, Volume 28 Issue 4
    

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    石油地质研究
  • The significance of Ordovician reef discovery in Tarim basin
    GU Jia-yu; FANG Hui and JIANG Lingzhi
    , 2001, 28(4): 115-0.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    Through the study of field outcrops and core examination and interpretation of seismic sections, some reefs are discovered in the Ordovician of Tarim basin. There is some law in distribution area and horizon of reefs. In horizon, reefs are mainly distributed in the Middle and Lower Ordovician. In region, reefs are mostly distributed in Tazhong, Lunnan, Bachu, Aerjin and Kuluketage areas. Reef-building organisms are Stromatoporida, Bryozoa, Coral, Cyanophyta, Solenoporaceae, Calathium, Spongia, and reef-associated organisms are Hornstone, Gastropoda, Echinodermata, Ostracoda, Lamellibranchia, Brachiopoda, Crinozoa, Algae, Trilobita, and Cephalopoda. The association of organisms differs from one area to another. The environments, which are favorable for development of reefs, are platform-edge and relatively high land in intraplatform. The discovery of reefs in the Ordovician is very important to petroleum exploration practice and development of the relevant theory.
  • A study on oil and gas accumulation in Lenghu area of the northern margin of Qaidam basin and some relevant exploration suggestions.
    MEN Xiangyong; ZHAO Wenzhi and YU Huilong
    , 2001, 28(4): 116-0.
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    There are good oil-generating conditions but bad reservoir physical properties in deep Jurassic system. However some good reservoir-cap rock assemblages existin the overlying Tertiary system, so building up a good lower source rock-upper reservoir assemblage in this region. Many faults developed in Lenghu structure and controlled oil and gas distribution; faults provided better migration path-way for oil and gas deep source rocks, and their good sealing ability is the key factor to preserve the oil and gas generated and migrated. The process of oil and gas accumulation includes two stages: one is the deep oil and gas pools formed at the end of E3, and it is possible to make large scale oil and gas accumulation in the Lower Tertiary system; the other is that the deep oil and gas pools were readjusted, and even destroyed at the end of N2. In the second stage, the secondary oil and gas accumulation formed in shallow Tertiary system, and part of oil and gas was lost. Based on their analysis, we acquire some enlighten, suggesting that exploration in the Tertiary system having oil pathway to oil source area should be strengthened, and fault sealing ability research should be paid more attention to.
  • Hydrocarbon sources of high waxy condensate oil and gas pools in Qianmiqiao buried-hill zone of Huanghua depression
    LU Hong; WANGTieguan; WANG Chunjiang; ZHU Dan and ZHU Lei
    , 2001, 28(4): 117-0.
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    Intensive researches on the chemical component of the C12－C35 liquid fraction of high waxy condensate-associated oil in Qianmiqiao buried-hill reservoir have been conducted. This is important to proceed the oil source correlation. In the light of carbon isotope analysis the crude oil is originated from humic-type organic matter. Owing to influences of fractionation effect in the procedure of condensate oil formation, Hopane and Sterane had lost their normal distribution features which could not be used to analyze the mature stage and correlate the source; condensate-associated oil has relatively concentrated rearranged-drimane, high Benzopyrene and single chrysene which can be the basis of choosing the oil source correlation indexes. The oil-oil correlation by the monometric hydrocarbon and fractional carbon isotope reveals that the Ordovician condensate oil in Qianmiqiao buried-hill reservoir is similar to some Tertiary crude oil such as the light crude oil in Es3 from Well Banshen 35 and the crude oil in Es2 from Well Ban G5 and Well Bai 21-4 et al., they should be the products of the same source. The oil-rock correlation by the monometric hydrocarbon and fractional carbon isotope and molecular biomarkers indicates that the condensate oils have the original relationship of mother material with the 3rd Member of Shahejie Formation mudstone which is reviewed as the effective hydrocarbon source rock of the condensate oil in the Qianmiqiao buried hill reservoir.
  • Relationship between deep abnormal pressure and oil and gas distribution in the Paleogene of Qibei area.
    LI Jun; YUAN Shuqin and WU Gang
    , 2001, 28(4): 118-0.
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    This paper demonstrates the fact that surpressure can restrain liquid hydrocarbon cracking under high temperature and make it possible that deep liquid hydrocarbon forms pool by the method of thermopressurized simulating experiment. It also states the relationship between deep surpressure and deep oil and gas distribution in the Paleogene of Qibei area. The authors hold that the oil and gas distribution has quite close relationship with abnormal surpressure zone which lies in that oil and gas mainly distribute in some sandstone intervals with relative low residual pressure and these intervals are underlying some mudstone intervals with high residual pressure vertically. Abnormal pressure distribution is obvious succession with the sub-stratum horizontally. The fluids flow from the surpressure area to sub-pressure area, and forms close relationship between oil and gas accumulation areas and oil and gas expulsion period and active faulting period. This paper also presents that oil and gas are accumulated in the relatively high-pressure part of the low pressure area and the pressure variation denseness zones. In view of the reason that prediction pressure now can be considered as an effective way to look for oil and gas accumulation location, the authors developed a kind of pressure prediction software based on the equivalent-depth theory and applied this software to the prediction of favorable target area.
  • The relationship between the characteristics of sand bodies and the properties of Lower Jurassic reservoirs in eastern Kuqa depression, Tarim basin
    WANG Gen-hai and SHOU Jianfeng
    , 2001, 28(4): 119-0.
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    On the comprehensive analysis of investigating outcrops, testing samples and drilling data, it is considered that the Lower Jurassic sand bodies in eastern Kuqa depression are predominately of braided distributary channel and subaqueous distributary channel subfacies and subordinately of distributary mouth bar subfacies, both of which belongs to braided delta depositional system. They can be subdivided into nine types of sand body according to their genesis; five kinds of sand body according to their sequence structures and two types of jigsaw puzzle and labyrinth reservoir architectures according to their shapes. The control of the characteristics of sand bodies on the reservoir properties is mainly of the grain size,that is the property of relatively coarser sandstones obviously becomes better. So it comes to the conclusion that braided distributary channel and subaqueous distributary subfa cies are the good oil and gas reservoir sand bodies.
  • The influence of depositional environment on the self-organization extent of detrital rocks
    SUI Shaoqiang; SONG Lihong and LAI Shenghua
    , 2001, 28(4): 120-0.
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    With the change of accommodation, hydrodynamism of depositional environment changes, which makes the distribution of grain size of detrital rocks have different characteristics. Such micro-characteristics of sandstone-conglomerates as distribution of grain size, et al., are the miniature of macro-characteristics of detrital rocks, which have self-resemblance and can be described quantitatively by fractal dimension. The averages of coefficient of sorting in TST are higher than that in HST and the fractal dimensions of distribution of grain sizes in TST are smaller than that in HST. With the change of that from TST to HST, the accommodation reduces gradually, the energy of lake water decreases, and the self-organization extent of grain size distribution becomes subtle.
  • An approach to the generating mechanism of secondary pores in Duqiaobai area of Dongpu depression.
    WANG Peng and ZHAO Chenglin
    , 2001, 28(4): 121-0.
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    Dongpu seg, Deep zone, Reservoir, Secondary pore, Origin
  • The cracking gas from crude oil and its significance in gas exploration.
    ZHAO Mengjun; ZHANG Suichang and LIAO Zhiqin
    , 2001, 28(4): 122-0.
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    In this paper, the topic about the cracking gas from oil is put forward through the discussion on the theory of hydrocarbon generation and the evolution process of Palaeo oil reservoirs. Here, the meaning of the cracking gas from oil is just related to the evolution of an oil reservoir, when it is buried deeply the crude oil will be cracked to gas and bitumen. The cracking gas from oil just takes place under special geological conditions; for example, the gas of Hetianhe field in Tarim basin is the cracking product of the crude oil in deep buried reservoir because of late tectonic movement. Both the gases from Sangtamu field in eastern Tabei Uplift and from Hetianhe field are derived from Cambrian source rocks, but the generation process for the two gases is different. The gases from eastern Tabei Uplift are mainly formed by kerogen cracking and the gases from Hetianhe field mainly formed by oil cracking. So there are obviously differences for the two gases in the components and their isotopes except the similar maturity. For example, the non-hydrocarbon gas content is higher and the methane isotopic ratio is lighter for the gases from Hetianhe field than that from eastern Tabei Uplift.
    • 综合勘探开发技术
  • The characteristics of organic inclusions of Kela 2 and Kela 3 gas fields and their indicative significance to oil and gas pool-forming in Kuqa depression
    ZHANG Nai
    , 2001, 28(4): 123-0.
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    The test and analysis of fluid inclusions in the reservoirs is a very effective method in studying oil and gas migration and the pool-forming times. The rock samples in Kela 2 gas field and Well KL3 are examined with polarization microscope, fluorescence microscope, the composition of inclusions has been tested with Laser Raman spectrometer, and the type and distribution of organic inclusions have comparatively been studied in this paper. The study results indicate that there are two stages in oil and gas migration-accumulation events in Kelasu trend. The first is early diagenesis stage (before tectonic uplift), during which petroleum charge were starting at the beginning of cement process in Kela 2 and Kela 3 traps, and preserved in the reservoirs since then. The content of organic inclusions is low, which shows that a large oil & gas accumulation has not been formed in this stage. The second is late Himalayas stage. The abundant gas inclusions indicate that the huge amount of gas has charged the reservoirs in Kela 2 trap. But the characteristics of organic inclusions in Kela 3 trap show that there is only the activity of migration-accumulation of light oil in early time and those of heavy oil in late time.
  • Predicting the oil/gas bearing potential of sand bodies with various seismic attribute parameters based on geological model of the reservoirs
    ZHANG Yong and SONG Weiqi
    , 2001, 28(4): 124-0.
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    Average seismic wave attenuation, inversion wave impedance and seismic amplitude of Jiangjiadian area in Huimin depression are sensitive to oil/gas-bearing sand bodies. On the basis of the research for relativity between above-mentioned attribute parameters, the geological models of different reservoirs of given oil/gas sand bodies were studied; multiple attribute parameters study model restrained by geological model was built up; average seismic wave attenuation of absorption attribution of sand bodies, which can be able to directly represent absorption attribute of sand bodies, was calculated by using cepstrum technology. With the restraint of geological model of reservoir, support vector network was used to judge oil/gas-bearing potential of sand bodies. Results calculated by this method are basically identical with the given location of productive strata, and the predicted results have been confirmed by drilling. The cepstrum analysis, with small error in results and very quick calculation speed, is a reliable method for identification of oil sand bodies. Its risks in predicting practical problems are much smaller compared with artificial nervous network.
  • The role of non-seismic techniques in exploration and development of oil and gas
    HE Zhanxiang; JIA Jindou and GOU Liang
    , 2001, 28(4): 125-0.
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    Non-seismic techniques are usually used only to investigate the basal structure, stratigraphic distribution and basin-mountain relationship in unexplored region and surrounding basin of earlier reconnaissance. Owing to the technical advances in recent years, non-seismic techniques play a great role in target-oriented exploration as well as their earlier reconnaissance. Non-seismic techniques are mainly aimed at where is no seismic reflection or low signal-noise ratio, and feature the mosaic-based remedy effects. Non-seismic techniques can be used to predict the boundary of a found (spotted) reservoir and evaluate its characteristics, from the macroscopic pattern point of view. Non-seismic techniques manifest themselves in time-lapse monitor, description of steam front direction of hydrocarbon recovery and enhancement of productivity during the stage of oilfield development. Under the current circumstances of market economy, it ought to be our common understanding making good use of non-seismic techniques in the exploration and development of oil and gas during the entire process and raising exploratory benefit with the cost-effective technical advantage.
    • 油田开发与油藏工程
  • Study on the fluid flow in low permeability reservoir
    YAO Yuedong; GE Jiali and WEI Junzhi
    , 2001, 28(4): 126-0.
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    In order to determine the rule of fluid flow in a low permeability reservoir, an experiment based on the non-dimensional analysis and micro-boundary theory has been conducted. Comparing the data obtained from experiment work with the result gained from analysis, we could draw out the conclusion: Nonlinear flow happens under low velocity. The calculation and analysis of an example has demonstrated the influence of porous media, fluid and development methods on the flow rate. The conclusion proposed here is of importance for low permeability oilfield development.
  • Some key technical measures used in progressively developing old fields of Jiangsu
    ZHANG Zhiying; ZHANG Zhiying; ZHANG Jianliang; LIAO Guangming; LIU Xin and AO Lide
    , 2001, 28(4): 127-0.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    The old oil fields of Jiangsu developed are located at Gaoyou, Jinhu, Haian sags and Wubao arch of Dongtan depression, Subei basin. These oil fields are composed of fault block reservoirs. The key to progressively develop these oil fields is making trap sure and getting a clear understanding of the distribution of reservoir. By using multi-subject theory and applying integrative progress development technology, the authors systemically summarized workflows and key technical measures of progress development in old oilfields. The great achievement such as new oil block and increasing reserve have been gotten through the application of full 3D processing and interpretation technology and multi-parameter inversion of seismic technology (SEIMPAR) in Songjiaduo and Huangjue oil fields.
    • 油田非注水开发
  • A polymer flooding pilot test in a strongly heterogeneous reservoir of Xiaermen oil field
    XIE Feng; MA Yan; DENG Zhizhan; LIU Wenhua and LUI Xiaohua
    , 2001, 28(4): 128-0.
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    The H2Ⅱzone in Xiaermen oil field is characterized by severe heterogeneity, large porous channels and high mobility ratio of water over oil. During waterflooding, water easily makes a breakthrough to oil wells, then the water cut increased swiftly, causing low sweep efficiency of waterflooding and waterflooding's recovery only 24% of OOIP. For this reason, a stronger agent of profile modification was developed to block thief zones in whole reservoir. Meanwhile, an ultra-high molecular weight polymer (polyacrylamid molecular weight: 20×106-28×106) was selected, which suits for being dissolved in produced water, to increase water viscosity, to correct the high permeability variation and adverse mobility ratio. Perfectly combining the technology of high strength profile modification with polymer flooding, the pilot test performance has been carried out in 7 injection wells and 18 production wells. Before injecting polymer, the profile modification for all injection wells has been accomplished to block the large porous channels efficiently. Before polymer injection, depth profile modification was carried out in all injectors, the average radius of the profile improvement is more than 30m, cross flow of big pore throat was effectively held back, resulting in the follow-up polymer liquid evenly entering into reservoir layers, which shows this is an effective method. At present, the injected polymer slug is 0.39PV, the total increase of oil production is 9.39×104t, the current recovery increase is 6.5% OOIP. The polymer flooding test has met expected development goal. The economic benefit of the development has been improved obviously.
    • 经济评价
  • An analysis of economic development model on natural gas industry in central and western China
    MU Xian-zhong
    , 2001, 28(4): 129-0.
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    The “up-and-down stream” industry integration is the economic developing models on natural gas industry in general. The major natural gas fields are situated in central and western China, so the “up-and-down stream” industry integration, which is the economic developing models on natural gas industry in China, is based on a great deal of natural gas resource supplied in central and western China and demanded in market in south-east China, Zhujiang delta region and Beijing-Tianjin-Hebei region. The equilibrium is existed between costing price and sale price nowadays, then the engineering of transportation gas, such as the project of “transmitting western gas to eastern China” etc., is a key of the “up-and-down stream” industry integration. The “forward-integration” is the first exploration and development, then transportation and the last marketing of the gas. We think that the “forward-integration” is the economic model of “up-and-down stream” natural gas industry integration in China because the gas fields in central and western China are far from the market of natural gas demand in eastern China.
  • The calculating method and application of economic limiting steam/oil ratio for steam flood and steam soak.
    SHI Qi-xin and FANG Kaipu
    , 2001, 28(4): 130-0.
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    Under the given technical and economic conditions, the steam-oil ratio at the balance between the output value after taxation and the cost for ton oil of heavy oil field developed under steam flooding is the economic limit steam-oil ratio under this condition. It mainly relates to oil price and direct operation cost. Under the circumstances of fixed commodity tax, ton oil tax and value-added tax, 4 main technical and economic parameters, such as oil consumption of steam, utilization ratio, operation cost of ton oil and sale price of ton oil have an effect on the calculation results of economic limit steam-oil ratio. Economic recoverable reserve is an important index for evaluation and decision, which mainly relates to economic limit steam-oil ratio and the law of the change of oil production.
    • 综合勘探开发技术
  • A practical TTI-Ro method for hydrocarbon maturity history reconstruction.
    SHI Guangren
    , 2001, 28(4): 490-0.
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    When the hydrocarbon maturity history is rebuilt in present basin modeling, usually the single TTI (time temperature index) -Ro (vitrinite reflectance) formula is only used, which may cause the bigger error of Ro history and obvious wrong concept. Therefore, the author presents a practical TTI-Ro method, the process of which is to firstly calculate the TTI history on the basis of the burial history from geohistory model and the temperature history from geothermal history model, and then to construct the Ro-TTI formulas for each geological period according to the field measured Ro and TTI at the maximum burial depth of each formation, and finally to work out the Ro history that is the hydrocarbon maturity history. Comprising the “general-purpose formula” with the practical TTI-Ro formulas from a well of Linqing depression and a well of Tarim basin, the bigger differences are found. These differences are come from the following two aspects: (1) the limitation of the assumption of the formula to calculate the TTI history due to the complexity of composition and chemical bonding in kerogen; and (2) the hydrocarbon generation thresholds of TTI and TTI-Ro formulas being both different in different areas due to the different geological condition and matrix in the different areas. In addition, limitation of TTI, poor calibration of Ro should be noted.
  • Timing marine petroleum accumulation in the Tarim basin by oil/gas-water contact retrospecting.
    ZHAO Jingzhou
    , 2001, 28(4): 491-0.
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    Oil- or gas-water contact retrospecting of reservoirs is proved to be an effective method in timing petroleum accumulations. The basic principle of this method is that a regular reservoir is formed with a level oil- or gas-water contact and the hydrocarbon charging time can therefore be determined by tracing the earliest occurring time of the leveled contact. By using this method, it can be concluded that the Carboniferous oil accumulations in the Tazhong uplift were mainly formed in the late Hercynian and adjusted and reformed in the late Yanshanian (Jurassic to Cretaceous) and Himalayan (Cenozoic). The Carboniferous CⅢ reservoir of Hede 4 oil field in the west Manjiaer region was also formed in the late Hercynian and adjusted and reformed in the late Jurassic and Neogene, whereas its C5 reservoir is possibly a secondary pool formed in the late Himalayan by adjustion of the CⅢ accumulation. The Lunnan Triassic oil accumulations were mainly formed in the Jidike period of Miogene, adjusted later in Kangcun period and finally reformed in Kuqa period. The analysis, together with other evidence such as fluid inclusion and authigenic illite's K-Ar dating, reveal that the late Hercynian is the major period for the formation of the Paleozoic marine oil reservoirs in the Tarim basin, whereas the Mesozoic oil accumulations were formed as secondary pools by the adjusting of the Paleozoic ones during the Himalaya period.
  • Logging interpretation method for gas reservoirs with low porosity and low pressure
    LI Wei; XIAO Yuxiang and LIAO mingshu
    , 2001, 28(4): 494-0.
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    EK gas field is a special gas reservoir with medium porosity (average value being 10.9%), low permeability (single well permeability being 10.1×10-3μm2) and low pressure (formation pressure factor being 0.866). Deeply invaded by drilling filtrate, the log profile of the main gas zone takes such abnormal phenomena as that the shale is high in resistivity and the permeable sand is low in resistivity. Through fully utilizing the measured data of cores and adopting un-conventional logging interpretation method, a set of models for interpreting reservoir parameters have been established. (1) Porosity model. The model is established based on the analysis for the correlation between measured porosity values and standardized interval transit times. In this correlation, the correctness of interval transit time in sandstone matrix can be examined through ascertaining the matrix s interval transit time obtained from the crossing point between abscissa and waterline, which are determined in the cross-plot of resistivity and interval transit time in terms of the layering data of the main gas reservoir. (2) Permeability model. Influenced by low-pressure formations, the lateral resistivity of the EK gas field is capable eflecting the permeability change of the reservoir. Meanwhile, due to the existence of a certain relationship between the permeability and the porosity of the reservoir, the model for permeability interpretation can be set up using resistivity and interval transit time and can be inspected by virtue of measured permeability. (3)Saturation model. In accordance with the relationship between the densities of the gas-water two phase fluid and between the interfacial tensions of the both, the ordinate in the map of capillary pressure curves can be converted into gas column height. In light of measured water saturation, porosity and permeability corresponding to the gas column height, the correlation between the saturation and the three parameters (gas column height, porosity and permeability) has been established. Inspected by the measured data of cores, the reservoir parameters interpreted with the abovementioned models are proved to be reliable.
  • The application of four-component seismic technology in offshore oil and gas exploration and development
    ZHANG Shulin
    , 2001, 28(4): 495-0.
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    The regularity of the seismic survey and its derivative parameters are studied. The information such as the core testing data, all-waves well-log information and seismic data are analyzed. For gas-bearing core, the bulk modulus, Vp/Vs and Poisson ration are distinctly lower than those of the brine-bearing core. The Velocity and Poisson ratio of sand are distinctly lower than that of shale. When burial depth is beyond 2,500m, the velocity and Poisson ratio are not influenced by the burial depth. The prediction graticule of the lithology and gas reservoirs in Yinggehai basin has been made. The method of predicting lithology and gas reservoirs is propounded. In this method, Poisson ratio is used. The lithology and gas reservoirs of LD8-3 structure are detected. The detecting result shows that exploration prospect of the medium-deep beds of LD8-3 is very good.
    • 油田开发与油藏工程
  • Fluid heterogeneity distribution of ZaoⅤoil formation in Shenjiapu oil field
    YIN Wei; JIN Xiaohui; CHEN Jianqing and LIU Haifu
    , 2001, 28(4): 498-0.
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    ZaoⅤoil measures, the main production horizon in Shenjiapu oil field cut by many faults is divided into five fault blocks, each of which has its independent oil and water system. Relations between oil and water are complex and reservoir fluid heterogeneity is strong in the area. The crude oil is characterized by “four heights” in density, viscosity, resin and asphalt content, sulfur content. The distribution of ZaoⅤ oil reservoir fluid heterogeneity was analyzed by using the combination of thin layer chromatographic-firing icon detect (TLC-FID) and the rock evaluation (Rock-Eval), and using dense samples and absolute quantity analysis for every fraction of extraction, and the cause was roughly analyzed. The result shows that oil saturation of Zao Ⅴ oil measures decreases vertically, but oil quality becomes better gradually, which is the results of lithological variation and oil fill orientation. Oil quality becomes lower, and the content of resin & asphalt decreases gradually, which is probably related to oil migration orientation and tectonic position.
  • Remaining oil distribution prediction based on high-resolution sequence stratigraphy.
    YIN Tai-ju; ZHANG Changmin; ZHAO Hongjing and FAN Zhonghai
    , 2001, 28(4): 499-0.
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    The sedimentary architectural framework is controlled by the sedimentary volumetric partitioning and facies differentiation during the courses of base level cycles, which are also key factors for the reservoir heterogeneities that affect making development projects and their efficiency. As a result, the remaining oil distribution is also affected by these matters. In the inter-medium and long term base level rise cycles, with the base level's rising, the properties of the sand-bodies become better and the upper zones are always developed as key layers, and there are little remaining oil which area is smaller. In the medium- and long-term base level fall cycles, the conditions are opposite. Short- term base level cycles affect heterogeneities in the sand bodies. The rising of short base level will make the properties of the sand-body upper better, while the falling make an opposite effect. And these will be sure to make different developing responses. When sand-bodies are put into the course and sediment response system, it should be easy to make decision where should be rich in remaining oil.
    • 油田非注水开发
  • The application of a thin polyacrylamide gel formed with produced water in Jiangsu oil field.
    ZHU Ping
    , 2001, 28(4): 502-0.
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    This paper discusses the application of a thin polyacrylamide (HPAM) gel formed with produced water in Zhen12 Unit, Jiangsu oil field. The result of experiments indicates that some coagulant aids could help the gelation of the phenol-formaldehyde/polymer in produced water. Whatever in produced water could react with the components in a polymer crosslinking system would result in the gel intensity weak or no gelation happened at a certain concentration. The study of the gel property shows that the gel intensity decreases with the increase of pH, salinity and the hydrolysis degree of the HPAM. On the contrary, it increases with the rise of the molecule weight of HPAM and the polymer concentration. Whatever makes the gelation time long would result in the gel intensity weak. The pilot test to apply a thin polyacrylamide gel formed with produced water in Unit Zhen12, Jiangsu oil field, is successful. First, the injection pressure increased from 11.5 MPa to about 15.5 MPa after the test. Then the water injection profile was improved greatly in the well. Finally, the oil increment in six months reached about 1,300t after the weak gel treatment.
  • Allocation of alkylbenzene sulfonate in oil or water phase
    WENG Rui and WANG Hongzhuang
    , 2001, 28(4): 503-0.
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    The mixed surfactants are usually used to obtain “synergism” in chemical flooding, but the synergism can be collapsed because of the chromatographic movement of different surfactants through porous media. Expect the absorption of surfactants; an important factor affecting chromatographic movement is the allocation of mixed surfactants in the various phases present in the reservoir. Variation of allocation for alkylbenzene sulfonate with different structure in oil or water phase is studied in this paper. The results indicate that the allocation of alkylbenzene sulfonate in oil or water phase is related to its structure. With molecular weight increase, the allocation loss of alkylbenzene sulfonate increases. For alkylbenzene sulfonate with same molecular weight, allocation loss of linear alkylbenzene sulfonate is larger than branched alkylbenzene sulfonate. The allocation for alkylbenzene sulfonate in oil or water phase is related to properties of oil and water phases. Oil-water ratio is an important factor influencing the allocation of alkylbenzene sulfonate in oil or water phase. With oil-water ratio increase, the allocation loss of alkylbenzene sulfonate increases.
    • 石油史研究
  • Some inspiration from exploration stratigraphic study in Qaidam basin
    YANG Ge-lian; SUN Zhencheng; JING Minchang and LI Dongming
    , 2001, 28(4): 508-0.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    Stratigraphy is one of the basic subjects of most significance in geology. Stratigraphic analysis takes an important role in theoretic research and practice of petroleum exploration and development; basin analysis, petroleum system analysis and preliminary exploration of traps even petroleum development depend on it. The design of well location and depth is mostly dependent on stratigraphic study. On the other hand, wells can provide new information that can give more accurate control over design of new ones. So stratigraphic study is one fundamental work throughout petroleum exploration and development. In petroleum exploration and development, the design of well is frequently deviation from the truth because of the complexity of underground geologic setting and limitation of people′s knowledge at that time. However, in some cases if more attention is paid to the stratigraphic study before drilling big mistake can be avoided. Abundant cases have been found in Qaidam basin during over forty years. Analysis of three exploration wells with incorrect stratigraphic study in Qaidam basin indicates that more attention must be paid to the stratigraphy study. Some advice on how to study statigraphy in petroleum exploration is given.
    • 石油地质研究
  • The structure evolution and the petroleum system in Hefei basin.
    ZHAO Zongju; LI Dacheng; ZHU Yan; ZHOU Jingao and FENG Jialiang
    , 2001, 28(4): 532-0.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    Hefei basin is located in the southern edge of Huabei plate, with an area of about 20,000 km, up to now still no oil (gas) reservoirs have been discovered there. There is obvious difference between upper and lower tectonic levels of Indosinides Plane (Lower Jurassic) in the basin. The upper tectonic level is continental cap rock, which is characterized by extensional structure; lower tectonic levels are marine series of strata, which are characterized by compressional structures. The development of the basin mainly underwent the stages of basement rock formation of the pre-Mesozoic and the development of continental basin of Mesozoic and Cenozoic, now the basin still exhibits the structure pattern of uplifting in central area and the depression in all around. According to the naming principle of “main source rock－major reservoir－major reservoir-forming epoch”, the basin can be divided into 3 petroleum systems: Pz-J1－Pz-J-(K1)-T3-K，K1-K-K2-E and Pz-Pz-K2-E-E. Daqiao depression is the most favorable exploration area and Zhuxiang slope comes second. The source rock conditions in Paleozoic Erathem are not clearly due to lack of drilling calibration to Paleozoic Erathem. Fluviolacustrine arenaceous-pelitic rocks are dominant, which were reformed and destroyed by multiple tectonic movements during Yanshan Movement, and regional evaporite rocks are absent as good cap rocks in the Jurassic and Cretaceous formations. These are unfavorable for the preservation of oil and gas. In addition, due to the lack of the structural traps in Mesozoic Erathem and Cenozoic Erathem, therefore, there is some considerable risk in the exploration of the basin in general.
  • Hydrocarbon generating and expulsion models of the marine source rocks in the Tibet Plateau.
    WANG Dong-liang; ZHANG Junfeng; LIU Baoquan and GUO Jianying
    , 2001, 28(4): 533-0.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    The author acquired a lot of samples after field survey on the World Ridge——the Tibet Plateau, and further selected some certain representative experimental samples which are adaptive to simulation based on the prophase experiments. After making a lot of conditional experiments and combining the simulation samples with experimental apparatus, the author selected some adaptive conditions for simulation experiments. Thus, the thermocompression simulation experiments have been successfully conducted on the marine hydrocarbon source rock in the Tibet Plateau. Furthermore, some generated oil and gas were successfully acquired. After measuring and examining the experimental products and residue, this paper summed up four kinds of hydrocarbon models for marine hydrocarbon source rock in the Tibet Plateau. The establishment of these models provides some reliable support for correct assessment, study and resource extent calculation for marine hydrocarbon source rock in this area. At the same time, this paper compared these models with normal models and got the similarities and differences between them, which is significant to the study in this area. Comparisons of the simulation experiment results with the actual analysis on outcrop section show that the models established through simulation experiments can approximately reflect the real situation of the subsurface hydrocarbon generating and expulsion, which in turn reflect the correctness of simulation experiment results.
  • Sequence stratigraphy and hydrocarbon distribution of the Eogene in the eastern slope of Chengdao area
    XU Yingxia; GAO Xilong; LI Zhaoyan and SUN Xirei
    , 2001, 28(4): 544-0.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    The Eogene in the eastern slope of Chengdao is divided into two sequences and seven system tracts according to the synthetical analysis of seismic, well logging and drilling data. It is demonstrated by the analysis results of stratum and its oilness that the lower stand system tracts, falling stage system tracts and upper high stand system tracts developed more sand bodies, at the same time they are the richest oil-bearing formations. In this area, the main oil-bearing sand bodies distributed over the formations near the sequence boundary between sequence II and sequence I. It shows that many types of hydrocarbon reservoir exist in this area, such as lithologic pinch out, unconformity and stratigraphic onlap. In this study, the affection of sequence boundaries to the oilness of sand bodies and the inner relationships between them are analyzed. Consequently, a hydrocarbon distribution model based on the sequence stratigraphy is built up.
  • The properties of volatile oil and its exploratory direction in Dongpu depression
    ZHANG Yang; DU Xiang; YANG Qingwen; LI Qi and GU Xiwei
    , 2001, 28(4): 545-0.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    The fluid properties of Wen72, Wen88 and Wen13 East structures, which have been proven as volatile oil reservoirs, are different from others clearly in Dongpu depression. These three reservoirs not only have the characteristics of “six high and two low” but also are very unique in chemical components, PVT feature, volume shrinkage feature and so on. Compared with other reservoirs, they also have some particularity in formation conditions. The oil source rock with better quality and high maturity is the material basis for their formation; the depositional combination of the massive salt rock, salt-mudstone or shale as cap rock and lateral sealing are their trap conditions. The deep burial is of benefit to the migration and accumulation of the fluid with high gas-oil ratio. The high geotemperature in deep depth is of benefit to the heavy hydrocarbon cracking into light hydrocarbon and to the improvement of gas-oil ratio. It is an important factor to preserve these reservoirs that structure movement after Guantao Period has not affected the formations. This paper demonstrates the development law for the type of reservoir. The authors consider that the main areas and formations to find the volatile oil reservoir in Dongpu depression are the S3M4-10－S3L in downthrow block of Changyuan Fault, the S3M4-10－S3L1-4 in the north part of Wendong structure belt, S3M－S3L submembers in the deep zones of Baimiao-Qiaokou Structure and the S2L of Liuzhuang area as well.
  • Diagenesis and diagenetic facies studies for Yanchang Formation of the Triassic in Ordos basin
    YANG Xiaoping and CHEN Lihua
    , 2001, 28(4): 568-0.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    The reservoirs of Yanchang Formation of the Upper Triassic in Ordos basin are low- and super- permeability reservoirs, which were formed by vigorous diagenesis. Generally, different sedimentary microfacies developed different types of cementation that controlled distribution of secondary pore dissolved by acid water solution. Through studying sedimentary microfacies of Chang 6 reservoir and analyzing about 500 thin sections, diagenetic facies of Chang 6 reservoir are classified as eight types. For the above-mentioned study and analysis, the authors discuss the relation of sedimentary facies and cementation types. Finally, the authors predict the distribution of diagenetic facies for Chang 621 Chang 612 reservoirs and obtain a result that the favorable sedimentary facies tract and favorable diagenetic facies of Zhijing and Ansai delta may extend towards lake area.
  • A study on the chemical fillings in the secondary pores of the Sinian reservoir, Sichuan basin.
    WANG Xingzhi; CHEN Kegui; HUANG Jixiang; FANG Shaoxian and HOU Fanghao
    , 2001, 28(4): 569-0.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    After multiple-phase dolosparite cementation, the primary pores in the Sinian reservoir, Sichuan basin basically disappeared, the present pore spaces are dominated by secondary pores, vugs and fractures, which largely shrank after filling of multiple-phase chemicals. According to their components, crystal shape, order of formation and geochemical characteristics, the chemical fillings can be grouped into two major types of dolomite and quartz, and five phases, they formed in different time and different diagenetic environment, with dominant dolomite, multiple phases and less quartz. The filling of the cements is the main reason that the secondary pore spaces within the reservoirs are hardly preserved, and the residual secondary pores are the main accumulation pore space in the reservoirs.
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