海上油田薄互层发育储层压裂充填工艺技术研究

渤海海上油田明化镇组、馆陶组是以河流相为主的沉积体系,含油目的层段跨度约300 m,属于典型的薄互层发育储层。由于储层胶结差、层间非均质强、泥质含量高、原油黏度大等原因,多采用压裂充填完井方式生产。受完井作业成本限制、平台数量有限等因素影响,近年来海上完井呈现出防砂井段长、井斜角度大、射孔簇数多等特点,导致海上压裂充填裂缝形态复杂,加砂困难,提前脱砂比例高达15%,压裂充填效果不理想。本论文通过对地层滤失类型、压裂液效率、净压力、地层砂比等施工参数进行分析研究,明确地层滤失类型是影响压裂充填效果的关键因素,并形成了一套根据储层漏失类型对压裂充填工艺参数进行优化调整的设计方法。此设计方法可有效提高海上压裂充填成功率,现场应用表明提前脱砂比例下降至1%,可为其他油田压裂充填作业提供指导与借鉴意义。同时结合国外压裂充填技术现状,推荐海上压裂充填井进行裂缝监测,以指导压裂充填工艺优化,提高压裂充填效果。

Study and application of frac-pack technology in thin interbedded reservoirs in offshore oilfield

The Minghuazhen formation and Guantao formation of Bohai offshore oilfield are sedimentary systems dominated by river facies.The oil-bearing target interval spans more than 300 meters and belongs to thin interbedded reservoirs.Due to the reservoir characteristics such as poor cementation,high heterogeneity,high shale content,and high viscosity of the crude oil,it is often produced by frac-pack completion.Affected by factors such as the cost of completion operations and the limited number of platforms,in recent years,offshore completions have been characterized by long sand control wells,large inclination angles,and large number of perforation clusters.So the proportion of early screen-out is as high as 15%.Through the analysis of formation filtration type,fracturing fluid efficiency,net pressure,formation sand ratio and other construction parameters,it is clear that formation filtration type is the key factor affecting frac-pack effect,and a set of design methods according to reservoir filtration type to optimize frac-pack parameters are formed.This design method can effectively improve the success rate of frac-pack operation.Field application shows that the proportion of early screen-out is reduced to 1%.Considering the present situation of frac-pack technology abroad,it is recommended to monitor fractures in offshore frac-pack operations to guide offshore frac-pack optimization.