EOR Steam Injection Huff and Puff Method: An Analysis of Production Response in Low Performance Well

Steam Injection Huff and Puff is one of the EOR methods by injecting heat energy in the steam phase to reduce oil viscosity and reproducing oil in the same well. The geological structure of this field is a complex-faulted anticline that compartmentalized the field into five blocks with two potential blocks for EOR Steam Injection Huff and Puff Method. The oil properties are categorized as heavy oil because of high viscosity, high pour point, high congealing point, and low API degree. Therefore, the Recovery Factor (RF) only reaches 14% with EOR method. Screening criteria is conducted for selecting well candidate with low performance. It means the well with oil temperature <110 oF and flow rate <20 BOPD. EOR Steam Injection Huff and Puff Method consists of three stages such as injection period, soaking period and production period. The steam design becomes a reference in determining the duration of each stage. The duration of EOR Steam Injection Huff and Puff Method has been estimated for a total of 20 days with 11 days for injection period and 9 days for soaking period. There are three parameters used to analyze the production response after EOR Steam Injection such as Productivity Index (PI), Inflow Performance Relationship (IPR) Curve, and Production Rate Test (PRT). These parameters show the comparison before and after EOR Steam Injection. Based on these three parameters, EOR Steam Injection Huff and Puff Method has successfully improved 76% of oil production in this well. This study concludes that there are four critical factors for the success of EOR Steam Injection using Huff and Puff Method, and will be described explicitly in this paper.

Studying the influence of the carbon dioxide injection period duration on the gas recovery factor during the gas condensate fields development under water drive

Purpose. Studying the process of carbon dioxide injection at the boundary of the initial gas-water contact in order to slow down the formation water inflow into producing reservoirs and increase the final hydrocarbon recovery factors. Methods. To assess the influence on gas recovery factor of the duration of carbon dioxide injection period at the initial gas-water contact, a reservoir development is studied using the main Eclipse and Petrel hydrodynamic modeling tools of the Schlumberger company on the example of a hypothetical three-dimensional model of a gas-condensate reservoir. Findings. The dependence of the main technological indicators of reservoir development on the duration of the carbon dioxide injection period at the initial gas-water contact has been determined. It has been revealed that an increase in the duration of the non-hydrocarbon gas injection period leads to a decrease in the formation water cumulative production. It has been found that when injecting carbon dioxide, an artificial barrier is created due to which the formation water inflow into the gas-saturated intervals of the productive horizon is partially blocked. The final gas recovery factor when injecting carbon dioxide is 61.98%, and when developing the reservoir for depletion – 48.04%. The results of the research performed indicate the technological efficiency of carbon dioxide injection at the boundary of the initial gas-water contact in order to slow down the formation water inflow into producing reservoirs and increase the final hydrocarbon recovery factors for the conditions of a particular field. Originality. The optimal value of duration of the carbon dioxide injection period at the initial gas-water contact has been determined, which is 16.32 months based on the statistical processing of calculated data for the conditions of a particular field. Practical implications. The use of the results makes it possible to improve the existing technologies for the gas condensate fields development under water drive and to increase the final hydrocarbon recovery factor.

Injection period pressure transient behaviour of two-phase water-oil flow: A semi-analytical study

This paper presents a study on the pressure transient behaviour during the injection period in a vertical well in the presence of wellbore storage and skin effect. The two-phase water-oil radial flow problem is solved using a semi-analytical technique called the Laplace-Transform Finite-Difference method. Moreover, the factors that influence the degree of wellbore storage and skin effect are analysed. The results demonstrated that the effect of wellbore storage on the pressure transient behaviour is significant during the early times. Factors such as compressibility of fluid, effective wellbore volume and endpoint mobility ratio significantly affect the duration of wellbore storage. The impact of the skin during the injection period is significant on the pressure transient behaviour and could last for a longer duration. A substantial effect of skin is observed for a positive skin factor and unfavourable endpoint mobility ratio. In addition, the duration of the effect is directly proportional to the thickness of the skin zone. Hence attention must be given to the parameters that could prolong these effects and included in the solution methods to precisely interpret the injection period pressure transient behaviour for a better estimation of the reservoir and well properties.

Improvements of Performance and Emissions of a Diesel-Gen-Set With Biodiesel Having Guide Vanes of Various Angles

Biodiesel has physiochemical properties similar to diesel fuel and it is renewable. It can be used in diesel engines with no or minor modifications. If biodiesel can be produced from renewable sources such as vegetable or other sources, the CO2 emission produced from the engine running on biodiesel can be consumed by the source itself. Then, the net production of CO2 emission in the atmosphere will be zero. However, the viscosity and density of biodiesel are higher than diesel fuel. These inferior properties make biodiesel less prone to evaporate, diffuse and mix with in-cylinder air resulting in inferior combustion and lower engine performance than diesel fuel. If the in-cylinder air-turbulence inside the combustion chamber can be increased, then this will probably enhance the higher viscous and lesser volatile biodiesel to evaporate faster and mix with air better resulting in better performance. Therefore, in this research, guide vanes were installed into the intake runner to increase the in-cylinder air turbulence especially during the injection period. Five guide vanes with the angles of 25°, 30°, 35°, 40° and 45° were fabricated and tested. The vanes were tested on a diesel-gen-set and run with 100% biodiesel. Based on the experimental results, the vane angle of 35° was found to be optimum as this vane angle showed the highest reductions of break specific consumption, CO and HC by 1.77%, 8.78% and 7.5%, respectively compared to the run with biodiesel without vanes. The other vanes showed lower improvements. Therefore, this research concludes that the improvement of in-cylinder air-turbulence can enhance the engine performance with higher viscous biodiesel.

Revisiting ocean carbon sequestration by direct injection: a global carbon budget perspective

In this study we look beyond the previously studied effects of oceanic CO2 injections on atmospheric and oceanic reservoirs and also account for carbon cycle and climate feedbacks between the atmosphere and the terrestrial biosphere. Considering these additional feedbacks is important since backfluxes from the terrestrial biosphere to the atmosphere in response to reducing atmospheric CO2 can further offset the targeted reduction. To quantify these dynamics we use an Earth system model of intermediate complexity to simulate direct injection of CO2 into the deep ocean as a means of emissions mitigation during a high CO2 emission scenario. In three sets of experiments with different injection depths, we simulate a 100-year injection period of a total of 70 GtC and follow global carbon cycle dynamics over another 900 years. In additional parameter perturbation runs, we varied the default terrestrial photosynthesis CO2 fertilization parameterization by ±50 % in order to test the sensitivity of this uncertain carbon cycle feedback to the targeted atmospheric carbon reduction through direct CO2 injections. Simulated seawater chemistry changes and marine carbon storage effectiveness are similar to previous studies. As expected, by the end of the injection period avoided emissions fall short of the targeted 70 GtC by 16–30 % as a result of carbon cycle feedbacks and backfluxes in both land and ocean reservoirs. The target emissions reduction in the parameter perturbation simulations is about 0.2 and 2 % more at the end of the injection period and about 9 % less to 1 % more at the end of the simulations when compared to the unperturbed injection runs. An unexpected feature is the effect of the model's internal variability of deep-water formation in the Southern Ocean, which, in some model runs, causes additional oceanic carbon uptake after injection termination relative to a control run without injection and therefore with slightly different atmospheric CO2 and climate. These results of a model that has very low internal climate variability illustrate that the attribution of carbon fluxes and accounting for injected CO2 may be very challenging in the real climate system with its much larger internal variability.