Research On Reservoir Characteristics And Favourable Region Of Carboniferous Gas Reservoir, In Xiangdong Area, Eastern Sichuan Basin

Regional sedimentary framework,petrology characteristic,slice observation are used to research of sedimentary environment and mutil-factor sedimentary microfacies of carboniferous carbonate rocks in Xiangdong area in this thesis ,as a guidance with principles of sedimentology of carbonatite ;As a guidance with petroleum geology , reservoir geology and geophysics , in order to analyses the characteristic of reservoir of carboniferous and its distribution discipline in area ; analyses the master control factor of reservoir and comprehensive sentenced to general the rank of reservoir of the well. On this condition , forecast the favourable region of Carboniferous reservoir . This thesis acquires the following main outcomes are as follows:(1) Dolomite, dust dolomite and dust limestone are primitive type of rock type of carboniferous, Huanglong formation, in Xiangdong area . The thickness of Huanglong formation between17m and 18m ,except the well of Xiang 21 whose carboniferous thickness only 13.8m. The Huanglong formation has three segments, only the well of Xiang 19 has the third segment. Each segment has its own lithology and electrical property characteristic.(2) The thesis analysed the new constructional drawing of carboniferous of Xiangdong area first, detailed studies the characteristics of its structure , faults,and traps.(3) Analysed and explained the environment of sedimentation of researched area by the mode of"evaporation anointed lake– lagoon–normal epicontinental sea of carbonatite depositional model". Analysed the microfacies of wells and drawing the microfacies plan of Huanglong formation. It is found that the shoal in lagoon is the best advantageous microfacies. (4) The carboniferous gas reservoir's type is fracture porosity reservoir. The carboniferous reservoir mainly growingⅢkind, lessⅡkind . The main gathering space are intergranular corrosion pore, intragranular corrosion pore, intercrystal corrosion pore; fissure majority is small horizontal fracture. The porosity and permeability in Xiangdong area is inferior to Xiangguoshi. The reservoir ofⅡkind is high grade reservoir in researched area.(5) By fine descriping and statisticing crack growth character, the research thought that the main type of fracture is structural, on longitudinal mainly concentrates in the C₂hl² section. On crosswise grows nearby the big fracture as well as the minor fracture, the main growth fracture region nearby Xiang 17 well, Xiang 21 well and Xiang 27 well.(6) The thesis divided the Carboniferous reservoir first, then drawing the Carboniferous reservoir well tie contrast and the aerosphere distribution sectional drawings of Carboniferous reservoir; Carboniferous reservoir spread plan. From these drawings, Carboniferous reservoir in researched area do not growth many Carboniferous reservoirs. The thickness of Carboniferous reservoir is thin and maldistribution in wells .(7) Analysed the governing factor of Carboniferous reservoir in researched area ; give the grade to each well and synthesized the research achievement to forecast favourable region of Carboniferous reservoir. By the research, Xiang 17 well, Xiang 21 well, Xiang 27 well and nearby area is the favourable region .