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    01 February 2023, Volume 44 Issue 1 Previous Issue    Next Issue
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    OIL AND GAS EXPLORATION
    Sedimentary Characteristics and Controlling Factors of Hyperpycnal Flow in Triassic Depressed Lake Basin,Northern Tarim Basin
    ZHONG Mihong, TANG Wu
    2023, 44 (1):  1-8.  doi: 10.7657/XJPG20230101
    Abstract ( 278 )   HTML ( 282 )   PDF (2830KB) ( 144 )   Save

    Previous studies on hyperpycnal flow mainly focused on modern marine environment and paid little attention to sedimentary characteristics and controlling factors of hyperpycnal flow in ancient continental depressed lake basins. In this paper,taking Tabei area as an example,the hyperpycnal flow deposits of the Triassic TⅡ oil member are analyzed by using core,drilling,logging and 3D seismic data. The results show that during the deposition of lacustrine transgressive system tract (TST) - highstand systems tract (HST),the TⅡ oil member in the study area developed two typical hyperpycnal flow sedimentary sequences,and each sequence is a compound of a basal coarsening-upward unit and a top fining-upward unit,with climbing ripples and ripple cross lamination. In one sequence,an erosive surface is developed between the two units,while in the other sequence,the two sedimentary units present a trend of gradual change,reflecting different flooding energy. The hyperpycnal flow in the study area mainly comes from two directions such as southwest and northeast,among which the hyperpycnal flow from southwest is the dominant with wide distribution,long extending distance and vertical superimposition of hyperpycnal flow deposits of multiple periods. The hyperpycnal flow in the study area has the characteristics of flood gravity flow,and its formation is closely related to flooding and controlled by multiple factors such as climate,tectonic activities,lake level,and provenance.

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    Fracture-Cave System in Collapsed Underground Paleo-River With Subterranean Flow in Karst Canyon Area,Tahe Oilfield
    ZHANG Changjian, LYU Yanping, MA Hailong, GENG Tian, ZHANG Xiao
    2023, 44 (1):  9-17.  doi: 10.7657/XJPG20230102
    Abstract ( 256 )   HTML ( 265 )   PDF (6529KB) ( 168 )   Save

    In order to study the development characteristics of paleokarst in the Middle-Lower Ordovician in the Tahe oilfield,by restoring the paleogeomorphology and the paleo-water system in the early Hercynian movement,the cave types in the karst canyon area were divided,and the genesis and evolution model of the collapsed fractures and caves with subterranean flow in the karst canyon area of the Tahe oilfield were established. The research results show that paleokarstification during the early Hercynian movement is found in the study area,the karst paleogeomorphology is generally high in the northeast and low in the southwest,the micro-geomorphology is mainly composed of low-amplitude karst mounds,karst peaks and depressions,and the paleo-water system is mainly composed of open channel flow,subterranean flow,underground river,and dry valley. The main water system shows a segmented structure consisting of deep incised meandering canyon in the south,canyon in the middle,and underground river-skylight in the north,and the tributary water system is a dendritic underground river network. The caves in the collapsed underground river with subterranean flow can be identified,mainly in four types,namely underground river,subterranean flow,undercurrent along river,and cave-through. The development and evolution of underground paleo-river system in the study area can be divided into free meandering flow,subterranean flow-deep incised meandering flow,and collapsed skylight subterranean flow.

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    Differences and Genesis of Upper Wuerhe Formation Reservoirs in Mahu Sag and Shawan Sag
    KUANG Hao, ZHOU Runchi, WANG Junmin, LIU Hao, TAN Xianfeng, CAI Xinyong, XIAO Zhenxing
    2023, 44 (1):  18-24.  doi: 10.7657/XJPG20230103
    Abstract ( 292 )   HTML ( 263 )   PDF (4617KB) ( 139 )   Save

    By means of thin section observation,scanning electron microscope (SEM) analysis,X-ray diffraction (XRD) analysis of clay minerals,and cathodoluminescence experiment,the diagenesis of the Upper Permian upper Wuerhe formation in the Mahu and Shawan sags in the Junggar basin were analyzed and compared,and the types of diagenetic products and pore evolution process were clarified. Compaction,carbonate mineral cementation and zeolite cementation are the main factors controlling the differences in reservoir physical properties in the study area. The compaction in the Mahu sag is relatively weak,while the dissolution in the Shawan sag is relatively strong. There are differences in diagenesis and pore evolution of sand bodies in the two sags. The reservoirs in the Mahu sag are dominated by feldspar particles and dissolved tuff debris pores,and the reservoirs in the Shawan sag are dominated by feldspar particles,dissolved tuff debris pores,and dissolved zeolite pores. There are a few primary pores developed in the reservoirs in both Mahu sag and Shawan sag. The differences between the reservoirs in the two sags are mainly caused by the different properties of diagenetic fluids and rock components. Specifically,the rock components represent the main cause for the differences in pore structure characteristics in the sandy conglomerate reservoirs in the Mahu sag and the Shawan sag.

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    Formation Mechanism of Secondary Quartz and Its Influence on Physical Properties of Xu 2 Member Reservoir in Western Sichuan Depression
    ZHANG Shunli, YANG Yingtao, ZHANG Ling, CAO Yanhui
    2023, 44 (1):  25-32.  doi: 10.7657/XJPG20230104
    Abstract ( 259 )   HTML ( 12 )   PDF (13157KB) ( 57 )   Save

    Secondary quartz cement is one of the important authigenic minerals affecting the physical properties of the second member of Xujiahe formation (Xu 2 member) reservoir in the Western Sichuan depression. In order to clarify the formation mechanism of secondary quartz and search for high-quality reservoirs,the silica source of secondary quartz in the Xu 2 member sandstone and its effect on the reservoir were analyzed by experimental methods such as casting thin section,scanning electron microscopy (SEM),cathodoluminescence,inclusion temperature measurement,and quartz oxygen isotopes. The secondary quartz in the sandstone of Xu 2 member can be divided into 3 stages. The silica formed by the dissolution of K-feldspar and acid plagioclase with the participation of early atmospheric fresh water and organic acid is the main contributor to the formation of secondary quartz in the early-middle diagenetic stage. The silica produced by the compaction and pressolution in the sandstone and the transformation of clay minerals is a key cause for the formation of secondary quartz at relatively high temperatures in the middle-late diagenetic stage. Although the early secondary quartz occupies a part of the pores,the mechanical strength of the rock can be enhanced to inhibit the compaction,which is beneficial to the preservation of primary pores. The secondary quartz formed in the middle-late diagenetic stages was mostly the product of dissolution and pressolution and occupies the dissolution pores and primary pores,which is an important factor for reservoir densification.

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    Stratification and Segmentation Characteristics and Tectonic Evolution of Shunbei No.5 Strike-Slip Fault Zone in Tarim Basin
    CHEN Ping, NENG Yuan, WU Xian, HUANG Cheng, WANG Laiyuan, GUO Man
    2023, 44 (1):  33-42.  doi: 10.7657/XJPG20230105
    Abstract ( 243 )   HTML ( 11 )   PDF (18034KB) ( 128 )   Save

    The ultra-deep fault-karst reservoirs in the Tarim basin are mainly distributed along strike-slip fault zones,and the oil and gas exploration effects are poor in the areas far away from fault zones,that is,the activity scale of strike-slip fault zones control the scale of hydrocarbon accumulation. The Shunbei No.5 strike-slip fault zone is a super-large strike-slip fault zone,which is characterized by deep burial,complex internal structure,and evident stratification and segmentation. Based on high-quality 3D seismic data,the geometry,kinematics and dynamics of the Shunbei No.5 strike-slip fault zone were systematically analyzed. It is recognized that the Shunbei No.5 strike-slip fault zone is evidently layered (including 5 structural layers),and also segmented,with the southern and northern segments having different kinematic characteristics. The southern segment has experienced 5 stages of evolution,and the northern segment has experienced 4 stages of evolution.

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    Controlling Factors and Physical Simulation Experiments on Formation and Evolution of Conjugate Strike-Slip Faults
    DAI Lan, WU Guanghui, CHEN Xin, ZHU Yongfeng, CHEN Siqi, LUO Xin, HU Ming
    2023, 44 (1):  43-50.  doi: 10.7657/XJPG20230106
    Abstract ( 285 )   HTML ( 12 )   PDF (3055KB) ( 169 )   Save

    The origins of X-shaped conjugate strike-slip faults are complex. Considering the geological conditions of large X-shaped conjugate strike-slip faults in the Tabei area of the Tarim basin,7 sets of sandbox experiments with different parameters were designed to explore the controlling factors and evolution process of the X-shaped conjugate strike-slip faults. The experimental results show that conjugate strike-slip faults tends to be formed in the model with large thickness,large width and high clay content under the rapid compression on both sides. In the experiment,the fault tail propagation and the dominant development of a group of faults are obvious,while the fault linkage growth and the localization of overlapping area are weak. The formation of conjugate strike-slip faults requires three conditions: certain caprock thickness,and lack of pre-existing faults; good physical homogeneity of rocks,certain viscoplasticity,and high movement rate; and two-way compression. In the natural world and experiments,symmetrical pure shear conjugate strike-slip faults can hardly be formed,but most faults are single-shear strike-slip faults that develop as a group in dominant direction. In the Tarim basin,the conjugate strike-slip faults are also asymmetric,and they are dominantly single-shear faults in NW-SE direction; the inherited development with small displacements is the main controlling factor for the formation of large-scale conjugate strike-slip faults.

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    RESERVOIR ENGINEERING
    Water-Gas Ratio and Early Warning of Water Invasion in Unconsolidated Sandstone Gas Reservoirs in Sebei Gas Field,Qaidam Basin
    CHAI Xiaoying, WANG Yan, LIU Junfeng, CHEN Fenjun, YANG Huijie, TAN Zhiwei
    2023, 44 (1):  51-57.  doi: 10.7657/XJPG20230107
    Abstract ( 247 )   HTML ( 5 )   PDF (614KB) ( 117 )   Save

    The Sebei gas field in the Qaidam basin is an anticline-type shallow unconsolidated sandstone gas field driven by weak edge water,and is exploited by depletion. According to water-gas ratio (WGR),the production process in the gas field can be divided into four stages: low water-cut steady production stage,initial water invasion stage,edge water breakthrough stage,and strong water invasion stage. The occurrence of water invasion can be accurately monitored based on WGR. The edge water breakthrough stage can be used as a time window for predicting the large-scale water invasion of edge water,so as to adjust the development plan and extend the steady production period. The strong water invasion stage with high water cut corresponds to a long production period,so it is an important stage for enhanced oil recovery while producing with water.

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    Lower Limits of Pore Throat Producing in Natural Gas Drive Reservoirs Based on Nuclear Magnetic Resonance
    BAI Zhenqiang, WANG Qinghua, SONG Wenbo
    2023, 44 (1):  58-63.  doi: 10.7657/XJPG20230108
    Abstract ( 203 )   HTML ( 6 )   PDF (586KB) ( 94 )   Save

    Based on the principle of nuclear magnetic resonance (NMR),the relationship between NMR relaxation time and pore throat radius of core sample was derived. Combining with the pore throat radius distribution obtained from high-pressure mercury intrusion test,the NMR T2 spectrum was converted into the pore throat radius distribution by using the numerical difference and the least square methods. Then,according to the law that the oil saturation and NMR signal amplitude gradually decrease synchronously during core displacement process,the changes in the NMR signal amplitude of different pore throat radii under different gas injection rates,gas injection pressures and positions were analyzed,and the lower pore throat producing limits for different development patterns were determined. The results show that the crude oil in micron-sized pores is the main contributor to water flooding recovery. The minimum pore throat producing limit is 0.04 μm at low gas injection rate and 0.01 μm at high gas injection rate. When the gas injection pressure increases from 5.0 MPa to 17.0 MPa,the lower pore throat producing limit decreases from 0.05 μm to 0.01 μm. When the gas injection pressure is high,the overall pore throat producing degree of the core is relatively uniform. With the increase of gas injection pressure,the remaining oil in the pores with the radius less than 0.01 μm is mainly produced.

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    Reasonable Productivity Optimization Methods and Application in Ultra-Deep Fault-Controlled Fractured-Vuggy Reservoirs
    GU Hao, KANG Zhijiang, SHANG Genhua, ZHANG Dongli, LI Hongkai, HUANG Xiaote
    2023, 44 (1):  64-69.  doi: 10.7657/XJPG20230109
    Abstract ( 229 )   HTML ( 4 )   PDF (2699KB) ( 156 )   Save

    In this paper,the geological and development characteristics in the FQ oilfield in the Tarim basin were analyzed,and then the productivity test method,nozzle flow method and reservoir numerical simulation method were developed to optimize the reasonable productivity in ultra-deep fault-controlled fractured-vuggy reservoirs. The results show that the primary oil recovery of ultra-deep fault-controlled fractured-vuggy reservoirs can be divided into early stage,middle stage and late stage,which differ greatly in development characteristics. The ultra-deep fault-controlled fractured-vuggy reservoirs in the FQ oilfield exhibit four types of productivity test curves: convex,linear,upturned and stepped. For wells showing the convex curves,the productivity at the inflection of the curves is the reasonable productivity. For wells showing the linear and upturned curves,the maximum test productivity is the reasonable productivity,but the nozzle testing productivity needs to be continuously expanded until the inflection of the curves appears. For wells following the stepped curves,the maximum test productivity after reaching the step will be the reasonable productivity. When the well productivity is optimized by the nozzle flow method,the productivity at the inflection of the nozzle flow curves is the reasonable productivity. The reservoir numerical simulation method is suitable for optimizing the well productivity in the middle and late stages of primary oil recovery,that is,the reasonable productivity is determined by optimizing the key indicators such as water breakthrough time,cumulative oil production,and recovery rate.

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    Establishment and Application of a New Mathematical Model of Oil/Water Relative Permeability
    LI Jing, FAN Hui, LIU Chunru, YANG Fang
    2023, 44 (1):  70-75.  doi: 10.7657/XJPG20230110
    Abstract ( 227 )   HTML ( 10 )   PDF (548KB) ( 109 )   Save

    Large errors often occur in the fitting of oil-water two-phase flow data with the Willhite mathematical model. In this paper,a new mathematical model of oil/water relative permeability was proposed. When fitting the relative permeability curves of oil phase and water phase,the new model can use the multiple linear regression method with a single variable to obtain the optimal solution. Especially,when fitting the arched relative permeability curves of water phase,the difference between the optimal estimate of undetermined parameters in the arched curves and the optimal estimate of undetermined parameters in common concave relative permeability curves of water phase is small,so that the relative permeability curves of the standard water phase for multiple rock samples determined by using the arithmetic mean method are basically located in the middle of the relative permeability curves of water phase. After obtaining the relative permeability curves of the standard oil/water phase,combining with the Welge equation after water breakthrough in the oil production well,and by using the water displacing oil analytical method,the formulas for calculating parameters such as the water saturation at the water flooding front,the average water saturation after the water flooding front,water cut,and oil displacement efficiency were determined. This study provides a new method for investigating the water flooding laws.

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    Experiments on Mobility of Mixed Shale Oil in Lucaogou Formation in Jimsar Sag
    GUO Haiping, WU Chengmei, ZHANG Jinfeng, XU Tianlu, XIAO Dianshi, GUO Xueyi
    2023, 44 (1):  76-83.  doi: 10.7657/XJPG20230111
    Abstract ( 225 )   HTML ( 9 )   PDF (9688KB) ( 103 )   Save

    In order to determine the pore-throat structure and the mobility of crude oil in the shale reservoirs of the Lucaogou formation in the Jimsar sag,the reservoirs were classified by means of thin section identification,scanning electron microscope (SEM),and experiments such as high-pressure mercury intrusion. The mobility of the shale oil was evaluated through a displacement-NMR combined experiment to reveal the movable oil proportion,pore size variation and its controlling factors,and then establish a quantitative evaluation model of shale oil mobility. The Lucaogou formation develops 5 types of reservoir spaces including intergranular pores,intergranular-dissolution-intercrystalline pores,dissolution pores,dissolution-intercrystalline pores,and intercrystalline pores. The intergranular pores are mainly found in the silty-fine sandstone and sandy dolomite,and exhibit the best mobility. The dissolution pores are mainly in the dolomitic siltstone,and exhibits moderate mobility. Other pores are mainly in mudstone,argillaceous dolomite and limy sandstone,and show poor mobility. The lower limit of pore throats for shale oil moving is determined to be 20 nm. When the pore throat size are 60 nm and 150 nm,the movability is significantly improved,which corresponds well to the tested production capacity. Shale oil occurrence and pore-throat structure jointly affect the mobility of shale oil. The pore throats and shale oil occurrence in silty-fine sandstone and dolomitic siltstone are the best,which are the most favorable lithofacies for developing the mixed shale oil in the Lucaogou formation.

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    Water Control Experiments in Huizhou Buried-Hill Fractured Condensate Reservoirs in Nanhai Oilfield
    QIU Hao, WEN Min, WU Yi, XING Xuesong, MA Nan, LI Zhandong, GUO Tianzi
    2023, 44 (1):  84-92.  doi: 10.7657/XJPG20230112
    Abstract ( 200 )   HTML ( 5 )   PDF (1460KB) ( 106 )   Save

    In order to establish an optimal water control model for buried-hill fractured condensate reservoirs, based on the parameters from Well H2-3 in Huizhou buried-hill fractured condensate reservoirs in Nanhai oilfield, a physical simulation experiment for water control in gas reservoirs was designed. Through heterogeneous reservoir design, experiment parameter design, fracture parameter design and water control experiment scheme design, 5 groups of water control experiments were conducted, including elastic production experiment, continuous packer experiment, water-sensitive gel experiment, variable density screen experiment and variable density screen + continuous packer experiment. Then, their water control effects were compared, and water control mechanism of each experiment was analyzed. On this basis, verification was performed by using numerical simulation, and the water control development scheme of gas reservoir was given. The results show that in the stage of early development driven by bottom water of gas reservoir, the water body advances in a gradual manner; in the middle-late stage, the water body advances in a conical manner; and in the late stage, once the bottom water contacts the fractures in the reservoir, the water body will intrude in a sudden manner. The water control effects of the five schemes are different. The schemes of continuous packer and water-sensitive gel exhibit unobvious water control effects in the gas production stage, and the scheme of variable density screen demonstrates good water control effect in the early gas production stage, but fails to avoid the risk of water channeling after water breakthrough in a gas well. The scheme of variable density screen + continuous packer shows good water control effect, with the bottom water coning effect changed, and with the water-free gas production period, total gas production period and gas production volume increased by 8.84%, 13.70% and 10.40%, respectively as compared with the scheme of elastic production.

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    APPLICATION OF TECHNOLOGY
    Leakage Pressure Model of Natural Fractures in Igneous Rocks in Kelameili Gas Field
    YANG Hu, XUE Xiaojun, CHEN Xianghui, LI Xiubin, XIE Junyu, ZHANG Wei
    2023, 44 (1):  93-99.  doi: 10.7657/XJPG20230113
    Abstract ( 235 )   HTML ( 5 )   PDF (2034KB) ( 92 )   Save

    Fractures are developed in the igneous strata of the Kelameili gas field. The composite structure consisting of natural fractures and pores or cavities in such fractured formations may result in a large difference between the leakage pressure and the formation fracture pressure during drilling. The leakage mechanism was investigated according to the fracture-pore occurrence and the fracture opening/closing,connection and filling of the igneous rocks in different well sections,the leakage pressure models under different fracture states were constructed,and the layered leakage pressure profile was plotted depending upon pore pressure,in-situ stress and other parameters,so as to determine the leakage law of natural fractures in the igneous rocks in the Kelameili gas field. The results show that the leakage pressure of closed fractures in the igneous rocks is controlled by in-situ stress,and the leakage pressure of open fractures is affected by formation pore pressure and filling state. Furthermore,combining with the drilling parameters from typical wells,the variation law of fracture leakage pressure under different well trajectories was analyzed,and the safe density window of drilling fluid was determined to ensure drilling safety.

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    Plugging Mechanism and Plugging Removal Technology for Unconsolidated Sandstone Gas Reservoirs in Sebei Gas Field
    LIAO Li, OU Baoming, CHEN Jun, WU Cheng, JIANG Qi, NI Yong, ZHAO Yu
    2023, 44 (1):  100-104.  doi: 10.7657/XJPG20230114
    Abstract ( 217 )   HTML ( 6 )   PDF (545KB) ( 129 )   Save

    The Sebei gas field,a major natural gas producing area in the Qaidam basin,is characterized by multiple layers,easy sand production,and gas reservoirs with edge water. With the progress of the gas field development,reservoir plugging due to the factors such as water blocking damage,clay mineral hydration swelling and migration,and increased volume of the fluid entering wellbore occurs frequently in gas wells,which seriously affects well productivity. In the Sebei gas field,the unconsolidated sandstone gas reservoirs have high shale content and are suffering intensified water production. Through simulation experiment,it is determined that the influencing factor of reservoir plugging is clay mineral content. In order to protect the reservoirs,by selecting proper and economical plugging removal fluids,a chemical plugging removal technology has been developed for unconsolidated sandstone gas reservoirs in the Sebei gas field. Field application shows that this plugging removal technology is featured with fast operation,high efficiency and long validity,showing a good performance and application prospect.

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    Interpretation Methods for High-Resistivity Water Layer in Chang 8 Reservoir in Huachi-Nanliang Oilfield
    ZHANG Demei, DUAN Chaowei, LI Gaoren, LI Yongsheng, LU Jingwu, LIN Weichuan
    2023, 44 (1):  105-111.  doi: 10.7657/XJPG20230115
    Abstract ( 207 )   HTML ( 6 )   PDF (4712KB) ( 77 )   Save

    In the Chang 8 reservoir in Huachi-Nanliang oilfield of the Ordos basin,high-resistivity water layers are present,and the contrast between oil and water layers is low,making it difficult to identify oil layers. In order to accurately identify oil layers,based on logging data and petrophysical experiment results,the controlling factors of the high resistivity of water layers were determined. According to the logging response characteristics of different types of high-resistivity water layers,by using the data of neutron,density and acoustic logging,the pore structure in the reservoir was evaluated to identify high-resistivity water layers with complex pore structures. By using the cross-plot of neutron and density logging curves,resistivity was corrected,so as to enlarge the contrast between oil and water layers,and then to effectively identify high-resistivity water layers with complex wettability. Based on the analysis of the logging responses of high-resistivity water layers controlled by different factors,different techniques and methods were adopted to effectively identify these layers,and the accuracy of oil-water characteristic values in identification chart and the coincidence rate of logging interpretation have been improved.

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    Productivity-Based Classified Logging Evaluation of Carbonate Reservoirs: A Case Study on Yijianfang Formation in Tuofutai Area, Tarim Basin
    TANG Jun, HE Ze, SHEN Wei, QI Gewei, GUO Weimin
    2023, 44 (1):  112-118.  doi: 10.7657/XJPG20230116
    Abstract ( 217 )   HTML ( 9 )   PDF (1434KB) ( 102 )   Save

    The diversity of pore types is the main cause for strong heterogeneity of the carbonate reservoirs in the Yijianfang formation in Tuofutai area of Tarim basin, making it challenging to evaluate the reservoir effectiveness. On the basis of core and thin section observations, and according to the imaging logging data, the vugs in the carbonate rock are divided into dissolved vug and cavity, and the fractures are divided into structural fracture, dissolution fracture and pressolution fracture. According to the pattern of vug-fracture association, the pore spaces of the Yijianfang formation carbonate reservoirs in the study area are classified as fracture, fracture-vug and vug. The quantitative classification criteria for the reservoirs were established by combining electrical conductivity, fracture porosity and deep lateral resistivity variation. To be specific, the reservoir with the electrical conductivity less than 0.008 and the fracture porosity less than 0.13% is considered as vuggy reservoir; the reservoir with the electrical conductivity ranging from 0.008 to 0.024 and the fracture porosity of 0.13%-0.60% is considered as fractured-vuggy reservoir; and the reservoir with the electrical conductivity greater than 0.024 and the fracture porosity higher than 0.60% is regarded as fractured reservoir. According to the cumulative effective pore thickness, average effective porosity and productivity, the classification and discrimination charts for fractured-vuggy type reservoirs and vug type reservoirs were established. The vuggy and fractured-vuggy reservoirs in the Yijianfang formation in Tuofutai area are mainly Category Ⅱ reservoirs, with the daily liquid production of more than 50 t and 55 t, respectively.

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    Development and Application of Velocity Modeling Method Based on Double Square Root Operator
    Alifjian REHMTULY, PAN Long, LI Xianmin, LIN Juan, MA Jingjing, DOU Qiangfeng
    2023, 44 (1):  119-124.  doi: 10.7657/XJPG20230117
    Abstract ( 210 )   HTML ( 9 )   PDF (4411KB) ( 139 )   Save

    The southern margin of the Junggar Basin is a mountainous area with severe surface fluctuations. The conventional seismic processing method cannot meet the needs of the assumptions of the processing method due to the actual geological structure of the surface and deep layers,resulting in an unsatisfactory imaging effect and a large error between the interpreted depth and the measured drilling depth. In order to improve the quality of seismic data processing in the area,a seismic data processing method based on rugged datum was explored by using the velocity modeling with double square root operator. The method can reduce the distortion of wave field caused by the horizontal datum correction of the common midpoint (CMP) gather and provide a velocity field similar to the real observation surface for pre-stack migration,thus realizing the efficient integration of the time-domain datum and the depth-domain datum. The actual application of the new method show good seismic data processing results,with accurate migration imaging homing,satisfactory focusing,and significantly reduced error between the depth obtained from seismic interpretation and the depth measured by drilling. The new method provides a reference for seismic data processing in similar mountainous areas.

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