Nowadays, in China nearly all the produced oil-fields have already entered the period of high water cut, and the six oil-fields of Daqing and Shengli oil-field etc. have exceeded eighty percent water cut. Beierdong Block has produced for nearly fifty years, and now it has entered into the descending output stage and its water cut has reached more than ninety percent. With oil field infill gradually in Beierdong Block, each series of well network production target getting worse gradually, intersecting with old well network stratigraphic position, and polymer flooding well network use part of water driving old well, making the contradictory of layer well network concatenate and dynamic regulation intensely. Especially as the block of infill adjustment proceeded earliest, acquired better developed effect at the beginning of regulation, but with the deep development of the field, after the phase of extra high water cut, exposed gradually some problems such as the perforating interval is too long, the contradiction of interlamination is obvious, the high water cut of multilayer is serious, bringing huge difficulty to dynamic analysis regulation.Basing on layer recombination and using the reservoir simulation method, the paper studied the distribution of remaining oil, forecast variation regular pattern of development indexes. By contrasting these indexes, the paper estimates the effect of layer recombination. It has important significance for the next period’s development.

For an oil well, when its water cut rises to a certain high point, the economical input gets equal to the economical output, at this time, this oil well produces nothing economically. If the water cut exceeds this point, then this oil well produces a deficit. This point is the so-called economical terminal water cut. Based on the theory of break even analysis, this paper determined the components of the cost of an oil well, analyzed the factors affecting the economical terminal water cut of oil well and developed a mathematical model to predict the value of economical terminal water cut.