关键词: 致密油, 可采储量, 评估方法, 产量, 物质平衡时间法, 类比法

Abstract: The production dynamic characteristic analysis and recoverable reserve estimation of tight oil is one of the difficulties in current reserve evaluation. Different from conventional oil reservoirs, the production of tight oil well is influenced by dual factors including reservoir quality and large-scale fracturing engineering technology. The larger the fracturing engineering strength is, the higher the production of tight oil reservoir will be. Under the same fracturing engineering technical condition, the better the quality of tight oil reservoir is, the higher the oil production will be. Therefore, tight oil horizons are still required to be divided into effective horizon and ineffective horizon during reserve evaluation. The production dynamics of single tight oil well has "dual-stage" characteristics. The initial stage shows high production and large decline rate, while the mid-late stage presents low production and slow decline rate. In the early production stage, a high uncertainty exists in the use of conventional production decline curve method to estimate recoverable reserves. Based on the production dynamic characteristic analysis of tight oil, two methods of recoverable reserve estimation are proposed in the early production stage. One is the material balance time method, mainly applied for estimating the recoverable reserves of a single well with boundary flow characteristics, thus providing more objective estimation results; the other is the production analogy method, primarily used to estimate the recoverable reserves of short-term test well. Thus, a set of objective simple methods are put forward to estimate the recoverable reserves of tight oil single well.

Key words: tight oil, recoverable reserve, estimation method, production, material balance time method, analogy