scholarly journals Countermeasures to Decrease Water Cut and Increase Oil Recovery from High Water Cut, Narrow-Channel Reservoirs in Bohai Sea

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Gaocheng Feng ◽  
Yuhui Zhou ◽  
Weiying Yao ◽  
Lingtong Liu ◽  
Zhao Feng ◽  
...  
Keyword(s):  
Oil Recovery ◽  
Bohai Sea ◽  
High Water ◽  
Narrow Channel ◽  
Optimization Strategy ◽  
Well Pattern ◽  
Remaining Oil ◽  
High Water Cut ◽  
Water Cut ◽  
Well Pattern Optimization

Most multilayer sandstone reservoirs in the Bohai Sea have already entered the middle or high water cut production stage with large amounts of remaining oil being scattered distributed. Therefore, there is an urgent need to find a suitable countermeasure to reduce water cut and increase oil recovery. In this study, taking the narrow-channel reservoirs in the M oilfield as an example, we qualitatively described the sand body scale and the contact relationships between different sand bodies, in addition to carefully analyzing the material base and remaining oil distribution characteristics. Accordingly, we proposed a countermeasure based on the injection-production structural adjustment to reduce water cut and increase oil recovery from high water cut, narrow-channel reservoirs. Herein, three optimization strategies were developed based on the proposed development mode: a seepage field optimization strategy was developed based on the quantified injection-production index; a well pattern optimization strategy for narrow-channel reservoirs was developed to overcome the production energy refueling problem; an injection-production measure optimization strategy was developed to tap the different types of remaining oil. Additionally, the well pattern optimization and injection-production optimization strategies were integrated to optimize and adjust the seepage field system. The findings reported herein this paper help understand the development of similar offshore oilfields with a high water cut.

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 Effects of oil viscosity on waterflooding: A case study of high water-cut sandstone oilfield in Kazakhstan

2020 ◽  
Vol 12 (1) ◽  
pp. 1736-1749
Author(s):  
Jincai Wang ◽  
Zifei Fan ◽  
Lun Zhao ◽  
Li Chen ◽  
Jun Ni ◽  
...  
Keyword(s):  
High Water ◽  
High Viscosity ◽  
Oil Wells ◽  
Oil Reservoirs ◽  
Low Viscosity ◽  
Well Pattern ◽  
Remaining Oil ◽  
Oil Water ◽  
High Water Cut ◽  
Water Cut

Abstract After a sandstone oilfield enters the high water-cut period, the viscosity of crude oil has an important influence on remaining oil distribution and waterflooding characteristics under the same factors of, e.g., reservoir quality and development methods. Based on a comprehensive interpretation of the waterflooded layers in new oil wells, physical simulation experiments, and reservoir numerical simulations, we analyzed the waterflooding laws of a high water-cut sandstone reservoir with different oil viscosities in Kazakhstan under the same oil production speed, and we clarified the remaining oil potential of reservoirs with different viscosities and proposed corresponding development measures. The results show that low-viscosity oil reservoirs (1 mPa s) have uniform waterflooding, thick streamlines, small waterflooding areas, and low overall waterflooding degrees because of their homogeneous oil–water viscosities. However, within waterflooded areas, the reservoirs have high oil displacement efficiencies and high waterflooding degrees, and the remaining oil is mainly concentrated in the unwaterflooded areas; therefore, the initial production and water cut in new oil wells vary significantly. High-viscosity oil reservoirs (200 mPa s) have severe waterflooding fingering, large waterflooding areas, and high overall waterflooded degrees because of their high oil–water mobility ratios. However, within waterflooded areas, the reservoirs have low oil displacement efficiencies and low waterflooding degrees, and the remaining oil is mainly concentrated in both the waterflooded areas and the unwaterflooded areas; therefore, the differences in the initial production and water cut of new oil wells are small. Moderate-viscosity oil reservoirs (20 mPa s) are characterized by remaining oil distributions that are somewhere in between those of the former two reservoirs. Therefore, in the high water-cut period, as the viscosity of crude oil increases, the efficiency of waterflooding gradually deteriorates and the remaining oil potential increases. In the later development, it is suggested to implement the local well pattern thickening in the remaining oil enrichment area for reservoirs with low viscosity, whereas a gradual overall well pattern thickening strategy is recommended for whole reservoirs with moderate and high viscosity. The findings of this study can aid better understanding of waterflooding law and the remaining oil potential of reservoirs with different viscosities and proposed corresponding development measures. The research results have important guidance and reference significance for the secondary development of high water-cut sandstone oilfields.

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.

Remaining Oil Development Study of a Nature Water Drive Reservoir in the High Water Cut Stage

2014 ◽  
Vol 522-524 ◽  
pp. 1346-1350
Author(s):  
Jian Huai Wang ◽  
Wei Nan Zhang
Keyword(s):  
Bottom Water ◽  
High Water ◽  
Distribution Law ◽  
Development Feature ◽  
Well Pattern ◽  
Barrier Region ◽  
Remaining Oil ◽  
High Water Cut Stage ◽  
High Water Cut ◽  
Water Cut

Taking M reservoir of D field as an example, analyzing the development feature of a thick sandstone reservoir in the high water cut stage which is driven by natural water, and studying the distribution law of remaining oil for this reservoir through 3 aspects: sweeping of the edge-bottom water, completeness of the well pattern and barrier of the partial interbed, and expounding the development method and effect of this thick sand reservoir in the high water cut stage through exploiting 3 kinds of remaining oil rich regions as fellows: the region which is not swept by the edge-bottom water; incomplete region of the well pattern and barrier region of the partial interbed.

Research and Application of Tapping Potential Remaining Oil of Low Permeability Reservoir in Hei47 Block, Jilin Oilfield

2013 ◽  
Vol 663 ◽  
pp. 753-758 ◽  
Author(s):  
Fang Ding ◽  
Xu Yang
Keyword(s):  
Study Design ◽  
Water Injection ◽  
High Water ◽  
Injection Wells ◽  
Well Spacing ◽  
Well Pattern ◽  
Remaining Oil ◽  
High Water Cut ◽  
Water Cut ◽  
High Place

At present, Hei47 block has already entered high water cut period, and it exists many problems, such as imbalance producing reserves, serious water flooded in main small layer, imperfect injection-production well spacing and so on. Aiming at these problems, this paper analyzed from two aspects of the potential: the first is the potentiality of well pattern thickening which would analyze the reasons of the remaining oil enrichment through four different imperfect patterns, the paper proposes different schemes. For example, this study design new wells in the injection-production incongruous area; As for the area without the control of well net, for example, the study design a horizontal well near the fault where concentrated much remaining oil, and the production conditions are good; The second is making some modification measures in high water cut layer, and perforating other potential small layers, in the light of the wells in low location and is high water cut can be considered to transfer to injection wells. Structural reservoir high-yielding well mainly concentrated in the structural high place, flooded well in the low position, this area is suitable for edge water injection.

Integrated Solutions for the Redevelopment Plan of Offshore Mature-Oilfield

2021 ◽  
Author(s):  
Hongfu Shi ◽  
Yingxian Liu ◽  
Lifu Jiang ◽  
Jingding Zheng ◽  
Liqin Gan
Keyword(s):  
High Water ◽  
Bohai Bay ◽  
Sand Body ◽  
Well Pattern ◽  
Open Hole ◽  
Average Water ◽  
High Water Cut ◽  
Water Cut ◽  
Stream Lines ◽  
Sand Bodies

Abstract Abundant faults, long oil-bearing intervals (up to 500m), and diverse fluids including conventional oil and heavy oil, result in P oilfield became one of the most complex oil fields in the Bohai Bay. The main characters ofinitial development plan are directional well with commingle production, open hole completion, large draw down, high oil production rate, and reverse nine-point well pattern. At present, the oilfield has entered a stage of high water cut, with average water cut more than 85%. What can we do next, decommissioning or rebirthing? An integrated solution was proposed to redevelop the oilfield which focus on the layers’ subdivision, the fine description of the sand body,a large number of horizontal wells on the top of the water-flooded layer are used to tap the potential, increase the water injector to transform the stream lines and rebuild the reservoir pressure, and search for potential sand bodies to increase reserves.

Study on 3D Fine Structural Modeling of Typical Block in Sanan Oilfield, Daqing

2014 ◽  
Vol 628 ◽  
pp. 348-353
Author(s):  
Tao Li ◽  
Zian Li ◽  
Jiang Wang
Keyword(s):  
Structural Model ◽  
3D Structure ◽  
High Water ◽  
Oil Distribution ◽  
Remaining Oil ◽  
Modeling Software ◽  
Remaining Oil Distribution ◽  
High Water Cut ◽  
Reservoir Description ◽  
Water Cut

Sanan oilfield has entered late stage of high water cut development. It urgently needs accurate prediction of remaining oil distribution. But previous studies on 3D structure were far could not meet the requirements of fine reservoir description. This paper applied RMS, a piece of excellent geological modeling software establishing the 3D fine structural model of typical block in Sanan oilfield on the bases of 3D fine seismic structural interpretation data. It included the 28 faults’ model, 11 horizons’ model and the structural model. And then measured and analyzed the faults elements data. Based on abundant geologic data, well data and seismic data of the block, this structural model reproduced the fine seismic interpretation results accurately. It was really fine enough to meet the requirements of the fine reservoir description. This research solved the problem that traditional modeling techniques could not handle complex cutting relationship of faults’ model. It laid a solid foundation for reservoir numerical simulation and remaining oil distribution prediction.

The Research of Flood Pattern Completeness in the Thin and Poor Oil Layers of South West II Area

2012 ◽  
Vol 594-597 ◽  
pp. 2541-2544
Author(s):  
Xiao Hui Wu ◽  
Kao Ping Song ◽  
Chi Dong ◽  
Ji Cheng Zhang ◽  
Jing Fu Deng
Keyword(s):  
Oil Recovery ◽  
Water Flooding ◽  
South West ◽  
Oil Distribution ◽  
Well Pattern ◽  
Remaining Oil ◽  
Tertiary Oil Recovery ◽  
Well Pattern Optimization ◽  
Numerical Simulation Technique

As line well pattern is the main development technique in the thin and poor oil layers of Daqing Oilfield South West Ⅱ PⅠ group, the layers have been idle and the degree of reserve recovery is far less than the region level. In response to these problems, we analyzed the balanced flood performance of various layers and the remaining oil distribution through numerical simulation technique. It shows that, the main remaining oil type of intended layers is caused by voidage-injection imperfection. Considering the needs of the follow-up infill well pattern and tertiary oil recovery, we decided to keep the well network independent and integrated without disturbing the pattern configuration and main mining object of various sets of well pattern. Finally we confirmed to perforate-adding the first infill wells of intended layers to consummate the water flooding regime. Through analyzing the production target of different well pattern optimization programs relatively, it shows that the best program has regular well pattern and large drilled thickness.

scholarly journals Qualitative interpretation method of water flooding in independent off surface reservoir of Lamadian Oilfield

2020 ◽  
Vol 165 ◽  
pp. 03039
Author(s):  
Li Hong Cui
Keyword(s):  
Outer Surface ◽  
High Water ◽  
Water Flooding ◽  
Qualitative Interpretation ◽  
Remaining Oil ◽  
High Water Cut ◽  
Water Cut ◽  
Surface Reservoir ◽  
Interpretation Method ◽  
Thick Layers

With Lamadian Oilfield entering the late stage of ultra-high water cut, the number of thick layers in water drive is becoming less and less, so it is imperative to study the remaining oil in thin difference reservoir. For the thin difference reservoir, the independent off surface reservoir has naturally become an important research object [1]. It is necessary to study the waterflooding condition of the independent outer surface reservoirs to find out the producing law of the thin difference reservoirs at present. In this paper, we mainly use thewater washing data of independent outer surface reservoir and core data of sidewall of coring well to find the water flooding interpretation law of independent outer surface reservoir.This paper focuses on the analysis of the characteristics of the electric logging curve of the independent off surface reservoir after water flooding, and summarizes a set of qualitative interpretation methods suitable for the independent off surface reservoir of Lamadian oilfield. This method can improve the accuracy of waterflooded layer interpretation and meet the needs of remaining oil potential tapping in the later stage of ultra-high water cut.

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