A Prospective Method to Increase Oil Recovery in Waxy-Shallow Reservoir
Waxy oil has been the main characteristics of The X field. Initial screening criteria studies indicated that cyclic steam stimulation (CSS) would be the optimum option because favorable reservoir condition. Based on this method we would like to know how much oil gain and the effect of steam for the stimulated and surrounding well. The injection of steam was done for 7 days followed by 14 days of soaking period. 39,000 liter of Marine fuel oil was used to generate steam for stimulation with an average produce steam quality about 80%. Average of 255 MMBTU of steam was injected each day with total steam injected was about 1.7 BBTU. The oil production was increased four times from 5 bopd into 21 bopd. Proper well candidate and high permeability are some reason for this method successfully increase oil production. Additional heat from steam reduced the damage near wellbore due to wax deposition. This is verifying by increasing productivity index from 3 bbl/psi to 4 bbl/psi. From results and observation data, this method can be a platform for typical shallow depth reservoir with high paraffinic content especially other reservoir in Sihapas formation.
Steam injection for heavy oil recovery: Modeling of wellbore heat efficiency and analysis of steam injection performance
Abstract The aims of this work are to present a comprehensive mathematical model for estimating wellbore heat efficiency and to analyze performance of steam injection for heavy oil recovery. In this paper, we firstly introduce steam injection process briefly. Secondly, a simplified approach of predicting steam pressure in wellbores is presented and a complete expression for steam quality is derived. More importantly, both direct and indirect methods are adopted to determine the wellbore heat efficiency. Then, the mathematical model is solved using an iterative technique. After the model is validated with measured field data, we study the effects of wellhead injection rate and wellhead steam quality on steam injection performance reflected in wellbores. Next, taking cyclic steam stimulation as an example, we analyze steam injection performance reflected in reservoirs with numerical reservoir simulation method. Finally, the significant role of improving wellbore heat efficiency in saving water and fuels is discussed in detail. The results indicate that we can improve the wellbore heat efficiency by enhancing wellhead injection rate or steam quality. However, high wellbore heat efficiency does not necessarily mean satisfactory steam injection performance reflected in reservoirs or good performance of heavy oil recovery. Moreover, the paper shows that using excellent insulation materials is a good way to save water and fuels due to enhancement of wellbore heat efficiency.
Solar-generated steam for oil recovery: Reservoir simulation, economic analysis, and life cycle assessment
Abstract The viability of solar thermal steam generation for thermal enhanced oil recovery (TEOR) in heavy-oil sands was evaluated using San Joaquin Valley, CA data. The effectiveness of solar TEOR was quantified through reservoir simulation, economic analysis, and life-cycle assessment. Reservoir simulations with continuous but variable rate steam injection were compared with a base-case Tulare Sand steamflood project. For equivalent average injection rates, comparable breakthrough times and recovery factors of 65% of the original oil in place were predicted, in agreement with simulations in the literature. Daily cyclic fluctuations in steam injection rate do not greatly impact recovery. Oil production rates do, however, show seasonal variation. Economic viability was established using historical prices and injection/production volumes from the Kern River oil field. For comparison, this model assumes that present day steam generation technologies were implemented at TEOR startup in 1980. All natural gas cogeneration and 100% solar fraction scenarios had the largest and nearly equal net present values (NPV) of $12.54 B and $12.55 B, respectively. Solar fraction refers to the steam provided by solar steam generation. Given its large capital cost, the 100% solar case shows the greatest sensitivity to discount rate and no sensitivity to natural gas price. Because there are very little emissions associated with day-to-day operations from the solar thermal system, life-cycle emissions are significantly lower than conventional systems even when the embodied energy of the structure is considered. We estimate that less than 1 g of CO 2 /MJ of refined gasoline results from the TEOR stage of production if solar energy provides all steam. By this assessment, solar thermal or supplemental solar generation systems appear to be a preferred alternative to fully conventional systems using natural gas in areas with large solar insolation.