| In view of the problem as production drawdown?high water cut?low rate of oil-vapor etc on the shallow and thin heavy oil formation in the later stage of after steam injection in Henan heavy oil field,systematacially developed integrated study upon change of formation physical property and distribution of remained oil,defined the change regular pattern of formation physical property in later stage of development in Gucheng and Jinlou heavy oil field,and the main factor to control the distribution of remained oil.Three steam-channeling models between wells of huff and puff and four distribution models of remained oil in plane were established.The standard of cored-distinguish and the methods of logging-identification toward the water flooding formation were improved.Then it proposes different methods for exploiting remaining oil in later steam stimulation which resolve many problems in later development stage effectively.The main results and innovative points are shown as follow:1.According to the analysis of mine monitoring data,Because of dissolved and the sand existed in steam stimulation process,after steam stimulation injection,reservoir pore of heavy oil reservoir was turn into emposieu-driving extensive pore,superhole and tubular pore.Porosity and permibility tended to increase,reservoir property become better.The reservoir porosity model,neutron porosity model,acoustic porosity model and acoustic wave-natural gamma permeability model in later steam stimulation process were established based on the relationship between rock and electricity.2.The explanation methods of water flooding in-place formation after huff and puff could be established based on the delicate description of well core and study on between sand and electricity,while the water flooding interval and water flooding degree of new wells can be identified with the application of cored technique which will provide the good service for the actual production.3.According to the minesites data analysis,combined the methods of reservoir engineering to methods of numerical model which study on the remained oil distribution in plane in difference heavy oil reservoirs of Henan oil field after steam stimulation,which indicated that after steam huff-puff,the distribution of remaining oil is controlled by sedimentary rhythm,reservoir thickness,stratigraphic dip,edge water,steaming quality,pattern well spacing,recovery degree of well group,cement job quality and well net completeness.Utilized the huff-puff production method in five-spot well pattern 100×141m thickening,the remainder oil saturation is still high in 60%of total area,development potential is great.Utilized the huff-puff production method in seven-spot well pattern 100×100m thickening,because of small well space,oil is exploited entirely in plane,development potential is small.According to channeling analysis and numerical model,4 remaining oil distribution models were established in plane:?Remaining oil distributes connectively between well groups.?Remaining oil distributes connectively in well groups.? Remaining oil distributes flaky between well groups.?Remaining oil distributes scattered in well groups.In vertical,remaining oil is affected by sedimentary rhythm and interlayer aeolotropy obviously.Three distribution models were identified:?Oil is mainly rich in middle and upper part of the formation ?1-2 on Jinloushan region.?Oil is mainly rich in upper and lower part of formation ? 9 of Gucheng Biqian10 Block.?Oil is mainly rich in middle and lower part of formation ?5-6 of Jinlou Yier Block.After thesis research results applied in actual production,the coincidence rate of water flooded layer interpretation will be reached more than 86%.For the remaining oil distribution character of different reservoir,the some methods such as steam injection hierarchically,update well drilling,perforations adding vertically,optimization streaming parameter and combination steam injection are proposed to improve the operation effectiveness of later period of steam injection. |
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