Trinidad and Tobago (TT) has a rich history of crude oil production and is still one of the largest oil- and gas-producing countries in the Caribbean region. The energy sector contributes approximately 35% of GDP to its economy; however, economic headwinds due to steadily decreasing oil production, low commodity prices and increased competition worldwide have highlighted the need for more economical methods of enhanced oil recovery (EOR) techniques. Although the use of low salinity polymer flooding for EOR has had success in other countries, critical information relating associated flooding system parameters such as soil type, additive type, adsorption characteristics, rheological (flow) characteristics, pH and salinity is not available and is critical if this type of EOR is to be implemented in TT. The nature and inter-relationship of these parameters are unique to a particular reservoir, and studies in this regard will provide key input data for simulations to produce near realistic projections of this EOR strategy. These projections can be used to evaluate the usefulness of a low salinity polymer flooding in TT and guide for the proper implementation of the strategy. The EOR 33 wells located in the lower Forest sands in Southern Trinidad was selected for study as they satisfied the screening criteria. Laboratory studies of the adsorption of xanthan gum concentrations of 0 to 4000 ppm in combination with NaCl solutions (0–40,000 ppm) onto gravel packed sand found that the mixture of 1000 ppm polymer containing 1000 ppm NaCl exhibited the lowest adsorption capacity. The Langmuir coefficients were derived for each salinity, and together with results from the viscosity studies were inputted within the simulation models. Simulations of a sector of the EOR 33 projected that the highest oil recovery occurred using NaCl < 2000 ppm was 11% greater than water flood. A combination of brine (NaCl < 2000 ppm) with gel technology (1000 ppm polymer) produced the highest oil recovery factor (54%), almost twice that of water flooding, the highest average reservoir pressure and lowest water cut value. The improved performance characteristics observed using low salinity water flood with xanthan gum gel for injection can be associated with improved displacement efficiency and improved the sweep efficiency suggesting the strategy to be a technically feasible option for the EOR well in Trinidad.

中文翻译：

---

特立尼达和多巴哥采用聚合物凝胶处理的低盐度水驱评价

特立尼达和多巴哥（TT）拥有丰富的原油生产历史，仍然是加勒比地区最大的石油和天然气生产国之一。能源部门为其经济贡献了约35％的GDP；然而，由于石油产量稳定下降，商品价格低廉和全球竞争加剧而带来的经济阻力凸显了对提高采收率（EOR）技术的经济方法的需求。尽管在其他国家/地区使用低盐度聚合物驱油已获得成功，但尚无与洪水系统相关参数有关的关键信息，例如土壤类型，添加剂类型，吸附特性，流变（流量）特性，pH和盐度如果要在TT中实施这种类型的EOR。这些参数的性质和相互关系是特定储层所独有的，在这方面的研究将为模拟提供关键的输入数据，以产生该EOR策略的接近实际的预测。这些预测可用于评估TT中低盐度聚合物驱的有效性，并指导该策略的正确实施。选择了位于特立尼达南部森林低层沙地中的EOR 33井进行研究，因为它们符合筛选标准。实验室研究了浓度为0至4000 ppm的黄原胶与NaCl溶液（0至40,000 ppm）在砾石填充的沙子上的吸附，发现含有1000 ppm NaCl的1000 ppm聚合物混合物表现出最低的吸附能力。朗格缪尔系数是针对每种盐度得出的，并将粘度研究的结果输入模拟模型中。对EOR 33扇区的模拟表明，使用氯化钠<2000 ppm时，最高的采收率比注水高11％。盐水（NaCl <2000 ppm）与凝胶技术（1000 ppm聚合物）的结合产生了最高的采油率（54％），几乎是注水率的两倍，最高的平均储层压力和最低的含水率。使用低盐度注水与黄原胶进行注射所观察到的改善的性能特征可以与提高的驱替效率和提高的波及效率相关联，这表明该策略是特立尼达EOR井的技术上可行的选择。对EOR 33扇区的模拟表明，使用氯化钠<2000 ppm时，最高的采收率比注水高11％。盐水（NaCl <2000 ppm）与凝胶技术（1000 ppm聚合物）的结合产生了最高的采油率（54％），几乎是注水率的两倍，最高的平均储层压力和最低的含水率。使用低盐度注水与黄原胶进行注射所观察到的改善的性能特征可以与提高的驱替效率和提高的波及效率相关联，这表明该策略是特立尼达EOR井的技术上可行的选择。对EOR 33扇区的模拟表明，使用氯化钠<2000 ppm时，最高的采收率比注水高11％。盐水（NaCl <2000 ppm）与凝胶技术（1000 ppm聚合物）的结合产生了最高的采油率（54％），几乎是注水率的两倍，最高的平均储层压力和最低的含水率。使用低盐度注水与黄原胶进行注射所观察到的改善的性能特征可以与提高的驱替效率和提高的波及效率相关联，这表明该策略是特立尼达EOR井的技术上可行的选择。采用凝胶技术（聚合物为1000 ppm）（2000 ppm）可获得最高的采油率（54％），几乎是注水率的两倍，最高的平均储层压力和最低的含水率。使用低盐度注水与黄原胶进行注射所观察到的改善的性能特征可以与提高的驱替效率和提高的波及效率相关联，这表明该策略是特立尼达EOR井的技术上可行的选择。采用凝胶技术（聚合物为1000 ppm）（2000 ppm）可获得最高的采油率（54％），几乎是注水率的两倍，最高的平均储层压力和最低的含水率。使用低盐度注水与黄原胶进行注射所观察到的改善的性能特征可以与提高的驱替效率和提高的波及效率相关，这表明该策略是特立尼达EOR井的技术上可行的选择。