Characteristics of clasolite reservoir at Wangjiang—Qianshan basin

Clasolite reservoirs are deposited widely in all strata at Wangjiang-Qianshan basin,of which the clasolite of marine facies are occurred at the bottom of each cycles,resulting from frequent transgressions and regressions.In terms of granularity,rock types are mainly sandstone,including coarse sandstone,medium sandstone,fine sandstone and siltstone,with scarcely conglomerates.Statistics show that the sandstones are medium-well sorted and sub-prism as the main rounding style.In terms of chemical composition, rock types mainly include lithic sandstone,sub-feldspar lithic sandstone and a few of quartz sandstone,with little pelitic matrix.The diagenetie stages of clasolite reservoir di- agenetic stages can be classified into early diagenetic phase, late diagenetic phase and epidiagenetic phase.The physical properties of clasolite reservoir are characterized by low po- rosity—low permeability and extremely low porosity—extremely low permeability.The storage and preservation capability of reservoirs are ordered from good to poor as fol- lows:Paleogene(E),Fentou Group (S2f),Longtan Group (P31),Huangmaqing Group(T2h),Zhongshan Group(J1z). Qingshui Group (S1q),Gaojiabian Group(S1g),Wutong Group(D3C1w) and Zhouchongcun Group(T2z).