Studies On The Fluids Distribution Of Ordovician Karst Reservoir In Block 8 & 10 Of Tahe Oil Field

With the combination of microcosmic and macroscopical, this paper studied the relation of the oil-gas distribution and the oil-water in fracture-cavity unit , and discussed the types of water. Under the restriction of the fluid distribution in single well section, and based on the oil field water geochemical behavior. Based on the study of the palaeo-geomorphology restoration of early Hercynian, karstification mechanism, reservoir character, fracture-cavity unit and connectivity analyse of predecessor. Combinated the date of core, logging, testing, oil field water geochemistry and exploitation dynamic data effective. Based on the study fruit mentioned above, used the study production of predecessor on the basin structure evolvement, source rock, the history of oil and gas migration, the fluid evolution of diagenesis, hydrodynamic force of sedimentary basin and so on, tried to analyze the cause of the fluid, and study the fluids distribution and controlling factor of Ordovician karst reservoir in Block 8 & 10 of Tahe Oil Field. There is the study production and recognition as follows:(1) This paper combinated the date of core, logging, testing, set up three type interpretation model for five type carbonatite reservoir, used CRA program to identify the fluid type of porous reservoir, cave reservoir filled with grit and mud, cave reservoir unfilled effectually, the coincidence rate is 84.4 percent, 85.7 percent, 86 percent of each other, and acquire satisfactory result.(2) In Ordovician of region of interest, there are three type formation water, atmospheric water from percolating endocentric flow in karst stage, sedimentary buried water from mudstone compact eccentric flow in later stage, and the mixture above-mentioned. In addition, there are three zone and one low value area in vertical of formation water chemical character in Ordovician region of interest, atmospheric water percolating desalinate area, palaeo evaporate- enrich area, mudstone compact sluicing and clay mineral dewater desalinate area, and a low value area about 5600 meters below which affected by atmospheric water in early Hercynian. In horizon there are also three area, atmospheric water percolating desalinate affect area, eccentric flow and endocentric flow cross flow dewatering area, mudstone compact sluicing and clay mineral dewater affect area.(3) Combinate karst Fracture cave geologic characteristic, oil and water production performance characteristic, geochemistry date of fluid, research for the relationship of oil and water in single well fracture-cavity unit and multiwell fracture-cavity unit effective, point out the relationship of oil and water in single well Fracture-cavity unit and multiwell fracture-cavity unit is versatile, the water genetic types of them are different, the water genetic types of single well fracture-cavity unit are percolating atmospheric water in karst stage remain, multiwell fracture-cavity unit are always fill up with oil, the water genetic types are main sedimentary buried water from mudstone compact eccentric flow in later stage, or the mixture them. So, the water genetic types of fracture-cavity unit have very important predictive significance in oil-gas exploration.(4) The distribution of different fluid types in different cave zones and cave cycles are different in horizon and portrait. The oil zone are main distributed in the caves of karst cycle I, water zone are main distributed in the caves of karst cycle II and karst cycle III; oil zone are main distributed in the 0～200 meter to plane of unconformity of early Hercynian, water zone are distributed in each depth, but the depth to early Hercynian unconformity is more deep, the probability of drill water zone is bigger. The distribution in horizon of cave reservoir fluid type in different karst cycle has certain differences, but the overall show that far away from the the axis zone of Akekule Uplift to the southern and southwest direction, the probability of drill water zone is rise.(5) There is not unified oil aqueous interface in Ordovician karst fracture-cavity reservoir in the Block 8 & 10 Tahe Oil Field, the control factor of oil and water distribution are complex in . Under the structure of Akekule Uplift, the dynamical and hydrochemical characteristic control the oil and water distribution in all, and the north-south fracture, the oil and gas migration in late Hercynian and Yanshanian, the development state of karst cave system control the oil and water distribution in different place, revealed the oil and water distribution of Ordovician in region of interest reasonably:①In the northwest and Block 8 & 10 of Tahe Oil Field , "one master and three minor fracture" which through south-north developed control the oil and water distribution. There are oil well centralize distribution along and near three fracture belt, and far away from the fracture belt and between the fracture belt are oil field water centralize distribution area.②In the south of Block 8 & 10 Tahe Oil Field , the Block 11, the history oil and gas migration in late Hercynian and the inadequacy migration in Yanshanian control the oil and water distribution. Near the line of Yanshanian oil-gas migration west, there is a oil field water concentrate area, it is may be controlled by "tail end influence" that caused by the main stage of oil-gas centralize from south to north in late Hercynian. Near the line of Yanshanian oil-gas migration east, there is a oil concentrate area, it is may be controlled by "front end influence" that caused by the main stage of oil-gas centralize from east to west in Yanshanian. ?Karst fracture-cavity unit development state control the oil and water distribution further. Insulated and small single well fracture-cavity unit maintained the atmospheric water percolating in karst stage, charactered by producing water, showing water well isolated distribution .full-bodied multiwell fracture-cavity unit charactered by producing oil,showing oil well concentrate distribution.