Water-flooding characteristics of lithologic reservoir in Ordos basin

He, Jiale; Liu, Xiaodong; Zhu, Xinyu; Jiang, Tao; He, Hongping; Zhou, Lin; Liu, Qinghai; Zhu, Yushuang; Liu, Linyu

doi:10.1038/s41598-021-82035-4

Cited by 13 publications

(7 citation statements)

References 34 publications

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“…Numerous studies show that the length of the three stages dictates the performance of a waterflooding reservoir. 1,13,26 The length of stage I and stage II is proportional to the volumetric sweep efficiency and displacement efficiency, respectively, and stage III is inversely proportional to displacement efficiency. 13,26 Therefore, the longer the lengths of stage I and stage II, the higher the oil recovery of a waterflooding reservoir.…”

Section: Eeor Mechanismmentioning

confidence: 99%

“…Numerous studies show that the length of the three stages dictates the performance of a waterflooding reservoir. ,, The length of stage I and stage II is proportional to the volumetric sweep efficiency and displacement efficiency, respectively, and stage III is inversely proportional to displacement efficiency. , Therefore, the longer the lengths of stage I and stage II, the higher the oil recovery of a waterflooding reservoir. With an increase of the DC electric field intensity and ion concentration, the electrokinetic phenomena are continuously strengthened so that the lengths of stages I and III are reduced, while the length of stage II is increased prior to its maximum DC electric field intensity and ion concentration.…”

Section: Eeor Mechanismmentioning

confidence: 99%

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Laboratory Evaluation of Electrically Enhanced Oil Recovery in Tight Reservoirs

Jia,

Ning,

Lyu

et al. 2023

Energy Fuels

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By coupling the electrokinetic phenomenon, the direct current (DC) electric field has recently been considered as a novel process to enhance oil recovery over waterflooding. We conducted a series of coreflood experiments to evaluate the performance of electrically enhanced oil recovery in tight reservoirs and identify the key underlying mechanisms. Results show that the oil recovery induced by the DC electric field is higher than that of waterflooding. The oil recovery increases first and then decreases with the enhancement of the DC electric field. Using 0.05 mol/L NaCl solution with 10 V voltage, the highest oil recovery of 55.6% was increased by 28.4% compared with the average oil recovery (43.3%) of waterflooding. Not only does electroosmosis reduce the required pressure from 19.20 to 15.89 MPa with its variation proportional to the DC voltage and ion concentration but also such an electrochemical reaction changes the core mineral compositions (i.e., increasing the clay content but decreasing the orthoclase and calcite content), evidenced by a decrease in both contact angle up to 27.34% and absolute zeta potential up to 22.21%. By reduction of the flow resistance of water and increase of the oil−water ratio, electroosmosis shortens the time for the water at the displacement front to reach the outlet and reduces the volumetric sweep efficiency. Meanwhile, electroosmosis causes a smooth velocity profile similar to the piston-like displacement and increases displacement efficiency. Once a reduction in volumetric sweep efficiency could not be offset by an increase in displacement efficiency, oil recovery would be first improved with an increase in both voltage and ion concentration and then decreased, among which the effect of ion concentration is not as significant as that of the voltage.

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Section: Eeor Mechanismmentioning

confidence: 99%

Section: Eeor Mechanismmentioning

confidence: 99%

Laboratory Evaluation of Electrically Enhanced Oil Recovery in Tight Reservoirs

Jia,

Ning,

Lyu

et al. 2023

Energy Fuels

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“…Ordos basin is a large sedimentary basin with multicycle evolution and multisedimentary types. 17 The area of the basin is about 25 × 10 4 km 2 . At present, the structure is a large syncline with slow width in the east and steep in the west, and the dip angle is generally less than 1°.…”

Section: Geological Backgroundmentioning

confidence: 99%

“…Ordos basin is a large sedimentary basin with multicycle evolution and multisedimentary types . The area of the basin is about 25 × 10 4 km 2 .…”

Section: Geological Backgroundmentioning

confidence: 99%

Modification of the Calculation Method for Dynamic Reserves in Tight Sandstone Gas Reservoirs

Guo²,

Cui³

et al. 2021

ACS Omega

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The determination of dynamic reserves is important for tight sandstone gas reservoirs in production. Based on the geological and gas data of the Yan’an gas field, the influence of pressure on the properties of natural gas is studied by mathematical methods. At the same time, the modified flowing material balance equation is established considering the changes in gas viscosity and compressibility. The result shows that (1) the viscosity of natural gas increases rapidly with pressure; (2) the deviation factor decreases with pressure (P < 15 MPa) and then increases (P > 15 MPa) with temperature; (3) the compressibility decreases rapidly with pressure and increases with temperature; (4) compared with the results of the material balance method, the average error of the flowing material balance method is 33.95%, and the accuracy of the modified flowing material balance method is higher with an average error of 1.25%; and (5) a large change in the production will affect the accuracy of the modified flowing material balance method, especially a shut-in for a long time before the pressure drop production is calculated at a certain time, so data points that are relatively consistent should be selected as far as possible to calculate the dynamic reserves. The findings of this study can help in the accurate evaluation of dynamic reserves of the tight gas reservoir in the Yan’an gas field and are an important guide for the formulation of a rational plan for the gas reservoir and its economic and efficient development.

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“…Heterogeneous characteristics of reservoirs, as one of the universal and toughest problems, severely constrains the enhancement of oil recovery (EOR). , Moreover, the heterogeneity can be divided into two types based on whether the fluid flowing in different regions is induced by interlayers: interlayer heterogeneity and intralayered heterogeneity. Intralayered heterogeneity only denotes that the regions with different permeabilities and porosities exist in the same layer, and interlayer heterogeneity is mainly caused by the barrier of interlayers so that no fluid exchanges in different layers. , The heterogeneity can be exacerbated by the long-term scouring of injected fluid with low viscosity, causing the remaining oil to be left in the unswept region . Therefore, the key to enhance oil recovery of multilayered heterogeneous reservoirs is optimizing the sweep effect among different layers and enhancing the remaining oil from the poor connectivity pores in the sweep region …”

Section: Introductionmentioning

confidence: 99%

Insights into Molecular Dynamics and Oil Extraction Behavior of the Polymeric Surfactant in a Multilayered Heterogeneous Reservoir

Zheng,

Liu,

Tong

2024

ACS Omega

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Interlayer heterogeneity, an inevitable and complex challenge during water flooding, seriously constrains the spread of the sweep region and oil recovery enhancement in multilayered heterogeneous reservoirs. To overcome this challenge, a novel polymeric surfactant, having an excellent performance in the reduction of interfacial tension (IFT) and the increase of viscosity of displacing fluid, is applied for enlarging the sweep resonance and increasing the oil washing efficiency. Through the molecular dynamics (MD) simulation, the molecular distributing mechanisms of the polymeric surfactant at the oil−water interface are analyzed to provide the theoretical basis for explaining the microscopic mechanism of oil extraction. To directly reflect the microscopic behavior of oil extraction, multiple transparent sand-packed models are designed to investigate the flowing behavior of different fluids and the extracted mechanisms of the remaining oil in both pore and macroscales. The multilayered heterogeneous reservoirs consisting of high-, moderate-, and low-permeability layers are fabricated to represent a heterogeneous characteristic. The recognition from the visual experiment and MD simulation can study the performance control, the extracting performance of the remaining oil, and the expression of the displacing front from different perspectives. The results from MD simulation demonstrate that the polymeric surfactant can promote the disintegration of the remaining oil and enhance its mobility. The experimental results indicate that the sweep efficiency is restricted by viscous fingering and tongue advance. Through the analysis of mathematical models, the rising mobility ratio and the location of the displacing front have a strong positive relationship with viscous fingering and tongue advance, which can reasonably explain the plugging performance of the polymeric surfactant, greatly improving the sweeping effect of the whole reservoir. Moreover, the Marangoni effect generated by the IFT gradient can induce the transformation of interfacial energy to displacement kinetic energy by the emulsification of the oil−water interface so that the remaining oil in the blind-end pore can be effectively extracted. However, by comparing data from image quantification techniques and production dynamic performance, the sweep efficiency (484%) was significantly greater than that of oil recovery (300%), demonstrating that the expanded sweep effect still plays a dominant role in the extraction of remaining oil after polymeric surfactant flooding. This study provides a novel plugging and effective washing agent that is expected to be an excellent and comprehensive method for solving the problem of low oil recovery in multilayered heterogeneous reservoirs.

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Water-flooding characteristics of lithologic reservoir in Ordos basin

Cited by 13 publications

References 34 publications

Laboratory Evaluation of Electrically Enhanced Oil Recovery in Tight Reservoirs

Laboratory Evaluation of Electrically Enhanced Oil Recovery in Tight Reservoirs

Modification of the Calculation Method for Dynamic Reserves in Tight Sandstone Gas Reservoirs

Insights into Molecular Dynamics and Oil Extraction Behavior of the Polymeric Surfactant in a Multilayered Heterogeneous Reservoir

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