致密油底水油藏水平井开发及管理实践

Development and management practice of horizontal wells in tight bottom water reservoir

本文以安塞油田沿19井区自2012年以长81致密油底水油藏勘探开发及管理实践为例,阐述了该井区地质特征、勘探开发历程、遇到的实际问题及开发瓶颈;通过近几年“安塞下面找安塞”,对安塞油田三叠系延长组油层的重新认识,致密油是油田勘探增储的重点及难点,开展了不同类型油藏水平井体积压裂攻关试验;沿19井区是底水较发育的致密油藏,既具有致密油藏特征,又具有底水油藏特征,在开发实践中两者均须兼顾,找到两者的结合点才是开发此类油藏最佳途径,因此围绕体积改造原则,在井区地质差异性研究的基础上,开展裂缝间距、导流能力、裂缝形态等压裂关键参数的优化,并结合改造需求,针对性设计压裂施工参数;通过实施差异化改造思路、精细化单井设计、精准化技术指导、严密组织实施,2019-2021年在该井区实施4口预探水平井,初期平均单井日产油3.94 t,取得了较好的开发效果,为今后同类型油藏的有效开发提供借鉴和思路。

Taking the exploration and development and management practice of Chang 81tight bottom water reservoir in Yan 19 well area since 2012 as an example, this paper describes the geological characteristics, exploration and development history, practical problems and development bottleneck of this well area. Through "looking for Ansai under Ansai district" in recent years, the paper re-understands the Triassic Yanchang formation oil layer in Ansai oilfield. The tight oil is the key and difficult point of oilfield exploration and reserve increase. We have carried out the key test of horizontal well volume fracturing in different reservoirs. Yan 19 well area is a well developed tight reservoir with bottom water, which has the characteristics of both tight reservoir and bottom water reservoir. In development practice, both of them must be considered. The best way to develop this kind of reservoir is to find the combination point of them, based on the principle of volume reformation and the study of geological difference in well area, the key parameters of fracturing, such as fracture spacing, conductivity and fracture morphology, are optimized. And design the fracturing construction parameters according to the transformation requirements. Through the implementation of the idea of differential transformation, fine single well design, precise technical guidance and strict organization and implementation, from 2019 to 2021, four pre-exploration horizontal wells will be implemented, with an average daily oil production of 3.94 t per well at the initial stage. Good development results have been obtained, which can be used for reference and ideas for the effective development of similar reservoirs in the future.