Study On Infilling Adjustment In SZ Oilfield

The SZ oilfield has entered the middle and late stages of development.Several problems gradually exposed such as severe pressure drop in the formation,prominent contradictions between injection and production,uneven water flooding conditions between and within layers,excessive single well controlled reserves,low oil recovery rate and low recovery factor.SZ oilfield is the first offshore oilfield to carry out overall infilling.At present,there is no mature infilling method that can be directly applied.In addition,due to the offshore oilfields adopts large well spacing,commingling production and short production cycle,the mature well pattern infilling mode cannot be directly applied to offshore oil fields.Therefore,it is necessary to study on the secondary well pattern infilling adjustment method of SZ oilfield according to the characteristics and development mode of SZ oilfield.In this paper,by analyzing the geological and development characteristics,the I stage of SZ oilfield is divided.Combined with the actual geological and development characteristics of the I stage of SZ oilfield,the distribution of remaining oil and streamlines are studied,and the distribution characteristics of the remaining oil in each region is obtained.Then the secondary infilling method of different regions was designed based on the partition,and the numerical simulation method was used to predict the development effect.The optimal secondary well pattern infilling method for each region was optimized.Among them,the pinch-out region adopts the method of ‘local infilling',the non-standard well row region uses the method of‘infilling in the injection well rows and local infilling between well rows',and the standard well row region employs the method of ‘infilling in the diagonal center of the wells'.Furthermore,according to the optimal infilling method of different regions,combined with the well location optimization method,the overall secondary well pattern infilling adjustment scheme for the I stage of SZ Oilfield is developed.By comparing and analyzing the development effect of the basic scheme,the initial infilling scheme and the optimized infilling scheme,it is shown that the secondary well pattern infilling optimization scheme given in this paper can effectively improve waterflooding in the target area.Moreover,it improves the matching degree of the infilling well location and reservoir development characteristics and provides technical support for the secondary well pattern infilling adjustment in the target area.