scholarly journals Experimental Study on Dynamic Characteristics of Shut-In and Restart Process in Water Drive Strong Heterogeneous Oil Reservoir

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Hao Chen ◽  
Mingyang Yang ◽  
Haizeng Yu ◽  
Shenglai Yang ◽  
Mibang Wang
Keyword(s):  
Oil Recovery ◽  
Dynamic Characteristics ◽  
Water Distribution ◽  
High Water ◽  
Vertical Heterogeneity ◽  
High Water Cut ◽  
Water Cut ◽  
Static Conditions ◽  
Bypassed Oil ◽  
Similarity Law

The main purpose of this investigation is to study the dynamic characteristics of shut-in and restart process in reservoirs with high water cut and strong vertical heterogeneity. The physical model, which includes three layers with low, medium, and high-permeability from top to bottom, was made according to the similarity law. Water drive test, the first restart test, and the second restart test were conducted, respectively. Water cut, oil recovery, and saturation distribution of the remaining oil were obtained during the tests. On this basis, mechanisms of shut-in and restart process of the reservoir were analyzed. It is concluded that appropriate developing plan such as layering mining and cyclic waterflooding should be implemented for developing strong heterogeneity reservoirs. The shut-in and restart tests showed that closing the water-flooded layer is beneficial for enlarging the sweep volume. Besides, water cut of 98% does not mean the economic limits of waterflooding. Under the effect of capillary force and gravitational differentiation, oil and water will redistribute in the formation. The redistribution of the oil and water, the fluctuation of the pressure difference, and the rebuild of the flow path, which produce parts of the bypassed oil, are the main mechanisms of the recovery enhancement by shut-in and restart operation. It should be noted that the shut-in and restart process indeed prolongs the waterflooding development. However, simply replying on the oil and water distribution under static conditions cannot greatly enhance the oil recovery.

scholarly journals Microscopic Determination of Remaining Oil Distribution in Sandstones With Different Permeability Scales Using Computed Tomography Scanning

2019 ◽  
Vol 141 (9) ◽  
Author(s):  
Yongfei Yang ◽  
Haiyuan Yang ◽  
Liu Tao ◽  
Jun Yao ◽  
Wendong Wang ◽  
...  
Keyword(s):  
Distribution Pattern ◽  
Oil Recovery ◽  
Distribution Patterns ◽  
High Water ◽  
Water Flooding ◽  
Oil Distribution ◽  
Computed Tomography Scanning ◽  
Remaining Oil ◽  
High Water Cut ◽  
Water Cut

To investigate the characteristics of oil distribution in porous media systems during a high water cut stage, sandstones with different permeability scales of 53.63 × 10−3 μm2 and 108.11 × 10−3 μm2 were imaged under a resolution of 4.12 μm during a water flooding process using X-ray tomography. Based on the cluster-size distribution of oil segmented from the tomography images and through classification using the shape factor and Euler number, the transformation of the oil distribution pattern in different injection stages was studied for samples with different pore structures. In general, the distribution patterns of an oil cluster continuously change during water injection. Large connected oil clusters break off into smaller segments. The sandstone with a higher permeability (108.11 × 10−3 μm2) shows the larger change in distribution pattern, and the remaining oil is trapped in the pores with a radius of approximately 7–12 μm. Meanwhile, some disconnected clusters merge together and lead to a re-connection during the high water cut period. However, the pore structure becomes compact and complex, the residual nonwetting phase becomes static and is difficult to move; and thus, all distribution patterns coexist during the entire displacement process and mainly distribute in pores with a radius of 8–12 μm. For the pore-scale entrapment characteristics of the oil phase during a high water cut period, different enhance oil recovery (EOR) methods should be considered in sandstones correspondent to each permeability scale.

scholarly journals A Novel Assisted Gas–Oil Countercurrent EOR Technique for Attic Oil in Fault-Block Reservoirs

Energies ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 402
Author(s):  
Kang Ma ◽  
Hanqiao Jiang ◽  
Junjian Li ◽  
Rongda Zhang ◽  
Kangqi Shen ◽  
...  
Keyword(s):  
Production Process ◽  
Oil Recovery ◽  
Production Efficiency ◽  
High Water ◽  
Gas Oil ◽  
Fault Block ◽  
High Water Cut Stage ◽  
High Water Cut ◽  
Gas Channeling ◽  
Water Cut

As the mature oil fields have stepped into the high water cut stage, the remaining oil is considered as potential reserves, especially the attic oil in the inclined fault-block reservoirs. A novel assisted gas–oil countercurrent technique utilizing gas oil countercurrent (GOC) and water flooding assistance (WFA) is proposed in this study to enhance the remaining oil recovery in sealed fault-block reservoirs. WFA is applied in our model to accelerate the countercurrent process and inhibit the gas channeling during the production process. Four comparative experiments are conducted to illustrate enhanced oil recovery (EOR) mechanisms and compare the production efficiency of assisted GOC under different assistance conditions. The results show that WFA has different functions at different stages of the development process. In the gas injection process, WFA forces the injected gas to migrate upward and shortens the shut-in time by approximately 50% and the production efficiency improves accordingly. Compared with the basic GOC process, the attic oil swept area is extended 60% at the same shut-in time condition and secondary gas cap forms under the influence of WFA. At the production stage, the WFA and secondary gas cap expansion form the bi-directional flooding. The bi-directional flooding also displaces the bypassed oil and replaced attic oil located below the production well, which cannot be swept by the gas cap expansion. WFA inhibits the gas channeling effectively and increases the sweep factor by 26.14% in the production stage. The oil production increases nearly nine times compared with the basic GOC production process. The proposed technique is significant for the development of attic oil in the mature oil field at the high water cut stage.

Study on Technical Limits of Single-Pipe Concatenation Gathering Process during High Water-Cut Stage

2013 ◽  
Vol 295-298 ◽  
pp. 3323-3327
Author(s):  
Li Xin Wei ◽  
Xin Peng Le ◽  
Yun Xia Fu ◽  
Zhi Hua Wang ◽  
Yu Wang
Keyword(s):  
Oil Recovery ◽  
High Water ◽  
Temperature Limit ◽  
Tertiary Oil Recovery ◽  
Recovery Technique ◽  
High Water Cut Stage ◽  
High Water Cut ◽  
Water Cut ◽  
Single Pipe ◽  
Oil Gas

In order to optimize the gathering system and reduce the energy consumption in the production, single-pipe concatenation process has been widely used after the tertiary oil recovery technique is applied and development enters into high water cut stage in the oilfield. Aiming at condensate oil in gathering pipeline and obvious increase of the high circle pressure wells in the operation of the process, the adaption relationship between oil gathering pipeline size and flow, as well as the temperature limit of the gathering system start are studied, through the hydraulic and thermodynamic calculations of oil-gas-water multiphase flow. It has directive function for making effective schemes to solve the production problems caused by the high back pressure of wells.

scholarly journals Dual Completion Petroleum Production Engineering for Several Oil Formations

2018 ◽  
Vol 26 (4) ◽  
pp. 217-221
Author(s):  
Tanyana Nikolaevna Ivanova ◽  
Aleksandr Ivanovich Korshunov ◽  
Vladimir Pavlovich Koretckiy
Keyword(s):  
Production Technology ◽  
Oil Recovery ◽  
Late Stage ◽  
Recovery Rate ◽  
High Water ◽  
Production Engineering ◽  
Petroleum Production ◽  
Cost Efficient ◽  
High Water Cut ◽  
Water Cut

Abstract Cost-efficient, enabling technologies for keeping and increasing the reservoir recovery rate of oil-formations with high water cut of produced fluids and exhausted resource are really essential. One of the easiest but short-term ways to increase oil production and incomes at development of oil deposits is cost of development and capital cost reduction. Therefore, optimal choice and proper feasibility study on the facilities for multilayer oil fields development, especially at the late stage of reservoir working, is a crucial issue for now-day oil industry. Currently, the main oil pools do not reach the design point of coefficient of oil recovery. The basic feature of the late stage of reservoir working is the progressing man-made impact on productive reservoir because of water injection increasing for maintaining reservoir pressure. Hence cost-efficient, enabling technologies for keeping and increasing the reservoir recovery rate of oil-formations with high water cut of produced fluids and exhausted resource are really essential. To address the above concerns the dual completion petroleum production engineering was proposed. The intensity of dual completion of formation with of different permeability is determined by rational choice of each of them. The neglect of this principle results a disproportionately rate of highly permeable formations development for the time. In effect the permeability of the formations or their flow rate is decreasing. The problem is aggravated by lack of awareness of mechanics of layers' mutual interference in producers and injectors. Dual completion experience in Russian has shown, that success and efficiency of the technology in many respects depend on engineering support. One of the sufficient criteria for the choice of operational objects should be maximal involvement of oil-saturated layers by oil displacement from seams over the economic life of well producing oil. If it is about getting high rate of oil recovery for irregular formations there is no alternative to dual completion and production. The recommended dual completion petroleum production technology enables development several formations by single well at the time. The dual completion petroleum production technology has been more important than ever because it is right not only for formations but for thin layers with undeveloped remaining reserves.

scholarly journals Techniques for improving the water-flooding of oil fields during the high water-cut stage

2019 ◽  
Vol 74 ◽  
pp. 69 ◽  
Author(s):  
Kuiqian Ma ◽  
Ao Li ◽  
Shuhao Guo ◽  
Jieqiong Pang ◽  
Yongchao Xue ◽  
...  
Keyword(s):  
Oil Recovery ◽  
Water Injection ◽  
Reduction Rate ◽  
High Water ◽  
Water Flooding ◽  
Variable Intensity ◽  
Remaining Oil ◽  
High Water Cut Stage ◽  
High Water Cut ◽  
Water Cut

The multi-layer co-exploitation method is often used in offshore oilfields because of the large spacing between the injection and production wells. As oilfields gradually enter the high water-cut stage, the contradiction between the horizontal and vertical directions becomes more prominent, and the distribution of the remaining oil is more complex. Oilfields are facing unprecedented challenges in further enhancing oil recovery. Using oilfield A, which is in the high water-cut stage, as the research object, we compiled a detailed description of the remaining oil during the high water-cut stage using the information collected during the comprehensive adjustment and infilling of the oilfield. In addition various techniques for tapping the potential reservoir, stabilizing the oil, and controlling the water were investigated. A set of key techniques for the continuous improvement of the efficiency of water injection after comprehensive adjustment of high water-cut fields was generated. Based on the determined configuration of the offshore deltaic reservoir, a set of detailed descriptive methods and tapping technology for extracting the remaining oil in the offshore high water-cut oilfield after comprehensive adjustment was established. By considering the equilibrium displacement and using a new quantitative characterization method that includes displacement, a new technique for determining the quantity of water that needs to be injected into a stratified injection well during the high water-cut stage was established. Based on the principle of flow field intensity reconfiguration, a linear, variable-intensity, alternating injection and withdrawal technique was proposed. With the application of this series of techniques, the increase in the water content was controlled to within 1%, the natural reduction rate was controlled to within 9%, and the production increased by 1.060 × 107 m3.

On the Feasibility of Applying Electric Field to Increase Oil Recovery in Old Oil Field

2014 ◽  
Vol 900 ◽  
pp. 677-680
Author(s):  
Chun Hong Nie
Keyword(s):  
Electric Field ◽  
Oil Recovery ◽  
Water Injection ◽  
High Water ◽  
Oil Field ◽  
Thin Layers ◽  
Stable Yield ◽  
High Water Cut Stage ◽  
High Water Cut ◽  
Water Cut

This paper has discussed the characteristics, roles, feasibility and obvious effects of the technology by applying electric field to enhance oil recovery when the oil field is in high water cut stage and super high water cut stage. In view that most oil wells in old oil field have entered into the super high water cut production, the remaining oil in the main reservoir is in fragmented distribution with poor results of water injection and new reserves of oil mostly have a low penetration rate and are thin layers of poor physical properties, the use of the direct current field in period of high water cut is the best policy to achieve high and stable yield and is fairly promising.

scholarly journals Effect of Emulsification on Enhanced Oil Recovery during Surfactant/Polymer Flooding in the Homogeneous and Heterogeneous Porous Media

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Xiaoyan Wang ◽  
Jie Zhang ◽  
Guangyu Yuan ◽  
Wei Wang ◽  
Yanbin Liang ◽  
...  
Keyword(s):  
Enhanced Oil Recovery ◽  
Oil Recovery ◽  
High Water ◽  
Heterogeneous Porous Media ◽  
Recovery Factor ◽  
Water Flooding ◽  
Core Flooding ◽  
Positive Role ◽  
High Water Cut ◽  
Water Cut

Surfactant polymer (SP) flooding has become an important enhanced oil recovery (EOR) technique for the high-water cut mature oilfield. Emulsification in the SP flooding process is regarded as a powerful mark for the successful application of SP flooding in the filed scale. People believe emulsification plays a positive role in EOR. This paper uses one-dimensional homogenous core flooding experiments and parallel core flooding experiments to examine the effect of emulsification on the oil recoveries in the SP flooding process. 0.3 pore volume (PV) of emulsions which are prepared using ultralow interface intension (IFT) SP solution and crude oil with stirring method was injected into core models to mimic the emulsification process in SP flooding, followed by 0.35 PV of SP flooding to flood emulsions and remaining oil. The other experiment was preformed 0.65 PV of SP flooding as a contrast. We found SP flooding can obviously enhance oil recovery factor by 25% after water flooding in both homogeneous and heterogeneous cores. Compared to SP flooding, emulsification can contribute an additional recovery factor of 3.8% in parallel core flooding experiments. But there is no difference on recoveries in homogenous core flooding experiments. It indicates that the role of emulsification during SP flooding will be more significant for oil recoveries in a heterogeneous reservoir rather than a homogeneous reservoir.

scholarly journals Response to the Variation of Clay Minerals During ASP Flooding in the Saertu Oilfield in the Songliao Basin

2021 ◽  
Vol 9 ◽  
Author(s):  
Liang Yingjie ◽  
Liang Wenfu ◽  
He Wang ◽  
Li Zian
Keyword(s):  
Clay Minerals ◽  
Oil Recovery ◽  
High Water ◽  
Songliao Basin ◽  
Residual Oil ◽  
Pore Throat ◽  
Asp Flooding ◽  
High Water Cut Stage ◽  
High Water Cut ◽  
Water Cut

In this paper, the variation of clay minerals and their influence on reservoir physical properties and residual oil before and after ASP flooding are analyzed. The results show that the total amount of clay minerals in reservoirs decreases after ASP flooding in the ultra-high-water-cut-stage reservoirs of the Naner Zone in the Saertu Oilfield, Songliao Basin. Therein, the illite content reduces, while the content of illite smectite mixed-layer and chlorite increases. The content of kaolinite varies greatly. The content of kaolinite decreases in some samples, while it increases in other samples. The clay minerals block the pore throat after ASP flooding. As a result, the pore structure coefficient and the seepage tortuosity increase, the primary intergranular pore throat shrinks, and the pore–throat coordination number decreases. Nevertheless, the dissolution of clay minerals reduces the pore–throat ratio and increases porosity and permeability. The variation of clay minerals after ASP flooding not only intensifies the reservoir heterogeneity but also affects the formation and distribution of residual oil. The residual oil of the oil–clay mixed adsorption state is a newly formed residual oil type related to clay, which accounts for 44.2% of the total residual oil reserves, so it is the main occurrence form of the oil in reservoirs after ASP flooding. Therefore, the exploitation of this type of residual oil has great significance to enhance the oil recovery in ultra-high-water-cut-stage reservoirs.

scholarly journals Screening and assessing the conditions for effective oil recovery enhancing techniques application for hard to recover high-water cut reserves

2021 ◽  
pp. 48-56
Author(s):  
V. V. Mukhametshin ◽  
◽  
R. N. Bakhtizin ◽  
L. S. Kuleshova ◽  
A. P. Stabinskas ◽  
...  
Keyword(s):  
Numerical Modeling ◽  
Enhanced Oil Recovery ◽  
Oil Recovery ◽  
Oil And Gas ◽  
Chemical Properties ◽  
High Water ◽  
Recovery Techniques ◽  
High Water Cut ◽  
Water Cut ◽  
Criterion Analysis

For the conditions of deposits in Jurassic and Paleozoic terrigenous reservoirs of the Sherkalinsky trough and Shaimsky swell of Western Siberia, a criterion analysis and screening of enhanced oil recovery techniques used in the fields of the West Siberian oil and gas province were carried out. For various groups of oil fields, a set of the most effective technologies for the development of residual hard-to-recover reserves of flooded fields has been proposed. The areas for effective application of the selected techniques for deposits introduced into development within the considered tectonic-stratigraphic elements are determined. The areas determination was carried out on the basis of 19 parameters characterizing the geological-physical and physical-chemical properties of formations and fluids, as well as the maximum and minimum values of the canonical discriminant functions determined by the situational map. Based on the numerical modeling of oil recovery processes, a forecast of an increase in the final oil recovery factor was made for five facilities-field test sites of the selected groups of facilities. Keywords: hard-to-recover reserves; terrigenous reservoirs; factor analysis; enhanced oil recovery techniques; numerical modeling; criterion analysis.

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