CO2 enhanced oil recovery and storage using a gravity-enhanced process

Abstract

CO 2 flooding offers a means to recover significant amounts of oil while simultaneously sequestering CO 2 . Recent methods for CO 2 geological storage have focused on CO 2 injection into deep brine aquifers, or by water-alternatinggas (WAG) injection in a miscible gas flooding process using vertical wells. There is significant uncertainty in the amount of CO 2 that can be stored using these methods owing to reservoir heterogeneity and variations in reservoir/fluid parameters. It would be useful therefore to have a more robust process that can also increase both CO 2 storage and oil recovery in a symbiotic relationship, where increased storage leads to greater oil recovery.This paper considers an alternative process that maximizes both storage and oil recovery simultaneously using only horizontal wells in a gravity-enhanced miscible process. A reduced-order model (ROM) is developed to consider a wide range of reservoir heterogeneities and fluid properties. Monte-Carlo simulations using the ROM show that achieving very high storage and oil recovery is possible using the gravity-enhanced process and that the approach is very robust. For example, after 2.0 moveable pore volumes injected (MPVI), probabilistic forecasts show that CO 2 storage efficiency across two standard deviations ranges from about 81 to 93%, indicating that nearly all of the available pore space (excluding immobile water) at the end of injection is occupied by CO 2 . Oil recoveries after 2.0 MPVI varied from 79% to 93% of the original mass of oil-in-place (OOIP). These storage and recovery efficiencies are significantly greater than any process reported to date. Response functions developed can also be used to estimate the maximum amount of stored CO 2 and corresponding oil recoveries for a wide range of reservoir and fluid properties. Such estimates are critical for regional and national assessment of CO 2 storage potential.

Chemical Flooding in Heavy-Oil Reservoirs: From Technical Investigation to Optimization Using Response Surface Methodology

“…Response surfaces are proposed to estimate the objective functions from the effective designed variables [44]. Typically, the final target NPV is always considered as an objective function.…”

Applicability of an Artificial Neural Network for Predicting Water-Alternating-CO2 Performance

“…Because the critical CO 2 condition is at 7.384 MPa and 31.1 • C, the reservoir condition is appropriate for consideration as a carbon capture project because it always exists at the super critical phase when injected into the reservoir. Dip angle usually occurs in most practical fields, and it partially affects the movement of the injected gas due to gravity [22], but this factor is not considered in this model. Salinity is also neglected in the CO 2 injection process, as its influence on solubility is negligible.…”

“…Dip angle usually occurs in most practical fields, and it partially affects the movement of the injected gas due to gravity [22], but this factor is not considered in this model. Salinity is also neglected in the CO2 injection process, as its influence on solubility is negligible.…”

Potential evaluation of CO2 EOR and storage in oilfields of the Pearl River Mouth Basin, northern South China Sea

“…Global and regional climate change caused by greenhouse gas emissions is still stimulating interest in the development of various technologies to reduce the concentrations of carbon dioxide (CO 2 ) in the atmosphere . Many countries have set targets for reducing the emissions of greenhouse gases to mitigate global warming.…”

“…G lobal and regional climate change caused by greenhouse gas emissions is still stimulating interest in the development of various technologies to reduce the concentrations of carbon dioxide (CO 2 ) in the atmosphere. [1][2][3][4][5] Many countries have set targets for reducing the emissions of greenhouse gases to mitigate global warming. Among these countries, and top on the list of CO 2 emission producers in the world, China aims to reduce 40%-45% of its CO 2 emissions per unit GDP by 2020, based on the 2005 level.…”