field was not feasible for a self-sustained combustion process.

Determination of biocorrosion of low alloy steel by sulfate‐reducing Desulfotomaculum sp. isolated from crude oil field

AbstractIn this study corrosion behavior of low alloy steel, in the presence of anaerobic sulfate‐reducing Desulfotomaculum sp. which was isolated from an oil production well, was investigated. In order to determine corrosion rates and mechanisms, mass loss measurements and electrochemical polarization studies were performed without and with bacteria in the culture medium. Scanning electron microscopic observations and energy dispersive X‐ray spectra (EDS) analysis were made on steel coupons.The effect of iron concentration on corrosion behavior was determined by Tafel extrapolation method. In a sterile culture medium, as the FeSO4 · 7H2O concentration increased, corrosion potential (Ecor) values shifted towards more anodic potentials and corrosion current density (Icor) values increased considerably. After inoculation of sulfate‐reducing bacteria (SRB), Ecor shifted towards cathodic values. Icor values increased with increasing incubation time for 10 and 100 mg/L concentrations of FeSO4 · 7H2O.Results have shown that the corrosion activity changed due to several factors such as bacterial metabolites, ferrous sulfide, hydrogen sulfide, iron phosphide, and cathodic depolarization effect.