Rational Water Injection Intensity In High Water Cut Stage Of East Of South8Region Block

Oilfield development is a process of energy consumption actually. Formation energygradually decreases as the extension of development time. Injecting water is one of the mostimportant measures to supply energy and to ensure that the field keeps a high and stable yield.And the determination of reasonable water injection strength is the foundation to realizestabilizing oil production and controlling water cut. Therefore, it is extremely necessary todevelop a quantitative optimization method about reasonably allocating water injection ratewhich can be generally used and the oil production can also be guaranteed.Reasonable water injection and injection intensity of the whole block, groups and everyinjection interval have been determined by applying reservoir engineering methods towardsthe east south-eight block of Sa-Nan oilfield in this paper. First of all, reasonable liquidproducing capacity, injection-production ratio, water injection have been determined by usingthe methods of waterflooding characteristic curve and linear regression, combined with thedynamic and static data. Then, the reasonable split coefficient of all groups has beencalculated by the BP neural network method. The oil saturation, water cut, rate of water cutincrease, net thickness of injectors, conductive thickness and connecting direction numbers ofthe well groups have been taken as influencing factors. So water injection of the whole blockcan be split into each well group. And based on this, the influence on the water injection rateof all injection intervals by thickness, conductive thickness, average permeability, connectingdirection numbers and average oil saturation have been considered. The group injection rate isrationally allocated into all water injection intervals by using weight split coefficient. Waterinjection rate and injection intensity of all intervals will be calculated.The development effect aiming at the target blocks in2011and2012has been forecastedby applying numerical simulation software. On the premise of the whole water injection rateis220.99×10~4m~3（in2011）and228.26×10~4m~3（in2012）, and the injection rate of all intervalsis the calculated value in this paper. Predicted results show that, the comprehensive water cuthas decreased by0.20and0.26%respectively in the injection optimization scheme of2011and2012; the oil production has increased by0.19×10~4t and0.30×10~4t, compared with theresults without adjustment. Reasonable water injection strength, therefore, is beneficial tocontrol water cut rising rate, and improve the development effect.