TTHW-趾端至跟部驱油法进行重力稳定注水开发的实验室研究——Hele Shaw模型试验结果

LABORATORY RESEARCH ON TOE-TO-HEEL WATERFLOODING BY USING HELE SHAW MODEL

论述了一种新颖的、重力稳定的注水开发过程——趾端至跟部注水开发（TTHw）的二维Hele—Shaw模型实验研究结果。该技术以直井作为注水井，水平井为生产井，采用井位交错排列的线性注水方式。水平井的趾端靠近直井，水平段位于油层上部，直井在油层下部处射孔，形成一种短距离驱油过程。油水重力分异作用使注入水向下流动，而水平井作为接收器引导水向上流动；两种力共同作用的结果是在跟部见水，然后是驱油前缘沿水平井段向前流动，从而使水流波及大部分生产层段。选用5种不同粘度的原油（10—12000mPa·s）进行实验，注水速率为2．5—320ml／h。总体来说，对中等粘度的稠油，传统水驱和TTHW水驱见水时的采收率相差不多，但水淹时，TTHW的最终采收率要高得多。

This paper presents the results of the laboratory investigations leading to development of a novel, radically different waterflooding process, which is gravity stable. The new process is called Toe-To-Heel waterflooding (TTHW). The technique uses vertical wells as water injection well, horizontal wells as production well. Normally, the system uses a staggered line drive configuration in which the toe of the horizontal well is close to vertical wells. The horizontal section of horizontal wells is located at the top of oil formation while the vertical wells are perforated on the lower section of the layer. By using the proposed configuration, a short-distance oil displacement process is achieved. The water/oil gravitational differentiation causes the induced water downflow, moreover, the horizontal well as a sink causes water upward flow. The combined action of two forces leads to an advancement of water through almost all pay section. Five different oils (with viscosity in the range 10 mPa.s to 12000 mPa.s) were carried out experiments, the water injection rates of 2.5 ml/h to 320 ml/h were obtained. A comparison between conventional waterflooding and TTHW showed that the recovery ratios of the heavy oils with moderate viscosities were similar at water-break-through, but at the water-out, the ultimate oil recoveries were much higher for TTHW.