Mechanisms of water flooding characteristic curve upwarping at high water-cut stage and influencing factors

Abstract Performance prediction is one of the important contents of oilfield development. It is also an important content affecting investment decision-making, especially for offshore oilfields with large investment. At present, most oilfields in China have entered high water cut stage or even extra high water cut stage, which requires higher prediction accuracy. Water drive curve is an important method for predicting performance. Traditional methods are based on exponential formulas, but these methods have poor adaptability in high water cut period. Because traditional methods deviate from straight line in high water cut period. In this paper, a robust method for predicting performance of offshore oilfield in high water cut period based on big data and artificial intelligence is proposed. Firstly, the reasons for the "upward warping" phenomenon of traditional methods deviating from the straight line are analyzed. It is found that the main reason for the deviation is that the relationship between the relative permeability ratio of oil to water and the water saturation curve no longer conforms to the exponential relationship. So a new percolation characteristic characterization equation with stronger adaptability is proposed, which focuses on the limit of high water flooding development. On this basis, the equation of the new water drive characteristic curve is deduced theoretically, and the dynamic prediction method is established. What's more, the solution of the method is based on large data and AI algorithm. This method has been applied to many high water flooding phase permeability curves, and the coincidence rate is more than 95.6%. The new water drive characteristic curve can better reflect the percolation characteristics of high water cut reservoirs. At the same time, the performance of adjustment wells and measures on the curve of development dynamic image is analyzed. Curve warping indicates that adjustment wells or measures are effective. Field application shows that the prediction error of the new method is less than 6%, which is more in line with the needs of oilfield development. Because of the application of artificial intelligence algorithm, the application is more convenient and saves a lot of time and money. This is a process of self-learning and self-improvement. As the oil field continues over time, each actual data will be recalculated into the database. Then the fitting and correction are carried out, and then the solution is learned again. This method has been applied to several oil fields in Bohai. And the effect is remarkable, which provides a good reference for the development of other oil fields.

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New Waterflooding Characteristic Curves Based on Cumulative Water Injection

Mathematical Problems in Engineering ◽

10.1155/2020/7415236 ◽

2020 ◽

Vol 2020 ◽

pp. 1-12

Author(s):

Zhiwang Yuan ◽

Zhiping Li ◽

Li Yang ◽

Yingchun Zhang

Keyword(s):

Characteristic Curve ◽

Water Injection ◽

Material Balance ◽

Oil Production ◽

High Water ◽

Difficult Problem ◽

Prediction Errors ◽

High Water Cut Stage ◽

High Water Cut ◽

Water Cut

When a conventional waterflooding characteristic curve (WFCC) is used to predict cumulative oil production at a certain stage, the curve depends on the predicted water cut at the predicted cutoff point, but forecasting the water cut is very difficult. For the reservoirs whose pressure is maintained by water injection, based on the water-oil phase seepage theory and the principle of material balance, the equations relating the cumulative oil production and cumulative water injection at the moderately high water cut stage and the ultrahigh water cut stage are derived and termed the Yuan-A and Yuan-B curves, respectively. And then, we theoretically analyze the causes of the prediction errors of cumulative oil production by the Yuan-A curve and give suggestions. In addition, at the ultrahigh water cut stage, the Yuan-B water cut prediction formula is established, which can predict the water cut according to the cumulative water injection and solve the difficult problem of water cut prediction. The application results show Yuan-A and Yuan-B curves are applied to forecast oil production based on cumulative water injection data obtained by the balance of injection and production, avoiding reliance on the water cut forecast and solving the problems of predicting the cumulative oil production of producers or reservoirs that have not yet shown the decline rule. Furthermore, the formulas are simple and convenient, providing certain guiding significance for the prediction of cumulative oil production and water cut for the same reservoir types.

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

Oil & Gas Science and Technology – Revue d’IFP Energies nouvelles ◽

10.2516/ogst/2019042 ◽

2019 ◽

Vol 74 ◽

pp. 69 ◽

Cited By ~ 1

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.

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The Research of Remaining Oil Distribution in High Water Cut Oilfield

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.591-593.2555 ◽

2012 ◽

Vol 591-593 ◽

pp. 2555-2558

Author(s):

Cheng Fu ◽

Bin Huang

Keyword(s):

High Water ◽

Water Flooding ◽

Production Plant ◽

3D Geological Modeling ◽

Oil Distribution ◽

High Efficient ◽

High Water Cut Stage ◽

High Water Cut ◽

Water Cut ◽

Oilfield Development

The western South-eight block which is located in the comprehensive tap demonstration area of NO.2 oil production plant, has already gone through three years’ fine development. The production has been stable, the rising amplitude of comprehensive water cut has been small, and the natural decline rate has been controlled effectively. But with the deep development, this block has gone into the late ultra-high water cut stage. To maintain high efficient water flooding development is more and more difficult, therefore fine 3D geological modeling and reservoir numerical simulation work have been carried out. And some practical residual oil saturation diagrams have been put forward finally towards this block, which has provided a reliable basis for the next oilfield development.

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The Analysis of Remaining Oil in High Water Cut Stage

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.274.675 ◽

2013 ◽

Vol 274 ◽

pp. 675-678

Author(s):

Cheng Fu ◽

Bin Huang

Keyword(s):

Characteristic Curve ◽

Material Balance ◽

High Water ◽

Oil Distribution ◽

Remaining Oil ◽

Remaining Oil Distribution ◽

High Water Cut Stage ◽

High Water Cut ◽

Water Cut ◽

Material Balance Method

The remaining oil distribution is very complex and the difficulty in tapping measures is more and more big when the west block of South-eight area has gone into the ultra-high water cut stage. So the remaining oil distribution in 109 units has been comprehensively studied on the condition that the composite water cut reaches 9.06% by establishing reservoir geologic model and proceeding reservoir numerical simulation according to recent tapping measures and remaining oil analysis experience in the process of adjusting scheme. And combined with some reservoir engineering methods such as: waterflooding characteristic curve and material balance method, obvious effects has been obtained in this research.

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Analysis all Kinds of Reservoir Water Degree Condition of East Xing Six District of Daqing Oilfield

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.868.585 ◽

2013 ◽

Vol 868 ◽

pp. 585-588

Author(s):

Yi Kun Liu ◽

Xue Ming Wang ◽

Shi Yuan Shao ◽

Ming Yang ◽

Yong Ping Wang

Keyword(s):

High Water ◽

Oil Field ◽

Water Flooding ◽

Reservoir Water ◽

Thickness Change ◽

Degree Condition ◽

Well Pattern ◽

High Water Cut Stage ◽

High Water Cut ◽

Water Cut

East Xing Six District of Daqing oilfield development has 50 years of history, the block has entered high well density, high water cut stage. The apricot East Xing Six District demonstration zone development belongs to the continental sedimentary system, it has reservoir types and physical properties have large differences, It was long-term effected by injected water, after water flooding, water degree condition becomes very complex and unpredictable, so the washing condition analysis is an important guarantee for Daqing oilfield stable production. Using the oil field sealed coring well data, various types of reservoirs washing degree thickness change and growth are analyzed, We can know that with the further water flooding development and well pattern infilling, all kinds of oil reservoir production status; and then analyzes the potential distribution of the oilfields, and provides a basis for the development of the block and the adjustment of the next step of work, has an important guiding significance.

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