Distribution of flow characteristics and productivity evaluation of herringbone wells in bottom water reservoirs

Abstract

Abstract With the characteristics of large drainage area and low drilling cost, the herringbone wells have become an important way to increase the well production, delay the coning and ridge of bottom water and improve the development effect. Due to the complexity of the herringbone wells flow characteristics, results that exists certain gap between the current production prediction and the actual production, so it is of great significance to study the flow and productivity of herringbone wells. In this paper, taking bottom-water reservoir as the research object, considering the interference between branch wellbore and perforations, analysis the flow characteristics and the productivity sensitivity factors of herringbone wells. The results show that the transient flow time in the reservoir is short, the closer to the wellbore, the greater the pressure changes. With the increases of the branches number, branches length and branch angle, the per unit length of the wellbore radial inflow decreases, and the decrease slows down after exceeding 3 branches. In the high anisotropy reservoirs, the phase angle has greater impact on the productivity of the herringbone well when the perforation density is low, at 180°, phase angle is best; when the perforation density exceeds 16 shots/m, the increase of productivity degree decreases. This study provides important guiding significance for the actual application in oil fields to optimizing the herringbone wells shape, rational production allocation, specifying reasonable work systems and enhance oil recovery in the bottom water reservoirs.