| Tahe Oil Field is located in the northeast of Tarim Basin; and the study area islocated in the southwest of Tahe Oil Field. The petroleum exploration work ofCretaceous strata starts later and is of lower degree of exploration, which leads to aserious shortage of physical data and test data of Cretaceous strata. There is a lack ofreference material of Cretaceous strata in the study area, which causes manydifficulties on the study area’s reservoir research.The paper’s research object is the reservoir of the Lower Cretaceous ShushanheFormation in southwest Tahe Oilfield, and the research approach of reservoir is theintegrated study of point（well data）-line-surface, geophysical exploration and geologyexplanation. In the paper, the main research contents include sedimentary facies,petrologic characteristics, reservoir physical properties and controlling factors ofreservoir development, and make an evaluation on the study area’s reservoir, as wellas present a prediction on the favorable reservoir by the application of seismicexploration and geology explanation.The Shushanhe Formation is divided into three members, which are respectivelyupper member, middle member and lower member. The stratigraphic section of uppermember is shown as sandstone and mudstone are interbedded with almost the samethickness; the middle member is presented as mudstone intercalated with sandstone;and the upper member is shown as sandstone intercalated with mudstone. Syntheticstudy on geology logging and well logging data, core data, seismic facies shows thatthe sedimentary facies of the upper member and the lower member are constituted byunderwater distributary channel and interdistributary channel of braided delta frontsub-facies, underwater distributary channel is shown as a banding distribution in theplane; while the middle member is mainly constituted by shallow lake mud oflacustrine facies and small mount of distal bar of braided delta front sub-facies, distal bar is presented as sheet distribution in the plane.The Shushanhe Formation sandstone reservoir, Southwest Tahe Oilfield,developed in the deltaic sedimentary system, which is mainly very finefeldspar-debris and debris-feldspar sandstone with medium porosity and mediumpermeability, and its component maturity is low to middle, while its structure maturityis middle to high. Based on the flake observation and physical properties data of thereservoir in Shushanhe Formation, the main reservoir space are residue originalintergranular pore, secondary dissolution intergranular pore and intragranulardissolved pore. The reservoir’s development is mainly influenced by sedimentarymicrofacies, the porosity and permeability of subaqueous distributary channelsandstone reservoir is better than distal bar sandstone reservoir. Research shows thatthe reservoir physical property is dominated by sandstone grain size, the more finesandstone content, the higher porosity is. The reservoir sandstone is now intermediatediagenetic period. The oil-bearing sandbodies distribute in the middle member andlower member of the Shushanhe formation. The middle member develop twooil-bearing sandbodies, which are K1s2-1ã€K1s2-2, and the lower member developK1s1-1oil-bearing sandbody.The reservoir’s extension space of underwater distributarychannel of the upper member and the lower member is smaller than distal bar of themiddle member, and has a banding distribution in the plane. |
