Performance and gas breakthrough during CO 2 immiscible flooding in ultra-low permeability reservoirs

Gao, Ying; Zhao, Ming; Wang, Jianbo; Zong, Changfu

doi:10.1016/s1876-3804(14)60010-0

Cited by 104 publications

(30 citation statements)

References 11 publications

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“…For hydraulic fracturing technology, only a small part of the injected fracturing fluid can be recovered, and most of the injected fracturing fluid remains in the formation, 29,30 and the remaining fracturing fluid plugs the original connected pores and throats, resulting in a decrease in physical permeability 31 . In addition, the residual fracturing fluid may form two‐phase seepage resistance and reduce the effective permeability of the oil phase 32 ; for CO 2 flooding, CO 2 injection may bypass the remaining oil zone and tend to flow through fractures, resulting in low sweep efficiency 33‐35 ; for profile control, the injected gel permanently blocks the high‐permeability layer 36 . In addition, the flexibility of the gel allows it to enter the low‐permeability layer and remain in the matrix, thus causing contamination in the low‐permeability region 37,38 .…”

Section: Introductionmentioning

confidence: 99%

Experimental evaluation of ASP flooding to improve oil recovery in heterogeneous reservoirs by layered injection approach

Huang

et al. 2020

Energy Science & Engineering

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To improve the oil displacement effect of ASP (alkali/surfactant/polymer) solution in heterogeneous oil reservoirs, layered injection technology is proposed for the first time for Daqing Oilfield. The technology uses partial pressure tools to control the injection amount of ASP solution in high‐permeability oil layers and uses a partial quality tool in low‐permeability oil layers. To study the experimental effect of this layered injection technology, the relationships between the different permeability, molecular weight, and concentration of the ASP solution, as well as the resistance coefficient and residual resistance coefficient, are first established, and then, a layered injection experimental model is established to carry out experimental research on injection capacity and oil displacement capacity. The experimental results show that the smaller the range of the core permeability is, the larger the molecular weight and concentration of the ASP solution are, and the poorer the injection capacity of the ASP solution is. After the action of a partial pressure tool and a partial quality tool, the injection capacity of ASP solution is improved to different degrees, and the oil displacement effect of low‐permeability cores is significantly improved, while the total oil recovery is increased, and the total oil recovery of heterogeneous cores under different conditions is increased by 1.4%‐4.05%. This experiment is of great significance to the study of improving the oil recovery of heterogeneous reservoirs.

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Section: Introductionmentioning

confidence: 99%

Experimental evaluation of ASP flooding to improve oil recovery in heterogeneous reservoirs by layered injection approach

Huang

et al. 2020

Energy Science & Engineering

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“…If it stays in the formation, it will block the pore canal and form seepage resistance at the staying place, which will affect the oil displacement effect, and it will also pollute the formation and form secondary pollution [16,17]. For CO 2 flooding, the process of transporting CO 2 will cause structural damage and corrosion of pipelines, and gas channeling will occur during the oil displacement process, reducing the sweep efficiency [18][19][20]. Therefore, under the condition of not changing the structure of the low permeability oil layer and not polluting the oil layer, it is of great significance to use a partial quality tool to improve the oil displacement effect.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on the Effect of ASP Flooding on Improving Oil Recovery in Low Permeability Reservoirs Based on a Partial Quality Tool

Huang

et al. 2020

Processes

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In order to solve the problem of the poor oil displacement effect of high molecular weight alkali/surfactant/polymer (ASP) solution in low permeability reservoirs, Daqing Oilfield uses a partial quality tool to improve the oil displacement effect in low permeability reservoirs. In the formation, the partial quality tool degrades the polymer through active shearing action, reducing the molecular weight of the polymer, to improve the matching degree to the low permeability oil layer and the oil recovery. In order to study the ability of the partial quality tool to improve the oil displacement effect, the matching degree of high molecular weight ASP solution to low permeability cores is studied, and the ability of quality control tools to change the molecular weight is studied. Then, experimental research on the pressure and oil displacement effect of high molecular weight ASP solution before and after the actions of the partial quality tool is carried out. The results show that ASP solutions with molecular weights of 1900 × 104 and 2500 × 104 have a poor oil displacement effect in low permeability reservoirs. After the action of the partial quality tool, the injection pressure is reduced by 5.22 MPa, and the oil recovery is increased by 7.79%. The injection pressure of the ASP solution after shearing by the partial quality tool is lower than that of the ASP solution with the same molecular weight and concentration without shearing, but the oil recovery is lower. On the whole, the use of the partial quality tool can obviously improve the oil displacement effect in low permeability reservoirs.

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“…The low sweep efficiency caused by gas channeling leads to the insufficient effect of CO 2 injection [15], hence some experts put forward the method of gas injection huff-n-puff to improve the effect of gas injection. Song used experimental techniques to estimate the performance of the CO 2 huff-n-puff process in Bakken tight oil reservoir [16].…”

Section: Introductionmentioning

confidence: 99%

Simulation Study of Allied In-Situ Injection and Production for Enhancing Shale Oil Recovery and CO2 Emission Control

Chen

et al. 2019

Energies

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The global greenhouse effect makes carbon dioxide (CO2) emission reduction an important task for the world, however, CO2 can be used as injected fluid to develop shale oil reservoirs. Conventional water injection and gas injection methods cannot achieve desired development results for shale oil reservoirs. Poor injection capacity exists in water injection development, while the time of gas breakthrough is early and gas channeling is serious for gas injection development. These problems will lead to insufficient formation energy supplement, rapid energy depletion, and low ultimate recovery. Gas injection huff and puff (huff-n-puff), as another improved method, is applied to develop shale oil reservoirs. However, the shortcomings of huff-n-puff are the low sweep efficiency and poor performance for the late development of oilfields. Therefore, this paper adopts firstly the method of Allied In-Situ Injection and Production (AIIP) combined with CO2 huff-n-puff to develop shale oil reservoirs. Based on the data of Shengli Oilfield, a dual-porosity and dual-permeability model in reservoir-scale is established. Compared with traditional CO2 huff-n-puff and depletion method, the cumulative oil production of AIIP combined with CO2 huff-n-puff increases by 13,077 and 17,450 m3 respectively, indicating that this method has a good application prospect. Sensitivity analyses are further conducted, including injection volume, injection rate, soaking time, fracture half-length, and fracture spacing. The results indicate that injection volume, not injection rate, is the important factor affecting the performance. With the increment of fracture half-length and the decrement of fracture spacing, the cumulative oil production of the single well increases, but the incremental rate slows down gradually. With the increment of soaking time, cumulative oil production increases first and then decreases. These parameters have a relatively suitable value, which makes the performance better. This new method can not only enhance shale oil recovery, but also can be used for CO2 emission control.

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Performance and gas breakthrough during CO 2 immiscible flooding in ultra-low permeability reservoirs

Cited by 104 publications

References 11 publications

Experimental evaluation of ASP flooding to improve oil recovery in heterogeneous reservoirs by layered injection approach

Experimental evaluation of ASP flooding to improve oil recovery in heterogeneous reservoirs by layered injection approach

Experimental Study on the Effect of ASP Flooding on Improving Oil Recovery in Low Permeability Reservoirs Based on a Partial Quality Tool

Simulation Study of Allied In-Situ Injection and Production for Enhancing Shale Oil Recovery and CO2 Emission Control

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