Study On The Principle Of Longitudinal Water Flooding And Remaining Oil Distribution Pattern Of LD10-1 Oilfield

The development of offshore oilfields is becoming more and more important to national security and national economic development.There are rich oil and gas resources at the sea area of our country,most of which are thick-layer reservoir,and polymer flooding is a typical developing mode in early exploition of offshore oil field.Because of the large thickness in the longitudinal direction of the reservoir,the prosodic characteristics are obvious.After the long-term injection,the longitudinal flooding laws and the remaining oil distribution are complicated,Enhanced oil recovery research in such reservoirs are based on the study of longitudinal flooding rule and the remaining oil distribution pattern.Firstly,from the point of view of seepage mechanics potential,the analytical method was used to establish the model of longitudinal flooding in the high water cut stage of thick oil reservoir displacement between injecting and producing wells,and different parameters of flooding were studied.Secondly,the typical geologic characteristics of Lvda 10-1 oilfield are extracted,and six sets of mechanism models are established,and the distribution of remaining oil under different deposition conditions is calculated.Based on the analysis of the exploitation condition and numerical simulation research of Lvda 10-1 oilfield,the distribution rules of remaining oil in II and III sand groups in oilfield were analyzed,use the statistical analysis method to creatively extract the "three parameters,two models" of the remaining oil quantitative analysis and evaluation technology,and the quantitative analysis and evaluation technique were established by using statistical analysis method.From the aspects of structure,thickness,permeability,pressure and other dimensions of the two sand groups of the plane and longitudinal residual oil was characterized,targeted measures proposed tapping potential.The results show that production rate ? rhythmicity ? the ratio of longitudinal permeability to horizontal permeability and the difference of oil density and water density are the main factors that affact the distribution of oil-water in the longitudinal direction.Sedimentary facies,well pattern,closed boundary and physical difference are the main factors that affact the horizontal remaining oil distribution.In the longitudinal distribution pattern of remaining oil,II sand group was mainly divided into four types: rhythm difference multi-stage water-flooded type,hyper-infiltration some layer severe flooding type,longitudinal sandwich blocking sub-bottom flooding type,sand body discontinuous longitudinal shielding and multi-stage flooding type.III sand group was dominated by thick layer gravity dominated bottom flooding type,rhythm difference multi-stage water-flooded type,sand body discontinuous longitudinal shield multi-stage water flooding type.It is suggested to adjust the flow field,streamline and change the direction of the flow,at the same time,with the closure,control the flow channel,optimize the perforation,gas top drive,later drilling and other measures to improve oil recovery.