Research And Application On Vadose Geological Characteristic Of Daqing Oilfield Reservoir

The combined water cut in Daqing Oil Field is 89.6% at present, the percentage of water of the main pay zones are higher. Contact relationship of oil and water is very complex, dimensional distribution of remaining oil is scattered. So the usual opinion of sedimentary facies can't make distribution of oil and water clear.Combined with the sedimentary characteristic of river-delta reservoir, the study of flow unit is carried out in Daqing oilfield, it develops the parameter selection study of classification method of genetic unit framework, five methods has been used in the selection test to determined the best parameter groups of flow unit. Owing to the test results, the classification method of parameter main factors of flow units is the best classification parameter groups. The study of flow unit offers oil field development new thoughts and ways. Based on the study of fine geological research and flow unit, it puts forwards the vadose geological model.Vadose geological model: a container which researches lithology and physics quality of rocks which effect the flow of liquids and describes internal relationships of ancient current, vadose speed, flooded and depositional feature.how to distinguish ancient current microfacies: Above water parts :The river channel sand in flooded plane facies, distributary plane facies is separated to 4 major parts: the main tributaries, the secondary current, the sluggish current, the crossing current.The interchannel sand is separated to the main flow belt, the secondary flow belt, the sluggish flow belt, the crossing flow belt .Under water parts: distributary river channel sand under water in inner front delta is also separated into 4 parts, that is the main tributaries, the secondary current, the sluggish current, the crossing current. Sheet sand is separated into 4 parts: the main flow belt, the secondary flow belt, the sluggish flow belt, the crossing flow belt.Main tributaries: usually it lies in middle parts of river channel sand area, the high speed belt and high vadose rate belt of ancient current.Secondary current: the flow speed of ancient is lower than main current and faster than sluggish current.Sluggish current: transitional boundary of river channel and thin sand section or transitional boundary of river channel sand and inter-channel clay. Speed is lower or even keeps static. It is low permeability belt.Crossing current vertical to main tributaries .the vadose rate fall down from middle totwo sides.Main flow belt: lay in thin sand section the ancient current speed here is the highest.Secondary flow belt: lay in thin sand belt the speed of ancient current here is lower than main flow belt but higher than sluggish belt.Sluggish flow belttransitional zone of thin sand section and inter-channel clay. Speed of ancient current here is lower or even keeps static and it is low permeability beltCrossing flow belt vertical to main flow belt .the rate vadose falls down from middle to two sidesThe significance of division of ancient current: Main tributaries, secondary current, sluggish current and crossing current determin physics quality of rock and lithology which effect the flow of liquid; nder a certain well of pattern, water, gas and oil run along main current secondary current, sluggish current with different flow number and flow rate; Main current, secondary current, sluggish current, crossing current shows container rock has the characteristic of unhomogeneous. And this characteristic is closely related to the distributing of remaining oil underground;After the study of main current, secondary current, sluggish current and crossing current we can carryout structure adjustment of injection and liquid production, control the rising speed of water cut, so we can make sure container rock supply more oil and improve the economic effect; The theory of flow development provides us the direction of performance analysis; The actual capacity of the oil well on main current is higher than others; The contradiction between strata is oil wells go through different stratum they lay on different ancient current or same current in different depositional environment or both different; the plane contradiction: main current, secondary current, sluggish current and crossing current determined physics quality of rock and lothology which effect the flow of liquid. K, 4> is vector not just a numerical value. Daqing oilfield have the characteristic of plain unhomogeneous not only because the numerical value of K $ changes but because vector changes. The direction of K is plane contradiction; Settled production and control water content: in same sedimentation unit we should control injection of water to main current while inject more water to secondary current and sluggish current.Whether the development effect is good or bad are mainly determined by the direction of ancient current. The paper study the distribution rule of ancient current and description the reservoir. It classifies the ancient current in sedimentary microfacies (single sandbody), improves the relationship of injection and production well in ancient current, puts forwards measurement, and improves development effects. The results apply to the field development, and the oil field...