基于多元回归的超短半径水平井累积产油预测方法

随着油田的持续开发和老油区作业频繁等原因使井况日趋恶化,加上油藏的非均质性,严重影响油田采收率的提高.如在开发区内补打更新井、加密井,其建井周期长、成本高.在套管内侧钻中短半径水平井,不但可以节约钻井成本,而且还可以增大油层裸露面积,提高采收率和经济效益.但若准确选择有利的侧钻井位,需要首先建立累积产油量与侧钻井相关参数的关系.根据建立的数值模拟概念模型和确定的水平井开采方案,用正交设计对有效厚度、无因次距顶高度、油水井距、平均渗透率、平均剩余油饱和度、水平井开采阶段完善程度等6项因素进行了组合,并计算了25个数值模拟方案.利用多元回归,从模拟计算结果得到计算注水正韵律油层10年累积产油量的多元回归公式,可作为下步优选侧钻井位的依据.

The Prediction Method Based on Multiple Regression for the Cumulative Oil Production of Ultra-Short Radius Horizontal Wells

With the continuous development and the frequent operation for old oil region,the situation of wells is deteriorating,coupled with reservoir heterogeneity,these factors seriously influence the improvement of oil recovery.If we drill some update wells or infill wells complementally,the period of well construction is long and the cost is high.However,if we side-track medium or short radius horizontal well inside the case,it can not only save the cost of drilling,but also increase the exposed area of the reservoir,enhanced oil recovery and economic benefits.In order to choose favorable side-track position exactly,firstly we need to establish the relationship between the cumulative oil production and the relevant parameters of side-tracking.This paper based on the conceptual model of numerical simulation and the determined production programs of horizontal wells,then the effective thickness,the dimensionless height from the top,the distance between ail wells and water wells,the average permeability,the average residual oil saturation and the degree of perfection in the recovery process of horizontal wells etc.six factors were combined by orthogonal design,finally calculated 25 numerical simulation programs.By multiple regr ssion,we can obtain the multiple regression formula for calculating 10-year cumulative oil production of injected positive rhythm reservoir,which can be used as a basis of the following optimization of side-track position.