Genetic Model And Hydrocarbon Exploration Potential Of Mixed Sediment In Li Wan Area Of Baiyun Sag, Pea Rl River Mouth Basin

Mixed sediment of terrigenous clastic and carbonate arises general concern due to its special sedimentary mechanism and crucial theoretical and practical significance.Because of the convention, we used to do research individually which make mixed sediment infrequently seen. Nowadays, there is no related study about mixed sediment on petrology scale in this area. Combining with regional geological information, well logging data, seismic data as well as description of well cores, the paper recounts sedimentary environment, characteristic, source significance, genetic type and its model, and the oil exploration prospect of mixed sediment. During late Oligocene, study area belonged to transitional environment with relatively stable tectonic action while Baiyun sag still was the center of sedimentation and subsidence. So it forms a mixed sedimentary environment which give priority to terrigenous clastic. According to research scale, mixed sediment performed Hunji rock in the micro level, mostly marlstone. In the macroscopic level, Hunji sequence consisted of interbedding between siltstone and limestone, limestone and marlstone as well as siltstone marlstone and limestone. In the mostly siliciclastic sedimentary environment, siliciclastic origin from Zhujiang and carbonate have two source:inorganic and organic. Besides, the inorganic source from extrabasin is major and the other from intrabasin is secondary. Speaking of the genetic type, the study area have facies mixing, punctuated mixing and in situ mixing contemporarily while its importance reducing successively. Based of the abovementioned opinions, the author come up with the genetic model.By contrast to its oil significance of mature area of mixed sediment,the mixed sediment have many oil and gas exploration potential accompany with shallow continental shelf delta and deep-water fan reservior producing multi-reservior systems which maybe offer new exploration idea for Baiyun sag even Pearl River Mouth Basin.