10 December 2016, Volume 27 Issue 12
    

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  • Forming mechanism and main controlling factors on the high-quality gas reservoirs restricted by paleokarst background:A case from Ordovician M54 1 carbonate,Ordos Basin
    Wang Qi, Xu Yong, Liu Xin-she, Ma Dong-xu, Ma Xiao-feng, Li Shu-tong
    Natural Gas Geoscience. 2016, 27(12): 2103-2114. https://doi.org/10.11764/j.issn.1672-1926.2016.12.2103
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    The karst palaeogeomorphology from west to east showing karst highland,karst slope and karst basin has laid the foundation for the formation of high-quality Ordovician reservoir in Ordos Basin.The study area experienced three types of karstification including contemporaneous interlayer karst,shallow burial weathering karst and burial karst to form lots of various pores and holes which provide the basis for later diagenetic alteration.M541 sublayer reservoirs mainly developed micrite dolostone,including anhydrite tuberculosis micrite dolostone,gypsum-containing dolostone,gypsum rock and karst breccias.Four kinds of reservoir spaces such as dissolution hole,primary intergranular pore,intergranular solution pores and microcracks are frequently observed with the dolostone reservoir.Gypsum dissolution mold pore is the main reservoir space.Based on field geological section,core description and thin sections,combined with cathodoluminescence,X-ray diffraction,and scanning electron microscopy analysis,it can be seen that the high-quality reservoir development in the study area is mainly controlled by two factors: karst palaeogeomorphology and late diagenetic dissolution.The former controlled reservoir distribution,physical property,gas and water distribution within the reservoir,so it is the basic condition to form the high-quality reservoir.And the latter reformed the pore system produced during karstification through three-periods of diagenetic dissolution.Therefore,the superimposition of these two geological processes is the key to the formation of high quality reservoirs in the study area.
  • Distribution characteristics of subsalt carbonate source rocksin Majiagou Formation,Ordos Basin
    Yao Jing-li, Wang Cheng-cheng, Chen Juan-ping, Gao Gang, Wang Fei-yan, Li Xiao-feng, Li Jia-ye, Liu Yan
    Natural Gas Geoscience. 2016, 27(12): 2115-2126. https://doi.org/10.11764/j.issn.1672-1926.2016.12.2115
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    Aimed at the fact of the self-preserved and self-generated characteristics of the Ordovician inside-scene subsalt gas reservoir and ambiguous recognition of the development of its corresponding source rocks,the distribution features of the Ordovician subsalt source rocks in the study area have been analyzed by jointly employing organic geochemistry and well logging technology.The gypsum layers are most widely developed in the 6 sub-members of the member 5 of the Ordovician Majiagou Formation with the widest distribution.The gas production points of the self-stored and self-generated natural gas discovered below the gypsum layers indicate that the marine carbonate source rocks are entitle certain ability for gas generation and discharging.It is indicated in the study that generally the subsalt carbonate source rocks in the Majiagou Formation have low organic matter abundance with a measured mean TOC content of about 0.2%,most of them being lower than 0.5%.The average rock pyrolysis peak temperature reaches 484℃,seating in the stage of highly-mature to overmature.On plane,the subsalt carbonate source rocks show high TOC content in the west,decreasing gradually in the east.It is higher in north Ordos Basin and decreased to the center;however it finally increased in south Ordos Basin.There are three favorable areas for the distribution of relative source rocks in the study area.
  • Exploration direction and potential of the Middle-Upper Proterozoic in Ordos Basin
    Hao Song-li, Sun Liu-yi, Bao Hong-ping, Liu Gang, Zhang Gui-song
    Natural Gas Geoscience. 2016, 27(12): 2127-2135. https://doi.org/10.11764/j.issn.1672-1926.2016.12.2127
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    The exploration potential of the Middle-Upper Proterozoic in Ordos Basin can’t be neglected,although it is still relatively unexplored.Considering gas sources and stratum distribution,the exploration of Middle-Upper Proterozoic can be divided into three directions.The direction of deep gas source is suited to be explored in the future,because the degree on geological research is low in this field.The direction of shallower gas source is the favorable exploration direction,because the gas source is better and the depth is shallower.However,the accumulation scope of this direction is limited by the scope of Carboniferous-Permiancoal measures strata.The third direction is the most important in which the gas sources is from the Middle-Upper Proterozoic.The Changcheng Formation is the most important target strata,because the source rock of Changcheng Formation has been found on the periphery of Ordos Basin and the reservoir quality of Changcheng Formation is better.Therefore,the areas of Dingbian-T59 and Chunhua-Luochuan are favorable exploration zones for source rocks.
  • Features of pore-throat structures and movable fluid in tight gas reservoir: A case from the 8th member of Permian Xiashihezi Formation and the 1st member of Permian Shanxi Formation in the western area of Sulige Gasfield,Ordos Basin
    Liu Deng-ke, Sun Wei, Ren Da-zhong, Zhang Xi, Ming Hong-xia, Chen Bin
    Natural Gas Geoscience. 2016, 27(12): 2136-2146. https://doi.org/10.11764/j.issn.1672-1926.2016.12.2136
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    In tight sandstone reservoirs,the study of accumulative regularity is very important in that it can represent flow regularity in pores.The movable fluid characteristics and the influence of micro-pore structures on it were studied by taking nuclear magnetic resonance as samples and supplemented by casting thin sections,scanning electron microscopic(SEM),cathode luminescence(CL),constant-rate mercury injection,clay mineral X-ray diffraction,high-pressure mercury injection and gas-water relative permeability experiments from the 8th member of Permian Xiashihezi Formation (He 8) and the 1st member of Permian Shanxi Formation (Shan 1) tight gas reservoirs in the western area of Sulige Gas Field as research objects.The study shows that,there are three types of reservoirs dominated by pore assembly types in research regions,including intergranular-dissolved pore type,dissolved-intercrystalline pore type and pore plus fracture type.The capacity of movable fluid occurrence becomes worse and the proportion of large pores decreases in turn.Movable fluid saturation is in positive correlation with the size of throats and pore-throat homogeneous degree.Hydrophilic enhancement contributes to the increment of thickness of water-film,which can block the throat and reduce the movable fluid saturation.The gas-bearing capacity predicted by well logging interpretations are well corresponding to pore assembly types,which provide a direct evidence to recognize the tight reservoir’s gas-bearing capacity.
  • Quantitative evaluation method of tight sandstone reservoir with low permeability
    Zhang Guang-quan, Hu Xiang-yang, Chen Shu-wei
    Natural Gas Geoscience. 2016, 27(12): 2147-2153. https://doi.org/10.11764/j.issn.1672-1926.2016.12.2147
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    In view of the existing problems and difficulties of evaluation of tight sand reservoirs with low permeability,by using the qualitative and quantitative parameters of static and dynamic data,this paper proposed a comprehensive quantitative evaluation method for the low-permeability reservoir.With this method,this study carries out a comprehensive analysis of the system,which has great significance on the evaluation of oil and gas field development in the quantitative evaluation of the reservoir and is directly used in production.The general idea is selecting the evaluation index,standardization of evaluation indexes,then the weight coefficient of each evaluation index,the comprehensive reservoir evaluation coefficient calculation and reservoir classification,combined with reservoir economic boundaries,determining the reservoir evaluation standard.The result is used to optimize the favorable zone and provide the basis for well deployment and capacity building and the method is used to perform the reservoir evaluation of X gasfield in the Ordos Basin.Based on the favorable zone,well deployment was carried out.Through the verification of the effective drilling catching rate of the new drilling,it is good anastomosis.The application of this method plays an important role in the productivity construction of the gasfield.
  • A new method of underground oil saturation measurementfor tight oil in the oil-water layer and a case study
    Gong Yan-jie, Liu Shao-bo, Zhao Meng-jun, Jiang Lin, Gao Xiao-hui
    Natural Gas Geoscience. 2016, 27(12): 2154-2159. https://doi.org/10.11764/j.issn.1672-1926.2016.12.2154
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    The paper analyzes the disadvantages of underground oil saturation measurements for tight oil in the oil-water layer through some routine methods such as pressure-maintaining sealed coring and nuclear magnetic resonance and compares the difference between core oil saturation and underground oil saturation,which is detected to be caused by volatilization resulting from fluid pressure release and dissipation from temperature variation because the in-situ conditions could not be preserved.Here a new method is presented to restore underground oil saturation through physical simulation of volatilization and correction of density coefficient.This method is applied to oil saturation measurement for Cretaceous Quan 4 sealed tight oil core samples acquired from Well X in south Songliao Basin.Restored underground oil saturation is 43.1% on average and mainly distributes between 40% and 50%,which are 20% higher than the average value of 23.3% and the range of 10%-30% derived from sealed coring and extracting.
  • Tectonic origin and the prospect of oil gas in west Kelasu structural belt：A case study of Awat segment
    Han Yao-zu, Gu Yong-xing, Liu Jun, Shang Guo-xi, Wang Ben-qiang, Lü Rui
    Natural Gas Geoscience. 2016, 27(12): 2160-2168. https://doi.org/10.11764/j.issn.1672-1926.2016.12.2160
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    Based on the high resolution 3D seismic data,combined with digital elevation model (DEM),field outcrop information,drilling data and the results of previous studies,we investigated the structure characteristics of west Kelasu.And also,we presented several elaborative interpretation with the representative seismic profiles.All of the research proves that the long distances overthrust structure model derives from three important reasons.The first is dynamics.With the long-distance effect of India-Tibet collision,the orogenic movement from Mesozoic developed large scale broken in west Kelasu tectonic zone,especially in Awate segment,the total thrusting displacement ratio reached 52%.Such a situation gives it enough energy source.The second is space.The exploration of Well A certificates that the Plaeogene’s plastic layer in Awate gets about 1 855m thickness,and the Bozi wells’ area nearby gets only 236m in average.Further research proves that Awate located near the center of an ancient saline lake,and the major lithology includes gypsum,salt,saliferous shale and gypsum-salt,all of which are characterized by high purity,plasticity and mobility.The third is overthrust condition.Awate was located near the edge of coal stratum in Jurassic,so the coal layer was thinner than everywhere else nearby.As we know,the coal’s internal friction coefficient is larger than the salt’s,but the decollement efficiency is just opposite.So when the early imbricate wedges move to the south consequently,No.5 Fault bulges above the Plaeogene’s salt layer.With the continuous thrusting power,the long distance overthrust structure appears near Well A,somehow instead of the early imbricate wedges south forward in the end.The thick plastic gypsum-salt layer has good vertical and lateral sealing performance,which provides excellent condition for hydrocarbon accumulation in Awate.
  • Controlling effects of sedimentation on organic matter maturation in Yinggehai Basin
    Xiong Xiao-feng, Xu Xin-de, Guo Xiao-xiao, Liang Gang, Luo Wei
    Natural Gas Geoscience. 2016, 27(12): 2169-2175. https://doi.org/10.11764/j.issn.1672-1926.2016.12.2169
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    Both Dongfang and Ledong areas are the main exploration field in Yinggehai Basin.When the organic matter is buried in the same depth,the thermal maturation level of organic matter is higher in Dongfang area than that in Ledong area.The high temperature and overpressure systems have affected the thermal maturation.But,the main reason of the difference of thermal maturation between Dongfang area and Ledong area is the different deposition rates which is caused by the migration process of depocenter during Neogene-Quaternary.The depocenter migration marked a differentiation hydrocarbon generation between Dongfang area and Ledong area.In Dongfang area,the generation begins early and lasts a long time.But,in Ledong area,it initiates late but is fast.The organic acid is also formed late in Ledong area,which contributed to the formation of secondary pore in mid-depth formations.Therefore,there is good accumulation condition and favorable exploration prospect in Ledong area.
  • Bacteria effects on geochemical characteristics of natural gas:A case study in the Shinan Oil-Gasfield,central Junggar Basin
    Wei Yan-zhao, Gong De-yu, Wang Feng, Wu Ai-cheng, Sun Jing, Fang Chen-chen, Liu Gang, Chen Gang
    Natural Gas Geoscience. 2016, 27(12): 2176-2184. https://doi.org/10.11764/j.issn.1672-1926.2016.12.2176
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    Five different types of natural gas were identified in the Shinan Oil-Gasfield,central Junggar Basin.The first type is original thermal gas derived from humic source rocks in the Middle Permian Wuerhe Formation and accounts for the main body of Shinan natural gas.The second type is mixed with a small amount of biotic gas including Ji001,Ji003,Shinan4 and Shinan5 which was resulted from the biodegradation of primary oil accumulation.Selective biodegradation on propane occurred in the third type whose carbon isotope of propane is 9.6‰ more positive than that of butane.Selective biodegradation on ethane occurred in the fourth type whose carbon isotope of ethane is more positive than that of propane.The fifth type is derived from sapropelic source rocks in the Lower Permian Fengcheng Formation with its methane being selectively biodegraded.Considering the present burial depth of biodegraded samples,two stages of bacteria process may occur in the study area.
  • Geochemical characteristics of natural gas and the contribution ratio of source rocksin the Yingshan Fault Depression of the Songliao Basin
    Zhang Bo-wei, Zhang Ju-he, Fu Guang
    Natural Gas Geoscience. 2016, 27(12): 2185-2192. https://doi.org/10.11764/j.issn.1672-1926.2016.12.2185
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    Based on the character of gas composition and isotope and light hydrocarbon fingerprint and source rock in Yingshan Fault Depression,gases in the Yingcheng Formation  and Shahezi Formation  are derived from a mixture of  humic and sapropellic  source rocks,and are at high-mature to over-mature thermal evolution stage.Shahezi Formation is a set of good-medium source rocks,and Yingcheng Formation  is a set of medium-good source rocks.The organic matter is dominated by type Ⅲ kerogen and followed by type Ⅰ and type Ⅱ.Jurassic is a set of good or non-poor source rocks,and the organic matter is type Ⅲ.It is at over-mature evolution stage.According to the gas geochemistry characteristic and source rock distribution feature in Yingshan Fault Depression,selecting source rock specimens in Yingcheng Formation ,Shahezi Formation  and Hushiling Formation  and according to the hydrocarbon fingerprint characteristic parameter of hydrocarbon source rocks,the calculating model uses mathematical simulation method to test the ration contribution and adjust per mouth of well of natural gas from three suits of hydrocarbon source rocks to analog computation.Results show,contribution of the Shahezi Formation  source rock is more than 50%.It is the first time to obtain natural gas ration source from and ration contribution of hydrocarbon source rocks in Yingshan Fault Depression.
  • The evidence of water soluble gas contribution to gas reservoir ofLongwangmiao Formation in Anyue Gasfield,Sichuan Basin
    Zhou Guo-xiao, Qin Sheng-fei, Hou Yao-hua, Lü Fang
    Natural Gas Geoscience. 2016, 27(12): 2193-2199. https://doi.org/10.11764/j.issn.1672-1926.2016.12.2193
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    Natural gas and reservoir solid bitumen of Lower Cambrian Longwangmiao Formation in Anyue Gasfield have been systematically analyzed using organic geochemical methods.It is found that the methane carbon isotope value is less negative than that of reservoir bitumen.It is difficult to explain this kind of phenomenon using the generally accepted idea that the gas is from oil cracking.According to the principle of the disproportionation reaction of carbon isotopic fractionation,if both methane and bitumen are from crude oil cracking,the carbon isotope of oil cracked methane should be significantly more negative than that of bitumen.In addition,the δ13C1 and the content of H2S have no obvious correlation,so it is impossible to think that the less negative value of δ13C1 is caused by thermochemical sulfate reduction.The carbon isotope of methane released from the gas field water is heavier than that of free gas reservoir.Water soluble gas adds to gas reservoir resulting in the carbon isotope value of methane carbon isotope bigger than that of reservoir bitumen from Longwangmiao Formation.At the same time,the majority of hydrocarbon inclusions with liquid phase methane characteristic peak are found by laser Raman measurement,which further confirms the existence of water soluble gas.Through the analysis of the geological conditions including the gas source,formation water,temperature and pressure environment,tectonic evolution and cover,the Longwangmiao Formation gas reservoir has good conditions of water soluble gas formation,preservation as well as degassing accumulation with the late tectonic uplift.Comparison of formation water solubility under the condition of Longwangmiao Formation deepest burial and present condition,estimating  that 1m3 formation water of Longwangmiao Formation can release 6m3 natural gas.
  • Research on the CO2 gas logging evaluation technologyof HTHP reservoir in western South China Sea Basin
    He Sheng-lin, Zhang Hai-rong, Yang Dong, Wu Yi-xiong
    Natural Gas Geoscience. 2016, 27(12): 2200-2206. https://doi.org/10.11764/j.issn.1672-1926.2016.12.2200
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    This paper discusses the problem of qualitative identification and quantitative evaluation of gas type by logging data in the high temperature and high pressure gas reservoir in the basin of the western  South China Sea.Due to the coexistence of hydrocarbon,non-hydrocarbon and water,the formation logging response gets complicate,and especially the additional conductivity has no obvious regularity when CO2 gas dissolved in water,making it very difficult to use the resistivity method for CO2 qualitative identification and quantitative calculation.So,we can calculate the parameter of Neutron-density intersection of the unit gas-bearing porosity,using Neutron-density intersection curve corrected by porosity and gas-saturation,on the basis of differences in neutron and density logging response of hydrocarbon and non-hydrocarbon gas.This parameter can be used to qualitatively identify non-hydrocarbon and hydrocarbon gas.By using the data of long & short source-distance and count-rate values of neutron logging which is corrected by standardized treatment and aqueous calibration,we can establish the numerical calculation model of CO2 content,according to the differences in thermal reduction and diffusion caused by hydrocarbon and non-hydrocarbon gas.The calculated CO2 content by this method is not quite different from the results of oil-testing and sampling,confirming the reliability of the quantitative calculation method of gas composition.
  • The seismic detection of gas bearing for Xujiahe Formation in the middle of Sichuan Basin
    Li Xin-yu, Ouyang Yong-lin, Bao Shi-hai, Zeng Qing-cai, Chen Sheng, Huang Jia-qiang, Zhang Lian-qun, Li Xuan
    Natural Gas Geoscience. 2016, 27(12): 2207-2215. https://doi.org/10.11764/j.issn.1672-1926.2016.12.2207
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    The tight sand reservoir in Xujiahe Formation of Upper Triassic in Sichuan Basin contains huge resources of natural gas,it is one of the most important exploration and development layer system.Practice shows that the Xujiahe Formation gas reservoir is very complex：Thin reservoirs,strong heterogeneity,complex  distribution of gas and water,so it seriously affects the Xujiahe gas reservoir exploration and development benefits.How to accurately identification the gas and water and improve the prediction accuracy of gas enrichment zone is essential to the development of the gas reservoir.Based on the analysis of reservoir rock physics and forward modeling,this study summarizes the AVO response characteristics of gas and water layer,establishes a new method of near stack section and far stack section comparative analysis and forms the key method of Main amplitude and Main frequency technique.The methods are used to detect gas and water and forecast gas-rich region in many blocks at Anyue-Gaoshiti areas in the middle of Sichuan Basin,and the reliability of the prediction results has been confirmed by a large number of new drilling wells.
  • Productivity log forecasting of low permeability gas reservoir of Shihezi Formation in X area of Ordos Basin
    Chen Yu-long, Zhang Chong, Shi Wen-rui, Guo Ji-ning, Qin Rui-bao, Yu Jie, Zhou Xing-bo
    Natural Gas Geoscience. 2016, 27(12): 2216-2222. https://doi.org/10.11764/j.issn.1672-1926.2016.12.2216
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    The process of oil-gasfield exploration and development,productivity log forecasting of low permeability gas reservoir is a key and difficult point.On the basis of log,testing and core experimental data,firstly,according to the different production measure,the lower limit of reservoir physical property is determined.Reservoirs with porosity and permeability greater than 10% and 1×10-3μm2,respectively,have natural productivity,and reservoirs with porosity and permeability less than 6% and 0.1×10-3μm2,respectively,have no productivity.Secondly,according to the production condition,productivity is divided into natural productivity,post-frac AOF>10 000m3/d,post-frac AOF 3 000-10 000m3/d and post-frac without production.Their log characteristics of different productivity levels are studied,and using GR,φD-N,porosity and permeability,four productivity levels can be forecasted.Then followed by permeation fluid mechanics and capillary theory,the relationship of post-frac AOF per meter and efficient flow pore,calculated by NMR,is index,and the model can be established.Finally,productivity of low permeability gas reservoir of Shihezi Formation in X area of Ordos Basin is calculated and the forecast results accord with test results well,and the relative error is less than 10%.
  • The application of geosteering technology for shale gas horizontal well:A case from Well A in southeast Sichuan
    Liu Jiang-tao, Li Yong-jie, Zhu Jie-ping, Han Ke-ning, Zhang Pei-xian, He Gui-song, Long Zhi-Ping
    Natural Gas Geoscience. 2016, 27(12): 2223-2230. https://doi.org/10.11764/j.issn.1672-1926.2016.12.2223
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    Southeast Sichuan has been at the forefront of shale gas exploration and production of China.However,problems such as relatively scarce well data,obvious contradiction between logging and seismic data,poor representativeness of cuttings,and longer horizontal section,have made it difficult to do geosteering drilling.Aimed at the difficulties,geosteering of exploratory Well A for shale gas has been executed by the geosteering method of three steps.First,based on regional geological data and logging curve characteristics of guide hole well,marker beds were determined,which provided a basis for correlation of strata while drilling.In geosteering stage before A target,combined with gas logging data,micro-characteristics of logging curve were analyzed to identify the maker beds,and the drilling track was adjusted according to the predicted depth of A target,to ensure precise target hitting.In the geosteering stage for the horizontal section,the variation trend of GR curve while drilling was analyzed,and the bit location was determined.The drilling track was controlled in target window by marker beds.Finally,the length of high quality shale of horizontal section is 1 317m,the drilling ratio was 100%,and the effect was remarkable.The geosteering technology is suitable for shale gas horizontal well drilling in southeast Sichuan,and can effectively improve the drilling ratio of high quality shale,and has high reference value to geosteering of other domestic shale gasfield.
  • Laboratory study on hydraulic fracture geometry of Longmaxi Formation shale in Yibin area of Sichuan Province
    Fu Hai-feng, Liu Yun-zhi, Liang Tian-cheng, Weng Ding-wei, Lu Yong-jun, Xiu Nai-ling
    Natural Gas Geoscience. 2016, 27(12): 2231-2236. https://doi.org/10.11764/j.issn.1672-1926.2016.12.2231
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    Hydraulic fracturing is an important technology in shale gas reservoir development.Due to complex geological conditions,it is hard to know fracture propagation mechanism clearly and how to maximize the stimulated reservoir volume (SRV) is the key issue for hydraulic fracturing.A series of tests have been done with shale blocks from Longmaxi Formation outcrop to simulate hydraulic fracturing in field.The effect of natural fractures,in situ stress conditions,and pump injection parameters on hydraulic fracture geometry have been studied respectively.Meanwhile,fracture propagation in real time was analyzed by acoustic emission monitoring technology.The experimental results showed that the existence and distribution pattern of natural fracture system determine the hydraulic fracture geometry.The higher injection net pressure would result in more complex hydraulic fracture system.But the pumping rate and fluid viscosity were not always directly proportional to the injection net pressure.Hydraulic fracture system would be simpler when the pumping rate and fluid viscosity exceed a limited level.According to the location of acoustic events in space,it could reflect the hydraulic fractures distribution range.The changing coherence of acoustic frequency,amplitude and pressure curve also confirmed fracture discontinuous propagation in shale due to high rock brittleness.This work has explored experimental methods for the research of shale fracturing mechanism,and provided an experimental basis for volume fracturing process design in field.
  • Microscopic mechanism of the fracture in the rock caused by hydraulic fracturing process
    Du Shu-heng, Zhao Ye, Pang Shan, Shi Yong-min
    Natural Gas Geoscience. 2016, 27(12): 2237-2245. https://doi.org/10.11764/j.issn.1672-1926.2016.12.2237
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    Since the microscopic mechanism of the fracture caused by hydraulic fracturing process has not been explained well,according to the linear elastic fracture theory and the gridding quantitative simulation method,through building up the simplified structure model of microscopic reservoir,simulation on microscopic laws of reservoir rocks fracture has been performed.Based on the simulation results,the micro fracture’s sequence and position have been analyzed.Two dominating modes of microscopic reservoir fracture during the hydraulic fracturing process were come up with,that is the “structure broken” which is breakthrough along the pore throats and the “body broken” which is fractured in the mineral materials.Between them the “structure broken” plays the most important role,and the "body broken" could increase the seepage channel which will play a significant role on enhancing oil recovery.
  • Visual simulation experimental study on water invasion rulesof gas reservoir with edge and bottom water
    Fang Fei-fei, Li Xi-zhe, Gao Shu-sheng, Xue Hui, Zhu Wen-qing, Liu Hua-xun, An Wei-guo, Li Cheng-hui
    Natural Gas Geoscience. 2016, 27(12): 2246-2252. https://doi.org/10.11764/j.issn.1672-1926.2016.12.2246
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    In view of the water invasion in development of gas reservoir with edge and bottom water,the visual physical experiment model is designed based on the main reservoir space characteristics of different types of gas reservoirs,and physical simulation experiment system is used to research the water invasion rules of pore type,fracture type,hole type and fracture-cavern type gas reservoir.The result shows that pore type gas reservoir recovery degree is high,the leading edge of water is approximately uniform advance,and water-gas ratio increases slowly after water breakthrough.Water goes in priority in a quick dash along the fracture,gradually invades matrix by the capillary force and block the gases in the matrix,so a large amount of gas is blocked in the fracture gas reservoir,which leads to sharp fall of fracture type gas reservoir recovery degree.The isolated holes and cracks in reservoir mainly provide storage space,and water first goes into the hole and slot,which has significant influence on local water invasion,but has little effect on the whole water invasion’s propulsion.The gas reservoir is linked by cracks and holes,water swiftly fills holes along the cracks.When the outlet contacts with the edge and bottom water through cracks and holes,gas reservoir will be shut down because of the water in a short time.At that time the gas reservoir only use the gases in the seams and holes.The results of research have important guidance and practical significance for the effective development of edge and bottom water reservoir.
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