Intraplatform Bank Reservoir Characteristics and Controlling Factor of Callovian-Oxflordian in Turkmenistan

Intraplatform bank reservoir is one of the most important reef bank reservoir types in carbonate rocks. Based on thin section, experimental data, well logging and seismic data, the Callovian-Oxfordian carbonate reservoir in the western region of the right bank of the Amu Darya Basin in Turkmenistan is comprehensively evaluated. The results show that the reservoir lithology is mainly composed of granular limestone, granular micritic limestone and micritic granular limestone, which is a porous reservoir with low porosity and low permeability. The morphological characteristics and distribution range of the reservoir in the intraplatform bank are affected by the paleostructure and high frequency sea level cycle. In the early diagenetic stage, the limestone particles were affected by the leaching of atmospheric fresh water, and the selective dissolution formed the mold pores and the intergranular dissolved pores in the syngenetic - quasi-syngenetic stage. In the middle diagenetic stage, limestone particles are dissolved by acid fluid, forming intergranular pores and intergranular pores. The two phases of dissolution effectively improved the reservoir capacity of the intraplatform bank and made it become a sweet spot in the west of the right bank of the Amu Darya Basin.