Influence of Well Pattern Type on Remaining Oil Saturation and Distribution after Development

Abstract

The reservoir heterogeneity of Q oilfield is more severe after long-term water injection development, and water flooding is ineffective. In this study, the combined technologies of profile control, profile control and flooding, and oil displacement were proposed to improve the water flooding development effect. Then, the influence of the well pattern type on the remaining oil distribution, after development, was investigated. Cr3+ polymer gel, which has an optimal gel-forming effect, was used as the profile control agent. Moreover, the entire molecular structure had a “network” structure. A polymer microsphere was used as a profile control and flooding agent, which showed a good hydration expansion capacity. The initial particle size distribution had a range of 7.2–11.1 μm, and the expansion multiple was 4.35–5.64 after 7 days. The surfactant was an oil displacement agent, and the interfacial tension was approximately 5.08–5.11 × 10−1 mN/m. After the “profile control + profile control and flooding + oil displacement” technologies, the horizontal well pattern had a large seepage area. The effect of expanding the sweep volume was significant, and the remaining oil saturation in each stage was lower than those of the vertical and horizontal–vertical combined well patterns. Compared with the first water flooding stage, the remaining oil saturation values of the three permeable layers changed by 11.9%, 17.3%, and 19.8% during the subsequent water flooding stage.

Investigation of the Flow Intensity in an Inverted Seven-Point Well Pattern and Its Influence on the EOR Efficiency of S/P Flooding

“…Therefore, it is necessary to explore the adaptability of S/P flooding in the inverted seven-spot well pattern. For that, clarifying the influence of flow field intensity on oil displacement effect and remaining oil distribution becomes a particularly important issue [28]. The flow intensity directly determines the swept volume and strength of the injected fluid, which also affects the properties of the polymer and physical parameters such as the relative permeability of the reservoir.…”