凝胶调剖剂长距离动态成胶规律模拟评价方法研究

Study on simulation and evaluation method for long distance dynamic gelation law of gel profile control agent

为了解决凝胶调剖剂在油藏深部动态成胶性能无法量化评价的问题,开展了长距离动态成胶规律模拟评价方法研究。将凝胶调剖剂注入1020cm长岩心模型系统,通过取样进行聚合物质量浓度和相对分子质量、交联剂质量浓度测试,评价剪切、稀释吸附作用对凝胶调剖剂成胶性能的影响;通过岩心取样电镜观察和压力多布点监控,评价凝胶调剖剂的微观成胶性能和宏观封堵性能。实验结果表明,在凝胶调剖剂连续驱替条件下,聚合物和交联剂注入前缘稀释吸附比例大,后续注入平衡速度快,交联剂和聚合物具有较强的结合性;岩心距入口680cm处有较强的网状成胶特征,距入口860cm处仍能观察到凝胶调剖剂成胶结构,能够满足地层深部封堵的要求。该项技术为凝胶调剖剂筛选评价、调剖方案参数确定和凝胶调剖技术的推广应用提供了理论支撑。

In order to solve the problem that the gel profile control agent can’t be quantitatively evaluated for its dynamic gelation performance in deep reservoirs,the simulation and evaluation method for long distance dynamic gelation law were developed.The gel profile control agent was injected into the core model system with the length of 1020 cm,and the mass concentration and relative molecular mass of the polymer,the mass concentration of crosslinking agent were tested by sampling to evaluate the effect of shear and dilution adsorption on the gelation performance of gel profile control agent.Through the electron microscope observation of core sample and pressure multi-point monitoring,the micro-gelation and macro-plugging properties of gel profile control agents were evaluated.The experimental results showed that the polymer and crosslinking agent had a large proportion of dilution and adsorption at the front edge under the continuous displacement of gel profile control agent,and the equilibrium speed of following injection was fast,resulting in strong binding properties between crosslinking agent and polymer.The core has strong network gelation characteristics at 680 cm far from the entrance,and the gelation structure of profile control agent at the distance of 860 cm from entrance can still be observed,which can meet the plugging requirement at deep depth.The technology provides the theoretical support for the selection and evaluation of gel profile control agents,the determination of profile control parameters and the popularization and application of gel profile control technology.