Relationship between porosity of Yingcheng sand-body migration channel and hydrocarbon injection of Dongling area, Changling Fault Depression, Songliao Basin

Hydrocarbon accumulation is a geological process. The reconstruction of reservoir porosity in a crucial period of hydrocarbon accumulation can help in quantitatively reconstructing geological conditions of that accumulation. A diagenetic sequence of the Dongling area, Changling Fault Depression was established based on a variety of technologies such as cast thin section interpretation, SEM observation, fluid inclusion analysis, mercury intrusion and petrophysical tests. Based on the timing of the diagenetic sequences of migration channel and the hydrocarbon accumulation period, the physical characteristics of a sand-body migration channel during each hydrocarbon accumulation period were restored by reservoir porosity inversion. Finally, combined with the sedimentary facies of the study area, the spatial distribution range of the advantageous hydrocarbon migration channel was clarified. The sand-body migration channel of the Yingcheng Formation in the study area mainly occurs during the A1 period of medium diagenetic stage. Compaction plays a controlling role, acid dissolution improves porosity, and cementation makes the migration channel more dense. The hydrocarbon source rocks of the Shahezi Formation generated hydrocarbon in two stages, with two hydrocarbon charges. After the oil and gas entered the Yingcheng Formation sand body, the transport performance of the sand body transport layer in the Yingcheng Formation has a significant influence. The oil and gas mainly migrated in the northwest oriented sand body with good physical properties and high connectivity, and finally accumulated in the eastern nose.