| Based on the understanding of regional structure and sedimentary evolution in the early stage, and making full
use of the basic data such as core, thin section, physical properties, scanning electron microscope, cathodoluminescence
and logging curves, the petrology, reservoir space type and physical properties of the thin interbedded dolomite reservoir
of tidal flat facies of Upper Submember of Leikoupo Member 4 in West Sichuan Gas Field are analyzed, and the vertical
distribution model of complete sedimentary cycle of tidal flat facies in the study area is established, and the controlling
factors of reservoir development are deeply discussed. It is shown that favorable reservoirs are mainly developed in algal
laminar dolomite, algal bonded dolomite, algal arenaceous dolomite and crystalline dolomite. The reservoir space is
mainly algal framework solution pore, intercrystalline (solution) pore and intergranular pore. The reservoir has the
characteristics of low porosity and low permeability. The microfacies of algae dolomite flat, arenaceous shoal and
dolomite flat in the intertidal zone are the material basis for the development of high-quality reservoirs. The
penecontemporaneous dissolution and the supergene dissolution are the key to control the development of a large number
of dissolution holes in Upper Submember of Leikoupo Member 4. The high parts of ancient and modern structures provide
favorable conditions for early pore preservation. |
