Theoretical and experimental studies on the fluid–solid coupling processes for oil recovery from low permeability fractured reservoirs

2004 ◽  
Vol 41 (3) ◽  
pp. 496
Author(s):  
Jian-Jun Liu ◽  
Xia-Ting Feng ◽  
Lan-Ru Jing
Keyword(s):  
Oil Recovery ◽  
Fractured Reservoirs ◽  
Experimental Studies ◽  
Low Permeability ◽  
Coupling Processes

scholarly journals Method for Calculating Productivity of Water Imbibition Based on Volume Fracturing Stimulations of Low Permeability Reservoirs

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Lisha Zhao ◽  
Xin Li ◽  
Shuhong Wu ◽  
Zhongbao Wu ◽  
Min Tong
Keyword(s):  
Oil Recovery ◽  
Fractured Reservoirs ◽  
Three Dimensional ◽  
Fracture Network ◽  
Economic Feasibility ◽  
Low Permeability ◽  
Diffusivity Coefficient ◽  
Two Phase ◽  
Water Imbibition ◽  
Volume Fracturing

Spontaneous water imbibition is an important mechanism in water-wet fractured reservoirs. For volume-fractured reservoirs, to evaluate the oil productivity and oil recovery through water counter-current imbibition, we propose an analytical method for optimizing the reservoir volume fracturing scheme. Based on the two-phase fluid flow differential equation for capillary force, a three-dimensional water imbibition productivity equation is derived analytically. The equation for the water imbibition productivity considering the fracture network is obtained. A numerical model is constructed to verify the validity of the average capillary diffusivity coefficient and the results of the analytical model. By applying this method to a low permeability reservoir, after volume fracturing and waterflooding huff and puff, the relationship between the tenth year’s oil recovery and oil production rate and the length, width, and density of the fracture network is predicted, which gives an optimization of the field fracturing construction scale. The results show that the length and width of the fracture network should be no less than 50% of the well spacing and row spacing to obtain a reasonable production. Considering the fracturing technique and economic feasibility, the higher the density of the fracture network, the better the production obtained. Through hydraulic volume fracturing and waterflooding huff and puff, water imbibition is brought into full play and the 10 year oil recovery is increased by 6%–8% in this area.

Numerical Simulation of Low-Permeability Fractured Reservoirs on Imbibition

2013 ◽  
Vol 712-715 ◽  
pp. 792-795 ◽  
Author(s):  
Yun Qiang Wu ◽  
Jing Song Li ◽  
Xin Hong Zhang ◽  
Jian Zhou ◽  
Tong Jing Liu
Keyword(s):  
Numerical Simulation ◽  
Oil Recovery ◽  
Capillary Force ◽  
Fractured Reservoirs ◽  
Channel Structure ◽  
Low Permeability ◽  
Dense Matrix ◽  
Fractured Reservoir ◽  
Capillary Suction ◽  
The Matrix

Low permeability fractured reservoir is a special reservoir with complex fracture distribution and dense matrix. Low permeability fractured reservoir always have small porosity, low pore pressure and permeability. Therefore, low permeability fractured reservoir has low oil recovery efficiency. Besides, the developing complex process and higher costs lead to lower economic benefit. Low permeability fractured reservoir production mechanisms in the fracture system mainly by the capillary force of water into the matrix. Therefore, the hydrophilic blocks of dense, self-priming effect of capillary water is the main mechanism of oil. In this study, numerical simulation, the establishment of a dual media model analysis showed that the capillary suction from the oil production rate and the final volume flow channel structure, the capillary force, viscosity of crude oil and other factors.

ASSESSMENT OF OIL WELL PRODUCTIVITY IN LOW-PERMEABILITY RESERVOIRS IN THE FIELDS OF EASTERN SIBERIA

2017 ◽  
pp. 30-36
Author(s):  
R. V. Urvantsev ◽  
S. E. Cheban
Keyword(s):  
Oil Recovery ◽  
Large Scale ◽  
Oil And Gas ◽  
Oil Extraction ◽  
Low Permeability ◽  
Oil Well ◽  
Eastern Siberia ◽  
Development Costs ◽  
Traditional Fields ◽  
Low Permeability Reservoirs

The 21st century witnessed the development of the oil extraction industry in Russia due to the intensifica- tion of its production at the existing traditional fields of Western Siberia, the Volga region and other oil-extracting regions, and due discovering new oil and gas provinces. At that time the path to the development of fields in Eastern Siberia was already paved. The large-scale discoveries of a number of fields made here in the 70s-80s of the 20th century are only being developed now. The process of development itself is rather slow in view of a number of reasons. Create a problem of high cost value of oil extraction in the region. One of the major tasks is obtaining the maximum oil recovery factor while reducing the development costs. The carbonate layer lying within the Katangsky suite is low-permeability, and its inventories are categorised as hard to recover. Now, the object is at a stage of trial development,which foregrounds researches on selecting the effective methods of oil extraction.

scholarly journals Mechanism of active silica nanofluids based on interface-regulated effect during spontaneous imbibition

2021 ◽  
Author(s):  
Xu-Guang Song ◽  
Ming-Wei Zhao ◽  
Cai-Li Dai ◽  
Xin-Ke Wang ◽  
Wen-Jiao Lv
Keyword(s):  
Contact Angle ◽  
Interfacial Tension ◽  
Oil Recovery ◽  
Dynamic Contact Angle ◽  
Liquid Interface ◽  
Spontaneous Imbibition ◽  
Wettability Alteration ◽  
Low Permeability ◽  
Oil Water ◽  
Solid Liquid

AbstractThe ultra-low permeability reservoir is regarded as an important energy source for oil and gas resource development and is attracting more and more attention. In this work, the active silica nanofluids were prepared by modified active silica nanoparticles and surfactant BSSB-12. The dispersion stability tests showed that the hydraulic radius of nanofluids was 58.59 nm and the zeta potential was − 48.39 mV. The active nanofluids can simultaneously regulate liquid–liquid interface and solid–liquid interface. The nanofluids can reduce the oil/water interfacial tension (IFT) from 23.5 to 6.7 mN/m, and the oil/water/solid contact angle was altered from 42° to 145°. The spontaneous imbibition tests showed that the oil recovery of 0.1 wt% active nanofluids was 20.5% and 8.5% higher than that of 3 wt% NaCl solution and 0.1 wt% BSSB-12 solution. Finally, the effects of nanofluids on dynamic contact angle, dynamic interfacial tension and moduli were studied from the adsorption behavior of nanofluids at solid–liquid and liquid–liquid interface. The oil detaching and transporting are completed by synergistic effect of wettability alteration and interfacial tension reduction. The findings of this study can help in better understanding of active nanofluids for EOR in ultra-low permeability reservoirs.

The Mechanism of Flue Gas Injection for Enhanced Light Oil Recovery

2004 ◽  
Vol 126 (2) ◽  
pp. 119-124 ◽  
Author(s):  
O. S. Shokoya ◽  
S. A. (Raj) Mehta ◽  
R. G. Moore ◽  
B. B. Maini ◽  
M. Pooladi-Darvish ◽  
...  
Keyword(s):  
Oil Recovery ◽  
Flue Gas ◽  
Gas Injection ◽  
Cost Effective ◽  
Air Injection ◽  
Oil Reservoirs ◽  
Flue Gases ◽  
Low Permeability ◽  
Light Oil ◽  
Light Oil Reservoirs

Flue gas injection into light oil reservoirs could be a cost-effective gas displacement method for enhanced oil recovery, especially in low porosity and low permeability reservoirs. The flue gas could be generated in situ as obtained from the spontaneous ignition of oil when air is injected into a high temperature reservoir, or injected directly into the reservoir from some surface source. When operating at high pressures commonly found in deep light oil reservoirs, the flue gas may become miscible or near–miscible with the reservoir oil, thereby displacing it more efficiently than an immiscible gas flood. Some successful high pressure air injection (HPAI) projects have been reported in low permeability and low porosity light oil reservoirs. Spontaneous oil ignition was reported in some of these projects, at least from laboratory experiments; however, the mechanism by which the generated flue gas displaces the oil has not been discussed in clear terms in the literature. An experimental investigation was carried out to study the mechanism by which flue gases displace light oil at a reservoir temperature of 116°C and typical reservoir pressures ranging from 27.63 MPa to 46.06 MPa. The results showed that the flue gases displaced the oil in a forward contacting process resembling a combined vaporizing and condensing multi-contact gas drive mechanism. The flue gases also became near-miscible with the oil at elevated pressures, an indication that high pressure flue gas (or air) injection is a cost-effective process for enhanced recovery of light oils, compared to rich gas or water injection, with the potential of sequestering carbon dioxide, a greenhouse gas.

Development of the Surfactant-Based Chemical EOR Formula for Low Permeability Reservoirs

2021 ◽  
Author(s):  
Nancy Chun Zhou ◽  
Meng Lu ◽  
Fuchen Liu ◽  
Wenhong Li ◽  
Jianshen Li ◽  
...  
Keyword(s):  
Phase Behavior ◽  
Oil Recovery ◽  
Aqueous Solubility ◽  
Low Permeability ◽  
Chemical Flooding ◽  
Residual Oil ◽  
Key Factors ◽  
Low Salinity ◽  
Low Tension ◽  
Low Permeability Reservoirs

Abstract Based on the results of the foam flooding for our low permeability reservoirs, we have explored the possibility of using low interfacial tension (IFT) surfactants to improve oil recovery. The objective of this work is to develop a robust low-tension surfactant formula through lab experiments to investigate several key factors for surfactant-based chemical flooding. Microemulsion phase behavior and aqueous solubility experiments at reservoir temperature were performed to develop the surfactant formula. After reviewing surfactant processes in literature and evaluating over 200 formulas using commercially available surfactants, we found that we may have long ignored the challenges of achieving aqueous stability and optimal microemulsion phase behavior for surfactant formulations in low salinity environments. A surfactant formula with a low IFT does not always result in a good microemulsion phase behavior. Therefore, a novel synergistic blend with two surfactants in the formulation was developed with a cost-effective nonionic surfactant. The formula exhibits an increased aqueous solubility, a lower optimum salinity, and an ultra-low IFT in the range of 10-4 mN/m. There were challenges of using a spinning drop tensiometer to measure the IFT of the black crude oil and the injection water at reservoir conditions. We managed the process and studied the IFTs of formulas with good Winsor type III phase behavior results. Several microemulsion phase behavior test methods were investigated, and a practical and rapid test method is proposed to be used in the field under operational conditions. Reservoir core flooding experiments including SP (surfactant-polymer) and LTG (low-tension-gas) were conducted to evaluate the oil recovery. SP flooding with a selected polymer for mobility control and a co-solvent recovered 76% of the waterflood residual oil. Furthermore, 98% residual crude oil recovery was achieved by LTG flooding through using an additional foaming agent and nitrogen. These results demonstrate a favorable mobilization and displacement of the residual oil for low permeability reservoirs. In summary, microemulsion phase behavior and aqueous solubility tests were used to develop coreflood formulations for low salinity, low temperature conditions. The formulation achieved significant oil recovery for both SP flooding and LTG flooding. Key factors for the low-tension surfactant-based chemical flooding are good microemulsion phase behavior, a reasonably aqueous stability, and a decent low IFT.

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