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Abstract This paper presents an enhanced oil recovery (EOR) evaluation for two heavy-oil fields in Africa. The objective of the evaluation is to identify the technically and economically viable EOR techniques for the fields. A total of thirteen established and emerging EOR techniques were evaluated in this study. The study included the first degree approximation of the oil recovery for the viable EOR techniques and the stand-alone project economics estimation. The data required for the study include:fluids and rock properties; driving mechanism; production data; OOIP and recoverable reserves; and relative permeability curves. Various EOR technique screening criteria, consisting of a list of reservoir parameters and their ranges which are likely to lead to a success, were applied to match the parameters of the study fields. The oil recovery predictions were estimated utilizing general reservoir parameters and developed correlations 1. The economic feasibility of the potential EOR techniques was then evaluated based on the stand-alone project economics that accounted for the revenue from the incremental oil and the associated operating and capital costs. The evaluation results showed that the thermal EOR techniques: steam flooding and in-situ combustion are technically the most viable EOR techniques for the fields. It was then followed by the chemical EOR techniques. The performances of steam flooding and in-situ combustion are both very promising, with oil recovery of up to 49% OOIP. Comparing to the oil recovery of water flooding, a significant incremental oil recovery of 24% OOIP was obtained. However, the in-situ combustion process is able to accelerate the oil production, which significantly impacts the economic viability assessment, rendering the in-situ combustion process as the most technically, and economically feasible EOR process for the fields. Based on the EOR evaluation, the oil recovery predictions and economic assessments of the thirteen EOR techniques, including the chemical, gas, thermal and microbial EOR techniques, served as a guideline to develop the long term corporate strategy regarding the EOR potential of the fields. Introduction Enhanced oil recovery (EOR) could increase technically and/or economically recoverable oil. In current reservoir management practice, various EOR options are considered much earlier in the productive life of a field. Adopting the same reservoir management strategy, EOR technology was considered to increase the oil recovery factor in two heavy-oil fields (18–24oAPI) in African region. The predicted water flood oil recoveries of these fields are relatively low at about 17% to 25% STOIIP only. Thus, an EOR process instead of water flooding is worth to be considered at the beginning of these fields' lives. Inevitably, economics always play the major role in "GO/NO GO" decision-making for expensive EOR projects. This screening study was carried out to rule out the less-likely candidates. The objectives of this EOR screening study are to:Identify suitable EOR processes for the study reservoirs by a quick GO/NO GO screening. Estimate the expected recovery for the process (performance prediction using analytical methods) that passes the first screening criteria (GO/NO GO criteria). Carry out preliminary stand alone project economics assessment on the best two processes for each reservoirs evaluated. Select the most technically and economically suitable EOR process (for reservoirs screened to have more than one suitable process). The screening study flow chart is shown in Figure 1.
- North America > United States > Texas (0.28)
- North America > United States > Louisiana (0.17)
- North America > United States > Louisiana > Alpha Field (0.99)
- North America > United States > Wyoming > Powder River Basin > Shannon Formation (0.98)
Abstract In this paper the effects of some ionic liquids elaborated with iron and molybdenum used to upgrade the properties of a heavy crude oil are discussed. The underlying objective is to increase the mobility of the oil in the reservoir reducing viscosity and improving the oil quality (e.g. diminishing the asphaltene and sulfur contents and increasing its °API gravity), using ionic liquids based on iron (10 wt%) and molybdenum (2 wt%) compounds, in a liquid phase homogeneously mixed with heavy crude oil in a batch reactor of 500 ml, at 673 K during 4 hours. The API gravity of a offshore heavy crude oil from the Gulf of Mexico increased from 12.5 until 20, kinematics viscosity decreased from 15,416 to 136.63 cSt at 288.75 K, asphaltene content was reduced from 28.65 to 10.82 wt%, while the sulfur was removed from 5.14 to 2.16%; and the distillation obtained by Simulated Distillation was increased from 48 to 71.2 vol%. Content of aromatics and saturated compounds were increased through the conversion of asphaltenes and resins, which contents decreased from 16.81 to 13.8 wt% and from 28.85 to 10.82 wt% respectively. Finally, the content of total nitrogen was reduced from 780 to 633 ppm in weight which represents a reduction approximately of 20 wt%. In this work upgrading of a heavy crude oil was obtained through the application of the thermal and catalytic hydrocracking with an ionic liquid. This ionic liquid could be applied into the reservoir combined with in-situ combustion process using unconventional wells in order to improve the recovery of heavy crude oil, producing an oil improved in-situ with lower viscosity, being easier their exploitation, increasing the productivity index in wells, and saving costs of transportation and refining at surface. Introduction Improving some oil properties as oil viscosity reduction and increasing API gravity are key properties to increase the wells productivity index of heavy crude oil. The thermal methods occupy an important place among enhance oil recovery techniques, especially in the production of high-viscosity oils and natural bitumen [1]. Different versions of thermal methods are used to upgrade heavy crude oil, among the more important methods are Steam Drive [2–4], Cycle Steam Injection [5], Steam Assisted Gravity Drainage (SAGD) [6, 7], Conventional Fire Flood [8, 9], Toe-to-Heel Air Injection Process (THAI) [10–12], Aquathermolysis [13, 14], and Down-Hole Catalytic Processes [15–17]. The last process mentioned is an interesting alternative to reduce of viscosity of the heavy crude oil improving the oil quality inside the reservoir. In order to be carried out the last process is necessary to combine the in-situ combustion process with a liquid consists only of ions [18–20] of metallic salts. The iron-base ionic liquid [21] would be distributed throughout the reservoir as a diluted salt solution. The polar molecules of the heavy crude oil probably would be diffused in ionic liquid favoring the contact between both phases. On the other hand, the iron-based ionic liquid may be modified during the preparation with anionic sulfates (SO42-) and promoters in a small percentage of transition metal such as molybdenum or tungsten. The metals compounds in the ionic liquid have been recognized because their catalytic properties in hydrocarbon oxidation, cracking, and hydrocracking reactions. In contrast, the metal also accelerated oxidation indirectly by destroying the antioxidants [22] that are naturally present in the most crude oil. In the present work the upgrading of the heavy crude oil from the Gulf of Mexico was carried out in a batch reactor as well as a continuous-stirred tank reactor (CSTR). The API gravity was increased from 13.5 until 20o, the kinematics viscosity was reduce from 15,416 to 136.63 cSt at 289 K, the hydrodesulfuration was reduced between 40–60 wt%, and the distillable fraction was increased from 48 to 71.2 vol.% which was carried out by True Boiling Point (TBP). Experimental Section The catalyst was prepared using ferric sulfate hydrate, water, phosphoric acid and phosphotungstic acid compounds.
- North America > Canada > Alberta (0.30)
- North America > United States > Texas (0.29)
- Energy > Oil & Gas > Upstream (1.00)
- Materials > Chemicals > Commodity Chemicals > Petrochemicals (0.35)
Abstract In-situ combustion is a thermal recovery method used for enhanced heavy oil recovery. In this process air is injected to the reservoir in order to achieve ignition and to maintain the combustion front while pushing the heated oil toward producing wells. This study deals with the feasibility of in-situ combustion process in fractured heavy oil reservoirs. A one dimensional, three-phase in-situ combustion simulator with six components, two cracking and three oxidation reactions is used in this study. Primarily, a conventional simulation model based on experimental data available in the literature was constructed and sensitivity study tests were performed. In the second part of this project, the conventional model was modified to a fractured model and various parameters and mechanisms such as oil recovery factor, average temperature of the system, cumulative oil and water production, diffusion, and wet combustion process were investigated. Results indicate the importance of grid block size, injection rates, kinetic models, and equilibrium ratios of heavy and light oil components on simulation process. Simulation results indicate that the optimum water/oil ratio leads to an increase in the amount of oil recovery and a reduction in the amount of air to be injected. The study presented here with its promising outcome is a pre-requisite to justify laboratory experimental investigation of the in-situ combustion process in naturally fractured reservoirs. Introduction In-situ combustion is a complex Enhanced Oil Recovery (EOR) process normally suitable for medium to heavy crude oils. The process involves all the complexity associated to the multi-phase fluid flow through porous media with chemical and physical transition of the crude oil components under high temperature and high pressure conditions. The process becomes further complex when it is aimed for the heavy oil recovery from naturally fractured reservoirs. Because of the complexity involved, its field application has been limited and difficult to handle. With the inevitable peak oil in horizon and the rising global demand for crude oil, renewal interest has been generated toward heavy oil reserves that thermal recovery techniques are mostly suited for their recovery. Conventional production methods are not suitable for heavy oil reservoirs and technological advancements are needed to make heavy oil deposits a more viable resource. Advanced technologies are essential to enable production, transportation, and refining of heavy crude oils at a reasonable cost. This is essential to make the share of heavy oil production to levels greater than the current 10% of overall crude oil production. There are several giant heavy oil reserves in the world such as heavy oil deposits belt encountered in a 700 kilometers long by 60 kilometers wide along the Orinoco River in eastern Venezuela. The middle east region has 36% of the world's heavy oil deposits followed by the United States with 11% and Russia with 6%. Table 1 presents the major deposits of heavy oil and tar sands in the world. In-Situ Combustion Process To appreciate the need for further investigation of the process, it seems useful to make a brief review of the process and the improvements achieved over a period of more than half a century. In-situ combustion is a thermal recovery technique in which a small fraction of the heavy end of the crude oil is burned to create the heat needed to raise the temperature of the reservoir and the crude. Since the viscosity of the crude oil reduces exponentially with temperature, the process helps the crude oil to flow more readily from the rock into the production well. Upgrading of crude oil because of thermal and catalytic cracking is another major phenomenon occurring during the process that facilitates the flow of crude oil through the rock. In-situ combustion has gone through a wide range of variations and improvements due to the needs encountered in its application to various types of reservoirs and crude oils involved.
- Asia (1.00)
- North America > United States > Texas (0.46)
- North America > Canada > Alberta (0.29)
Impact of the viscosity reduction on the Productivity Index using a Simulation Study in two networks in the Golf of Mexico
Ramirez-Garnica, Marco Antonio (Inst. Mexicano del Petroleo) | clavel-lopez, Juan de la Cruz (Instituto Mexicano del Petroleo) | Hernandez-Madariaga, arturo (Pemex) | Cazarez-Candia, Octavio (Instituto Mexicano del Petroleo) | nares, Ruben (Instituto Mexicano del Petroleo) | Schachat, Persi (Instituto Mexicano del Petroleo)
Abstract The use of catalysts in crude heavy oils can improve substantially their viscosity, API and reduce the content of porphyrins, sulfur, and asphaltenes [1]. In this work a simulation study of the heavy crude oil production in networks (localized in the Golf of Mexico) was done to evaluate the effects of a smaller viscosity and a bigger API on the Productivity Index (J). This work can be applied to study the increment of the J as well as the savings of operation costs in surface to transport and treatment of heavy oil before send it to refineries. Simulation was done in two networks: first one, Network I performed by 8 wells offshore producing 13 °API crude oil, and the second one, Network II, producing 8 °API crude oil. In both cases, J is referenced here considering one effect of the catalyst benefits: mainly reduction of viscosity. In the case of the network producing 13 °API crude oil (with 145.26 cP @ 25C, dead oil) the actual global J is in total 1201.5 Barrels per Day per psi (BPD/psi), and accordance to the simulation (with a modified viscosity to 1.08 cP @ 25C) the new global J should be 5411.26 BPD/psi, which it should represent an increase of 350.38 %. In the second net similar result was obtained, the actual global J is about 549.52 BPD/psi (with a viscosity of 515 cP @ 25C, dead oil) while the simulation result gives a global J about 2062.57 BPD (with a viscosity of 133.9 cP @ 25C), which would represent an increase about 275.34 %. The significance of this simulation results is very important since the economical point of view because of the better quality of the improved oil and saving costs avoiding surface treatment previous their transport to refineries. Introduction Heavy and extraheavy oil represent a large quantity of hydrocarbon resources, unfortunately their viscosities makes them difficult to produce and to transport. Actually there are methods to produce heavy and extraheavy oil such as steam injection [2], Steam Assisted Gravity Drainage (SAGD) [3], water injection [2, 4], THAI - ‘Toe-to-Heel Air Injection’ [5], and CAPRI [5, 6]. When these methods are applied the oil viscosity is smaller than the original oil viscosity. Under this order of ideas in the Instituto Mexicano del Petróleo (IMP), a catalyst was formulated which allows decreasing the viscosity of heavy and extra heavy oil [1]. This article investigates the effect of the possible use of air-catalyst injected in the reservoir in order to improve the productivity index J, increasing the oil production as a consequence of a reduction of viscosity. In this case the production system from the platforms I and II was analyzed considering the change in the oil properties as a catalyst effect. A commercial simulator was used to do the analysis of fluid flow through pipes. Using this software the analysis of Network I and Network II was done, and after adjust the wells some simulations were practiced considering the change of viscosity in the oil. Every analysis starts knowing the structure of every component of the system, the parameters and their influence in the simulation process.
- North America > Mexico (0.85)
- North America > Canada > Alberta (0.15)