Research On Subdivision Of Layer Series Of Development And Effect Evaluation

The subdivision of layer series of development is one of major means for reservoir of interlayer heterogeneity to relieve the conflicts between layers in high water cut development period and enhance oil recovery.Variable methods have be used to establish the subdivision plan.There are many differences between offshore and onshore oilfield on the principle of series segmentation and the screening or evaluation method of evaluation index,for the difference of the development technology limited and abandoned condition offshore oilfield.A detailed study on subdivision of layer series of development in high water cut period and effect evaluation is presented in this paper.The reservoir engineering theory and numerical simulation method were used in this paper.The results of the study are shown as following:(1)The research of subdivision principle of SZ36-1 oilfield layer series and subdivision plan of typical well group were carried on.At first,we demonstrated the necessity of subdivision by analyzing oil field development contradictions.Then,we formulated the development sequence combination principle according to the particularity of oil field.The well group B15 was chosen as experimental group to take the pilot test of subdivision using numerical simulation method.We made many subdivision series simulation plans and simulating,and then get the production data of the appropriate scheme.(2)The evaluation of the development effect of subdivision of layer series was taken in the research.We also classified the thirty evaluation indexes which are chosen to evaluate into three categories.After studying the water flooding effect evaluation system,we screened out 13 evaluation indexes following the principle.These indexes can be classified into three categories: geological evaluation index,development foundation evaluation index and development dynamic evaluation index.The evaluation indexes include permeability max-min ratio,permeability variation coefficient,permeability rush coefficient,recovery percent of reserves,limited recovery factor,water cut,utilization factor of water injection,water storage rate,water drive index,increasing rate of pore volume injected,decreasing rate of injected water utilization factor,increasing rate of water cut and composite decline rate.(3)Three index analysis methods were putted forward at the ends,and we also formulated reasonable technical countermeasures to deal with development contradictions.As we all know that different indexes have different evaluating direction,so the evaluation standards and the variation characteristics are analyzed at first.Three index analysis methods were established by studying single index variation characteristics.The methods include different scheme the same index analysis method,the same index at different stages analysis method and double indexes combined analysis method.We used specific evaluation index to analysis development contradiction of SZ36-1 oilfield.At last,formulating reasonable technical measures by analyzing the characters of development contradiction after subdivision layers measures was taken.