延迟硅酸凝胶堵剂研究

Preparation of Delayed Gelating Silicic Acid Sol as Water Control Agent

用模数2.8～3.2、含量40%的硅酸钠(工业水玻璃)、一种活化剂(HHJ)和2种延迟活化剂(YHJ 1和YHJ 2)在清水中配成了可延迟胶凝的硅酸溶液,根据初凝时间和凝胶相对强度(用加荷圆锥沉入法估测)评价其胶凝性能。由3.0%水玻璃、0.1%HHJ、3.0%YHJ 1和0.3%YJH 2组成的基本配方溶胶溶液的初凝时间,60℃下为15d,80℃下为94h,110℃下为6.5h。对基本配方作适当调整,在不同温度下考察了组分用量的影响,得到以下结果:水玻璃最低必需量为2.0%;胶凝温度低时可加大HHJ用量;在高温(90℃)下加大YHJ 1用量,低温(40℃)下加大YHJ 2用量,均可导致初凝时间缩短。在初始水测渗透率1.97～2.63μm2的3支洗油砂填充管中注入实验配方溶胶并在90～95℃胶凝,水测渗透率降至0.164—0.263μm3,堵塞率为90.0%～91.7%,突破压力为1.0～1.5MPa/m。表7参4。

A delayed gelating silicic acid sol is prepared from 40% aqueous solution of sodium silicate (SS) of modulus 2.8—3.2 (a commercial water glass), an activator, HHJ, and 2 retarders/activators, YHJ-1 and YHJ-2, in fresh water. Its gelation behavior is evaluated by measuring its presetting time and relative gel strength. The latter is estimated by a unique loading cone penetration method. The presetting time of a sol of basic formula (3.0%SS+0.1%HHJ+3.0%YHJ-1+0.3%YHJ-2) is of 15 days at 60℃, 94 hrs at 80℃, and 6.5 hrs at 110℃. It is shown through experiments at different temperatures on sols of properly adjusted formulas that the minimal use level of SS is of 2.0%, the use level of HHJ is to be raised at lower gelation temperatures and increasing the use level of YHJ-1 at 90℃ and of YHJ-2 at 40℃ leads to shortening the presetting time to a constant value. In the core plugging experiments performed on washed reservoir sand packs of water phase permeabilty 1.97—2.63 μm^2 with a sol gelated at 90—95℃, the permeability of these plugged sand packs is reduced to 0.164—0.263 μm^2 with plugging rate being of 90.0—91.7% and breakthrough pressure—1.0—1.5 MPa/m. The field trial use of this gelling system starts recently for profile modification in injection wells and water plugging in production wells at Henan oil fields.