Table of Content

01 August 2015, Volume 37 Issue 4

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A Study on Sedimentary Facies of Oil Group I in Member 2 of Zhujiang Formation in Wenchang 19-1 Oilfield

Lei Xiao1, Hu Yu2, Liang Wenfeng1, Liao Jijia2*, Liao Mingguang2

2015, 37(4):  1-12.  DOI: 10.11885/j.issn.1674-5086.2015.01.17.02

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The aim of this paper is to study the characteristics of sedimentary facies of oil group I in Member 2 of Zhujiang
Formation in Wenchang 19 1 Oilfield，west Pearl River Mouth Basin，according to the analysis of lithology and logging
facies as well as regional structural and sedimentary background. The research shows that this stratum is littoral facies. And the
littoral facies can be divided into foreshore and shoreface，which include foreshore beach bar microfacies，shoreface beach sand
microfacies，shoreface beach mud microfacies，and flooding mud microfacies. Foreshore beach bar microfacies developed in
the intertidal zone，the lithology of which is mainly flesh pink terrigenous clastic mass bioclast limestone and gray calcareous
sandstone，with massive structure，unobvious beddings，and reverses rhythm vertically. The low range gamma ray takes the
forms of date pit，zigzag or box curves. Shoreface beach sand microfacies and shoreface beach mud microfacies developed in
the subtidal zone. The lithology is mainly fine sand and politicsilt stone，and occasional pelitic strip. with ripple bedding，poor
cementation，good sorting，and bioturbation structure. The middle range gamma ray form of shoreface beach sand microfacies
are funnel curves. The high range gamma rays of shoreface beach mud microfacies are bell curves. Flooding mud microfacies
developed in the area where the water deepened，and the hydrodynamic force weakens. And it is a set of widely scattered
fine-grained sediments，the lithology of which is mainly mudstone and silty mudstone. With lentoid bedding，and bioturbation
structure. The high range gamma rays are zigzag or bell curves.

Mixing Reservoir Characteristic of Limestone Member in West  Slope of Jinhu Depression

Liu Chensheng1，2*, Yu Wang1，2

2015, 37(4):  13-21.  DOI: 10.11885/j.issn.1674-5086.2013.11.14.04

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Limestone member is the important oil production layer，but its reservoir is of strong heterogeneity. Based on
cores，physical property test and casting slice data，reservoir feature and controlling factors can be analyzed. Three deposition
cycles comprise limestone member. The lower part of every cycle consists of mudstone and marlstone；the upper part consists
of biolithite limestone and muddy biolithite limestone. With average porosity of biolithite limestone of 12.7%，and average
permeability of 21 mD，the reservoir falls into low porosity and low permeability type. The relationship between porosity and
permeability is poor，so secondary pores develop well，with little primary pores. Reservoir space mainly consists of dissolving
pore distributed inter-grains，and dissolving pore distributed inner-grains and mold pore are little. Cracks are filled or half filled
by calcite. Based on casting slice data，pore and throat of reservoir is of poor sorting and strong heterogeneity. Physical property
and heterogeneity of reservoir are controlled by sedimentary facies，M level cycle and diagensis. Horizontally，biolithite
limestone developed well on high structural point，and physical property is good and heterogeneity is poor. Vertically，biolithite
limestone developed well on upper M level cycle，with good physical property.

Application of Multi Level Fuzzy Comprehensive Evaluation Method in the Research of Remaining Oil Distribution in Xing 6 District

Hu Wei1*, Yang Shenglai1, Li Siming2, Wang Zhilin1, Li Ying1

2015, 37(4):  22-28.  DOI: 10.11885/j.issn.1674-5086.2013.08.30.31

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After 43 years of water flooding development，Xing 6 district of Daqing Oilfield has now entered the late period
of high water cut stage. It had many problems，such as a high degree of overall recovery，serious flooding and complex
underground oilwater relationship. Therefore，a detailed research of the distribution of remaining oil is urgently needed. On the
basis of comprehensive analysis of the geological factors and development factors affecting the distribution of remaining oil，
and making use of the dynamic and static data of the Xing 6 district reservoir，we selected four geological factors：the types
of sedimentary facies，reservoir thickness，plane connectivity，structure，and five development factors：injection relationship，
injection distance，well network，water status，direction by the effect. All the nine static and dynamic factors constitute the
remaining oil potential evaluation factors. With coring well data and water data of each layer，we made hierarchical division
and statistical weights of all the factors，and studied the distribution of remaining oil with multi level fuzzy comprehensive
evaluation method. We used the final remaining oil evaluation results of each well to draw out the remaining oil plane distribution
probability plots of layer S2 7. A comparison of the results with numerical simulation and core analysis results proved that
remaining oil of single layer recognition accuracy is 86.7%，which means this method can predict the remaining oil distribution
accurately，ang has higher practicability and reliability. This method provides a basis researches on remaining oil distribution
of similar reservoir.

Reef Sediment Distribution and Exploration Fields of Changxing Formation in Fuling Block，Southeast Sichuan Basin

Li Yuping*

2015, 37(4):  29-34.  DOI: 10.11885/j.issn.1674-5086.2013.08.29.07

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According to the analyses on features of regional sedimentary facies and outcrops，studies from perpendicular
sequence stratigraphy overlapping and evolution relationship in surrounding wells in Fuling Area in Sichuan Basin，the seismic
interpretation model is firstly built up to carry out seismic interpretation of regional great seismic profile，then by using regional
great sequence stratigraphy seismic profile，interpretation on seismic facies and sedimentary facies are carried out and faciesdevelopment
mode of reservoirs is built up，thus the exploration ranges of Changxing Formation and their seismic responding
features are clear. There develop two sedimentary cycles in Changxing Formation as well as high energy reef-beach facies belts
at the margin of platform. There existed two terrain slope laps before Changxing Formation deposited，the one lap is from
platform margin to shelf transiting area，the other one is the lap located in the inner part of platform. The two laps control two
rows of the development of high-energy facies belts of reef-beach，which are main targets for gas exploration.

Technical Strategy for Fine Geological Modeling in Later Development Stage of Complex Fault-block Oilfield

Zou Tuo1*, Xu Fang2

2015, 37(4):  35-40.  DOI: 10.11885/j.issn.1674-5086.2013.12.08.03

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To produce the remaining oil in the late secondary development of complex fault block old oilfields，we need an
accurate understanding of three-dimensional spatial distribution of reservoir，fine prediction of property parameters of reservoir，
therefore the study on fine geological modeling techniques is carried out. The step controlling and modeling approach
effectively solves structure modeling difficulties on many complex multi-block faults，complicated configuration relationships，
and many thin multi-layers of sand. SKUA′s geological grid system is used to avoid modeling mesh deformation，collapse and
instability etc. Meanwhile multi-conditional control and nested constraint property modeling are taken to ensure excellent correlation
between physical parameters. And a model with 30.0 m×30.0 m×0.5 m is established to accurately represent reservoir
heterogeneity based on GPU acceleration，multi-core parallel computing techniques，and particular attention is focused on key
single sand layers analysis. This paper takes fault two of Area V in Gangxi Oilfield as an example，and the above technical
strategies are used for three-dimensional geological modeling in the area to achieve a fine three-dimensional visualization of
reservoir，and improve the prediction accuracy of reservoir parameters. It provides a scientific and reliable geological model
for the subsequent fine numerical simulation in predicting residual oil.

The Evaluation Method of Marine Carbonate Source Rocks′ Hydrocarbon Potential by Fuzzy AHP

Xiong Deming1，2*, Zhang Mingfeng1, Wu Chenjun1，2, Tuo Jincai1

2015, 37(4):  41-50.  DOI: 10.11885/j.issn.1674-5086.2013.10.17.01

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Source rocks include mudstone，shale and carbonate rocks. And carbonate source rocks are also the basis for oil
or gas accumulation and petroleum system. The evaluation of marine source rock in the past is only focused on the study of
the physical and chemical properties. Because different basins have different marine sedimentary environments，the entrance
material types and degree of thermal evolution are different. If only the physical and chemical properties are considering，it is
difficult to objectively evaluate hydrocarbon potentiality and to rank the hydrocarbon generation potentiality of the carbonate
source rocks. So，to quickly and efficiently evaluate hydrocarbon potentiality of carbonate source rocks，we investigate and
survey the current research data，build a new evaluation index system and ensure the range of each parameter. In this paper，
there are four factors being considered，the abundance of organic matter，organic matter type，organic maturity and hydrocarbon
generation. With the criteria，we have built a new evaluation model of marine carbonate source rock which is based on fuzzy
AHP mathematics. Using this model，we can avoid the paradox in the evaluation process of the carbonate source rocks and
blindness in selecting parameters. It also helps to improve efficiency of carbonate source rocks evaluation. It is found that the
method is rapid，practical and reliable in the application of Bohai Bay Basin，so it is worth promoting.

Activity Characteristics of Meitai Fault of Fushan Depression and its Controlling on Sedimentation

Liu Qinqin1，2*, Huang Chuanyan2，3, Jin Siding2，3, Liu Entao2，3, Xia Cunyin4

2015, 37(4):  51-59.  DOI: 10.11885/j.issn.1674-5086.2013.03.18.01

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This paper analyzes the activity characteristics of Meitai fault in west of Fushan Depression with the reference of
drill/logging and 3D seismic data，on the basis of interpreted seismic results，and by fault activity ratio analysis methods. Meitai
fault started to develop in E2ls2. Its activity was stronger in E2ls2 and E2ls1，thereafter the activity gradually decreased. In space，
the site with the greatest activity intensity migrated with the time passing by，while fault activity intensity differed significantly
in different parts of the study area. Generally speaking，the intensity of fault activity changed in a way of dying down from the
middle to the two flanks. We made a preliminary study on the fault controlling effect on basin settlement and sedimentary system
types with the combination of basin sedimentation rate and analysis of sedimentary system types and discussed the controlling
effect of fault activity on the deposition of sedimentation and sedimentary facies distribution.

The Comprehensive Evaluation of the Deviation Factor Calculation of Natural Gas in Northeast Sichuan

Xiong Zhifu*, Deng Jinhua, Chen Dan

2015, 37(4):  60-66.  DOI: 10.11885/j.issn.1674-5086.2014.03.28.04

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Natural gas deviation factor is one kind of important data that can be obtained through PVT experiment or calculation
methods. Because the applicable conditions and accuracy of its calculation methods are not particularly clear in Northeast
Sichuan，evaluation is carried out to study the various calculation methods. Based on the comparative analysis and evaluation
on the predictions with four kinds of common calculation methods，deviation factor z-value in Standing-Katz chart under
pseudo-reduced pressure and temperature and the measured z-value of natural gas deviation factor in Northeast Sichuan，the
scope of various calculation methods is proposed. It is pointed out that both DAK and DPR methods have wide practical scope
and higher accuracy，besides，they are applicable to calculate the deviation factor of gas reserves under high temperature and
high pressure in northeast Sichuan.

A Study on the Interlayer Within Thick Reservoir in KunBei Oilfield，Qaidam Basin

Li Yanli1*, Wang Aiping1, Zheng Hongjun1，2, Chen Gengxin1, Gou Yingchun1，2

2015, 37(4):  67-72.  DOI: 10.11885/j.issn.1674-5086.2013.01.05.03

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In the middle and late stage of oilfield development，the distribution of the interlayer within thick reservoir is the
main factor affecting the injection-production relation of single sand body and the remaining oil distribution. The lower segment
of Xiaganchaigou formation（E13）develops thick reservoir in the Q6 Block of Kunbei oilfield，Qaidam basin，and the thick oil
reservoir develops muddy interlayer. In this paper，an identification model of Muddy interlayer was set up by core calibration
logging，and this model is taken as a standard to carry out the identification of the interlayer in the entire area. According to the
profiles，plane distribution characteristics of the interlayer，the interlayer in the study area is divided into the stable，sub-stable
and unstable types. On the analysis of distribution law of 3 kinds of interlayer，the shale content parameter lower limit value is
taken as constraint condition，and stochastic modeling is used to predict the space distribution of the interlayer，3D distribution
model of the interlayer is establishedto improve geological basis for injection-production relationship adjustment and water
drive reserves producing degree of the reservoir.

The Synthetic Approach of Fixed Depth of Investigation for Resistivity Logging While Drilling

Duan Baoliang1, Song Dianguang1，2*, Wei Baojun3, Zhang Guibin2

2015, 37(4):  73-80.  DOI: 10.11885/j.issn.1674-5086.2013.10.04.01

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To solve the problem of uncertain investigation depth of the original logging curves electromagnetic LWD Resistivity
instrument，this paper studied on synthesizing the original logs into curves with fixed depth of investigation. We firstly
used a simple and fast iterative inversion algorithm for shoulder-bed correction，followed by Gauss Newton-gradient descent
algorithms to inverse invaded formation resistivity，true formation resistivity and invasion radius for each layer. Then according
to the concept of the pseudo spacing，we drew the chart of investigation depth and source spacing，source spacing and apparent
resistivity by using the three parameters obtained before. Finally we obtained curves with fixed depth of investigation by
interpolation. Through a series of numerical simulation，we found that the different curves which were synthesized showed the
separation phenomenon with regularity in the invaded formation，which coincided with the geological characteristics well，and
can reflect invasion characteristics more directly compared to the original curves. So this method could improve the application
effect of this kind of instrument，and can be compared with the array induction curves，which makes geological interpretation
on formation evaluation more accurately.

Unsuitability of Using Superposition Principle to Solve Equation Incorporated with Threshold Pressure Gradient

Li Daolun1，2*, Yang Jinghai3, Zha Wenshu2, Wang Lei4, Lu Detang1

2015, 37(4):  81-89.  DOI: 10.11885/j.issn.1674-5086.2014.11.28.01

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Equation incorporated with threshold pressure gradient（TPG）is not homogeneous，and the error exists if it is solved
based on superposition principle. A mathematical single-phase flow model incorporated with the threshold pressure gradient
is proposed to describe the flow behavior in low permeability reservoirs by coupling the well storage effect. The fully implicit
numerical simulation based on PEBI grid is developed to study the transient pressure response for a vertical well. Buildup
pressure based on numerical simulation shows that TPG quickly makes buildup pressure stabilize，and makes buildup pressure
lower than initial pressure，and thus leads to the drops of curves of pressure derivative during buildup period. However，buildup
pressure based on superposition principle increases with time and cannot stabilize even after 4 800 days，which makes curves of
pressure derivative go up during buildup period. Comparing well test curves based on numerical solution with well test curves
based on superposition principle，we find that solution based on superposition principle is totally different from the solution
based on numerical simulation，which exhibits that superposition principle cannot be used to solve flow equation incorporated
with threshold pressure gradient.

Study on the Pseudo-saturation Vapor Pressure of the Methane on Shales

Xiong Jian*, Liu Xiangjun, Liang Lixi

2015, 37(4):  90-100.  DOI: 10.11885/j.issn.1674-5086.2015.03.05.07

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Adsorption of methane on shale is physical adsorption，and methane in supercritical state exists in the shale reservoir.
We introduced a concept of excess adsorption amount to modify adsorption gas volume of the adsorption experiment and
improved the Dubinin Astakhov（D A）equation，which is used to investigate the adsorption characteristics curve of supercritical
methane on shales，and the empirical formula of pseudo-saturation vapor pressure calculation was also investigated. The
result shows that the pseudo-saturation vapor pressure calculated by the Dubinin method and Reid method was lower and the
pseudo-saturation vapor pressure calculated by the extrapolation Antoine equation method and Astakhov method was higher.
The Amankwah method was an optimal method to calculate the pseudo-saturation vapor pressure. The adsorption characteristics
curve of supercritical methane on shales is independent of temperature，and the mathematical expression of adsorption
characteristics curve with physical parameters is described by the improved Dubinin-Astakhov equation.

Main Controlling Factors of Interlayer Interference in Big Intervals Commingled Production Oil Wells

Zhang Jicheng1，2*, He Xiaoru1，2, Zhou Wensheng2，3, Geng Zhanli2，3, Tang Engao2，3

2015, 37(4):  101-106.  DOI: 10.11885/j.issn.1674-5086.2015.03.12.02

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The oil wells with the commingled production with big intervals faced with the problem of serious interlayer heterogeneity.
By analyzing interlayers interference，the main controlling factors of interlayer interference are determined. Combining
field test practice，and by using interlayer interference coefficient as quantitative evaluation indicator of the degree of interlayer
interference，we carried out productivity test on some wells and found that the flowing pressure，drawdown pressure，water-cut
and other factors can affect the degree of interlayer interference. We collect data，and calculate the factors，including permeability
contrast，thickness contrast，layers，formation pressure coefficient contrast，drawdown pressure contrast，average viscosity，
porosity contrast，flowing pressure contrast and other factors. The multiple correlation coefficient method was adopted to screen
the factors. According to the grey correlation method based on weighted entropy，the correlation degree between the factors
and the interlayer interference coefficient was calculated. Permeability contrast，layers，formation pressure coefficient contrast，
commingled water cut，drawdown pressure contrast，flowing pressure contrast were determined as the main control factors.

Study on Excess Pore Pressure by Natural Gas Hydrate Dissociation

Zhang Wei1，2*, Li Xinzhong1, Li Qingping1, Cao Jing1

2015, 37(4):  107-116.  DOI: 10.11885/j.issn.1674-5086.2013.04.16.01

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For the engineering risk caused by natural gas hydrate dissociation during the offshore hydrocarbon resource exploitation
and ocean engineering construction processes，a theoretical model is proposed for the analysis of excess pore pressure
due to the gas hydrate dissociation. The theoretical-analytical method is adopted in the study. Firstly，based on the phase behavior
models before and after the hydrate dissociation and the general gas law in thermodynamics，the volume expansion model
of sediments caused by the hydrate dissociation is derived，and then，according to the soil compression and swelling behavior
in soil mechanics，the theoretical-analytical model is obtained for the analysis of excess pore pressure by the hydrate dissociation.
The reasonability and validity of the model have been verified by the representative submarine landslide case. Besides，a
parametric analysis has been performed to investigate the complex affecting parameters in the model. This study is of important
theoretical value and practical significance to understand the evolution mechanism of the excess pore pressure resulting from
the hydrate dissociation，ensure the hydrate reservoir stability and avoid the project risk.

A Coupling Model of Fishbone Multilateral Horizontal Well in Bottom Water Reservoir

Yue Ping*, Du Zhimin, Chen Xiaofan, Mo Fei, Li Wei

2015, 37(4):  117-126.  DOI: 10.11885/j.issn.1674-5086.2013.05.07.01

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In order to solve the problems of productivity prediction and pressure distribution of herringbone branched horizontal
wellbore in bottom water reservoir，a coupling model of multilateral horizontal well and seepage flow in the reservoir is investigated.
Based on characteristics of the constant pressure supply boundary condition and micro-unit method，by subdividing
the reservoir rather than subdividing the well bore，a new coupling model of herringbone branched horizontal well in bottom
water reservoir is established. Subdivision of the reservoir is a new resolution type of micro-unit treatment and research method.
The obtained simplified model greatly decreases the calculation work and compute cost when productivity and pressure drop
profile are calculated. The results of the simplified model accord with the basic principles of accurate model. Meanwhile this
paper proposes the modified ratio of simplified model transferring to the accurate model. It′s an effective and convenient way
to apply the simplified model modified by this ratio to do the rapid evaluation of productivity. Moreover the simplified model
provides the research basis for productivity prediction of herringbone branched horizontal well in bottom water reservoir. And
it contributes to the further calculation of parameters like critical production and critical pressure drop to delay the occurrence
of bottom water breakthrough.

Single Factor Analysis of Casing Force Based on the Numerical Simulation

Yu Xianbin1，2*, Chen Xiaoqing1, Ji Youjun3

2015, 37(4):  127-134.  DOI: 10.11885/j.issn.1674-5086.2015.03.04.02

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Casing damage is always a problem in the process of oil field development，so it is significance for the study of
casing failure mechanism and its influencing factors to ensure the casing security. Based on fluid-solid coupling theory，a
new mathematical model which was used to simulate the stress distribution of the combination about casing-cement sheath
-formation was established considering seepage and stress interaction during oil development process. Besides，the numerical
simulation was carried out by the finite element software ABAQUS that describes radial compressive force of casing under
different water injection pressure，formation parameters，casing parameters and in-situ stress. The results show that radial
compressive force of casing will increase as the water injection pressure，casing wall thickness and poisson′s ratio and elasticity
modulus of formation increasing. However，radial compressive force of casing will decrease with elastic modulus and diameter
of casing，formation permeability and in-situ stress increasing. The results can provide the theoretical guidance for protecting
and preventing casing damage.

The Distribution of Residual Polymer and the Synergistic Action of Binary Combination Flooding After Polymer Flooding

Xie Xiaoqing1，2*, Feng Guozhi1，2, Liu Liwei1，2, Shi Yao1，2, Zeng Yang1，2

2015, 37(4):  135-140.  DOI: 10.11885/j.issn.1674-5086.2013.04.02.02

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To maximize the benefit of residual limited polymer in the reservoir，we carried out a study on the distribution of
residual polymer and the synergistic action of binary combination flooding after polymer flooding. On the basis of the survey
and summary of the improved oil recovery methods after polymer flooding at home and abroad，the 3D plane large physical
model experiments were carried out which accorded with the geological characteristics in offshore oil field S block. By sampling
and monitoring the contour diagram of polymer solution viscosity field，concentration field and stress field during the different
stages of water flooding，polymer flooding，binary combination flooding and subsequent water flooding，the distribution law of
residual polymer and the influence of binary combination flooding after polymer flooding were obtained. The results show that，
at the end of the polymer flooding，the concentration of mainstream line was the highest，and the concentration of two wings
was the smallest. At the end of subsequent water flooding，the concentration of mainstream line was the smallest，and most
of the polymer was driven out. The more residual polymer in core，the stronger the auxiliary function of binary combination
flooding. After the polymer injection，the earlier implement of replacement technology，the better development effect. The
study has important guiding significance for research on how to use the replacement technology after polymer flooding.

A New Screening Evaluation Method for Candidate Reservoirs by CO2 Injection Miscible Flooding

Zhang Yanyu1*, Li Yanjie2, Sun Xiaofei1, Bai Xuzheng3, Su Yuliang1

2015, 37(4):  141-146.  DOI: 10.11885/j.issn.1674-5086.2013.05.27.04

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Before the implementation of CO2 injection EOR project，screening evaluation of the candidate reservoirs can improve
the success rate and economic benefits of CO2 injection. Based on CO2 miscible flooding mechanism，this paper picks out
12 reservoir parameters and fluid parameters affecting CO2 injection miscible flooding results as comprehensive evaluation parameters
to screen out the candidate reservoirs. According to the investigation of a large number CO2 miscible flooding projects
at home and abroad，the quantitative method is determined by theoretical analysis，field experience and probability statistics.
Through calculating the combinational weight by improved AHP and entropy method and combining the advantages of TOPSIS（
Technique for Order Preference by Similarity to Ideal Solution）with gray relational analysis，the weighted GC TOPSIS
model is established to screen out the candidate reservoirs. This screening method was used to assess five classical candidate
reservoirs about CO2 injection miscible flooding. The results show that：by combined both subjective and objective impact，
this method can correctly evaluate the potential of CO2 miscible flooding of the candidate reservoirs.

The Research for Relieving Damage and Stimulation of Injection Well in Karamay Oilfield

Hu Shuyong1*, Liu Xue2, Huang Jing3, Wang Yong4, Li Jianguo4

2015, 37(4):  147-151.  DOI: 10.11885/j.issn.1674-5086.2013.03.11.02

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Along with the waterflooding development，the subsurface contradiction is becoming obvious，that is，the increase
of water production brings about decline of production. Karamay Oilfield has been carrying out waste-water reinjection since the
beginning of the development，which cause formation plugging for inferior quality，resulting in high injection pressure and low
injection rate. Based on the analysis of performance data and stemming，the plugging mechanism is studied and plug remover
is developed. The experiments of dissolved rock sample，degraded polymer and the removed iron sulfide scale indicate that
the plug remover have great dissolving capability，which can reduce the viscosity of polymer solution，oxidize and decompose
polymer gel，and remove iron sulfide scale. The FP 1 anti-swelling agent is adopted in the acidizing technology for watersensitive
sandstone reservoirs. The effectiveness of field application is remarkable，which is of certain model significance to
other similar oilfields.

The Mobilization Mechanism of Residual Oil by Marangoni Convection Caused by Binary Flooding

Luo Litao1，2，3*, Liu Xiangui3, Liao Guangzhi4, Liu Weidong3, Cui Bin5

2015, 37(4):  152-160.  DOI: 10.11885/j.issn.1674-5086.2015.03.05.02

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Marangoni convection of the binary flooding plays an important role in mobilizing residual oil in reservoir. Researches
on the microscopic mechanism will contribute to the application of binary flooding to enhanced oil recovery. In this paper，
the authors used Na2CO3 solution，KPS surface active agent solution and mixed solution to contact with crude oil respectively.
The experiments verified their marangoni convection effect. Microscopic simulation model of oil displacement experiment was
made with Na2CO3 and KPS binary flooding that result in strong Marangoni convection. The results show Na2CO3 solution，
KPS surface active agent solution and mixed solution could all have marangoni convection effect. The greater the concentration
is，the better the effect of marangoni convection is. Na2CO3 and KPS have synergy for marangoni convection.The binary
flooding mixed with 1.2% Na2CO3 and 0.3% KPS can cause the interfacial turbulence and spontaneous emulsification. It has a
significant effect on mobilizing residual oil in membrane，island and blind side. The binary flooding which can produce strong
marangoni convection should be used in the oil field.

A Laboratory Study on the Micro Mechanism of Oil Displacement with CO2 Flooding

Xiao Pufu1*, Yang Zhengming2, Wang Xuewu2, Dai Xingxing3

2015, 37(4):  161-165.  DOI: 10.11885/j.issn.1674-5086.2015.03.09.03

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Through one-dimensional physical simulation experiment with the cores of ultra low permeability reservoir in the
peripheral part of Daqing，this paper studies the micro mechanism of oil displacement mechanism by water flooding、CO2
flooding and CO2 flooding after water injection，furthermore，the suggestion for the field application of gas flooding after
water injection is put forward. The main advantage of this experiment is reducing oil viscosity and extraction of CO2，etc.
Compared with water flooding，CO2 flooding oil displacement is more efficient with notable oil increment. Result shows that：
for low permeability reservoir，the effect of water flooding is the worst，about 40%，at different time of water injection gas
driving can lead to better effect，the earlier timing of water injection the better effect，to have better economic benefits the rate
of water content should be 10%～20%；flooding recovery degree is best by gas injection，can reach to about 67%. By means of
NMR，we can compare the different development ways，CO2 displacement and water displacement extracts most of movable
fluid in macro pores，however，the CO2 can increase the sweep volume effectively after water injection，which also make the
parts of the small pore crude oil become movable.

A New Method for Oil Well Dynamic Fluid Level Detection Based on the Column Sound Field Model

Zhou Wei1*, Jia Wei2, Guo Xiaoyu3, Li Taifu1, Yi Jun1

2015, 37(4):  166-172.  DOI: 10.11885/j.issn.1674-5086.2013.10.17.11

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It is important to measure the depth of dynamic liquid level of oil well in order to set reasonable oil extraction
technology. In this paper，we proposed a detection method of oil well dynamic fluid level based on the sound field model of
the column，in order to solve the problem of weak echo signal，large noise disturbance and difficult identification of liquid
level wave in the traditional echo method. In this method，the typical string structure can be analyzed with the pipeline acoustic
theory. Moreover，the relationship between the well dynamic fluid level depth and the natural frequency of the tube sound field
is established，according to the sound field characteristic of the column and resonance theory of tube air column，inspired by the
fact that the vocal frequency of wind instrument can reflect the acoustic pipe length. Then we measured the natural frequency
of the sound field in tube by Fast Fourier Transform（FFT），and liquid level depth of tube will be obtained. The experimental
results confirm the relationships between the string air resonance frequency and dynamic liquid level，and show that the tube
liquid level depth is more accurate within 2% relative error by using this method which provides a new way for the accurate
detection of the well dynamic fluid level depth.

A Self-regulation Tube-type ICD Design and Its Numerical Validation

Zeng Quanshu1, Wang Zhiming1*, Wei Jianguang2, Wang Xiaoqiu1, Guo Xiao1

2015, 37(4):  173-180.  DOI: 10.11885/j.issn.1674-5086.2013.10.11.01

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In this paper，the tube-type inflow control device（ICD）is improved to overcome the constant Flow Resistance
Rating（FRR）which is both too large at low flow rate and too small at high flow rate，and this improvement is verified
by numerical simulation. To highlight the excellent performance of the self-regulation tube-type design，three other designs
（nozzle-based，helical channel，and tube-type）with a same FRR of 0.8 were compared to study fluid property sensitivities and
structural parameter optimization. The results show that the main fluid property sensitivity differences among the four designs
are flow rate，density，and viscosity respectively. And viscosity sensitivity is of the most. The structural parameters that affect
FRR are minimum flow area and flow path length. In addition，minimum flow area has a great influence on both erosion and
plugging resistance. To sum up，the self-regulation tube-type design has low viscosity sensitivity，large minimum flow area，
high erosion resistance，high plugging resistance，and its FRR will be adjusted automatically according to the reservoir flow
rate，thereby a more uniform inflow profile was maintained and total production was maximized.

Optimization of Well Patterns Based on Flow Field Intensity

Feng Qihong1, Wang Bo2*, Wang Xiang1, Wang Shoulei3, Han Xiaodong4

2015, 37(4):  181-186.  DOI: 10.11885/j.issn.1674-5086.2013.01.16.02

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With the impact of geology，well patterns and fluid properties，injected water will break fast and circulate invalidly
in somewhere of the water flooding reservoir，which is the feature of unbalanced displacement. However，in order to pursue
a relatively higher balanced displacement and attain more oil recovery for heterogeneous reservoirs，well pattern optimization
design must consider the heterogeneity of reservoirs. Based on reservoir flow field，the optimal object is to minimize the
coefficient of variation of streamline field intensity in the mathematical model. By solving the mathematical model of well
pattern optimization with genetic algorithm to match the heterogeneity of reservoir，the optimal well allocation can be obtained.
The analysis on the application of above theory in oil reservoir shows that the optimal well allocation can improve waterflooding
situation and recovery.