珠江口盆地白云凹陷中新统珠江组深水灰岩沉积-成岩作用特征

he deep-water limestones can produce a large number of oil and gas. The deep-water limestones of Zhujiang Formation were deposited by deep-water tractive currents (such as internal tides, internal waves) and the research on the deep-water limestones and tractive currents is of great geological significance. Using impregnating thin sections, scanning electron microscopy and X-ray diffraction, a detailed study of the diagenetic characteristics was made on the deep-water limestones of Zhujiang Formation. It's believed that all the significant diagenetic changes were destructive that occluded the pores. The mechanical compaction, pressure solution, filling and cementation of secondary minerals in burial processes were major factors causing the loss of the primary porosity. Though the limestones were buried in the depth of 2920-3220m, they only suffered from the mechanical compaction and pressure solution equal to about 1-1.5km burial process because they went into overpressure cycles early and lacked later tectonic fracturing, and eventually became potential pore-dominated reservoirs with medium-high porosity and low - very low permeability.