体膨颗粒非均质裂缝封堵效果与改善

体膨颗粒已广泛应用于高温高盐裂缝性油藏控水,且其封堵效果与颗粒尺寸、颗粒分流率密切相关。采用人工造缝的碳酸盐岩露头岩芯组模拟非均质裂缝储层,在130℃、19.8×10⁴ mg/L条件下进行体膨颗粒裂缝堵水效果评价与改善实验。结果发现,粒径过大、窄裂缝分流率过高的体膨颗粒可能加剧裂缝产液的非均质性,而粒径过小的体膨颗粒不适用于出水强度较高的储层。将可固化覆膜颗粒与体膨颗粒联用,前者在油藏高温下固化于宽裂缝内形成不可动筛网段塞,令后者从宽裂缝中突破的压力梯度显著高于窄裂缝,进而可有效改善非均质裂缝的产液剖面,并消除因体膨颗粒尺寸、分流率不当对裂缝封堵带来的负面影响。研究有助于进一步认识体膨颗粒的非均质裂缝封堵行为,对提高裂缝油藏的控水效果具有积极意义。

Water Plugging Performance and Improvement of Preformed Particle Gel in Heterogenous Fractures

Preformed particle gels (PPGs) have been widely used to control water production in high-temperature and high-salinity fractured reservoirs and their plugging effect is closely related to particle size and diversion. In this paper, carbonate outcrop cores with artificial fractures are used to simulate heterogeneous fracture reservoirs, and the water plugging evaluation and improvement experiments are carried out under the condition of 130 ℃ and 19.8begin{document}$ times $end{document}10begin{document}$ ^4 $end{document} mg/L. The results show that the oversized PPGs or the excessive PPG-diversion in low-permeability fractures may aggravate the heterogeneity of fluid production, while the undersized PPGs are not suitable for the reservoirs with high water production strength. Therefore, we propose combining the curable resin-coated particles (CRPs) with PPGs to improve the water plugging performance. The CRPs form immobile packs in high-permeability fractures at reservoir temperature, which results in the larger breakthrough pressure gradients of the PPGs in high-permeability fractures relative to that of the PPGs in low-permeability fractures. The combined CRPs and PPGs can reverse the liquid-producing profiles of the heterogeneous fractures and eliminate the negative effects of improper PPG size and diversion rate on the water plugging. This study is helpful to further understand the water-plugging behaviors of PPGs in heterogeneous fractures and has positive significance for improving the water control effect in fractured reservoirs.