The Porous Medium of Ultra-Low Permeability Reservoir has an Effect on Oil Recovery

2013 ◽  
Vol 779-780 ◽  
pp. 1457-1461
Author(s):  
Xian Wen Li ◽  
Chun Mei Xu ◽  
Fang Yuan Guo ◽  
Xing Hong Wang
Keyword(s):  
Porous Medium ◽  
Oil Recovery ◽  
Research Result ◽  
Water Injection ◽  
Injection Pressure ◽  
Injection Rate ◽  
Particle Migration ◽  
Low Permeability ◽  
Reservoir Water ◽  
Low Permeability Reservoir

This paper from the research of the porous medium pore structure characteristics of ultra-low permeability reservoir, combined the core flow test with reservoir characteristics analysis and fluid properties analysis studying the reservoir water injection development effect. The research results show that: the microscopic heterogeneity of ultra-low permeability reservoir is strong, pore connectivity of porous medium is poor, seepage throat is very fine and microcrack is growth. During the process of water injection development there exist particle migration phenomenon, could easily cause pore throat blockage, and lead to water injection pressure rebound. According to the research result targeted on the organic mud acid deep broken down experiment, the result shows that it can achieve the purpose of depressure and increasing injection rate.

The Research and Evaluation of Finely Layered Water Injection Standard in Low-Permeability Reservoirs - A Case from Block A in one Low-Permeability Reservoir

2014 ◽  
Vol 1073-1076 ◽  
pp. 2310-2315 ◽  
Author(s):  
Ming Xian Wang ◽  
Wan Jing Luo ◽  
Jie Ding
Keyword(s):  
Oil Recovery ◽  
Water Injection ◽  
Injection Pressure ◽  
Injection Rate ◽  
Low Permeability ◽  
Reservoir Permeability ◽  
Engineering Parameters ◽  
The Common ◽  
Common Problems ◽  
Low Permeability Reservoirs

Due to the common problems of waterflood in low-permeability reservoirs, the reasearch of finely layered water injection is carried out. This paper established the finely layered water injection standard in low-permeability reservoirs and analysed the sensitivity of engineering parameters as well as evaluated the effect of the finely layered water injection standard in Block A with the semi-quantitative to quantitative method. The results show that: according to the finely layered water injection standard, it can be divided into three types: layered water injection between the layers, layered water injection in inner layer, layered water injection between fracture segment and no-fracture segment. Under the guidance of the standard, it sloved the problem of uneven absorption profile in Block A in some degree and could improve the oil recovery by 3.5%. The sensitivity analysis shows that good performance of finely layered water injection in Block A requires the reservoir permeability ratio should be less than 10, the perforation thickness should not exceed 10 m, the amount of layered injection layers should be less than 3, the surface injection pressure should be below 14 MPa and the injection rate shuold be controlled at about 35 m3/d.

scholarly journals A Novel Nanodrag Reducer for Low Permeability Reservoir Water Flooding: Long-Chain Alkylamines Modified Graphene Oxide

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Hong Chen ◽  
Lin Xiao ◽  
Yuan Xu ◽  
Xiang Zeng ◽  
Zhong-Bin Ye
Keyword(s):  
Graphene Oxide ◽  
Water Injection ◽  
Injection Pressure ◽  
Water Flooding ◽  
Oxide Surface ◽  
Low Permeability ◽  
Reservoir Water ◽  
Water Contact ◽  
Low Permeability Reservoir ◽  
Modified Graphene Oxide

Chemical modification of graphene oxide (GO) by grafting hydrophobic chains on the surface has drawn much attention nowadays in the academic world, and it was suggested that modified GO could lead to new functionalized materials with specific structure and different properties. In this paper, modified GO (M-GO) were synthesized by chemically grafting alkylamines with varying chain lengths on the graphene oxide surface. Successful grafting of alkylamines was confirmed using Fourier transform infrared (FTIR) spectra, X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscope (SEM), and Raman spectroscopy measurements. In addition, we investigated the properties of M-GO as nanodrag reducer in low permeability reservoir water flooding. Water contact angle (CA) measurements revealed that the hydrophobic nature of GO depended on the chain length of the grafted alkylamines. And flooding experiments showed that the hexadecylamine- and octadecylamine-modified GO had an ability to reduce water injection pressure and improve water-phase permeability of the low permeability reservoirs during water flooding. So the M-GO would have potential applications in oilfield exploitation.

Parametric Study of Channeling Flow in Low Permeability Reservoir with Mudstone Interlayer

2012 ◽  
Vol 524-527 ◽  
pp. 1190-1195
Author(s):  
Jian Jun Liu ◽  
Quan Shu Li ◽  
Gui Hong Pei
Keyword(s):  
High Pressure ◽  
Water Injection ◽  
Injection Pressure ◽  
Element Model ◽  
Low Permeability ◽  
Low Permeability Reservoir ◽  
Injection Process ◽  
Well Spacing ◽  
Pressure Water ◽  
Channeling Flow

Channeling flow frequently occurs during the high pressure water injection of low permeability reservoir. The injection process is complex and covers so many parameters of which the contribution to channeling flow is necessarily to be studied. In this paper, numerical simulation is combined with sensitivity analysis method to calculate the significance of the weight of parameters to the channeling flow. First the values of different parameters are produced by using Latin hypercube method; second, by using these parameters, finite element model have been established and simulated, and the quantity of channeling flow has been calculated; then Spearman rank relation is applied to measure the relation of parameters and channeling flow. The results states that, in 10 years continuous injection, the well spacing and injection pressure have significant impact on the channeling flow. This states that during the application of high pressure water injection, the pressure and well spacing should be controlled especially.

Research of Improving Water Injection Effect by Using Active SiO2 Nano-Powder in the Low-Permeability Oilfield

2010 ◽  
Vol 92 ◽  
pp. 207-212 ◽  
Author(s):  
Ke Liang Wang ◽  
Shou Cheng Liang ◽  
Cui Cui Wang
Keyword(s):  
Oil Recovery ◽  
Pore Volume ◽  
Water Injection ◽  
Field Tests ◽  
Injection Pressure ◽  
Rock Surface ◽  
Low Permeability ◽  
Injection Wells ◽  
Decompression Rate ◽  
Nano Powder

SiO2 nano-powder is a new type of augmented injection agent, has the ability of stronger hydrophobicity and lipophilicity, and can be adsorbed on the rock surface so that it changes the rock wettability. It can expand the pore radius effectively, reduce the flow resistance of injected water in the pores, enhance water permeability, reduce injection pressure and augment injection rate. Using artificial cores which simulated geologic conditions of a certain factory of Daqing oilfield, decompression and augmented injection experiments of SiO2 nano-powder were performed after waterflooding, best injection volume of SiO2 nano-powder under the low-permeability condition was selected. It has shown that SiO2 nano-powder inverted the rock wettability from hydrophilicity to hydrophobicity. Oil recovery was further enhanced after waterflooding. With the injection pore volume increasing, the recovery and decompression rate of SiO2 nano-powder displacement increased gradually. The best injected pore volume and injection concentration is respectively 0.6PV and 0.5%, the corresponding value of EOR is 6.84% and decompression rate is 52.78%. According to the field tests, it is shown that, in the low-permeability oilfield, the augmented injection technology of SiO2 nano-powder could enhance water injectivity of injection wells and reduce injection pressure. Consequently, it is an effective method to resolve injection problems for the low-permeability oilfield.

The Research on Effect Factors of the Polymer Flooding in Low Permeability Reservoir of Daqing Oilfield

2011 ◽  
Vol 383-390 ◽  
pp. 3809-3813
Author(s):  
Yong Li Wang ◽  
Tao Li ◽  
Zhi Guo Fu ◽  
Shu Xia Liu ◽  
Bai Lin Yu ◽  
...  
Keyword(s):  
Oil Recovery ◽  
Injection Rate ◽  
Polymer Flooding ◽  
Low Permeability ◽  
Effect Factors ◽  
Field Development ◽  
Low Permeability Reservoir ◽  
Well Pattern ◽  
Simulation Results ◽  
Enhance Oil Recovery

The pilot block is a heterogeneous reservoir with low permeability which is only 100-200(mD). Polymer flooding will be used to enhance oil recovery (EOR). Therefore, some experiment will be carried out in this pilot block .According to the simulation results, we can infer the effect factors of the polymer flooding such as concentration, injection rate, slug amounts, and well pattern. It gives us effective information for the field development plan.

scholarly journals Experimental Study on Enhanced Oil Recovery by Nitrogen-Water Alternative Injection in Reservoir with Natural Fractures

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Xiang Li ◽  
Yuan Cheng ◽  
Wulong Tao ◽  
Shalake Sarulicaoketi ◽  
Xuhui Ji ◽  
...  
Keyword(s):  
Oil Recovery ◽  
Gas Injection ◽  
Water Injection ◽  
Injection Pressure ◽  
Injection Rate ◽  
Water Flooding ◽  
Orthogonal Experimental Design ◽  
Fractured Reservoir ◽  
Natural Fractures ◽  
Nitrogen Injection

The production of a low permeability reservoir decreases rapidly by depletion development, and it needs to supplement formation energy to obtain stable production. Common energy supplement methods include water injection and gas injection. Nitrogen injection is an economic and effective development method for specific reservoir types. In order to study the feasibility and reasonable injection parameters of nitrogen injection development of fractured reservoir, this paper uses long cores to carry out displacement experiment. Firstly, the effects of water injection and nitrogen injection development of a fractured reservoir are compared through experiments to demonstrate the feasibility of nitrogen injection development of the fractured reservoir. Secondly, the effects of gas-water alternate displacement after water drive and gas-water alternate displacement after gas drive are compared through experiments to study the situation of water injection or gas injection development. Finally, the reasonable parameters of nitrogen gas-water alternate injection are optimized by orthogonal experimental design. Results show that nitrogen injection can effectively enhance oil production of the reservoir with natural fractures in early periods, but gas channeling easily occurs in continuous nitrogen flooding. After water flooding, gas-water alternate flooding can effectively reduce the injection pressure and improve the reservoir recovery, but the time of gas-water alternate injection cannot be too late. It is revealed that the factors influencing the nitrogen-water alternative effect are sorted from large to small as follows: cycle injected volume, nitrogen and water slug ratio, and injection rate. The optimal cycle injected volume is around 1 PV, the nitrogen and water slug ratio is between 1 and 2, and the injection rate is between 0.1 and 0.2 mL/min.

scholarly journals Effect evaluation and influencing factors of stratified water injection in low permeability reservoir

2021 ◽  
Vol 292 ◽  
pp. 01014
Author(s):  
Xin Bai ◽  
Shiyan Hao ◽  
Chunfen Guo ◽  
Shenglin Yao
Keyword(s):  
Influencing Factors ◽  
Oil Recovery ◽  
High Efficiency ◽  
Water Injection ◽  
Low Permeability ◽  
Injection Timing ◽  
Effect Evaluation ◽  
Low Permeability Reservoir ◽  
Drive Control ◽  
Injection Effect

The main production layers in Danba oil area of Yanchang oilfield are Chang 4 + 5 and Chang 6 oil layers, which are the main development areas for increasing reserves and production. In view of the unclear influencing factors of water injection effect and the disunity of effect evaluation in the study area, the stratified water injection effect evaluation and influencing factors of low permeability reservoir are studied by means of production data statistical analysis and numerical simulation. The results show that the effect of water injection in the study area is affected by five factors: intraformational heterogeneity, interlayer heterogeneity, interlayer pressure difference, fracture and water injection timing, the results show that the water injection effect is obvious in the study area by using the five indexes of water drive reserves producing degree, water storage rate, water drive index, oil recovery rate and water drive control degree. The research results provide ideas for the study of high-efficiency separate layer water injection in low permeability reservoir, and provide guidance for the next step of potential mining.

Optimized Cyclic Water Injection Strategy for Oil Recovery in Low-Permeability Reservoirs

2018 ◽  
Vol 141 (1) ◽  
Author(s):  
Xiaofei Sun* ◽  
Yanyu Zhang ◽  
Jie Wu ◽  
Mengke Xie ◽  
Hang Hu
Keyword(s):  
Oil Recovery ◽  
Water Injection ◽  
Tracer Tests ◽  
Oil Prices ◽  
Fuzzy Comprehensive Evaluation ◽  
Low Permeability ◽  
Operational Parameters ◽  
Recovery Method ◽  
Low Permeability Reservoir ◽  
Low Permeability Reservoirs

With the worldwide decline in conventional oil production, tremendous unconventional resources, such as low-permeability reservoirs, are becoming increasingly important. Cyclic water injection (CWI) as an oil recovery method has attracted increasing attention in the present environment of low oil prices. However, the optimal CWI strategy is difficult to determine for a mature oilfield due to the involvement of multiple wells with multiple operational parameters. Thus, our main focus in this paper is to present a novel and systematic approach to optimize CWI strategies by studying a typical low-permeability, namely, reservoir G21. To this end, a comprehensive method that combines the advantages of streamline simulation and fuzzy comprehensive evaluation (FCE) was proposed to identify water channeling in the reservoir. Second, the reliability of the method was verified using tracer tests. Finally, a new hybrid optimization algorithm, the simulated annealing-genetic algorithm (SAGA), coupled with a reservoir simulator was developed to determine an optimal CWI strategy for the low-permeability reservoir. The results show that the CWI technique is viable as a primary means in the present environment of low oil prices to improve the waterflood performance in low-permeability reservoirs. The oil recovery of the most efficient strategy increases by 6.8% compared to conventional waterflooding. The asymmetric CWI scheme is more efficient than the symmetric CWI scheme for the low-permeability reservoir.

A Study of Seepage Characteristics of Unsteady Waterflooding Development for Fractured Ultra-Low-Permeability Reservoir

2021 ◽  
Author(s):  
Qing Liu ◽  
Xiangfang Li ◽  
Jian Yang ◽  
Sen Feng ◽  
Minxia He ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Simulation Model ◽  
Water Injection ◽  
Injection Rate ◽  
Low Permeability ◽  
Tensor Model ◽  
Capillary Imbibition ◽  
Low Permeability Reservoir ◽  
Water Cut ◽  
Low Permeability Reservoirs

Abstract Unconventional fractured ultra-low-permeability reservoirs play an important role in continental sedimentary basins in China, and their formation characteristics and seepage laws are greatly different from that of traditional reservoirs. In this paper, the influence of microfractures and unsteady waterflooding on the productivity of fractured ultra-low permeability reservoirs are studied deeply. The reservoir parameters used in the study are from an actual fractured ultra-low-permeability reservoir in Ordos Basin, where microfractures are developed but macroscopic fractures are not. The microfractures have a small opening and are widely distributed in the reservoir, so the reservoir numerical simulation model adopts the equivalent continuous matrix model to simulate waterflooding. On one hand, the physical model of micro-fractured reservoir and the permeability tensor model of the equivalent continuous matrix are established. The results show that the existence of microfractures can increase the permeability of matrix by 1.4 times. On the other hand, an ideal heterogeneous numerical simulation model composed of pure matrix and equivalent continuous matrix considering microfracture is established according to actual geological parameters of the fractured ultra-low-permeability reservoir. To simulate and compare the unsteady waterflooding and continuous waterflooding development in 10-year development under the condition of constant annual injection rate, the results indicate that unsteady waterflooding development make higher productivity and lower water cut and lower formation water saturation than that of continuous waterflooding. By conducting unsteady waterflooding development simulation for sensitivity analysis, the results demonstrate that the greater the capillary force, the better the role of capillary imbibition in a certain range, meanwhile, the unsteady waterflooding has the best exploitation effect when the value of water injection cycle time is 100 days and the fluctuation amplitude of water injection rate is 1. At the above situation, the displacement and capillary imbibition and pressure disturbance achieve the desired effect of reducing water cut and increasing oil production.

Injection Strategies To Overcome Gravity Segregation in Simultaneous Gas and Water Injection Into Homogeneous Reservoirs

SPE Journal ◽  
2009 ◽  
Vol 15 (01) ◽  
pp. 76-90 ◽  
Author(s):  
W.R.. R. Rossen ◽  
C.J.. J. van Duijn ◽  
Q.P.. P. Nguyen ◽  
C.. Shen ◽  
A.K.. K. Vikingstad
Keyword(s):  
Water Flow ◽  
Oil Recovery ◽  
Water Injection ◽  
Injection Pressure ◽  
Injection Rate ◽  
Numerical Dispersion ◽  
Horizontal Distance ◽  
Mixed Gas ◽  
Gravity Segregation ◽  
Vertical Well

Summary We extend a model for gravity segregation in steady-state gas/water injection into homogeneous reservoirs for enhanced oil recovery (EOR). A new equation relates the distance gas and water flow together directly to injection pressure, independent of fluid mobilities or injection rate. We consider three additional cases: coinjection of gas and water over only a portion of the formation interval, injection of water above gas over the entire formation interval, and injection of water and gas in separate zones well separated from each other. If gas and water are injected at fixed total volumetric rates, the horizontal distance to the point of complete segregation is the same, whether gas and water are coinjected over all or any portion of the formation interval. At fixed injection pressure, the deepest penetration of mixed gas and water flow is expected when fluids are injected along the entire formation interval. At fixed total injection rate, injection of water above gas gives deeper penetration before complete segregation than does coinjection, but again exactly where the two fluids are injected does not affect the distance to the point of segregation. At fixed injection pressure, injection of water above gas is predicted to give deeper penetration before complete segregation. When injection pressure is limited, the best strategy for simultaneous injection of both phases from a vertical well would be to inject gas at the bottom of the reservoir and water over the rest of the reservoir height, with the ratio of the injection intervals adjusted to maximize overall injectivity. The 2D model applies equally to gas/water flow and to foam, and to injection of water above gas from separate intervals of a vertical well or from two parallel horizontal wells, as long as injection is uniform along each horizontal well. Sample computer simulations for foam injection agree well with the model predictions if numerical dispersion is controlled.

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