| From geological background of the deep gas deposits in Xujiaweizi depression, we analyzed systemly these gas reservoir formation condition( gas source condition, reservoir condition, sealing condition, trap condition). From the study on the gas distribution law and typical gas reservoir, we established gas reservoir formation model of Xujiaweizi depression. We divided gas reservoir systems by gas potential energy extremum. Then we divided gas deposits subsystems by separation groove. Based on these research, we described each gas reservoir system dynamicly. From the research on the history of gas formation, caprock sealing and the history of depression activitv, we analvzed the formation and evolution character of gas accumulation systems. Then we discussed its controlling effect on the gas deposit formation. Finally, based on these research, we prediced the favorable gas exploration target of this depression. The main achievements are:I. The main gas source rock in Xujiaweizi depression is deep color shale of K^^ . Its reservoir is glutenite and volcanic rock.. The caprock are shale of Kid2 and K]qi+2. Kiqi+2 has only capillary sealing ability. hi addition to this capillary sealing ability, Kjd2 also has concentration sealing effect.II. In Xujiaweizi depression, we can divide rvvo gas accumulation system: Klsh+yc~Kid2 and KiSh+yc+ Kid2~Kiqi+2. Kish+yc~ Kjd2 gas deposit system has 18 subsystems. Klsh+yC+ Kid2~K1qi+2 has 17 subsystems.III. Because of the fracture movement and openness in Xujiaweizi depression, the gas accumulation system moved up and the scope of gas reservoir formation expanded, which resulted in the phenomenon of "one formation, multi-source" and "one source, multi-formation".IV. Xujiaweizi depression has gas depcsit formation rnodcl of baserock, fault block, foiiiiaiiuii ovcrlap, lithology, inorganic CO2.V. The favorable gas exploration targets for next step are: westem slope of Xujiaweizi depression, Shengping nose structure, Changwu nose strucrure. |
PDF Full Text Request