Analcite cementation facies and forming mechanism of high-quality secondary clastic rock reservoirs in western China
Sun Yushan1, Liu Xinnian2, Zhang Yanqiu1, Dong Yukai2, Xu Yanlong1
Shi Guixia3, Lin Yanbo3, Li Anqiong1
1 Research Institute of Exploration and Development,Tarim Oilfield,PetroChina,Korla 841000,Xinjiang
2 Research Institute of Exploration and Development,Xinjiang Oilfield,PetroChina,Karamay 831000,Xinjiang
3 The Fifth Oil Production Plant of Changqing Oilfield,PetroChina,Xi′an 710018,Shaanxi
In petroliferous basin,the generation of high-quality secondary clastic reservoirs are linked with calcite cementation facies; and in western China,it is also related to another cemented diagenetic facies of authigenetic zeolite,of which the high-quality secondary formed by the corroded analcite facies is closely connected with the hydrocarbon accumulation. It is showed by the examples that the diagenetic facies of analcite texture is controlled by the fan(braid river)-delta front,volcanic cinder and the alkaline condition in an eogenetic stage. The high-quality secondary clastic reservoirs were formed in stage A of middle diagenetic period. The distribution is decided by the source rocks nearby,traps and the connection of channel systems. The characters of analcites pressure resistance,erodibility(organic acid)are super to that of other authigenes minerals(cements). Therefore analcite is the ideal place for the development of induced porosity,and the ratio of emposieu to the porosity is 50％～75％. It is real and workable to prospect high-quality secondary emposieu-oriented reservoirs formed by intergranular dissolution pores in the environment of analcite distributed area.
