High Oil Production Research Articles

Quantitative study of CO2 huff-n-puff enhanced oil recovery in tight formation using online NMR technology

Recent evidence suggests that CO2 huff-n-puff can significantly enhance the oil recovery in tight/shale oil reservoirs after primary depletion. However, the key driving forces of CO2 huff-n-puff for oil displacement, especially their effect on the enhanced oil recovery are still unclear. In addition, the CO2 effective distance in matrix, which is a critical parameter impacting the performance of huff-n-puff, has not been accurately studied. In this work, to identify and quantify the contribution of the related enhanced-oil-recovery (EOR) mechanisms, an online nuclear magnetic resonance (NMR) instrument was used to monitor the real-time migration of the matrix oil at all stages of the CO2 huff-n-puff process. The experiment results show that the dissolved CO2 drive controlled by molecular diffusion is the dominant mechanism during the huff-n-puff process. This EOR mechanism mainly works on the oil stored in the macropores, while the oil stored in the micropores is hardly mobilized. Base on the dynamic oil saturation distributions converted from the 1-D NMR profiles during huff-n-puff, we designed a novel 2-D evaluation system, which focuses on microscopic displacement efficiency and CO2 effective distance, to investigate the effect of the operation parameters on oil production. We found that simply increasing the injection pressure mainly improves the displacement efficiency but has less effect on the expansion of the sweep area, which limits the CO2 huff-n-puff EOR on the reservoir scale. Lengthening the soaking period extends the effective distance significantly but delays oil production. A cyclic huff-n-puff scheme with variable soaking time was proposed to maintain a high oil production rate and a large sweep area. Periodic optimization of the soaking time in the cyclic CO2 huff-n-puff process is needed for an optimal development plan.

Detecting olive grove abandonment with Sentinel-2 and machine learning: The development of a web-based tool for land management

The abandonment of rural areas is an important environmental and socio-economic issue in Europe, threatening the stability and profitability of agricultural production. The identification and quantification of abandoned land is key for temporal and spatial monitoring of the process and for applying alternative management measures. Italy is one of the most important European countries for the production of high quality olive oil, accounting for a large slice of the current certificated production (i.e., PDO, PGI). In this study, we present a machine learning model (i.e., Random Forest) for the identification of abandoned olive tree groves using field observations and NDVI time series, tested in a typical agroecosystem in central Italy dominated by olive groves. An application for smartphones able to record the geographic position was developed and used to collect field points, which in turn were utilised to train the model. The data of NDVI from January to December 2020, calculated on Sentinel-2 images, were extracted for each monitoring point and gap-filled to obtain a 10-days interval time series. The Random Forest model used the annual NDVI time series as features and classified the sampling points in the test dataset with an accuracy of 0.85. The model showed a higher capacity of classifying cultivated than abandoned points, sensitivity being equal to 0.88 and specificity equal to 0.82. Results demonstrated the applicability of the combined approach for discriminating cultivated from abandoned olive tree groves, in case that the parcels destined for olive tree cultivation are known. A web-based tool was implemented to support land monitoring and management.

Production Analysis of Horizontal Wells in a Two-Region Composite Reservoir Considering Formation Damage

The horizontal well is extensively used to exploit oil at the Bohai offshore oilfield, China. It has been proved by practice that formation damage always happens during the production of wells. However, it is a challenging task to evaluate the formation damage for horizontal wells. In this paper, a flow model considering formation damage is established for horizontal wells. The reservoir geometry is divided into two regions: the inner region represents the region of formation damage and the outer region that without damage. The finite element method is used to solve the flow model. The well production rate can be determined by using the material balance method. For different scenarios, such as when the horizontal well is completely in the inner region or when the horizontal well passes through two regions, the effects of some key parameters such as damage radius, damage region permeability, and well position on the oil production rate and pressure distribution characteristics are analyzed. The results show that a smaller damage radius, higher damage zone permeability, and a horizontal well closer to or in greater contact with the outer region result in a higher oil production rate and faster pressure drop propagation. The presented model and obtained results enrich production analysis of horizontal wells in a two-region composite reservoir considering formation damage, which has significance for efficient offshore reservoir development.

Engineering the Lipid and Fatty Acid Metabolism in Yarrowia lipolytica for Sustainable Production of High Oleic Oils

Oleic acid is widely applied in the chemical, material, nutritional, and pharmaceutical industries. However, the current production of oleic acid via high oleic plant oils is limited by the long growth cycle and climatic constraints. Moreover, the global demand for high oleic plant oils, especially the palm oil, has emerged as the driver of tropical deforestation causing tropical rainforest destruction, climate change, and biodiversity loss. In the present study, an alternative and sustainable strategy for high oleic oil production was established by reprogramming the metabolism of the oleaginous yeast Yarrowia lipolytica using a two-layer "push-pull-block" strategy. Specifically, the fatty acid synthesis pathway was first engineered to increase oleic acid proportion by altering the fatty acid profiles. Then, the content of storage oils containing oleic acid was boosted by engineering the synthesis and degradation pathways of triacylglycerides. The strain resulting from this two-layer engineering strategy produced the highest titer of high oleic microbial oil reaching 56 g/L with 84% oleic acid in fed-batch fermentation, representing a remarkable improvement of a 110-fold oil titer and 2.24-fold oleic acid proportion compared with the starting strain. This alternative and sustainable method for high oleic oil production shows the potential of substitute planting.

Macular pigment-enriched oil production from genome-edited microalgae

BackgroundThe photosynthetic microorganism Chlamydomonas reinhardtii has been approved as generally recognized as safe (GRAS) recently, this can excessively produce carotenoid pigments and fatty acids. Zeaxanthin epoxidase (ZEP), which converts zeaxanthin to violaxanthin, and ADP-glucose pyrophosphorylase (AGP). These are key regulating genes for the xanthophyll and starch pathways in C. reinhardtii respectively. In this study, to produce macular pigment-enriched microalgal oil, we attempted to edit the AGP gene as an additional knock-out target in the zep mutant as a parental strain.ResultsUsing a sequential CRISPR-Cas9 RNP-mediated knock-out method, we generated double knock-out mutants (dZAs), in which both the ZEP and AGP genes were deleted. In dZA1, lutein (2.93 ± 0.22 mg g−1 DCW: dried cell weight), zeaxanthin (3.12 ± 0.30 mg g−1 DCW), and lipids (450.09 ± 25.48 mg g−1 DCW) were highly accumulated in N-deprivation condition. Optimization of the culture medium and process made it possible to produce pigments and oil via one-step cultivation. This optimization process enabled dZAs to achieve 81% higher oil productivity along with similar macular pigment productivity, than the conventional two-step process. The hexane/isopropanol extraction method was developed for the use of macular pigment-enriched microalgal oil for food. As a result, 196 ± 20.1 mg g−1 DCW of edible microalgal oil containing 8.42 ± 0.92 mg g−1 lutein of oil and 7.69 ± 1.03 mg g−1 zeaxanthin of oil was produced.ConclusionOur research showed that lipids and pigments are simultaneously induced in the dZA strain. Since dZAs are generated by introducing pre-assembled sgRNA and Cas9-protein into cells, antibiotic resistance genes or selective markers are not inserted into the genome of dZA, which is advantageous for applying dZA mutant to food. Therefore, the enriched macular pigment oil extracted from improved strains (dZAs) can be further applied to various food products and nutraceuticals.

Exploration breakthrough and its significance of Gulong lacustrine shale oil in the Songliao Basin, Northeastern China

Lacustrine shale oil resources are abundant in many petroliferous basins in China. The shale oil formations are characterized by low API gravity, high viscosity, poor mobility, high clay content, low brittleness and etc. Exploration of lacustrine shale oil started relatively late in China, but its progress is very rapid and breakthroughs have been made successively. In this short communication, we introduced the most significant shale oil discovery which is made recently in the Qingshankou Formation of the Gulong sag in the Songliao Basin. Key exploratory wells including Guye 1H (GY1H), Yingye 1H (YY1H) and Guye 2HC (GY2HC) tested stable and high oil flow in shale reservoirs, revealing the relatively stable and high oil production capacity of shale in the Gulong sag of Daqing Oilfield. It marks a leap of petroleum theoretical recognition from lacustrine shale generating oil to producing oil and from the theory of traditional oil migration and accumulation to the theory of indigenous oil accumulation in organic-rich shale. Although lacustrine shale oil exploration and development still faces many challenges in China, its prospect is quite promising.

ISOLATION WORKS AGAINST IRRIGATION WITH GEL COMPOSITION IN OIL RESERVES AT THE FINAL STAGE OF PROCESSING

At a time of high demand for energy carriers, it is important for the dynamic and long-term development of the oil industry of the country to increase the oil yield of long-term wells using various new methods of impact, along with the discovery, development and development of new and promising facilities. For the intensive development of the economy of the Republic of Azerbaijan, it is important to increase gas and oil production from oil fields in the Caspian Sea basin and onshore. In this regard, it is important to increase the efficiency of oil production in offshore and onshore fields, to improve the development system, work with the well fund, as well as the application of artificial impact methods. Due to the complications that occurred during the development of oil fields in the country, some of the wells are either temporarily or completely removed from the exploitation fund. One of these complications is the watering of the well product. Experience in the development of oil fields with different geological and physical properties shows that premature irrigation of existing wells, geological structure of fields, ratio of oil and water viscosity in the extracted fluid, heterogeneity of layers, oil composition, volume of injection and discharge affect. At present, there is a decrease in the amount of oil in the production of offshore and onshore oil fields, and an increase in water. Although many irrigated wells are insulated and repaired to prevent irrigation, the economic and technological efficiency of these wells is insufficient. Therefore, the creation of new and effective technologies to prevent the flow of water into wells remains relevant. Premature watering of oil wells results in reductions in oil production, reduced interval between repairs in wells, and corrosion of underground and surface equipment of wells. Many researchers have noted that it is not advisable to use long-term, large-scale and economically inefficient methods to increase oil production, so the development of more layers with local impact technologies is considered promising. These methods have significant results in the isolation of irrigated areas with higher permeability. This problem can be solved in two ways: 1) Isolation of water channels with injection wells 2) Isolation of water flow to production wells Numerous studies have shown that isolating water flow in wells gives better results. The contradiction in pumping oil with injection wells is that, on the one hand, oil production must be maintained high, and on the other hand, a well with high oil production must be irrigated prematurely and subsequently reduce the phase permeability of oil. Most of the oil fields in the Republic of Azerbaijan are in the final stages of development. As a result, it is important to increase the efficiency of the development of complex oil fields by reducing the volume of associated water and increasing oil production from partially irrigated formations. The effectiveness of isolating water-washed areas with different compositions is ambiguous. Using a 10% solution of liquid glass and hydrochloric acid as the base material, it is possible to prepare an elastic buffer material to strengthen the wellbore area. It is also possible to create a gel with adjustable setting time by adding a certain amount of a third component to the initial base mixture. Preliminary studies with the added third reagents have shown that an elastic binding composite can be formed by adding urea, laprol and chromium salts to the liquid glass and hydrochloric acid solution. In subsequent studies, 0.1 to 10% Na2SiO3 and 10% HCl solution; Viscosity was measured by adding CO(NH2)2, CrCl3, KMS and Laprol at 0.5 and 1% by mass. Keywords: related water, watering rate, gel, liquid glass, urea, laprol, chromium salts, hydrochloric acid

Three-Dimensional Physical Simulation of Heavy Oil Exploitation by Hot Solvent Injection

To improve the thermal effects of solvents on heavy oil reservoirs and realize the combined action of multiple flooding mechanisms, such as solvent heating and extraction, without steam mixing, based on the M Block heavy oil reservoir in Canada, three sets of comparative hot solvent-assisted gravity drainage experiments under different temperatures and pressures were carried out through an indoor three-dimensional (3D) physical simulation device. The development characteristics of the solvent chamber in the hot solvent-assisted gravity drainage technology were studied under different pressures and temperatures, and the recovery factor, cumulative oil exchange rate, and solvent retention rate were analyzed. The results showed that due to the effect of gravity differentiation, the development morphology of the solvent chamber could be divided into three stages: rapid ascent, lateral expansion, and slow descent. When the temperature was constant, the reservoir pressure decreased, the recovery rate increased, the cumulative oil exchange rate increased, and the solvent retention rate decreased; when the pressure was constant, the temperature increased, the viscosity of heavy oil decreased, the recovery rate increased, the cumulative oil exchange rate increased, and the solvent retention rate was low. Additionally, the study also showed that for hot solvents in different phases, the use of hot solvent vapor not only required less injected solvent but also exhibited a high oil production rate, which shortened production time and reduced energy consumption. Moreover, the oil recovery rate was higher than 60%, the solvent retention rate was lower than 10%, and the cumulative oil exchange rate was higher than 3 t / t , which constituted better economic benefits and provided a reliable theoretical basis for onsite oilfield applications.

Comprehensive logging identification method of shell limestone fractures in the Lower Jurassic Da'anzhai Member in the Dongpo area of the Western Sichuan Depression

Shell limestone tight reservoirs are developed in the Lower Jurassic Da'anzhai Member of the Sichuan Basin. Fractures are important storage spaces and seepage channels in shell limestone tight oil reservoirs and are key factors for high oil and gas production in wells. In this study, considering the shell limestone reservoir of the Da'anzhai Member on the eastern slope of the Western Sichuan Depression as an example, we used multiple fracture interpretation models based on conventional logging to identify fractures. Our results show that: (1) the reservoirs in the Da'anzhai Member primarily showed low-angle structural fractures, mostly filled with calcite. The effective linear density of fractures in each well varied greatly, which primarily explains the strong heterogeneity of tight reservoirs. (2) The logging response characteristics of the fractured and non-fractured segments differ considerably, and the fractured segment shows the characteristics of high acoustic time difference and low resistivity. (3) The well log recombination method, principal component analysis method, multivariate discriminant method, backpropagation (BP) neural network method, and K-nearest neighbor (KNN) algorithm are used for fracture identification. According to the consistency of the fracture identification results with the core observation results, we established a comprehensive fracture identification standard using the multi-logging method. In this study, we established a fracture identification method based on the coupling of multiple linear and nonlinear multi-logging models through core calibration, which avoids the errors and uncertainties caused by using a single method. Additionally, this study provides a foundation for the control factors and the prediction of fracture distribution.

Comparisons of predictive ability of THAI in situ combustion process models with pre-defined fuel against that having fuel deposited based on Arrhenius kinetics parameters

Toe-to-heel air injection (THAI) is an in situ thermal-enhanced oil upgrading and recovery technology that makes use of a horizontal producer well for mobilised partially upgraded oil production to the surface. To design operation of the THAI process requires up-scaling lab-scale numerical model to field-scale reservoir numerical model. There are a number of up-scaling methods that were developed. However, these previous up-scaling methods only concentrated on the qualitative nature of the physicochemical processes. Furthermore, these methods have deficiencies ranging from assumption of 100% oxygen utilisation, failing to compare oil production rates for up-scaled reservoir models with and without fuel pre-defined, not reporting on the dynamics inside the reservoirs with and without fuel pre-defined, etc. As a result, this work provided in depth comparative studies of both the qualitative and quantitative physicochemical processes in numerical models containing Arrhenius-based coke deposition thermal cracking reaction (i.e. model A) and that having pre-defined fuel concentration (i.e. model F) as an initial parameter respectively. It is found that oil production started earlier in model A compared to in model F even though they have approximately similar trajectories. It is shown that by the end of the combustion period, oil recovery of 28.5% OOIP is achieved in model F which is greater than that in model A by an additional of 4.8% OOIP. It is found that the peak temperature, which indicates how healthy the combustion is at a single point only at different times, is generally considerably higher in model A than that in model F. It is further discovered that in some cases the combustion at all points might be stable and rigorous but in other cases the combustion might not be stable and rigorous at all points thereby implying that the peak temperature alone does not give the measure of the efficiency and spread of the combustion front. It is shown for the first time that pre-defining fuel concentration throughout the reservoir as is done in model F resulted in faster downward advancement and expansion of the combustion front compared to in the reservoir where the fuel is deposited based on the Arrhenius kinetics parameters (i.e. like in model A). It is also discovered that higher areal sweep of the reservoir is achieved in model F when compared to that achieved in model A. Overall, it then follows that higher volume of the reservoir of model F is combustion-swept, heat-affected, and oil-depleted compared to that in model A. These findings explain the reason why more oil is produced during the combustion period in model F than in model A. Conclusively, this first-of-a-kind study shows that pre-defining the fuel has no effect on the qualitative nature of the physicochemical processes, but has considerable influence on the quantitative parameters such as the rate of and cumulative oil production, peak temperature, areal and volumetric sweeps by the combustion zone, size of the oil-depleted zone, and size of the heat-affect zone. • Full analysis of predictive ability of THAI model F with pre-defined fuel is reported. • Model F predicted unrealistic high oil production rate & thus cumulative oil recovery. • Model F has faster downward-advancement & general expansion of the combustion fronts. • Higher reservoir volume is combustion-swept, heat-affected, & oil-depleted in model F. • Qualitative behaviours in model F are similar to those in the Arrhenius-based model A.

Selection of Elite dura-Type Parents to Produce Dwarf Progenies of Elaeis guineensis Using Genetic Parameters

The low annual growth rate of the stipe in oil palm progenies is desirable to increase these crops’ productive and economic life. Recurrent reciprocal selection (R.R.S.) has allowed the development of oil palm populations through several breeding cycles with an increased frequency of favorable alleles associated with traits of interest. The present study evaluated families derived from Deli dura × African dura crosses. For 12 years, the yield, vegetative characteristics, and the amount of oil in seven dura progenies were assessed to estimate, from the information collected, the genetic parameters, heritability, and phenotypic correlations among quantitative genetic traits of high-yielding dwarf progenies. The analysis was carried out using analysis of variance, followed by a comparison of means for all estimated traits. The effect of the progenies was highly significant (p ≤ 0.01) for most traits. The yield values, expressed in fresh fruit bunches (FFB) for the progenies, ranged from 165 to 208 kg per palm per year. The oil-to-bunch ratio (O/B) ranged from 17% to 19%, with an overall average of 18%. One of the essential characteristics in this study was the vertical growth of the stipe. Progenies P6 and P7 were identified as those with the lowest annual increase in height, with values of 0.29 and 0.33 m year−1. The values indicate that these are slow-growing cultivars with a high FFB yield and O/B. The highest heritabilities were found for the vegetative trait height (71.62%) and the number of leaflets (46.64%). The development of dura parents with slow growth characteristics in combination with a high bunch and oil production allows extending the productive life of the crop to more than 35 years, providing added value to obtaining differentiated cultivars of oil palm.

Integrated Hierarchy-Correlation Model for Evaluating Water-Driven Oil Reservoirs.

With the increasing demands on energy and environmental domains, not only high oil production but also its accurate quantification has become one of the most important topics in academia and industry. This paper initially proposes a comprehensive workflow in which an integrated hierarchy–correlation model is used to thoroughly evaluate the influences of all relevant reservoir parameters on the ultimate oil recovery for water-flooding oil reservoirs. More specifically, the analytic hierarchy process, grey relation, and entropy weight are combined through the multiplicative weighting method to quantitatively describe the production parameters. Accordingly, novel multivariable linear and nonlinear correlations are developed to predict the production performance and validated through comparisons with numerical reservoir simulations. Seven factors, including five reservoir parameters, namely, permeability and its contrast, porosity, thickness, and saturation, and two production parameters, namely, the injection–production ratio and the operating pressure, have been identified as the most influential factors on recovery performances and thus are employed in the proposed correlations to predict the ultimate oil recovery factor. The results obtained by the proposed method are quite close to the real-time simulation data, while the accuracy is retained. The numerical results show that the recovery factors of water-flooding oil reservoirs are about 33.5–59.5%, and the corresponding linear and nonlinear correlation coefficients are 0.903 and 0.789, respectively. In comparison with the numerical simulation, the approximation error by the linear correlation is about 0.5%, which is lower than that of nonlinear correlation, for example, 12.3%. This study will be beneficial to analyze the reservoir-related parameters and provide a useful tool for rapid production performance evaluation of the water-flooding production scenario.

Agricultural LCA for Food Oil of Winter Rapeseed, Sunflower, and Hemp, Based on Czech Standard Cultivation Practices

The demand for food vegetable oil is rising and this trend is reflected in the agricultural sector of the Czech Republic. The traditional oil crops of the Czech Republic are winter rapeseed and sunflower. These oil crops have high demands on energy inputs, for example, in the form of land preparation and chemical protection. At the same time, they are characterized by high food oil production and oiliness. Moreover, marginal oils crops, such as hemp, are also gaining prominence. This work aimed to evaluate the environmental impacts associated with the cultivation of winter rapeseed and sunflowers based on standard cultivation practices typical of the conditions of the Czech Republic. For comparison, an intensive cultivation strategy for hemp was modelled, also corresponding to the conditions of the Czech Republic. This study assessed the environmental impact of traditional oil crops from the agricultural Life Cycle Assessment (LCA) perspective. The system boundaries included all the processes from the cradle to the farm gate. Mass-based (volume of food oil) and area-based (land demand for generating the same volume of food oil) functional units were employed. The results cover nine impact categories related to the agricultural LCA. ReCiPe Midpoint (H) characterization and normalization models were used for the data expression. Hemp is a plant with generally low demands on the inputs of the growing cycle but generally has a low oil production, which affects the character of the results relating to the goal and scope definition of the study. Hemp food oil thus generated a higher environmental impact per unit of production and area compared to sunflower and rapeseed food oil.

Production of Pyrolytic Oil from Cassava Peel Wastes

This study investigated the production of pyrolytic oil from cassava peel wastes. Pyrolysis is a very important thermochemical method for converting biomass into biofuel. In recent times, the production of biofuel has taken center stage due to concerns over the sustainability of conventional energy sources. Pyrolysis has received much attention by researchers because it can be used to optimize the production of high calorific value pyrolytic oil. A fixed bed pyrolysing unit was constructed for the production of liquid fuel in this study. Cassava peels were pyrolysed in the reactor. The temperature of reaction was varied to investigate the effect of temperature variation on the product distribution in terms of the percentage weight distribution and the calorific value of the pyrolytic oil. A maximum pyrolytic oil yield of 28.4 wt.% was obtained at 500 °C. The effect of temperature changes on calorific value was also investigated and it was observed that the maximum calorific value of 29.7 MJ/kg was obtained at 600°C.

The use of improved cajuput seeds to encourage self-sufficiency in cajuput oil in Indonesia

Melaleuca cajuput sub sp cajuput is an indigenous species in Indonesia which primarily used for the cajuput oil industry. The demand for cajuput oil is reported at around 3,500 tons/year, while the national capacity production is only around 600 tons years−1 due to lack of grower interest in planting and low productivity of the existing plantations. Following the success of the genetic improvement of cajuput in which oil yield and cineole content are improved, carried out by CFBTI, a program to increase oil production through developing plantations using genetically improved seeds was developed in six provinces. Five small-growers and one company were involved in the program covering 35 ha and 2000 ha of a plantation, respectively. This paper aims to report the progress of the program by focusing on the impact of the improved seed and people’s participation in developing cajuput plantations. The paper also discusses the projected impact for further development of the plantations, including government policy to support increased national production of cajuput oil as well as ensuring the market. The results showed that oil productivity varied among small-grower sites ranging from 93.75 to 171.6 kg ha−1 year−1, while for the company it could be increased to reach oil productivity of 175.5 kg ha−1 year−1 through innovative technology either in the plantation or in the distillation process. As compared to the previous system using ordinary un-improved seed, the oil productivity in the program increased around 62 – 116 %. The program also revealed that the cajuput industry could be managed effectively and efficiently while maintaining the sustainability and continuity of high oil production so that Indonesia will become self-sufficient in cajuput oil.

Use of two vertical injectors in place of a horizontal injector to improve the efficiency and stability of THAI in situ combustion process for producing heavy oils

The current commercial technologies used to produce heavy oils and bitumen are carbon-, energy-, and wastewater-intensive. These make them to be out of line with the global efforts of decarbonisation. Alternative processes such as the toe-to-heel air injection (THAI) that works as an in situ combustion process that uses horizontal producer well to recover partially upgraded oil from heavy oils and bitumen reservoirs are needed. However, THAI is yet to be technically and economically well proven despite pilot and semi-commercial operations. Some studies concluded using field data that THAI is a low-oil-production-rate process. However, no study has thoroughly investigated the simultaneous effects of start-up methods and wells configuration on both the short and long terms stability, sustainability, and profitability of the process. Using THAI validated model, three models having a horizontal producer well arranged in staggered line drive with the injector wells are simulated using CMG STARS. Model A has two vertical injectors via which steam was used for pre-ignition heating, and models B and C each has a horizontal injector via which electrical heater and steam were respectively used for pre-ignition heating. It is found that during start-up, ultimately, steam injection instead of electrical heating should be used for the pre-ignition heating. Clearly, it is shown that model A has higher oil production rates after the increase in air flux and also has a higher cumulative oil recovery of 2350 cm3 which is greater than those of models B and C by 9.6% and 4.3% respectively. Thus, it can be concluded that for long-term projects, model A settings and wells configuration should be used. Although it is now discovered that the peak temperature cannot in all settings tell how healthy a combustion front is, it has revealed that model A does indeed have far more stable, safer, and efficient combustion front burning quality and propagation due to the maintenance of very high peak temperatures of mostly greater than 600 °C and very low concentrations of produced oxygen of lower than 0.4 mol% compared to up to 2.75 mol% in model C and 1 mol% in model B. Conclusively, since drilling of, and achieving uniform air distribution in horizontal injector (HI) well in actual field reservoir are costly and impracticable at the moment, and that electrical heating will require unphysically long time before mobilised fluids reach the HP well as heat transfer is mainly by conduction, these findings have shown decisively that the easy-and-cheaper-to-drill two vertical injector wells configured in a staggered line drive pattern with the horizontal producer should be used, and steam is thus to be used for pre-ignition heating.

Income inequality and oil resources: Panel evidence from the United States

The resource curse is sometimes associated with poor resource-rich countries. However, using panel evidence from the United States, we find that the resource curse is also prevalent in a wealthy resource-rich country. This study investigates the impact of oil resources on income inequality, with a particular focus on distinguishing between the effects from oil abundance (i.e. production) versus oil dependency (i.e. consumption). We observe contrasting non-monotonic outcomes from oil abundance in comparison to oil dependency. For oil abundance, states with low oil production will have less inequality if they increase oil production, and states with high oil production will have increased income inequality if they increase production. The opposite holds true for oil dependency. The findings suggest several channels of concern. For example, oil-rich states are more vulnerable to rent-seeking behaviour as oil production and oil revenues increase, which can adversely affect the income distribution gap. On the other hand, oil-dependent states are more likely to be affected by commodity price shocks which can increase income inequality.

Revealing of the effect of borehole deviation on its productivity

The wells drilled with the deviation angle compared to the vertically drilled ones cover more of oil-bearing area. By increasing drainage zone it is possible to obtain high final oil production and therefore, to enhance oil recovery rate. With the purpose of reducing the drilling costs, the increase of drainage zone gives positive outcomes. From economic point of view, it is more efficient to operate the field increasing the well quantity (i.e. well density) or to use horizontal wells drilled with deviation angle.

DYNAMIC FRACTURE PROPAGATION MECHANISM AND APPLICATIONIN TIGHT OIL RESERVOIR

Tight oil reservoirs have achieved certain oil increase effect by supplementing formation energy with water-injection huff and puff. However, formation pressure and production decrease rapidly after multiple rounds of water injection. In order to improve the oil enhancement effect of tight oil reservoirs, changing the development method quickly became hotspot research. This paper analysis the stress field distribution near the tip of type I fracture considered the complex fracture morphology of tight oil reservoirs based on Irwin theory and elastic mechanics. A multi-fracture cross-fracture propagation model is established based on seepage mechanics, fractured tight reservoir characteristics and dynamic fracture seepage characteristics. The fracture propagation length is obtained based on the fracture propagation mechanism and the energy conservation principle. It is proposed to turn water-injection huff and puff into unstable pulse water injection according to the principle of reverse imbibition in tight oil reservoirs. Comparative analysis of two energy supplementary generation methods, water-injection huff and puff and pulse water injection, predicting cumulative oil production, pressure and remaining oil distribution in 10 years. The results show that the net internal pressure of the fracture increases with the increase of water injection, and the stress field intensity factor also increases. When the stress field intensity factor reaches the fracture toughness, it will expand at the fracture tip. The expanded and extended natural fractures communicate with each other, presenting irregular and complex fracture networks. Reverse imbibition mainly occurs in the complex fracture networks. Pulse water injection has a high cumulative oil production, a wide area of water injection and strong reverse imbibition. The findings of this study can help for better understanding of the transformation of water-injection huff and puff into pulsed water injection from horizontal wells in fractured tight oil reservoirs. It can give full play to the effects of reverse imbibition and linear displacement. This research provides guidance for it can achieve the purpose of effective oil displacement of the dynamic fracture network.

Physicochemical characterization of bunches and oil composition in a backcross progeny (caiaué x oil palm) x oil palm

Hybrids between caiaué and oil palm (IEH OxG) are explored in genetic improvement with the main objective of associating the high palm oil productivity of oil palm with resistance of caiaué to Bud Rot disease. In addition, caiaué has better oil quality and greater resistance to some pests and diseases than oil palm and these characteristics are transmitted to the hybrid between species. Due to fertility problems, IEH OxG plantations require assisted pollination, which raises the production costs. Backcrossings using oil palm as recurrent parent (BC OGxG) are being evaluated as a solution to restore the fertility of IEH OxG, however, the species contrast to physicochemical characteristics of the bunch and to oil composition, therefore, there is a need to observe how these characteristics vary in BC OGxG. Physicochemical characteristics of the bunch and fatty acid composition of the oil produced by 90 plants from an BC OGxG progeny were analysed. A large variation was observed in the progeny, with mean values of 9.0 kg for bunch weight, 46.0% of parthenocarpic fruits in the bunch weight, 72.2% of mesocarp in normal fruit and 86.5% in parthenocarpic fruit, 37.6% of oil in the humid mesocarp of normal fruits and 35.9% in parthenocarpic fruits and 16.4% of oil content in the freshfruits bunch (FFB). The unsaturated fatty acids oleic (52.5%) and linoleic (10.8%) and the saturated fatty acids palmitic (30.7%) and stearic (4.4 %) stood out in the oil composition. In the progeny BC OGxG is possible to select individuals for high OCB and for a greater or lesser percentage of saturated or unsaturated fatty acids in the oil composition.