Research On The Remaining Oil Distribution Characteristics And Horizontal Well Development Technology Of Thick Channel Sand Reserviors In The Western Block 7, Gudong Oilfield

The thick oil-bearing channel sandstone reservoir of the Upper Guantao Formation has already developed into its high water cut stage, but the recovery factor remains in a low level. Therefore, the Upper Guantao Formation of the western Block 7 of Gudong Oilfield was selected as the research target in this paper. To enhance the thick oil-bearing channel recovery, in the research work, sedimentary features and architecture elements, as well as the electric properties of intercalated bed became the recognition criteria. On the basis of detailed geologic research on the thick oil-bearing finning upward sequence segment, the thick channel oil sand body research of filtration mechanism, development characters and regular and the remaining oil pattern was done to find the rich domain and to locate the potential targets. Finally, by developing policy limitation research of horizontal well development technique for finning upward sequence channel reservoir, horizontal well development techniques were formed. In this thesis, the main results are as follows:(1) By using sedimentology theory, the correlation and subdivision research were done to the channel sand reservoir, and relationship between core and electric responses was founded from the cored well. High-resolution well log and fine interpretation technique are used to identify single well intercalated bed. Interwell intercalated bed was forecasted by rhythmic layer correlation, physical property cutoff and conditional simulation, and three-dimensional distribution of intraformational intercalated bed was described.(2) The technique set of combination geologic analysis, reservoir performance analysis, reservoir engineering, numerical simulation were formed to described remaining oil enriched area in qualitative and quantitative way.(3)Distribution characteristics of intercalated bed, degree of water sweep, length of horizontal section , producing pressure drop and liquid increase timing were studied systematically to the development effect of horizontal well. Technical support limitation of horizontal well of channel sand reservoir was confirmed.(4)On the condition of late high water cut stage and small-spaced well pattern, we extracted remaining oil successfully by horizontal wells aiming at the distribution character of remaining oil of thick oil layer. 12 horizontal wells were drilled with increment of recoverable reserves of 35×10~4t, i.e. 2.1% of the OOIP.