scholarly journals The Effect of Interlayer on Water Cut Rise in a Bottom Water Reservoir

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Yunpeng Hu ◽  
Xiaoling Zhang ◽  
Wei Ding ◽  
Ziyun Cheng ◽  
Liangchao Qu ◽  
...  
Keyword(s):  
Bottom Water ◽  
Water Reservoir ◽  
Inhibitory Effect ◽  
Upper Body ◽  
Two Phase ◽  
Control Laws ◽  
Water Breakthrough ◽  
Short Period ◽  
Water Cut ◽  
The Impact

A bottom water reservoir is universal in all reservoirs in the world. In the exploitation process of the bottom water reservoir, because the reservoir is in complete contact with bottom water, the natural energy supply of the bottom water reservoir is sufficient. At the same time, in the production process, the pressure drop generated by the formation is mainly concentrated near the wellbore, which leads to a short period of waterless oil production, fast water breakthrough, and fast water cut rise, which seriously affects the overall recovery factor and increases the risk of oil filed exploitation. Since the distribution of an interlayer enhances the heterogeneity of the reservoir, it has a prominent impact on the flow of oil and water in the bottom water reservoir. However, people know little about the impact of the interlayer on the bottom water reservoir. In this paper, the mathematical model of two-phase flow in the bottom water reservoir with the interlayer is proposed, and the numerical solution of the model is obtained by a finite element method. The influence of the distribution of the interlayer on the water cut rising law of the bottom water reservoir is analyzed. The results show that the bottom water is blocked by the interlayer and its own gravity and the rising height of the bottom water is limited, so that the interlayer has a significant inhibitory effect on the coning of the bottom water. The closer the interlayer is to the oil-water interface, the faster the water cut will rise; the narrower the interlayer is, the faster the bottom water ridge will advance; when the width of the interlayer is the same as that of the reservoir, the water cone will not appear; the higher the permeability of the interlayer is, the faster the upper body of the water cut will be; when the permeability of the reservoir and the interlayer is over 1000, the influence of the interlayer on the water cut rise is not obvious; the thickness of the interlayer on the water cut rise law has little effect. Finally, through the case analysis, it is proposed that the new horizontal wells should be arranged in the position where the interlayer develops. The findings of this study can help for the better understanding of control laws of the interlayer on the bottom water and providing a crucial theoretical basis for the development of the bottom water reservoir.

scholarly journals Water Breakthrough Shape Description of Horizontal Wells in Bottom-Water Reservoir

2014 ◽  
Vol 2014 ◽  
pp. 1-9
Author(s):  
Shijun Huang ◽  
Baoquan Zeng ◽  
Fenglan Zhao ◽  
Linsong Cheng ◽  
Baojian Du
Keyword(s):  
Physical Model ◽  
Horizontal Well ◽  
Bottom Water ◽  
Water Reservoir ◽  
Horizontal Wells ◽  
Analysis Model ◽  
Heterogeneous Reservoir ◽  
Water Breakthrough ◽  
Original Oil In Place ◽  
Water Cut

Horizontal wells have been applied in bottom-water reservoir since their advantages were found on distribution of linear dropdown near wellbore, higher critical production, and more OOIP (original oil in place) controlled. In the paper, one 3D visible physical model of horizontal physical model is designed and built to simulate the water cresting process during the horizontal well producing and find water breakthrough point in homogenous and heterogeneous reservoir with bottom water. Water cresting shape and water cut of horizontal well in between homogenous and heterogeneous reservoir are compared on the base of experiment’s result. The water cresting pattern of horizontal well in homogeneous reservoir can be summarized as “central breakthrough, lateral expansion, thorough flooding, and then flank uplifting.” Furthermore, a simple analysis model of horizontal well in bottom water reservoir is established and water breakthrough point is analyzed. It can be drawn from the analysis result that whether or not to consider the top and bottom border, breakthrough would be located in the middle of horizontal segment with equal flow velocity distribution.

scholarly journals Experimental study on waterflooding development of low-amplitude reservoir with big bottom water

2021 ◽  
Author(s):  
Yanlai Li ◽  
Jie Tan ◽  
Songru Mou ◽  
Chunyan Liu ◽  
Dongdong Yang
Keyword(s):  
Bottom Water ◽  
Water Injection ◽  
Water Reservoir ◽  
High Water ◽  
Recovery Factor ◽  
Low Viscosity ◽  
Well Spacing ◽  
High Water Cut Stage ◽  
High Water Cut ◽  
Water Cut

AbstractFor offshore reservoirs with a big bottom water range, the water cut rises quickly and soon enters the ultra-high water cut stage. After entering the ultra-high water cut stage, due to the influence of offshore production facilities, there are few potential tapping measures, so it is urgent to explore the feasibility study of artificial water injection development. The quasi-three-dimensional and two-dimensional displacement experiments are designed using the experimental similarity criteria according to the actual reservoir parameters. Several experimental schemes are designed, fluid physical properties, interlayer distribution, and development mode according to the actual reservoir physical properties. Through the visualization of experimental equipment, the bottom water reservoir is visually stimulated. The displacement and sweep law of natural water drive and artificial water injection in bottom water reservoir with or without an interlayer, different viscosity, and different well spacing is analyzed. The following conclusions are obtained: (1) For reservoirs with a viscosity of 150 cp. The recovery factor after water injection is slightly higher than before water injection. However, the recovery factor is lower than that without injection production. The reason is that the increment of injection conversion is limited to reduce one production well after injection conversion. (2) For reservoirs with a viscosity of 30 cp. The recovery factor after injection is 39.8%, which is slightly higher than 38.9% without injection. (3) For reservoirs with a viscosity of 150 cp. In the case of the interlayer. The recovery factor after injection is 30.7%, which is significantly higher than 24.8% without injection. (4) After the well spacing of the low-viscosity reservoir is reduced, the recovery factor reaches 46.1%, which is higher than 38.9% of the non-infill scheme. After the infill well in a low-viscosity reservoir is transferred to injection, the recovery factor is 45.6%, which has little change compared with non-injection, and most of the cumulative production fluid is water. The feasibility and effect of water flooding in a strong bottom water reservoir are demonstrated. This study provides the basis for the proposal of production well injection conversion and the adjustment of production parameters in the highest water cut stage of a big bottom water reservoir.

An Innovated Water Shutoff Technology in Offshore Carbonate Reservoir

2021 ◽  
Author(s):  
Yong Yang ◽  
Xiaodong Li ◽  
Changwei Sun ◽  
Yuanzhi Liu ◽  
Renkai Jiang ◽  
...  
Keyword(s):  
Heavy Oil ◽  
Bottom Water ◽  
High Water ◽  
Carbonate Reservoir ◽  
Oil Reservoir ◽  
Water Production ◽  
Water Shutoff ◽  
Water Breakthrough ◽  
Heavy Oil Reservoir ◽  
Water Cut

Abstract The problem of water production in carbonate reservoir is always a worldwide problem; meanwhile, in heavy oil reservoir with bottom water, rapid water breakthrough or high water cut is the development feature of this kind of reservoir; the problem of high water production in infill wells in old reservoir area is very common. Each of these three kinds of problems is difficult to be tackled for oilfield developers. When these three kinds of problems occur in a well, the difficulty of water shutoff can be imagined. Excessive water production will not only reduce the oil rate of wells, but also increase the cost of water treatment, and even lead to well shut in. Therefore, how to solve the problem of produced water from infill wells in old area of heavy oil reservoir with bottom water in carbonate rock will be the focus of this paper. This paper elaborates the application of continuous pack-off particles with ICD screen (CPI) technology in infill wells newly put into production in brown field of Liuhua, South China Sea. Liuhua oilfield is a biohermal limestone heavy oil reservoir with strong bottom water. At present, the recovery is only 11%, and the comprehensive water cut is as high as 96%. Excessive water production greatly reduces the hydrocarbon production of the oil well, which makes the production of the oilfield decrease rapidly. In order to delay the decline of oil production, Liuhua oilfield has adopted the mainstream water shutoff technology, including chemical and mechanical water shutoff methods. The application results show that the adaptability of mainstream water shutoff technology in Liuhua oilfield needs to be improved. Although CPI has achieved good water shutoff effect in the development and old wells in block 3 of Liuhua oilfield, there is no application case in the old area of Liuhua oilfield which has been developed for decades, so the application effect is still unclear. At present, the average water cut of new infill wells in the old area reaches 80% when commissioned and rises rapidly to more than 90% one month later. Considering that there is more remaining oil distribution in the old area of Liuhua oilfield and the obvious effect of CPI in block 3, it is decided to apply CPI in infill well X of old area for well completion. CPI is based on the ICD screen radial high-speed fluid containment and pack-off particles in the wellbore annulus to prevent fluid channeling axially, thus achieving well bore water shutoff and oil enhancement. As for the application in fractured reef limestone reservoir, the CPI not only has the function of wellbore water shutoff, but also fills the continuous pack-off particles into the natural fractures in the formation, so as to achieve dual water shutoff in wellbore and fractures, and further enhance the effect of water shutoff and oil enhancement. The target well X is located in the old area of Liuhua oilfield, which is a new infill well in the old area. This target well with three kinds of water problems has great risk of rapid water breakthrough. Since 2010, 7 infill wells have been put into operation in this area, and the water cut after commissioning is 68.5%~92.6%. The average water cut is 85.11% and the average oil rate is 930.92 BPD. After CPI completion in well X, the water cut is only 26% (1/3 of offset wells) and the oil rate is 1300BPD (39.6% higher than that of offset wells). The target well has achieved remarkable effect of reducing water and increasing oil. In addition, in the actual construction process, a total of 47.4m3 particles were pumped into the well, which is equivalent to 2.3 times of the theoretical volume of the annulus between the screen and the borehole wall. Among them, 20m3 continuous pack-off particles entered the annulus, and 27.4m3 continuous pack-off particles entered the natural fractures in the formation. Through the analysis of CPI completed wells in Liuhua oilfield, it is found out that the overfilling quantity is positively correlated to the effect of water shutoff and oil enhancement.

scholarly journals SHORT-TERM IMPACT OF A HYDROELECTRIC POWER PLANT’S RESERVOIR ON THE TREE COMPONENT IN AN ECOTONAL AREA IN SANTA CATARINA

2018 ◽  
Vol 41 (3) ◽  
Author(s):  
Carla Luciane Lima ◽  
Ana Carolina da Silva ◽  
Pedro Higuchi ◽  
Amanda da Silva Nunes ◽  
Juliana Pizutti Dallabrida ◽  
...  
Keyword(s):  
Structural Organization ◽  
Riparian Forest ◽  
Water Reservoir ◽  
Hydroelectric Power ◽  
Importance Value ◽  
Santa Catarina ◽  
Reservoir Water ◽  
Short Period ◽  
Tree Component ◽  
The Impact

ABSTRACT This study was conducted in an ecotonal area between the Mixed Ombrophilous Forest (MOF) and the Deciduous Seasonal Forest (DSF) in Santa Catarina, Brazil, to identify the impact of the water reservoir of the Garibaldi hydroelectric power plant on the mortality and floristic-structural composition of the tree component in a riparian forest adjacent to it. One year after the reservoir water filling, 48 200 m2 plots were systematically allocated in three sectors: adjacent to the water reservoir, intermediate slope and upper slope. The tree species individuals with circumference at breast height (CBH) > 15.7 cm were identified and measured (CBH); dead individuals were quantified. The geographic coordinates of each plot were obtained. Species diversity was analyzed by Shannon and Pielou indexes and the floristic-structural organization was evaluated through phytosociological estimates, Non-Metric Multidimensional Scaling (NMDS) and Mantel test. Variations on mortality and floristic-structural organization regarding environmental sectors were tested with Generalized Linear Models (GLMs). 70 species have been found in the community with Shannon and Pielou values of 3.10 and 0.73, respectively. Dead individuals have shown the second highest importance value (9.59%) with the highest mortality in the lower sector (p < 0.05), which may be associated with its proximity to the water surface. The community organization has shown spatial structure; however, the NMDS and GLMs have shown no floristic-structural differentiation among sectors, probably on account of the short period of exposure to reservoir filling impacts.

Carbonate Karstified Oil Fields Geological Prediction and Dynamic Simulation Through Equivalent Relative Permeability Curves

2021 ◽  
Author(s):  
Vincenzo Tarantini ◽  
Cristian Albertini ◽  
Hana Tfaili ◽  
Andrea Pirondelli ◽  
Francesco Bigoni
Keyword(s):  
Relative Permeability ◽  
Learning Algorithm ◽  
Correct Prediction ◽  
Two Phase ◽  
Water Breakthrough ◽  
The Matrix ◽  
Production History ◽  
Karst Reservoir ◽  
Relative Permeability Curves ◽  
Water Cut

Abstract Karst systems heterogeneity may become a nightmare for reservoir modelers in predicting presence, spatial distribution, impact on formation petrophysical characteristics, and particularly in dynamic behaviour prediction. Moreover, the very high resolution required to describe in detail the phenomena does not reconcile with the geo-cellular model resolution typically used for reservoir simulation. The scope of the work is to present an effective approach to predict karst presence and model it dynamically. Karst presence recognition started from the analysis of anomalous well behaviour and potential sources of precursors (logs, drilling evidence, etc.) to derive concepts for karst reservoir model. This first demanding step implies then characterizing each cell classified as karstified in terms of petrophysical parameters. In a two-phase flow, karst brings to fast travelling of water which leaves the matrix almost unswept. This feature was characterized through dedicated fine simulations, leading to an upscaling of relative permeability curves for a single porosity formulation. The workflow was applied to a carbonate giant field with a long production history under waterflood development. Firstly, a machine learning algorithm was trained to recognize karst features based on log response, seismic attributes, and well dynamic evidence, then a karst probability volume was generated and utilized to predict the karst presence in the field. Karst characterization just in terms of porosity and permeability is sufficient to model the reservoir when still in single phase, however it fails to reproduce observed water production. Karst provides a high permeability path for water transport: classical history match approaches, such as the introduction of permeability multipliers, proved to be ineffective in reproducing the water breakthrough timing and growth rate. In fact, the reservoir consists of two systems, matrix, and karst: however, the karst is less known and laboratory analysis shows relative permeability only for the matrix medium. The introduction of equivalent or pseudo-relative permeability curves, accounting for both the media, was crucial for correct modelling of the reservoir underlying dynamics, allowing a proper reproduction of water breakthrough timing and water cut (WCT) trends. The implementation of a dedicated pseudo relative permeability curve dedicated to karstified cells allowed to replicate early water arrival, thus bringing to a correct prediction of oil and water rates, also highlighting the presence of bypassed oil associated with water circuiting, particularly in presence of highly karstified cells.

The Deliverability of Horizontal Wells of the Oil-Water Fluid in Bottom Water Drive Reservoir

2013 ◽  
Vol 318 ◽  
pp. 473-476
Author(s):  
Chun Sen Zhao ◽  
Chao Li ◽  
Pei Jing Li
Keyword(s):  
Horizontal Well ◽  
Bottom Water ◽  
Two Phase Flow ◽  
Superposition Principle ◽  
Water Reservoir ◽  
Phase Flow ◽  
Practical Application ◽  
Two Phase ◽  
Well Productivity ◽  
Oil Water

First, we researched permanent infiltrating fluid of horizontal well of the bottom water reservoir using the method of the mirror reflex ion and the potential superposition principle, so we obtained productivity formula of bottom water reservoir in the condition of monophase flow; On the basis of monophase flow, with the horizontal well productivity of monophase flow as the initial production, we deduced horizontal well productivity formula of two-phase flow of bottom water drive reservoir using the potential superposition principle and the method of equivalent filtrational resistance. This formula fit in with the field data in the practical application, therefore the theoretical study of this article has a certain guiding significance to the research and application on bottom water drive reservoir oil-water two phase flow.

Production Dynamic Method to Determine the Critical Production of Bottom Water Reservoir

2012 ◽  
Vol 616-618 ◽  
pp. 985-991
Author(s):  
Liang Zhang ◽  
Shang Ming Shi ◽  
Chang Hui Yan ◽  
Ning Gan
Keyword(s):  
Bottom Water ◽  
Water Reservoir ◽  
Simulation Method ◽  
High Water ◽  
Single Well ◽  
Water Blocking ◽  
Low Efficiency ◽  
High Water Cut Stage ◽  
High Water Cut ◽  
Water Cut

Tahe oilfield of Triassic oil under low amplitude anticline group monolithic sandstone reservoirs with bottom water features, having a uniform oil-water interface, water energy sufficient. The current production wells generally see water, water cut rising too fast. Horizontal well bottom water coning phenomenon is outstanding, later period of high water cut stage manages difficulty to increase, water blocking measures have a low efficiency. Determine critical output, to improve production well life, efficient development reservoir has important significance .Based on the study of dynamic characteristics of single well and geological analysis of factors determining the critical output, and the application of numerical simulation method to verify the reasonable threshold quantity production. This method is simple and practical, can accurately make the critical output of single well.

Theoretical Investigation of Factors Affecting Water Breakthrough Time in a Horizontal Well Subject to Bottom Water Drive

2013 ◽  
Vol 824 ◽  
pp. 394-400
Author(s):  
M.C. Ogbue ◽  
E. Steve Adewole
Keyword(s):  
Bottom Water ◽  
Radial Flow ◽  
Water Reservoir ◽  
Early Time ◽  
Late Time ◽  
Breakthrough Time ◽  
Factors Affecting ◽  
Vertical Permeability ◽  
Water Breakthrough ◽  
Time Linear

Water breakthrough marks end of economic life of a reservoir. It has negative influence on recovery, operations, and economics. This means that delaying the encroachment and production of water is a means of maximizing the ultimate oil recovery, operating at higher efficiency and maximizing profit. This theoretical research is aimed at solving for time water will breakthrough a horizontal well placed in bottom-water reservoir. And subsequently, suggest ways to delay the water breakthrough time. Thus the model herein is a repository of three aims of reservoir modeling; predict, optimize and monitor oil production. Well modifications strategies were suggested to achieve significant delay of water breakthrough. The well in a bottom-water reservoir, which is much longer than the well, experiences four flow regimes, namely, early-time radial flow, early-time linear flow, late time pseudo radial flow and late-time linear flow period within which water breakthrough occurred. Each flow regime was represented mathematically. The resulting integrals were evaluated numerically. From the mathematical model, factors affecting water breakthrough were chiefly wellbore, reservoir fluid and reservoir properties. Their effects are evident in computed dimensionlesss pressure,, end of early radial flow, tDe, and dimensionless flow time, tD. Water breakthrough was evidenced by constant PD value. Delayed water breakthrough is favoured by narrow well, shorter well, low viscous fluid, low flow rate and high horizontal permeability relative to vertical permeability. Viscosity of oil can be reduced by gaslifting, EOR thermal process, etc. Higher values of and tDe can be achieved by increasing the horizontal permeability,kh, while vertical permeability,kv, is reduced. Suitable stimulation process can achieve improved permeability.Special functionserf error function =Ei exponential integral function Ei(x) = [

scholarly journals Prediction Method of Bottom Water Coning Profile and Water Breakthrough Time in Bottom Water Reservoir without Barrier

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Yahui Li ◽  
Haitao Li ◽  
Ying Li
Keyword(s):  
Bottom Water ◽  
Radial Flow ◽  
Water Reservoir ◽  
Prediction Method ◽  
Flow In Porous Media ◽  
Fluid Viscosity ◽  
Breakthrough Time ◽  
Water Breakthrough ◽  
Irreducible Water Saturation ◽  
Water Coning

During the exploitation of bottom water oil reservoir, bottom water coning influences the breakthrough of bottom water significantly. Because water cut rises quickly after the breakthrough of bottom water, measures should be taken before the breakthrough to postpone production period without water, thus improving oil recovery. So accurate prediction of water coning profile and breakthrough time is very essential. Through mathematical derivation, this paper proposed a prediction method of bottom water coning profile and bottom water breakthrough time in bottom water reservoir without barrier. Based on theory of fluids flow in porous media, this paper assumes that the flow models are plane radial flow in opened intervals and spherical radial flow in unopened intervals. Further, factors of fluid viscosity, irreducible water saturation, residual oil saturation, and oil-water contact (OWC) movement are also taken into account. Compared with other prediction equations, this method achieves more precise bottom water breakthrough time, and the relative deviation is only 1.14 percent.

Systematic Evaluation on Horizontal well Performance in Bottom Water Reservoir

2013 ◽  
Vol 411-414 ◽  
pp. 3129-3133 ◽  
Author(s):  
Yun Ting Li ◽  
Yue Dong Yao ◽  
Tao Peng ◽  
Dan Sang ◽  
Xiang Chun Wang
Keyword(s):  
Oil Recovery ◽  
Horizontal Well ◽  
Bottom Water ◽  
Water Reservoir ◽  
Systematic Evaluation ◽  
Research Trend ◽  
Well Performance ◽  
Key Factors ◽  
Water Breakthrough ◽  
Calculation Results

Development of bottom water reservoir with horizontal well can effectively slow down water coning and avoid early water breakthrough in oil wells, which promotes the extensive application of horizontal well in bottom water reservoir. In this paper, literatures about horizontal well are investigated, and the latest research trend is summarized. All factors such as reservoirs, fluid property and production mode to influence horizontal well performance in bottom water reservoir are systematically studied by using reservoir numerical simulation. Based on the calculation results of reservoir parameters of the pilot area, comprehensive analysis to the key factors which affecting horizontal well performance is carried out and the influence degree of various factors on oil recovery is obtained. In a word, the research results in this paper can provide criteria for the design or optimization of horizontal well development in bottom water reservoir.

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