The Study On Reservoir Facies Belt, Watered-out Mode And Distribution Of Residual Oil In Wenxi Three Area

As an important component of oil construction in Xinjiang, the Tuha oilfield had put intodevelopment in the early90’s. After about20years of exploration and development, most ofmain region have turn into medium-high water cut stage. The key problem restricting thegrowth in oil reserve and production is obvious. Because many factors have influence on thedegree of water flooding in oil layer, in fact, the scale and feature of reservoir rock is basicelement. So it is necessary to evaluate the water flooded layers in mature oil province andestablish the matching relation between reservoir facies belt and watered-out mode based onthe studies of fundamental geology and connection of static sand and dynamic waterflooding.It is the key to determine the distribution of remaining oil and point out development potentialin medium heavily waterflooded region. At the same time, it can also provide thetheoretical foundation and technical support for the stable production.The paper put forward the theory of the energy of single permeability sand layerthickness, which can be used to subdivide sedimentary micro facies, and study on the reservoirfacies belt according to the analysis of core, logging and testing oil. The error of recognitionon advantages facies belt and omissions of non-subject is avoided effectively. Proposed isthe thought that establishes seven kinds of watered out mode to evaluate distribution ofremaining oil in braid-river deltas front subfacies basede with the variation characteristics ofthe water out degree and logging response. The positive rhythm and superimposed rhythm ofthe main microfacies often form uneven distribution of water line. It is the mid-weakwateredflooded area that appeared in the top or offending layer of oil formation.Waterflooding usually performs poorly in secondary microfacies, including sand sheet anddistal sands, and form weak or non wateredflooded area in the layers. After the analysis ofused and unused remaining oil distribution, it can show the exploring potential andenrichment of remaining oil. And then the study provide the favorable target for developingthe old oilfield.