Lithologic Reservoirs

The reservoir, which cannot be found or identified directly by nowadays theory and technique, could be all called as subtle reservoir. It can be classified by discrimination difficulties, concealed modes, oil and gas accumulated dynamics mechanism, and it was put forward by the concealment of trap and difficulty of exploration discovery. So its meaning and content change with the development of exploration techniques as w ell as exploration theory. It should not be equaled to lithologic stratigraphic reservoir or nonstructural reservoir as some specific reservoirs would be ignored if only the two latter ones are regarded. Lithologic stratigraphic reservoirs are still the major exploration emphasis in subtle reservoirs which is a general expression of all the nonstructural trap sand includes some structural reservoirs that are difficult to find nowadays.The reservoir, which cannot be found or identified directly by nowadays theory and technique, could be all called as subtle reservoir. It can be classified by discrimination difficulties, concealed modes, oil and gas accumulated dynamics mechanism, and it was put forward by the concealment of trap and difficulty of exploration discovery. So its meaning and content change with the development of exploration techniques as w ell as exploration theory. It should not be equaled to lithologic stratigraphic reservoir or nonstructural reservoir as some specific reservoirs would be ignored if only the two latter ones are regarded. Lithologic stratigraphic reservoirs are still the major exploration emphasis in subtle reservoirs which is a general expression of all the nonstructural trap sand includes some structural reservoirs that are difficult to find nowadays.

Analysis of the mess in sequence hierarchy applied in the industrialized application of the sequence stratigraphy

WANG Yingming

2007, Vol.19(1): 9–15 Abstract ( 502 ) PDF (236 KB) ( 866 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2007.01.002

The mess and absence of unified criterion of sequence hierarchy have constrained the industrialized application and its assurance and effect. The origin of the present confusion mainly contributes to the different analysis about the control on sequence pattern which lead to them issue of both nomenclature cyclist and stage. Based on the practical effect and feasibility and consideration of both cyclist and stage, a suite of terminology system is presented. Firstly 3rd sequence is considered as the base which can be grouped into 2nd or 1st order sequence or subdivided in to 4th, 5th even 6th sequence based on the suite of criterion. The only criterion of the division of 3rd sequence is the unconformity, which also implies the absence of the unconformity in such sequence. Owning to such base, the system tracts can be discriminated and divided according to the first flooding surface and the maximum flooding surface. So called 4th sequence is a system tract practically with no cyclist. Based on the reconcilability of seismic data, the 3rd sequence can be subdivided in to A and B type. Such three hierarchies could correspond to the basin analysis & resource evaluation, play evaluation and objective prediction, reservoir characterization and progressive exploration and development respectively. Among the above mentioned terminology, the 4th sequence plays the key role in sedimentary mapping and the prediction of the promising area of the subtle traps.

Cultivation of exploration creativity

ZHANG Xia

2007, Vol.19(1): 16–20 Abstract ( 719 ) PDF (166 KB) ( 989 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2007.01.003

Exploration is a kind of creative activity. Cultivating creativity is very important for strengthening searching ability in exploration. The author considers that setting up strategic target and to pic and satisfying high-level demands,such as dedication to the work, are good for inspiring creativity. Building up a better collective environment may benefit creativity development, and strengthening self-cultivation could improve creativity.

Predict ion technique study for hydrocarbon-rich areas in low permeable oil f ield:A case on Fuyang reservoir in Songliao Basin

ZHAO Yingcheng, WANG Tianqi,TIAN Guangrong,ZHANG Qiaofeng,WANG Jiangong

2007, Vol.19(1): 21–26 Abstract ( 429 ) PDF (1216 KB) ( 660 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2007.01.004

Low permeable oilfield of large shallow-water lacustrine basin in China is one of the important exploration areas.The characteristics,reservoir forming conditions and exploraiton difficulties of low permeability reservoirs are indicated systematically according to the study of Fuyang reservoir in Songliao Basin.By using geologic and seismic techniques association,the authors present a processing system of efficient prediction in development areas of major channal and relative oil enrichment areas, and form sucha set of exploration proposals and technique countermeasures as searching hydrocarbon-rich areas in hydrocarbon-poor area so flow permeable oil field.

Study of the relationship between lithostratigraphic reservoirs and lakeshore line:An introduction on lakeshore line controlling oil /gas reservoirs in sag basin

WEI Pingsheng, PAN Shuxin, WAN G Jiangong,LEI Ming

2007, Vol.19(1): 27–31 Abstract ( 450 ) PDF (891 KB) ( 544 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2007.01.005

According to the study of the relationship between the distribution of lithostratigraphic reservoirs and lakeshore line,the result shows that the most favorable facies tracts of lithostratigraphic reservoirs are alone lakeshore line.In brief,lakeshore line controls the distribution of sands,traps and oil reservoirs.The followings are characters of lithostratigraphic reservoirs distributional one lakeshore line: ① Alone lakeshore line there are multiple kinds of sedimental sandbodies in littoral and shallow lake to form different oil reservoirs. ② Shore line migration is cycling and episodic so there are the best conditions provided for reservoir-seal assemblage formations. ③ Various lithostratigraphic traps can form different reservoirs, such as coastwisebar,shore sandstone,lacustrine bay sandstone and stratigraphic unconformity reservoirs;reservoir-forming mechanisms include that unconformity and trench systems link up the source rocks for lateral migration of oil and gas but longitudinal migration depends on faults. ④Lithostratigraphic reservoirs are in belt and in scale alone lakeshore line. The stratigraphic overlap reservoirs are mainly located near the shore lines of LST and TST. The stratigraphic of flap reservoirs are mainly near the shore line of RST. But the reservoirs of coastwise bar,lacustrine bay sandstone and shore sand occur in each tract.

Provenance analysis of Chang 6 oil-bearing formation of Baibao-Huachi region in Ordos Basin

ZHENG Rongcai, WANG Changyong, Li Hong, LEI Guangming, XIE Chunhong

2007, Vol.19(1): 32–38 Abstract ( 457 ) PDF (877 KB) ( 680 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2007.01.006

Provenance analysis mainly includes comparison of debris compositions, heavy mineral assemblages,sedimentary facies, geochemical analysis,cathodoluminescence image of quartz and so on.The research area is relatively large and it is influenced by multiple sediment supplies,so multiple analysis methods are adopted to define the characteristics of source rocks and source direction of Chang 6 oilbearing formation in Baibao-Huachi region.Furthermore mainly by contrast analysis between debris compositions and light/heavy mineral assemblage and quartz cathodoluminescence analysis,two material source directions existing in the research area a reproved.The main material source direction is located in the north and northeast of the research area,and the source rocks are ancient hybridization rocks of granite and low-middle/middle rank metamorphic rocks that come from ancientland of Yin Mountain in north Ordos Basin; the secondary material source direction is in the southwest,and the source rock is located in Lower Palaeozoic strata which come from Kongtong Mountain in southwest of Ordos Basin.

Depositional filling models and controlling factors on Mesozoic and Cenozoic fault basins of terrestrial facies in eastern China:A case study of Dongying Sag of Jiyang Depression

YU Xinghe, J IANG Hui, LI Shengli, CHEN Yongqiao

2007, Vol.19(1): 39–45 Abstract ( 614 ) PDF (593 KB) ( 1109 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2007.01.007

A majority of oil and g as reserves have been discovered that are located in the Mesozoic a nd Cenozoic fault basins of terrestrial facies in eastern China. These basins have different sizes and types with great discrepancy of reserves, whereas most of oil and gas fields that have been discovered and developed are obvious structural trap. With the continual enhancement of Chinese hydrocarbon exploration activity,the difficult increasing and type transferring,the targets of hydrocarbon exploration have been changed to subtle li thologic and stratigraphic trap. Therefore it is much necessary to analyze and research the characteristics of depositional filling at different structural zone during different evolutive phrases in this basin in order to provide geological theories and science evidences for the exploration of lithologic and stratigraphic trap.Dongying Sag belongs to Jiyang Depression of Bohaiwan Basin, which is a typical lake basin of half-garben with the terrestrial coarse clastic deposits. The depositional filling pattern and extensional characteristic of sandstone within Dongying Sag are very representative to study this type of basin.So,the paper emphasized that Dongying Sag has been analyzed from both spatiality and timein the view of sedimentology. A set of corresponding relationship has been expatiated that structural characteristic directly controls the depositional filling characteristics,climate straightly determines the property of deposits, sediment supply and lake-level changes mainly dominate the patterns of spatial depositional filling.The depositional filling model and corresponding relationship in the v arious structural zones during each evolutive stage have finally been summed up. These results can provide help and evidences for hydrocarbon generation and distribution in faul t basin of terrestrial facies.

Favorable condition and exploration prospecting of lithologic hydrocarbon reservoir in large-scale saline basin:Case study on the Eogene in the southwest of Qaidam Basin

CHEN Qilin

2007, Vol.19(1): 46–51 Abstract ( 562 ) PDF (503 KB) ( 582 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2007.01.008

In the Eogene and Neogene,Qaidam Basin experienced the multiphase tectonic movement;the paleoclimate evolved from warm-humid to arid;the water in the basin was gradually salinized;the depocenter migrated from west to east.The master factors and developmental characters of lithologic hydrocarbon reservoirs have their own particularity.Taking the fine exploration zones of the southwest hydrocarbon-rich depression in Qaidam as the key point, with the analysis of source-rock distribution,sedimentary evolution and sedimentary system distribution,the author proposes that the density difference increases after the fluvial water enters,then dam and bar sand bodies are formed easily due to density flow.Highstand system tract and transgressive system tract below the maximum flooding surface are the main exploration areas of lithologic reservoir.The Eogene slope setting sin southwest Qaidam provide the basic accumulation condition for lithologic reservoirs. The broad structures and the nose-like uplifts are favorable for lithologic reservoirs;structural settings and sand genesis determine the local accumulation of oil and gas; the broad platforms within slope settings are the main oil-gas accumulation areas of downsource and within-source lithologic reservoirs.The dam and bar sandbodies in saline lake basin, the meare dam sand bodies of the transgressive system tract,the insular sandbodies within the fan-delta and delta front,and the algal limestones widely distributed over the meare are the main exploration domains of lithologic hydrocarbon reservoirs.

Lake basin evolution of Ordos Basin during Middle-Late Triassic and its origin analysis

LIU Huaqing, YUAN Jianying, LI Xiangbo, WAN Yanrong, LIAO Jianbo

2007, Vol.19(1): 52–56 Abstract ( 636 ) PDF (635 KB) ( 739 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2007.01.009

Taking Chang 7 of the Triassic Yanchang age as the turning point, the depocenter of Yanchang Lake in Ordos Basin migrated southwestwardly from Wuqi-Fuxian area in Early Triassic to Huachi Huangling area in Middle-Late Triassic. Affected by the migration, the southwest depositional system and the northeast depositional system developed unsymmetrically. The southwest system was more basinward extending in Early Taiassic than in Late Triassic, however the northeast system has the opposition condition. The intensive orogenic movement of late Indo-Chinese epoch in western Qinling caused the SW to N E compressive force to Ordos Basin and the vertical uplift of Yinshan region caused the tilt of the northeast part of the Basin. The compressive force and the tilt may be the origin of the depocenter migration and the unsymmetrical development of the south and north depositional systems during Middle Late Triassic in Ordos Basin.

The pool-forming pattern in the condition of arching in the southeast uplift in Songliao Basin

LI Jun, HUANG Zhilong, LI Jia, LIU Bo

2007, Vol.19(1): 57–61 Abstract ( 518 ) PDF (521 KB) ( 653 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2007.01.010

The southeast upwelling area is first-order tectonic unit of Songliao Basin from the research of structural evolution in south of Songliao Basin.Under the effect of tectonic reversal during the end period of Nenjiang and Early Tertiary,the southeast upwelling area is in the state of uplifting all the time, which caused Nenjiang Group eroded seriously.And it did not accept the Sifangtai Group and Mingshui Group of Cretaceous and Teriary sediment, which caused the thinning of sedimentary seal and the influence on the diagenetic evolution, drainage, geotemprature and geopressure fields.This state not only controls the migration,accumulation and reservoir-forming,but also changes the hydrocarbon-generation.So the accumulation condition is complicated.It is significant to buildup the reservoir-forming model of the residual reservoir, secondary hydrocarbon reservoir and reservoir controlled by mature source rocks formed in late period for the exploration of oil and distribution.

Petroleum accumulation condition analysis and lithologic reservoir exploration in Shengbei Depression of Turpan-harmy Basin

YANG Zhanlong, PENG Licai, CHEN Qilin, GUO Jingyi,LI Zaiguang, HUANG Yunfeng

2007, Vol.19(1): 62–67 Abstract ( 464 ) PDF (694 KB) ( 647 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2007.01.011

The lithologic trap is one of main relay exploration domains of Shengbei Depression in Turpanharmy Basin and apractical domain for reserve increasing too. At the beginning of lithologic traps exploration in Shengbei Depression,it is necessary to systematically analyse the basic petroleum accumulation conditions of the Depression to specify the potential exploration zones of lithologic traps clearly.There are hydrocarbon source rocks in Shuixigou Group of Lower-Middle Jurassic and Qiketai mudstone formation of lacustrine facies,so the hydrocarbon source condition is good and hydrocarbon resources are rich in this depression;there are 7 reservoir-seal assemblages in Jurassic and above sequences.Oil reservoirs mainly are structure,lithologic-structure type of middle Jurassic,shallow secondary reservoir of upper Jurassic and Cretaceous. Petroleum accumulation is mainly in Yanshan period and Himalaya period. With the total situation of the present exploration of structural hydrocarbon reservoirs, the main exploration direction is to take lithologic trap identification,preference, description and evaluation to find structural hydrocarbon reservoirs surrounding the palaeostructure background.The east slope of Pubei,the north slope of Putaogou and the Shengbei structure zone situated at the cross position of north and south sedimentary source in the middle of the Depression,are favorable exploration zones of lithologic traps at present time.

Sequence stratigraphy and subtle reservoir of Aershan Formation in Baorao Trough of Jiergalangtu Sag

YI Dinghong, SHI Lanting, JIA Yirong

2007, Vol.19(1): 68–72 Abstract ( 434 ) PDF (653 KB) ( 914 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2007.01.012

The recent hydrocarbon exploration in Baorao Trough of Jierg alangtu Sag shows that Aershan Formation has huge resource potential.In this paper,the sequence stratigraphic theory based on base-level cycles is used to divide Aershan Formation into one secular cycle(the third-level sequence) and three corresponding middle-term stratigraphic circles(the forth-level sequence)MSC1,MSC2 and MSC3.Within the isochronal framework of the Sag,the distribution of reservoir rock and caprockand the development charactersof reservoir-cap rock assemblages are analyzed.The authors point out that two series of reservoir-cap rock assemblages, MSC1+MSC2 and MSC3, are developed in the Formatio n,but MSC3 is more favorable.The subtle reservoir exploration analysis indicates that such areas as the dropped side of the II fault of Xilin in the southeast glacies area and the developmental region of inshore subsea apron and sublacustrine fan in the northeast Gubiliang of the J68 well field are favorable regions for subtle reservoir exploration.

The temperature-pressure systems and the oil and gas accumulation in Moliqing Sag of Yitong Graben

SHI Lanting, LI Bencai,GONG Gu, LI Nan, DING Ye

2007, Vol.19(1): 73–76 Abstract ( 538 ) PDF (500 KB) ( 412 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2007.01.013

The depositional basin often has two or more than two temperature-pressure systems,including one temperature-pressure system of shallow-formation and one or more than one temperature-pressure systems of deep-formation.The temperature and the formation pressure keep the line relationship in the same temperature-pressure system,but in different temperature-pressure systems,the line slope of temperature-pressure relationship is different.The authors analyse Moliqing Sag's temperature pressure system characters in Yitong Graben.There are two superimposed temperature-pressure systems in the shallow and deep formations of Molingqing Sag.The deep one is prone to high pressure.It is also showed that Shuang yang Group, the west of Moliqing Sag, is the low temperature and high pressure zone; the northwest is the low temperature and low pressure zone; Maanshan fault belt is the normal temperature and normal pressure zone;Jianshan uplift fault belt is the high temperature and low pressure zone. The vertical and planar distribution characters of temperature-pressure systems have some influences on the formation and distribution of petroleum pool.

Research on Triassic Chang 6 reservoir in Nanzhuang area

ZHU Xiaoyan, WANG Binting, HU Jianji, GOU Yingchun

2007, Vol.19(1): 77–80 Abstract ( 455 ) PDF (643 KB) ( 466 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2007.01.014

Nanzhuang is one of the important areas for exploration and evaluation to Longdong Oilfield,which is located in the most promising area of oil producing in Ordos Basin. According to the microcosmic and macrovisual study on Chang 6 reservoir and the contrast to Baima area, it is considered that the properties of the reservoir are poor, and that it is good for the sedimentary microfacies porosity permeability of the distributary channel and mouthbar developed in the area which is proved to be a advantage ground for oil and gas accumulation.

Nonlinear inversion of the reservoir prediction—— example of Seimpar Inversion

LIU Quanxin, GAO Jianhu, DONG Xuehua

2007, Vol.19(1): 81–85 Abstract ( 586 ) PDF (830 KB) ( 606 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2007.01.015

Nonlinear inversion in the reservoir prediction is a very important field of geophysics.On the base of nonlinear methods,such as artificial neural network,fractal and fractal dimension etc.,the authors expound that, as a method of nonlinear inversion,Seimpar Inversion could carry out wave impedance inversion without using convolution equation, and also inverse logging parameter byseismic records under the logging constrained.This method of inversion could resolve complex geological problems which are hardly to be solved by routine inversion, and it is applied well in practice.

3D frequency and space domain amplitude-preserved migration with viscoelastic wave equations

YANG Wuyang, YANG Wencai, LIU Quanxin, WANG Xiwen

2007, Vol.19(1): 86–91 Abstract ( 601 ) PDF (389 KB) ( 663 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2007.01.016

The paper studied a new algorithm of 3D frequency and space domain amplitude-preserved migration with viscoelastic wave equations.This code gives an alternative method which compensates Q and transmission losses in the seismic data during scalar finite-difference migration.The geometrical spreading, Q and transmission losses and dispersion are compensated simultaneously as part of the migration.Firstly,starting from the viscoelastic wave equation, high-order finite-difference format of amplitude-preserved migration operator viscoelastic was derived.Secondly,the imaging condition was modified in order to include a ttenuation effecting in seismic propagating wavefield.Then,3D migration was realized by using a 3D one-way depth stepping extrapolation.Good processed results of synthetic data proved that algorithm is stable,reliable and widely applicable.

Seismic prediction technique of thin interbed channel sand in SongLiao Basin

ZHANG Qiaofeng, WANG Yuqing, WANG Tianqi

2007, Vol.19(1): 92–95 Abstract ( 412 ) PDF (740 KB) ( 457 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2007.01.017

In the most areas of SongLiao Basin in China, the primary target strata prospected at present is characterized as thin interbed,and the sandstone type is mainly the delta branch channel sand varying fast,having poor continuity and being 2～5 meters thick.Specially at FuYang oil layer,the channel changes frequently,the stratum contrast characters are not clear and lack of distinct contrast marks,so it is indicated that the reflection energy of these sections is weak,the continuity is poor, the wave wiggle changes a little,the tuning effect is heavy on seismic section,and the development of the faults and the rolling changes of the structure destroyed the completeness of the channel. All those factors increased the difficulties for reservoir prediction.By a lot of theory studies and practical work,it has been proved that applying seismic reservoir inversion techniques and full 3D visualization interpretation techniques can recognize the main channels and predict favorable reservoir more easily depending on the reasonable use of the existing seismic data and the accurate demarcations of reservoir.

Application of relative ampl itude method to merging processing of 2-D seismic data and reservoir predict ion technique in southwestern Tarim

TAO Yunguang, YUAN Gang, CHEN Xinan, NIU Huiyun,KONG Xu, ZHAO Weidong

2007, Vol.19(1): 96–100 Abstract ( 447 ) PDF (972 KB) ( 748 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2007.01.018

Exploration and investigation indicate that there is a structure zone of multi-target stratum subtle traps at Markit slope of southwestern Tarim in the recent years,and its main target strata are the Paleogene,the Carboniferous and the Silurian.To realize the evaluation of lithologic reservoir characters as the present research requirement ,amount of 2-D seismic data from different sources,geophones and acquisition are deal t with merging relative preserved amplitude processing and reservoir prediction researchof seismic inversion.In this paper, all of the data in this area are accurately processed with the relative amplitude techniques, such as static correction, pre-stack attenuation, surface consistency processing method.Good effects are proved by theactual processing result and all seismic sections with high consistent.Ov erall corrections for amplitude,time difference,frequency,phase and waveform are achieved.Those new seismic sections have already got the application in subtle traps research.

A method study of carbonate reservoir ident ification by using post-stack seismic data

LIU Weifang, DUAN Yonghua, GAO Jianhu, ZHANG Ximei, SUN Qinhua

2007, Vol.19(1): 101–104 Abstract ( 444 ) PDF (828 KB) ( 1002 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2007.01.019

The lateral prediction becomes more difficult because of the strong heterogeneity of carbonate reservoir. A measurement is presented in this paper, which determines seismic response of reservoir by horizon calibration of two-step method and seismic interpretation, predicts the distribution characters of carbonate reservoir with analysing many different kinds of seismic characters including amplitude,frequency, signal-to-noise ratio, and especially waveform, and delineates favorable reservoir zones inTazhong A area.

The inf luences of geologic and data factors on the seismic attribute

XIN Guangzhu, L IU He, PENG J ianliang, SHAO Hongjun

2007, Vol.19(1): 105–108 Abstract ( 376 ) PDF (786 KB) ( 647 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2007.01.020

In order to study the influential factors on seismic attribute,the authors use the rock modeling software to simulate the changes of mineral constituent, porosity, fluid property and saturation of rocks and further study the changes of the seismic attribute basing on the velocity of S-wave,the velocity of P-wave and various elastic modeling quantities of the rocks by means of forward modeling.Acco rding to the actual data, the authors analyze the effect of various processing projects and parameters in the seismic data processing on the seismic attribute.

The appl ication of forward model ing for interpretat ion of seismic data of carbonatite reservoir

LIU Junying, YONG Xueshan, GAO Janhu

2007, Vol.19(1): 109–112 Abstract ( 445 ) PDF (834 KB) ( 627 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2007.01.021

According to the designs of various geological models for different carbonatite depositions, the authors carry through the calculation of numerical simulation.Basing on these numerical modeling,the authors analyse the responsive seismic wave-field characteristics of objects,such as limestone cave,organic reef, and expose the feints and pitfalls in the seismic data interpretations,and then point out the correct methods and references. These methods and references have the important referential value of enhancing the reliabirlity of seismic interpretation within the carbonatite-developed zones,and increasing the success rate of the carbonatite reservoir exploration.

Initial study on focusing point controlled il lumination wave equat ion prestack depth migration

LU Bin, LI Fei, LI Zhenchun, YE Yueming

2007, Vol.19(1): 113–116 Abstract ( 453 ) PDF (467 KB) ( 490 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2007.01.022

Although prestack depth migration of shot records can make a high-quality image,it needs too much computation for wavefield extrapolation and lowers the efficiency of the computation.Prestack depth migration of areal shot records and controlled illumination can get high-quality images by source wavefield controlling and highly efficient areal shot records migration. How to calculate the synthesis operator is the key problem of controlled illumination prestack depth migration. In this paper the inverse time focusing operator is synthesized based on the travel time calculation method of finite difference approach, and with this synthesis operator the authors calculate the focusing point controlled llumination prestack depth migration using Fourier finite difference.The test results of Marmousi model show its effectiveness and the great advantage of improving computational efficiency.

Comparison of several post stack time migration methods in western area with low S/N ratio

SU Qin, LU Bin, LI Fei

2007, Vol.19(1): 117–119 Abstract ( 401 ) PDF (375 KB) ( 654 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2007.01.023

Currently prestack time migration technology has been extended greatly,while the application result of post stack time migration is even more effective than that of prestack migration because of the high calculation efficiency and low S/N ratio in some place. So the authors consider that post stack time migration should not be abandoned completely but the proper migration methods should be chosen according to the characters of seismic data. Aiming at some western area with low S/N ratio ,three usual methods of poststack time migration are chosen for experiments.The experiments validate the relative merits and applicability conditions of these migration methods and provide reliable reference to how to choose proper migration methods.

Model and method to the productivity calculation for horizontal well of condensate gas reservoir

GUO Kangliang,GUO qi,CHENG Shiqing

2007, Vol.19(1): 120–123 Abstract ( 425 ) PDF (239 KB) ( 902 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2007.01.024

Big error may occur in using the productivity analysis of single phase gas well for condensate well. According to the steady state theory of the condensate gas reservoir, the productivity equation of gas-liquid multiphase flow was run. On the basis of comparing various productivity calculation formulas,the authors put forward the productivity calculation method for the horizontal well of condensate gas reservoir, which proves a high accurate rate in the cases.

Strategy and water flood condition research on Jurassic reservoir of ZJ2 well-area, Jing 'an Oilf ield

LIU Xiaoyan,XIE Jibin,LIAOJianbo,ZHANG Jiabin

2007, Vol.19(1): 124–129 Abstract ( 424 ) PDF (495 KB) ( 671 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2007.01.025

Aiming at the present development situation of Jurassic reservoir in ZJ2 well-area of Jing'an Oilfield,the authors analyzed the waterflood status of the reservoir and themain reason of therising watercut,and then formulated areasonable boundary of the development technique ratios,such as thefluid producing intensity and velocity and the injection-production ratio, at last proposed the adjustment to improve the waterflood state of the reservoir.

Determination of reasonable pressure difference for horizontal well test of condensate gas reservoir testing in TH Oilfield

LI Dongmei

2007, Vol.19(1): 130–133 Abstract ( 349 ) PDF (233 KB) ( 582 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2007.01.025

The horizontal well productivity test is mainly to obtain the productivity equation and absolute open-flow capacity, and to select nozzle for production. The determination of reasonable pressure difference for horizontal well test is relevant to the reasonable productivity which is determined by the selection of nozzle. The key of the well test design for productivity is to design reasonable nozzle in order to obtain steady and reliable productivity and pressure data.