Iranian Journal of Oil & Gas Science and Technology
Volume:11 Issue: 1, Winter 2022

Knowing the characteristics of suitable environments for precipitation of oil prone source rocks facilitates oil explorations and leads to development of oil fields. The current study investigates the organic matter properties and sedimentary environment conditions of the Garau Formation in various outcrop sections in Lurestan province from south-west of Iran (High Zagros) with using elemental analysis, visual kerogen analysis and Rock-Eval pyrolysis data. The geochemistry parameters indicate that the Garau Formation is an excellent oil prone source rock and composed of kerogen type I and II. The oxygen index (OI) is very low which reveals that organic matter deposited in an anoxic sedimentary environment and suitable for the preservation of organic matter and hydrocarbon generation. The visual analysis of isolated kerogens from source rock samples indicates the abundance of dark amorphous organic matter (AOM) with small amounts of phytoclasts and pyrite with no palynomorphs. Sedimentation seems to have occurred in deep and reduced parts of a carbonate basin during a rapid transgression. In addition, due to the effect of thermal maturation, the color of amorphous organic matter has darkened. The elemental analysis and Van-Krevelen diagram was shown that the type of organic matter and reveals the thermal maturity of the oil window. Moreover, amount of pyritic sulfur (Sp) and organic sulfur (So) contents have been calculated, and it was reveals that the high content of organic sulfur is a key element in the structure of organic matter.

One of the most important ways to enhance oil recovery in oil reservoirs is chemical flooding. The study of performance and efficiency of these processes in increasing the range of oil recovery from reservoirs depends on several factors, including the rock and fluid properties of the reservoir, and therefore one of the most important steps in evaluating the performance of these methods for a reservoir is the laboratory study and calculating the chemical agent potential to recover oil. For this purpose, a laboratory study and integrated simulation in order to identify the effective mechanisms in the injection of smart water polymer in order to identify the necessary and dominant conditions of this method was performed to improve the recovery of Iranian carbonate reservoirs. Initially, four injection scenarios, water injection-polymer injection-smart water injection, water injection-smart water injection-polymer injection, water injection-smart water polymer injection and smart water injection- smart water polymer injection were tested in a laboratory and then simulation of smart water polymer flooding using Eclipse simulator 100 and the effect of polymer injection on oil recovery and oil trapping in the reservoir rock was performed and finally the results of the simulator and the results of laboratory data were validated. The results showed that smart water injection- smart water polymer injection have better performance in improving secondary oil recovery by 63.45% and wettability changing is one of the main mechanisms to improve oil recovery. The results also showed that in optimal conditions, despite the mechanical degradation of the polymer, initial oil in place recovery is achieved up to 85% by controlled adsorption of polymer on the rock surface.

The petrophysical parameters of the Ghar Formation are characterized in this study. A combination of pre-stack seismic data gathers and well-log data is used to estimate water saturation and shale volume in the Ghar reservoir. For such a purpose, first, the highest possible correlation between the well logs and the seismic inverse data was established. After extracting the best wavelet, an accurate relationship between the estimated and the values from core data was obtained. Secondly, using the data of another well, the validity of the constructed model was examined. The results showed that the combination of three attributes of instantaneous cosine of phase, √(Z_P ), and √(V_P ) is suitable to estimate the shale volume of the reservoir with considerable accuracy with a correlation coefficient of about 70%. Although the two layers in the Ghar section have a shale volume of about 10%, in general, the shale volume in the reservoir area is negligible. The logarithm of the ratio of compressional wave velocity to shear wave velocity attribute shows the highest correlation, about 62%. Finally, validation of the results of the mentioned properties with unintroduced well-log data showed an accuracy of about 90% in prediction.

This work pertains to investigate the values of the stress intensity factor (SIF) in a functionally graded spherical pressure vessel with an embedded surface defect (semi elliptical crack) under thermo-mechanical loading. The three dimensional finite element analysis is performed to evaluate the SIFs through the crack front for a wide range of crack profiles and the various layer thickness. It is assumed that the elastic modulus of sphere varies exponentially in the radial direction of the vessel. The effect of non-uniform coefficient of thermal expansion (CTE) on the fracture parameters is also studied. The obtained results show that the material gradation of spherical pressure vessel can considerably affect the distribution of the SIFs along the crack front. The gradation of material, the wall thickness of spherical pressure vessel and the profile of crack front can affect the critical point through the crack front which is apt to the crack growth.

Among the different operating parameters must be carefully controlled during the drilling operation penetration of drilling mud into permeable zone of formations is one of the most important one can introduce a destructive effect on the productive zone. Respect to this, the current investigation is concentrated to investigate the effects of different nanoparticles (NPs) namely SiO2, CuO, and ZnO considering their size, type, and concentration (0.2 wt. % to 2 wt. % for each of the NP) on drilling fluid properties including rheology and high and low temperature filtration. NPs can improve rheological properties of the mud by changing friction coefficient favorably. Moreover, the effects of temperature and pressure as two important thermodynamic parameters are examined. The results show that it is possible to enhance the rheological properties (viscosity) of the drilling mud to a maximum value of about 20 % by if NPs with concentration of 2 wt % added to the drilling fluid. Excessive gel strength will lead to high pump initiation pressure to break circulation after mud is in a static condition for a period of time, the results reveal that it is possible to reduce the gelation properties of the drilling mud using low concentrations of NPs. Also, the obtained results reveal that among the examined NPs, SiO2 and ZnO exhibit lower filtration rate than CuO. Finally, the effects of temperature and pressure investigated which reveal that regardless of reductive effect of NPs (reducing filtration rate from 17.7 cm3 to about 10 cm3), increasing the pressure and temperature lead to an increase in the filtration rate (reducing filtration rate from 67 cm3 to 35 cm3) while mud rheological properties remain rather constant.

Every day’s large amount of gas is consumed which is transported through pipelines. Due to irreparable consequences of gas related accident and their heavy financial losses; therefore, the safety of pipeline is one of the priorities of gas companies, government and consumers. Hazard is part of every human endeavor, so hazard identification and risk management is very important. As some of event may not be exactly predictable, the study of risk is very important. The risk management is a determinative step of the health, safety and environmental management system (HSEMS). In this study performance of Hazard and operability (HAZOP) method for asses of hazards and risks, for all process, that present in Kermanshah Province Gas Company was evaluated. There are different risk analysis techniques. As the HAZOP is Process Hazard Analysis that not only identifies system hazards, but also determines their probability of occurrence by the effects of any deviations from design conditions and it gives us the accurate results, it’s used for risk assessment in this project. This research was conducted by a team of 3 experts and identified the process hazards by means of quid words. At the end of this study in Kermanshah Province Gas Company’s about 282 risks were identified and only 03 risk is unacceptable e and 111 are Conditional that must be eliminated without delay , the others are acceptable that the risk must be eliminated but it is not an emergency

The Asphaltene and metal naphthenate components of crude oil samples from ten different wells within an oil reservoir were determined using different analytical techniques. The asphaltene content was determined by gravimetric analyses while the metal naphthenate components were determined by obtaining the metal ion concentration of the produced water and the naphthenic acid concentration of the crude using Atomic absorption spectrometer (AAS) and potentiometric titration respectively. Results obtained showed that the asphaltene content of the crude samples ranges from 2.0000 – 8.000 %w while the naphthenic acid concentration indicated by the total acid number (TAN) ranges from 0.3000 – 1.4600 mg/KOH/g. All the crude samples possess asphaltene components as well as the propensity to form calcium and sodium naphthenate scale deposits having a Ca2+ concentration between 32.5000 – 94.5000 mg/L and a Na+ concentration between 27.7 – 105.1 mg/L respectively, however the formation of naphthenate scale deposits is highly dependent on the pH of the produced water of the crude which makes well FT01 less likely to form naphthenate scales since it has a pH < 6. Both asphaltene and naphthenate deposits are directly proportional to the specific gravity of the crude and inversely proportional to the API gravity implying that both components reduce the quality of the crude. Asphaltene and metal naphthenate solid deposits in the crude can cause a lot of flow assurance difficulties such as, blocking of expedition lines, pore plugging, wettability, crude oil parameter alteration, as well as reduction in oil recovery.