The Gas Reservoir-forming Conditions Research Of Denglouku Formation In Gulong Area Of Songliao Basin

Though comprehensive analysis the data of12wells and seismic of Gulong area Denglouku formation, Denglouku formation in Gulong area is divided into4High resolution sequence stratigraphy, established sequence stratigraphy of Denglouku formation in Gulong area. Identification of Gulong area Denglouku formation for6major sedimentary systems (alluvial fan, fluvial, Delta, fan, lacustrine plain, Terminal fan, and the shallow lake), Material source and its evolution indicate that, Ring fault depression, source, near more coarse segmentation fault depression of shallow and deep lake slope system in the Denglouku1-2section, to basin, the main ring far, fine source unified large depression shallow gentle slope system in the Denglouku3-4section, sedimentation center of Gulong area Denglouku group is limited distribution, presents a plurality of sedimentation center, water distribution has limitations, dispersion, migration and the characteristics of shallow water.From the conditions of gas source of the Gulong area Denglouku formation, gas source rocks of the rift period, Natural gas generation strength greater than20×108m3/km2regions were sporadic shape distribution, Natural gas genereted the total volume of14.19×1012m3in faulted period of Gulong area. Denglouku1-2section total volume of Natural gas generation is the biggest, Denglouku2section Natural gas genereted is3.48trillion; and Denglouku3section Natural gas genereted is1.57trillion, they Occupy80%volume of the Gulong area Denglouku formation. From the reservoir conditions, Gulong area Denglouku formation reservoir are well developed not only including alluvial fan, braided river, meandering river, fan delta plain, terminal fan sedimentary facies formed the "sand deposited mud", also developed a flood plain, delta front, flood plain, Binhu, shallow lake sedimentary formation in the "mud pack sand" deposition. From the cover layer conditions, Denglouku2section cover layer with a good sealing ability, good sealing ability of cap rock accounted for the entire region2/3. From migration conditions, Gulong area favourable area of oil and gas are developed in the South of Gulong fault depression and Xingshenl well nearby in the north of Daqing fault zone, mainly developed source fault and the source sand body migration system. Through the accumulation conditions and distribution of gas reservoirs of Gulong area, main of the natural gas reservoir controlling factors:rift period and Denglouku2section effective gas source rock distribution control of gas distribution; Denglouku2section effective gas source rock range control typical tight sandstone gas reservoirs distribution; channel source faults distribution of natural migration and accumulation has a control function. According to natural gas reservoir forming favorable target area classification criterion, Gulong area Denglouku1-2section natural gas reservoir forming main favorable zone is Ⅱ2and Ⅲ,12is followed; other types of favorable Zone is limted, Denglouku3-4section favorable zone is Ⅱ2, class Ⅲ is followed.