Table of Content

20 August 2010, Volume 32 Issue 4

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地质勘探

OOLITIC RESERVOIR PREDICTION METHOD BASED ON NONLINEAR ENERGY ANALYSIS

XIONG Xiao-jun WANG Xiao-pin HE Zhen-hua

2010, 32(4):  1-5.  DOI: 10.3863/j.issn.1674-5086.2010.04.001

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Non linear Teager Kaiser energy (TK energy) can be classified as the amplitude of the seismic attributes,but it is different from the conventional seismic attributes,because it is proportional to the square of amplitude and frequency.When the oolitic reservoir is full of oil or gas,seismic records often present “high"frequency attenuation” phenomenon.As TK energy is proportional to the square of frequency,TK energy of the reservoir which contains oil or gas is weak.Since the oolitic reservoir′s top and bottom is different from the surrounding in rock properties,“bright spot” reflection often presents on top and bottom of the reservoir,so TK energy of the top and bottom of the reservoir is stronger.With seismic profile after extraction of seismic attribute of TK energy,the top and bottom of the reservoir on the seismic profile is much “brighter”,while TK energy is relatively weak in the internal reservoir.These characteristics can be used to predict the oolitic reservoir.The computational result of the real data shows that the predicted distribution of oolitic reservoir based on TK energy method is completely consistent with the real work data.

STUDY ON THE MAIN CONTROLLING FACTORS OF MID SHALLOW LAYERS′ HYDROCARBON ACCUMULATION OF ANDA DEPRESSION

SHI Zhong-sheng WANG Tian-qi WANG Jian-gong HAN Xiao-qiang LEI Ming

2010, 32(4):  6-11.  DOI: 10.3863/j.issn.1674-5086.2010.04.002

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Based on the integrated study on the source rocks,expulsion driving force,vertical migration pathway,and reservoir of Anda Depression in the northern part of Songliao Basin,this paper identifies the main controlling factors of mid shallow layers′ hydrocarbon accumulation and achieves a big exploration breakthrough of Anda Depression.This study reaches four conclusions as follows:1.The maturity of source rocks is the most important controlling factor of hydrocarbon accumulation and it determines the distribution and scale of the mid shallow oil pools;2.The overpressure of the 1st member of Qingshankou Formation in the mature source rocks is the main controlling factor of hydrocarbon accumulation of the 4th member of Quantou Formation;3.As for the Qingshankou Formation,the vertical migration pathway is the basis of the hydrocarbon accumulation and the developing level of the 2 nd and 3 rd reservoir of Qingshankou Formation is the key factor of hydrocarbon accumulation;4.The relatively low maturity (the Ro of most Anda Depression is less than 0.9%) and thin thickness (the thickness of most Anda Depression is less than 80m) of source rocks result in the relatively low generating hydrocarbon potential,which may control the hydrocarbon accumulation of Yaojia Formation.

THE LITHOLOGY RECOGNITION OF VOLCANIC ROCKS WITH ROCK MECHANICS PARAMETER

LIU Zhi-di

2010, 32(4):  12-15.  DOI: 10.3863/j.issn.1674-5086.2010.04.003

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The lithology recognition of volcanic rocks is the foundation of the lithofacies division,reservoir synthetic evaluation and forecast,well pattern deployment and establishment of developing plan.Volcanic rocks have various types,their lithologies related to their ingredients and structures.So it is very difficult to recognize their lithologies.Mechanical parameters of rocks are rich in characterization of lithologic information,providing a lot of volcanic lithologic data.This paper takes the carboniferous volcanic rocks in Junggar Basin District69 for example.The rock mechanic parameters of 40 core samples are tested in the area,and the Poisson′s ratio,Young′s modulus,bulk elasticity modulus which are very sensitive to the volcanic rock lithology are optimized.Based on the three parameters of rock mechanics the lithological identification plate is established.At the same time,the model of Poisson′s ratio,Young′s modulus,bulk elasticity modulus which are calculated by using logging data are given,so that the identification of lithology of the volcanic rocks in the work area are calculated point by point.The recognition result indicates that this method can recognize lithology accurately in this work area.The recognition rate is fully capable of meeting the requirements of reservoir evaluation.

STUDY ON THE WEATHERED CRUST OF CONGLOMERATE IN UPPER TRIASSIC YANCHAGN FORMATION OF ZHENJING FIELD

DING Xiao-qi ZHANG Shao-nan

2010, 32(4):  16-19.  DOI: 10.3863/j.issn.1674-5086.2010.04.004

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There is a favorable oil sign in clastic weathered crust of Zhenjing field,making it the next important exploring target.The clastic weathered crust of Yanchang Formation is researched by using well logging data,thin sections of the cast,trace elements,BES and so on.It is showed that the weathered crust includes hydrolyze zone and leaching zone.Hydrolyze zone is made up of stable mudstones,and can be used as cap rocks.Because fresh water leaching,then feldspar and watersoluble minerals are altered,leaching zone is full of sandstones with a lot of secondary pores,which are “desserts” of tight sandstones,and desserts can be found in slope of pale geomorphology of upper Jurassic usually.This structure has a good combination of reservoirs and caps.It can form large reservoirs if the traps are developed.

STUDY ON GEOLOGICAL 3D RESERVOIR ARCHITECTURE MODELING OF MEANDERING RESERVOIR AND ITS APPLICATION

LAN Li-feng;BAI Zhen-qiang YU De-shui HUO Zheng-wang

2010, 32(4):  20-25.  DOI: 10.3863/j.issn.1674-5086.2010.04.005

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Considering the meander river sand bodies at late high water cut stage which is under dense pattern,with the core,well logging and production data,the analysis hierarchy method is applies in subsurface architecture anatomy.According to this method,five architecture hierarchies including sedimentary units,sedimentary facies,single meandering belt,single point bar and lateral accretion bodies are identified and analyzed.Based on a large amount of modern deposition data and outcrop research,this paper introduces the relationship between width/thickness ratio of sand body and lateral accretion interlayer′s dip angel.Lateral accretion interlayer′s scale and model of river sand body are developed and the four parameters of lateral accretion interlayer including dip direction,dip angel,expanded range and horizontal range are described.Using sequential indicator simulation method and human computer exchange method,3D reservoir architecture model are established with Direct software.The method improve the efficiency of 3D architecture stochastic modeling of reservoir.According to different relations of 3D reservoir architecture model and injection production well patterns,three recovery measures for the remaining oil in lateral accretion shale bedding are proposed.Better measurement results are obtained.

PREDICTION OF DOMINANT MIGRATION PATHWAYS AND FAVORABLE EXPLORATION ZONES IN BOZHONG DEPRESSION

WANG Ming;JIANG Fu-jie;PANG Xiong-qi;

2010, 32(4):  26-32.  DOI: 10.3863/j.issn.1674-5086.2010.04.006

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Oil and gas distribution is not clear in Bozhong Depression.This restricts the choice of exploration direction.So the dominant migration pathway researches which are closely related to oil and gas distribution are to be carried out urgently.According to the four basic dominant migration patterns:the separation advantage,level difference advantage,flowing pressure advantage and flowing direction advantage,the dominant pathway of hydrocarbon migration of Baozhong Depression is analyzed systematically by using single element coupling analysis method and multi element superposition analysis method.As a result,four dominant pathway directions are summarized:from the center of depression to Bonan Low Uplift,Shijiutuo Uplift,Shaleitian Uplift and North of Bodong Low Uplift.Compared with the distribution of source rocks and reservoir characteristics,two kinds of favorable hydrocarbon migration accumulation reservoir models are summarized.They are respectively self generation and selfpreservation in Shahejie Formation and dominant pathway cap rock traps.Many kinds of dominant pathways are believed to coexist among Bonan Low Uplift,Shijiutuo Uplift and Shaleitian Uplift according to the comprehensive analysis.Besides,sand bodies are well developed,and there are also various types of traps,making them favorable exploration zones.Traps with complete cap rocks in those zones are favorable exploration targets.

HYDROCARBON MIGRATION CHARACTERISTICS OF LINNAN SAG IN HUIMIN DEPRESSION

ZHU Zhi-qiang ZENG Jian-hui WANG Jian-jun

2010, 32(4):  33-38.  DOI: 10.3863/j.issn.1674-5086.2010.04.007

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Based on the detailed analysis of dynamic systems,pathway conditions,directions and times of petroleum migration in Linnan Sag,a systematic research on oil migration characteristics in Linnan Sag is made.The results show that:(1) oil migration system in Linnan Sag varies distinctly from formation to formation.Normal pressure system appears in formations above 3000m,while mix pressure system appears below 3000m.And buoyancy and abnormal pressure are the main oil migration dynamics in Linnan Sag;(2) Near east west fault and interconnected sand bodies are the pathways for oil migration from Sag center to margin;(3) Four superior migration directions exist for oil migration from Sag center to margin;(4) Oil migration happened in Oligocene Dongying Period.

TRAP FEATURES OF THE NORTHERN KUNLUN FAULTS ZONE IN QAIDAM BASIN

CHEN Guo-min WAN Yun ZHANG Pei-ping XIA Min-quan ZHANG Dao-wei

2010, 32(4):  39-43.  DOI: 10.3863/j.issn.1674-5086.2010.04.008

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The north Kunlun faults zone lies in the southern edge of the western Qaidam Basin.It has a lower degree of exploration and complicated hydrocarbon accumulation.In order to make a deep probation of the major exploration targets and hydrocarbon accumulation law,the authors make a research on the types and controlling factors of traps in this area.The major types of trap are structural traps including the faulted nose,faulted anticline and faulted block.The horizontal distributions are mainly subject to the development of fractures and degrees of tectonic deformation.It has an obvious dependent relation with faults system,and most of them are fault dissections which have a less completeness.They are featured by the linear and zonal distribution.What′s more,most traps are formed in Miocene and Pliocene epoch and there is a big difference among tectonic positions in hydrocarbon bearing.Thus,the conclusions will be helpful to the next hydrocarbon exploration in this area.

CONTROLLING EFFECT OF METEJAN PALEOSTRUCTURE ON THE FORMATION OF GAS RESERVOIR

LI Hong-xi CHENG Xu-bin LIU He-nian WU Lei BU Cheng-zhong

2010, 32(4):  44-49.  DOI: 10.3863/j.issn.1674-5086.2010.04.009

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In order to obtain the controlling factors of reservoirs and gas productive concentration rules,the formation and evolution of Metejan fracture are studied by layer flattening technique.From the study,the forming period and scale of Palaeostructure and Neotectonics are clarified.Through the study of the timespace relationship between gas generation,migration and formation,the main controlling factors of reservoirs are found.The research result shows that Neotectonics have little effection on the formation of gas reservoir,while Paleostructure have more effects on the formation of gas reservoir.The size of Paleostructure determines the reservoir scales and gas distribution.The research on controlling factors of reservoirs has clarified the gas reservoir type and highyield & enrichment rules.Wells located in super or upslope of Paleostructure have high level of production and better physical property.On the contrary,wells located in the bottom or downslope have a low level of production and poor physical property.

IDENTIFY THE BOUNDARY OF DEPOSITIONAL SYSTEM BY USING SEISMIC SEDIMENTOLOGY

LI Quan LIN Chang-song WU Wei YUAN Hua-juan

2010, 32(4):  50-55.  DOI: 10.3863/j.issn.1674-5086.2010.04.010

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ShuangYang Formation of Paleogene can be divided into two three order sequences and five system tracts through recognizing the subaerial unconformity,the maximum regression surface,the maximum flooding surface on the basis of well logging and seismic data.The sequence stratigraphyⅠincludes the first and second section of Shuang Yang Formation and is composed of the lowstand system tract,transgressive system tract and highstand system tract.The sequence stratigraphy Ⅱ includes part of section three of Shuangyang and is composed of the lowstand system tract and transgressive system tract.This paper identifies the sedimentation of forced regression in highstand system tract,the developing process and the boundary of deposition system in different period by using seismic sedimentology approach which is seismic attribution halving method.At last,four combination caps and reservoirs are predicted.

PROPERTY ANALYSIS AND STOCHASTIC MODELLING OF FRACTURED RESERVOIRS

TANG Yong MEI Lian-fu TANG Wen-jun CHEN You-zhi HU Zhi-wei

2010, 32(4):  56-66.  DOI: 10.3863/j.issn.1674-5086.2010.04.011

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Compared with conventional reservoirs,fractured reservoirs have a higher heterogeneity due to the existence of fractures.The key of describing this type of reservoir lies in a complete and accurate quantitative description of fracture networks.The purpose of modeling fractured reservoir is integrating the information and data of relevant fractures,making a statistical analysis and spacial analysis of the fracture characteristics with the optimal probability distribution function,and choosing a theoretical model according to the regional geologic background and research purposes.According to this principle,a multidisciplinary analysis on the probabilistic simulation method of fractured reservoir is made.From the analysis,some conclusions are made as follows.First,the nonlinear analysis method can reduce the errors caused by the integration of multi source and multiscale data maximally.The fracture data analyzed comprehensively is comparatively good.Second,we can draw a relatively reasonable conclusion with circular statistics method and artificial intelligence method when we analyse fracture attributes.Third,compound model cannot only show the discreteness of fractures but also reflect the continuous effect of fractures.However,due to the complexity of the fracture development,fracture modeling still need to be improved by multidisciplinary analysis and multi technique research.

PETROLEUM ACCUMULATION AND DISTRIBUTION LAW OF CHANG 2 FORMATION IN PANLONG OILFIELD ORDOS BASIN

BAI Yu-bin ZHAO Jing-zhou ZHANG Ai-cheng CHEN Xiao-ping

2010, 32(4):  67-71.  DOI: 10.3863/j.issn.1674-5086.2010.04.012

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The formation and distribution of Chang 2 accumulations in Yanchang Formation in the North Shanxi Slope are considered to be controlled by sedimentary facies and high quality reservoir.Other geological factors such as structure and fracture have a relatively weak effect on the formation of reservoir.The present study shows that the formation and enrichment of Chang 2 reservoir are subject to multiple factors such as:sedimentary facies,high quality reservoirs,the background of noseshaped uplift，regional seal,local seal and migration pathway etc in Panlong Oilfield,among which the nose shaped uplift and local cap rocks are the most important conditions for the formation and enrichment of Chang 2 reservoir because the periclinal structure of nose shaped uplift is rich in hydrocarbon reservoirs and the local cap rocks expand the longitudinal distribution range of oil.Besides lithologic accumulations,structure lithologic composite accumulations are the main types of the Chang 2 accumulations．

GENESIS OF CO₂ AND RESERVOIR FORMING CONDITIONS IN EASTERN PART OF LINQING DEPRESSION

GENG Chun-yan

2010, 32(4):  72-76.  DOI: 10.3863/j.issn.1674-5086.2010.04.013

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CO₂ resources are well developed in eastern part of Linqing Depression,and have been discovered both in Paleozoic and Neogene system.Based on the latest exploration and research achievements,combing with practice in adjacent Jiyang Depression and Dongpu sag,this paper analyzes the genesis of CO₂ in eastern part of Linqing Depression,and point out that it is mantle magma derived CO₂,while shallow buried gas may contain associated gas during generation of coal derived gaseous hydrocarbon.Based on the sectional anatomy of typical gas reservoir,it can be concluded that tectonic movements such as faulting and magmatic activity are significant to reservoir forming of CO₂ in eastern part of Linqing Depression,and consequently summarized favorable exploration structural belts and CO₂ resource potential.

石油与天然气工程

3D NETWORK MODELING OF LONG TERM WATER FLOODED SAND RESERVOIR PORETHROAT STRUCTURE VARIATION

XU Hui WANG Chang-jiang PANG Xiao-hua JIANG Han-qiao

2010, 32(4):  82-86.  DOI: 10.3863/j.issn.1674-5086.2010.04.015

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Based on water flooding test,3D network model of long term water flooded sand reservoir pore throat structure variation is constructed to analyze its variation law by using the 3D particle migration model and finite difference solution method.The result indicates that the throat radius and its variation range increase after long term water flooding behavior while radius of the minima throat decreases.The distribution pattern of channels which includes the original larger radius throats and the big pores after water flooding is determinated by the original rock structure.In fact,not all the channels are connected to each other all over the pore scale network and form a crossed channel,but several big radius pores in the start and end face of the pore scale network are connected to each other and formed a channel group.The modeling result together with oil well testing can provide more reasonable solution to the adjustment of injection profile.

THE EARLY RECOVERY OF FLOW PATTERN AND PARAMETER INTERPRETATION IN WELL TEST

HU Xiao-hu ZHENG Shi-yi;

2010, 32(4):  87-91.  DOI: 10.3863/j.issn.1674-5086.2010.04.016

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The impact of noise data on the pressure derivative is characterized by rapid dampening with time,and the after flow rate for the closure of constant surface rate with constant wellbore storage coefficient is recovered by segmented exponential function in inverted order according to the wellbore material balance equation.Based on this recovered after flow rate,the early time radial flow is uncovered by D.Ilk′s pressure rate deconvolution algorithm by removing specified percent of wellbore storage effect,and parameters of reservoir and wellbore are interpreted according to this recovered radial flow.This method is very stable and accurate according to the data test of pressure which contains 30 kPa random noise.

QUANTITATIVE EVALUATION OF CONGLOMERATE RESERVOIR WATER FLOODED LAYERS BY OIL SATURATION RESTORATION METHODS

TAN Feng-qi;LI Hong-qi;MENG Zhao-xu;XU Chang-fu YAO Zhen-hua

2010, 32(4):  92-98.  DOI: 10.3863/j.issn.1674-5086.2010.04.017

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Due to the strong heterogeneity,conglomerate reservoir has a complex lithological and physical property background and a large rangeability of oil layer resistivity.All the above makes the quantitative evaluation of the conglomerate reservoir water flooded layers the focus and difficulty of the second regulation and development in oilfield.Based on well logging,coring,testing data and reservoir quality index,under the guidance of petroleum migration and accumulation theory,the computational model of the initial oil saturation of conglomerate reservoir is built.The differential value between initial oil saturation and current oil saturation is defined in the computational model.And the ratio between differential value and initial oil saturation is defined as the productivity index,which is the dynamic waterflood characteristic parameter of the reservoir from the beginning of waterflood development to the current reservoir state.Compared with the traditional waterflood characteristic parameter such as water production ratio and oil saturation,the advantage of productivity index lies in that it takes the dynamic waterflood process of reservoir into account.As a result,it has successfully avoided the great variation of resistivity rangeability of conglomerate reservoir and the shortcoming of quantitative evaluation on water flooded layers only by using current oil saturation.This method is used in the evaluation of conglomerate reservoir water flooded layers in Karamay Oilfield.and the results show that productivity index is the highest sensitive to quantitative evaluation of water flooded layers by comparative study of three waterflood parameters,with the rate of recognition accuracy of 89.58%.The evaluation results provide technical support for the adjustment of well pattern and the design of development program in Karamay Oilfield.

STUDY ON SAGD TECNOLOGY FOR ULTRA HEAVY OIL IN DUAL HORIZONTAL WELLS

XI Chang-feng MA De-sheng LI Xiu-luan

2010, 32(4):  103-108.  DOI: 10.3863/j.issn.1674-5086.2010.04.019

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Steam assisted gravity drainage is an advanced technique to develop extra heavy oil.Nowadays,there are two methods to start up SAGD process.One is cyclic steam stimulation and the other is circulation steam.Relative to cyclic steam stimulation,steam injected cycle preheating is more uniform and more stable to start up SAGD process.However,the completion string structure to apply circulating steam is complicated.It is difficult to attain optimizing parameters of startup Phase.In terms of a fully coupled discretized wellbore model,circulating phase′s parameters are optimized during three phases of initial circulation phases,pressure differential phase and converted full SAGD phase.Reasonable parameters about steam rate,steam quality,steam pressure and chance and magnitude of pressure differential are attained.

EXPERIMENTAL STUDY ON THE MOVABLE FLUID T2 cutoff VALUE OF VOLCANIC GAS RESERVOIR

SUN Jun-chang;GUO He-kun LIU Wei LI Hai-bo JIANG Peng;

2010, 32(4):  109-114.  DOI: 10.3863/j.issn.1674-5086.2010.04.020

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The most suitable centrifugal force to calibrate the T2 cutoff of volcanic gas reservoir rock in Jilin,Daqing and Xinjiang and the low limit of centrifugal force for the movable fluid is 2.76MPa,which is determined by nuclear magnetic resonance（NMR） technique and laboratory experiment on centrifugal force of fluid.The low limit of throat radius for movable fluid is 0.05 μm which is figured out according to the capillary law.There is no obvious functional relationship between T2 cutoff and porosity or permeability of volcanic rock.The research indicates that the range of the T2 cutoff value is very wide and there is a big difference between the T2 cutoff values of different regions or lithologies.But the relationship between T2 cutoff and porosity or permeability of Jilin tuff or Xinjiang graniteporphyry is a little obvious.The order of the T2 cutoff value for the movable fluid of different regions is as follows:Daqing，Jilin and Xinjiang.The average of the T2 cutoff value of rhyolite sampled from Daqing is the largest one and that of Xinjiang basalt and andesite is the smallest one.

FORMATION DAMAGE MECHANISM ANALYSIS OF HIGH TEMPERATURE AND LOW PERMEABILITY RESERVOIR IN WELL YI 65

HUANG Xiang WU Xiao-dong

2010, 32(4):  115-118.  DOI: 10.3863/j.issn.1674-5086.2010.04.021

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The Jiusha Formation in Sha 3 member of well Yi 65 is a typical reservoir characterized by medium water sensitivity and speed sensitivity;the crude oil is light thin oil possessing high solidification point,low density,viscosity and sulphur content;the salinity of the formation water can be as high as 1100~19900mg/L in general,and the water belongs to sodium hydrogen carbonate typed water.This paper investigates the formation damage mechanisms of well Yi 65 with high temperature and low permeability,and evaluates the possible damage and damage conditions from the aspects of formation characteristics,injected water quality,suspended particle blocking,free oil,emulsified oil,scaling,bacteria and past stimulation treatments.The internal factors of the damage to water injection wells include water sensitivity,speed sensitivity and low permeability,and the external factors contain solid suspended particles,poor water quality,excessively high oil content and bacteria numbers.

THE STUDY ON INJECTION PERFORMANCE OF WATER ABSORBING PARTICLES INDEPTH FLUID DIVERSION AGENT

MA Tao

2010, 32(4):  119-122.  DOI: 10.3863/j.issn.1674-5086.2010.04.022

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The water swelling materials with molecule interpenetrating networks structure have many excellent characteristics，such as controllable swelling speed and super intension after swelling.The injection performance and the migration characteristics after swelling of water absorbing particles indepth fluid diversion agent are studied by physical simulation experiment of sand packed model and telescoping pipeline model.The experiment results indicate that the particles before swelling can be injected successfully when the diameter of particles is less than that of pore throat.After particles swell，they can successfully pass the pore throats whose diameter is more than that of particles by extending deformation.The deformation can be immediately restored after passing.The permeability of sand packed model decreases during injection process of particles.The permeability is less after particles swell.The swelling particles can pass through pore throat when the displacement pressure is enough.

PHYSICAL SIMULATION OF LONG CORE BY MISCIBLE FLOODING OF ENRICHED GAS IN ZARZATINE OILFIELD

WANG Sheng-kui;WEI Xu-guang;LI Yi-bo

2010, 32(4):  123-126.  DOI: 10.3863/j.issn.1674-5086.2010.04.023

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Combined with the result of long tube test,the impact of injecting time,means and quantity of enriched gas miscible drive on the miscible effect is evaluated by the experiment of long core test.Under reservoir condition,the miscible fluids,composed of GPL and gas with their mol proportion of 36:64,are capable of being fully miscible with crude oil,and enhance the recovery rate of 15% compared with water drive.In terms of the injecting technical parameters,early injection of miscible fluids is favor of enhancing production rate,and WAG is propitious to controlling gas out.Injecting quantity of miscible fluids has a great impact on drive effect and differential pressure of sequent water drive,and it is advised to optimize injecting plug size of miscible fluids by means of numerical simulation in order to increase the economic benefits of miscible drive.

A NEW PARAMETER CAUCULATING MODEL FOR STEAM FLOODING HORIZONTAL WELLBORE

WANG Yi-ping LI Ming-zhong Gao Xiao YAO Zhi-liang

2010, 32(4):  127-132.  DOI: 10.3863/j.issn.1674-5086.2010.04.024

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When steam flows in horizontal wellbore,the mass flow rate will decrease with steam draining into the formation.Acceleration pressure drop will cause the change of steam physical parameters,which play an important role in the distribution of steam properties.Based on the rules of mass conservation and energy conservation,a model for steam quality variation along with the horizontal section length is built.Pressure drop and temperature distribution of injected steam along horizontal wellbore are deduced by using the principle of momentum conservation,and some models such as work done by friction,density of wet steam mixture,amount of steam absorption and the heat transfer calculation model between wellbore and formation are built,and the models are solved by the method of pressure increment iteration.The comparison between examplebased calculation results and reservoir numerical simulator shows that the new model has a higher accuracy.

TEST TECHNOLOGY STUDY OF LOW PERMEABILITY RESERVOIR IN JUNGGAR BASIN

ZHENG Wei-donga BI Quan-fua HU Guang-junb LI Xue-binb

2010, 32(4):  133-137.  DOI: 10.3863/j.issn.1674-5086.2010.04.025

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Fluid flow of low permeability reservoir has obvious non Darcy flow characteristic.The fluid will not flow until the formation fluid overcomes certain actuating pressure gradient in the process of test,provided the reservoir is not polluted.As a result,obtaining precise fluid properties and quantity is difficult.Getting stable formation pressure and reservoir properties are more difficult.Through the test technology research,reasonable time plan of test is adopted,stratification straddle test technology is popularized positively and the fracture effect is evaluated by test technology.The difficulty of getting data during the process of testing low permeability reservoir is solved perfectly.

油气化学工程与化工

LABORATORY STUDY ON CEMENTING SPACER FLUID SYSTEM FOR DEEP WELL IN SALT GYPSUM BED AND BRINE WATER LAYERS

TENG Xue-qing LI Zao-yuan XIE Fei-yan AI Li

2010, 32(4):  138-142.  DOI: 10.3863/j.issn.1674-5086.2010.04.026

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Recently salt gypsum beds and brine water layers are frequently encountered when drilling deep wells.The conventional spacer system has a relatively poor salt and temperature tolerance.When the temperature exceeds 100℃,the system loses its stability in the low concentration of saline water and can cause serious cementing accidents and has a great potential safety hazard of injection and displacement of slurry.A polysaccharide polymer is chosen as high temperature and anti salt suspension stabilizer,and supplemented by salt tolerant fluid loss additive and pattern adjusting agent,a high temperature and anti salt spacer system is developed.The system could maintain its stability in the sodium,calcium and magnesium salt solution.It can be used in a temperature of 140℃ and has a preferable regulation ability of density which can be adjusted between 1.3 and 2.4g/cm3.It also has a good compatibility with conventional drilling fluid and cement slurry.The system is expected to be used in cementing job of the deepwell,high deep well,and salt gypsum bed,composite rock salt layer,and brine water layer.

THE PROPERTIES ON PROFILE AND SHUTOFF OF A KIND OF NANOCOMPOSITES VIA INTERCALATIVE POLYMERIZATION

LV Xin HOU Ji-rui YUE Xiang-an CHEN Qiu-shi

2010, 32(4):  143-148.  DOI: 10.3863/j.issn.1674-5086.2010.04.027

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Aiming at higher requirement on profile and shutoff agent,the allyl monomer and clay as well as selfmade inlayer dressing agent CTS and chain extender are formed to nanocomposites via polymerization.Its properties is evaluated.It behaves those performance as follows.Under the condition of 80~140℃ and aging for 30 days,there is little change of break stress;under the condition of 140℃,the variance ratio of break stress is only 3.2%;this kind of system is not sensitive to salinity;the viscosity of basic liquid is 39.54mPa·s;under the condition of fracture,the block strength is 23.6MPa,the pressure gradient is 0.393MPa/cm,the sealed ratio is 98%;recovery ratio can increase 5% compared with that of water flooding.It shows the material is of high temperature resistance and salt tolerance,low injection pressure and strong shutoff capacity.The contradiction between injection and shutoff performance is resolved successfully.

THE SYNTHESIS OF THE HUMIC ACID GRAFT COPOLYMER USED FOR ULTRA HIGH TEMPERATURE DRILLING FLUID LOSS ADDITIVE

WANG Zhong-hua

2010, 32(4):  149-155.  DOI: 10.3863/j.issn.1674-5086.2010.04.028

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Based on the molecular design of high temperature treatment agent，with the humic acid and acryloyloxyethylbutyl acid(AOBS),acrylamide (AM),acrylic(AA) graft copolymerization,by orthogonal experiments,in consideration of the solution viscosity of the product,the impact of the product on drilling fluid viscosity and fluid loss results,further studies of the humic acid dosage is made and the synthesis formula is determined:non ionic monomer and ionic monomer ratio is 1.5:1.0,the ionic monomers neutralization degree is 100%,the reaction mixture mass fraction is 50%,humic acid dosage is 34%.The low molecular weight AOBS AM AA / humic acid graft copolymer is synthesized,and by the using of infrared spectroscopy and thermal analysis,the structural and thermal stability of products is analyzed.Experimental results show that the graft copolymer has good thermal stability,resistant temperature reaching 240℃.It has a good fluid loss control effect both in fresh water,salt water and saturated salt water drilling fluid.Besides,it has little effect on drilling fluid viscosity.Graft copolymer has a certain viscosity reduction effect in drilling fluid which has a high content of bentonite,so it can control the high temperature thickening of drilling fluid effectively.It has good compatibility with the SMC,SMP.It can effectively control the high temperature and high pressure filtration loss volume and rheological property of drilling fluid when used in KCl drilling fluid which has a density of 2.57g/cm³.

EFFECT OF REDUCING SUBSTANCES ON PHPAM AQUEOUS SOLUTION IN LOW CONCENTRATION

LU Hong-sheng HUANG Zhi-yu ZHENG Chuan-jiang

2010, 32(4):  156-159.  DOI: 10.3863/j.issn.1674-5086.2010.04.029

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Considering the polymer solution viscosity loss of polymer flooding,the effect of hydroquinone,triethylamine,ferrous ions,sulfur ions and sulfate reducing bacteria on low concentration partial hydrolyzed polyacrylamide solution is investigated with capillary viscometer method.The results indicate only the low concentration triethylamine can keep the partially hydrolyzed polyacrylamide solution viscosity stable,the others will make the polyacrylamide solution degraded,resulting in the drastic decrease of polyacrylamide solution viscosity during a short period.This paper also presents the degradation mechanism of hydroquinone,triethylamine,ferrous ions,sulfur ions and sulfate reducing bacteria on low concentration partial hydrolyzed polyacrylamide solution.Besides,the fluoscrecne picture is used to illustrate that the PHPAM solution degradation could be fastened by sulfate reducing bacteria.All the above will provide a theoretical and technical basis for the polymer flooding technique.

STUDY ON POLYACRYLAMIDE COAGULANT

MAO Yuan ZHANG Gui-cai GE Ji-jiang TANG Cun-zhi SUN Ming-qin

2010, 32(4):  163-166.  DOI: 10.3863/j.issn.1674-5086.2010.04.031

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To reuse the retained polymer after water flooding for polymer flooding oilfield,a three dimensional polymer coagulant with cationic groups is prepared via microemulsion polymerization.Performance evaluation tests show that when the shear rate is 170s^-1 and the cationic degree of this polyacrylamide coagulant is 5%,the viscosity of solution with equal polymer mass fraction and a volume ratio of 1:1 can be improved by 10mPa·s.In addition,when the solution is bathed in 80℃ water bath for 4 hours,the viscosity reduction is only 3%.Viscosity of the compound system stays at 32.9mPa·s even with the NaCl concentration rising to 1%.This polyacrylamide coagulant shows great potential in viscosity increase and deep profile control.

石油机械工程及其他

CORROSION PERFORMANCE OF WELL CEMENT ANNULUS IN FORMATION WATER OF EAST SICHUAN GAS FIELD

REN Cheng-qiang GUO Ming-lin CHENG Xiao-wei WANG Xu GUO Xiao-yang

2010, 32(4):  167-170.  DOI: 10.3863/j.issn.1674-5086.2010.04.032

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The corrosion of cement in the formation water of east Sichuan gas field,including electrochemical performance,microstructure feature and element distribution,is investigated by the methods of electrochemical test,scanning electron microscope (SEM) and energy spectrometer.The results shows that:the hydration enhances the stability of the interface of cement and casing steel at the initial immersion period due to the increasing of capacitive loop in high frequency region and appearance of Warburg resistance in low frequency region.However,the potential rapidly decreases by 200 mV after 26 days immersion,which means the corrosive medium reach the surface of steel.Though the integrality of cement is not broken,the stability of interface is lost.Thus,the capacitive loop in high frequency region decreases,and capacitive loop also occurs in the low frequency region.The concentration of Ca and O decrease in the surface layer,but the inversed change is found for C,S and Mg.It can be concluded that the cement is eroded by hydrogen sulfide,carbon dioxide and magnesium salt.The hydrogen sulfide plays a very important role in the corrosion.The soluble type corrosion is observed at the surface of the cement,but the corrosion products are inside the cement in the deep zone.Corrosion degrades the pore space and cementing property.Cl^- has strong transfer ability in cement.The research results are of instructive meaning to well cementation in sour gas field which contains H₂S and CO₂.

STUDY ON WEAR PREDICTION OF SUCKER ROD AND TUBING BASED ON FINITE ELEMENT METHOD

KUANG Yu-chun YAN Jin-lin WANG Qin WU Jing

2010, 32(4):  171-174.  DOI: 10.3863/j.issn.1674-5086.2010.04.033

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At present,there are more and more complex wellbores in oilfields,such as inclined well,directional well,lateral well and so on.Sucker rods bucking and wellbore bending can lead to serious eccentric wear of sucker rods.To solve this problem,this paper presents a finite element method (FEM) for dynamics behavior of sucker rods.The wear prediction model of sucker rod and tubing is established based on the energy principle.The fraction power which is generated by the robpipe wear and energy loss are connected in making this model.By using this FEM simulation in an instance,we can calculate the contact force on the rob.As a result,wear volume loss between sucker rods and tubing could be quantitatively analysed.The results show that FEM analysis is effective to predict the wear situation of eccentric wear between sucker rods and tubing.It also helps oil fields in adopting reasonable measures to preventing eccentric wear.

博导论评

ANALYSIS ON THE FAILURE OF AIR FLUSH ROTARY PERCUSSIVE DRILLING BIT TEETH AND EXPERIMENTAL STUDY ON NEW MATERIALS

HUANG Zhi-qiang SHEN Yue BU Yan HUANG Ji-liang HUANG Wei

2010, 32(4):  175-178.  DOI: 10.3863/j.issn.1674-5086.2010.04.034

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The teeth of Air flush Rotary percussive Drilling bit often breaks,falls and badly worn,which leads to a low efficiency of rock breaking and a short service life.To solve the problem,we adopt the Nano modification technology which adds nanoAl₂O₃ to the hard alloy,then develop the Al₂O₃/WC Co Nano/Micro Composite Material.An analysis of its performance,micro structure and an experimental study on its resistance and impact resistance are made.The results indicates that adding 3% of nano Al₂O₃,appropriate amount of inhibitors,and Rare Earth Element(REE) can distinctly improve the micro structure of Al₂O₃/WC Co Nano/Micro composite and refine grains.It also greatly increases the wear resistance and impact resistance to 4~8 times than Hard alloy(YG8).All the above provide a possibility of improving the efficiency of rock breaking and extending the bit′s service life.

探讨与争鸣

THE OPTIMAL SEISMIC SURVEY BASED ON THE COMMON REFLECTION　POINT

XU Feng WANG Xiao-tao YANG Jin-hua ZHAO Hu

2010, 32(4):  179-184.  DOI: 10.3863/j.issn.1674-5086.2010.04.035

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The surface condition of Keshen area,Tarim Basin is very rough,besides,the subsurface structure of it is very complicated too,causing a lot of difficulties in data collection.In light of the low signal to noise ratio and inaccuracy of imaging,a stack depth migration treatment on the existing data is made at first,then the array length,receiving lines,guns density and other basic observation parameters are acquired.Based on the above parameters,the geophysical model of this area is constructed and the illumination of the target stratum is calculated too.According to the Common Reflection Point(CRP) energy homogeneous principle and maximum receiving efficiency,geophone distance,receiving lines and guns density are optimized.The research results are instructive to improve the quality of seismic data acquisition in complex mountainous area.