Carbon dioxide flooding has been recognized widely as one of the most effective enhanced oil recovery processes applicable to light to medium oil reservoirs. Moreover, the injection of CO2 into an oil reservoir is a promising technology for reducing greenhouse emissions while increasing the ultimate recovery of oil.
Numerical reservoir simulation is an important and inexpensive tool for designing EOR CO2 projects and predicting optimal operational parameters. In this work, reservoir simulations performed with a compositional simulator were applied to investigate the macroscopic mechanisms of CO2 injection processes. Horizontal injectors were used to increase injectivity. Compared to traditional vertical wells, horizontal wells are more attractive to improve CO2 flooding economics by increasing injection rate, improving areal sweep and increasing CO2 storage. The effects of several important parameters on the performance of the CO2 process were studied to optimize the process. Operational parameters such as the primary production time, the injector pressure and length, injection time as well as production well pressure and different production schemes were investigated to determine the optimal operating conditions for simultaneous objectives of higher recovery and higher CO2 storage.
The application of CO2 flooding using horizontal wells can shorten project life, which is critical to its economics. The simulation results served as the basic input parameters for the economic analysis performed. Furthermore, NPV (net present value) results were used to optimize the profitability of the project and to compare the CO2 application using vertical and horizontal wells. The analysis used actual design parameters, including equipment and operating costs similar to the ones associated with current ongoing projects. The evaluation emphasized the importance of reservoir characteristics, optimum design of operation parameters and economical factors in the economic feasibility of CO2 injection projects for enhanced oil recovery and sequestration.
Carbon dioxide flooding process can increase oil recovery by means of swelling, evaporating and lowering oil viscosity. Many injection schemes using CO2 have been applied[1], including CO2 gas injection (continuously), CO2 gas slug followed by water, etc. Currently, atmospheric concentration of CO2 is raising increasingly concerns and different possibilities for CO2 sequestration are being studied, including CO2 storage in abandoned gas and oil fields. This paper studies CO2 flooding process using horizontal wells to simultaneously enhance recovery and increase CO2 storage. Obviously this is an economic and environmental issue which optimization will contribute to reach the two abovementioned objectives. Although usually specific economic, social, and environmental indicators should be studied systemically, this paper mainly focuses on the economic analysis of CO2 flooding and sequestration processes. Economic analysis is especially important in a CO2 flooding project because most of such projects have high investment and operating costs and low profit expectation.
This paper studies the application of conventional CO2 miscible flooding process (continuous injection) using horizontal wells. Horizontal wells are become more cost effective with increasing productivity performance and decreasing drilling and completion costs. Comparison is made between schemes using vertica
