Nuclear magnetic resonance features of low-permeability reservoirs with complex wettability

Feng, Cheng; Shi, Yuqing; Hao, Jianfei; Wang, Zhenlin; Mao, Zhiqiang; Li, Gao‐Ren; Jiang, Zhihao

doi:10.1016/s1876-3804(17)30030-7

Cited by 31 publications

(8 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In a nutshell, the oilwater interface in natural sandstone porous media is complex due to the influence of capillary trapping and the existence of oil-wetting clay. This phenomenon is in agreement with Trantham and Clampitt and Feng et al [37,38].…”

Section: Microoccurrence Of Irreducible Water In the Pore Andsupporting

confidence: 92%

The Visual and Quantitative Study of the Microoccurrence of Irreducible Water at the Pore and Throat System in a Low-Permeability Sandstone Reservoir by Using Microcomputerized Tomography

Huang

Khan

et al. 2018

Geofluids

View full text Add to dashboard Cite

The microflow equipment monitored with micro X-ray computerized tomography (CT) is employed to investigate the microoccurrence of the irreducible water in a low-permeability sandstone core. By means of image segmentation and the threedimensional (3D) image reconstruction technique, the visual microdistribution characteristics of irreducible water in twodimensional (2D) slices and the 3D pore-throat system are quantitatively evaluated. Some interesting findings are list as below. Firstly, due to the variant micro geometric structures of the pore-throat systems, specific core slices showed significantly different irreducible water saturation even though these slices had same areal porosity. Secondly, due to the influence of capillary trapping and the existence of oil-wetting clay (main chlorite), the irreducible water saturation in the throat system (64%) is much larger than that in the pore system (36%). Furthermore, the wetting phase (irreducible water) did not spread all over the surface of the pore-throat network which caused a much more complicated oil-water two-phase interface. Thirdly, in micro scale, the main irreducible water occurrence mode in the pore system is much different from that in the throat system. In the pore system, the irreducible water principally existed in the corner of the pores which are linked through a water film. While in the throat system, the irreducible water occurrence is dominated by the water film. However, 25.5% of the throats are blocked by the irreducible water which cut off the crude oil drainage channels.

show abstract

Section: Microoccurrence Of Irreducible Water In the Pore Andsupporting

confidence: 92%

The Visual and Quantitative Study of the Microoccurrence of Irreducible Water at the Pore and Throat System in a Low-Permeability Sandstone Reservoir by Using Microcomputerized Tomography

Huang

Khan

et al. 2018

Geofluids

View full text Add to dashboard Cite

show abstract

“…The detailed procedure is listed as follows: Cores were treated with SC-CO 2 fracturing fluid with different concentrations of thickener for 120 min, respectively. Cores were dried in an oven at 120 °C for 12 h to confirm CO 2 and cosolvent had completely disappeared. Put the core in the special cell to measure the T2 signal within the sample. The adsorption of thickener could be monitored and the corresponding adsorption pores could be inferred from the T2 spectra graph. , …”

Section: Experimental Sectionmentioning

confidence: 99%

Wettability Alteration Study of Supercritical CO₂ Fracturing Fluid on Low Permeability Oil Reservoir

et al. 2017

View full text Add to dashboard Cite

Hydraulic fracturing has become an important stimulation technique for low/ultralow permeability reservoirs. Supercritical CO 2 (SC-CO 2 ), as a no water phase material of fracturing fluid, receives wide attention. Current researches on SC-CO 2 fracturing fluid has mainly focused on its viscous properties and superiorities. However, little attention has been devoted to the interaction between SC-CO 2 fracturing fluid and the oil reservoir during the fracturing process. Besides, in a low permeability reservoir, the wettability determines the oil recovery by imbibition, which is a main way to explore oil for a matrix. Therefore, it is crucial to study the wettability alteration on a low permeability oil reservoir introduced by SC-CO 2 fracturing fluid. In this study, a contact angle goniometer was introduced to characterize the wettability alteration on low permeability cores by SC-CO 2 fracturing fluid. Meanwhile, nuclear magnetic resonance T2 spectra, a scanning electron microscope, and a energy dispersive spectrometer were used to explain the mechanisms of wettability alteration and the adsorption of fracturing fluid was analyzed. In addition, spontaneous imbibition tests were conducted to definite the impact of wettability alteration on oil production. The results showed that the thickener in SC-CO 2 fracturing fluid, fluid filter loss, and reservoir permeability were all responsible for wettability alteration on the core surface. With the increasing thickener contents and filter loss of fracturing fluid, cores turned to be intermediate and slightly water-wet from initial strongly water-wet, which was unfavorable for oil production.Comparatively low permeability cores which consist of more micro-small pores were more likely to make treated cores oleophilic, as well. Thickener adsorption was confirmed to be the main mechanism on wettability alteration by SC-CO 2 fracturing fluid, which resulted in different pore surfaces, and thus a more oleophilic cores surface. On the basis of the results of spontaneous imbibition, strong lipophilicity cores corresponded to lower oil recovery, which illustrated that wettability alteration caused by SC-CO 2 fracturing fluid was not favored for oil flow.

show abstract

“…Generally, the reservoirs with an average permeability of >0.3 mD can be developed by water flooding, but their ultimate recovery factor is less than 10%. In recent few years, many researchers have been working actively on the ways to improve water flooding, such as surfactant injection and nanofluid injection. − Previous research studies indicated that the oil displacement efficiency depends mainly on the imbibition effect generated by capillary force during water flooding of the tight reservoir. , However, the existing surfactants are mostly micron-sized, making them fail to efficiently enter the pores and throats of the tight reservoir matrix. Thus, the field injection–production relationship fails to be built, resulting in serious imbalance of injection and production.…”

Section: Introductionmentioning

confidence: 99%

“…8−14 Previous research studies indicated that the oil displacement efficiency depends mainly on the imbibition effect generated by capillary force during water flooding of the tight reservoir. 15,16 However, the existing surfactants are mostly micron-sized, making them fail to efficiently enter the pores and throats of the tight reservoir matrix. Thus, the field injection− production relationship fails to be built, resulting in serious imbalance of injection and production.…”

Section: Introductionmentioning

confidence: 99%

Mechanism of Improving Water Flooding Using the Nanofluid Permeation Flooding System for Tight Reservoirs in Jilin Oilfield

et al. 2021

View full text Add to dashboard Cite

In Jilin Oilfield, development of water-flooding operations in tight oil reservoirs is not satisfactory due to low effective permeability, tiny pore throats, and low mobility of crude oil in the matrix. In the interest of improving water-flooding efficacy for tight oil reservoirs, researchers in this study developed one nanofluid permeation flooding system through microemulsion preparation. This paper presents the experiments evaluating the characteristics and mechanism of improving tight oil recovery using nanofluids. The study results demonstrate that (1) the nanofluid permeation flooding system, with an average particle size of <25 nm, is very stable under the reservoir conditions and can effectively expand the swept volume ratio of the matrix with low porosity and ultralow permeability; (2) under the flow condition, the system can split the tight oil in Jilin Oilfield into "oil droplets in nanosize" which can be easily displaced from the matrix, with both swept volume and oil displacement efficiency exceeding 90% according to the micro etching model; and (3) the system has a good interfacial activity, leading to an interfacial tension with the tight oil in Jilin Oilfield of up to 10 −1 mN/m, so that it can greatly promote the efficacy of oil displacement in the matrix with tiny pores. According to the flooding experiments with cores retrieved from the oilfield, the nanofluid permeation flooding system with a concentration of 0.3% improves the oil displacement efficiency of water flooding by more than 27% averagely and reduces the injection pressure by over 38%. NMR evaluation results of tight cores indicate that the flooding system allows crude oil to be more efficiently displaced from meso/micropores. The nanofluid permeation flooding system is presumed to effectively improve the swept volume and oil displacement efficiency of water flooding and replenish formation energy. It can be a great support for efficient water-flooding development and continuous enhanced oil recovery in tight oil reservoirs of Jilin Oilfield.

show abstract

Nuclear magnetic resonance features of low-permeability reservoirs with complex wettability

Cited by 31 publications

References 6 publications

The Visual and Quantitative Study of the Microoccurrence of Irreducible Water at the Pore and Throat System in a Low-Permeability Sandstone Reservoir by Using Microcomputerized Tomography

The Visual and Quantitative Study of the Microoccurrence of Irreducible Water at the Pore and Throat System in a Low-Permeability Sandstone Reservoir by Using Microcomputerized Tomography

Wettability Alteration Study of Supercritical CO₂ Fracturing Fluid on Low Permeability Oil Reservoir

Mechanism of Improving Water Flooding Using the Nanofluid Permeation Flooding System for Tight Reservoirs in Jilin Oilfield

Contact Info

Product

Resources

About

Nuclear magnetic resonance features of low-permeability reservoirs with complex wettability

Cited by 31 publications

References 6 publications

The Visual and Quantitative Study of the Microoccurrence of Irreducible Water at the Pore and Throat System in a Low-Permeability Sandstone Reservoir by Using Microcomputerized Tomography

The Visual and Quantitative Study of the Microoccurrence of Irreducible Water at the Pore and Throat System in a Low-Permeability Sandstone Reservoir by Using Microcomputerized Tomography

Wettability Alteration Study of Supercritical CO2 Fracturing Fluid on Low Permeability Oil Reservoir

Mechanism of Improving Water Flooding Using the Nanofluid Permeation Flooding System for Tight Reservoirs in Jilin Oilfield

Contact Info

Product

Resources

About

Wettability Alteration Study of Supercritical CO₂ Fracturing Fluid on Low Permeability Oil Reservoir