一种超低密度支撑剂的可用性评价

摘要

Conventional proppants usually have a high density, which greatly affects the creation of effective hydraulic fractures and makes these proppants inapplicable for long fracture induction. Whereas, ultra-low-density proppants can be used to increase the effective length of fractures and thereby improve the performance of fractured wells. In this paper, an innovative hollow and coated ceramic proppant (ST-I) was evaluated for its basic properties (e.g. acid solubility and crush resistivity) through the combination of lab experiment and software simulation, and the changes of its conductivity with closure pressure and sanding concentration were analyzed. Moreover, this ultra-low-density proppant was compared with ordinary ceramic proppant for performance, and its settlement behaviors in fracturing lfuids with different viscosities were tested. The results show that this ultra-low-density proppant has good physical per-formance and conductivity, and it settles at an apparently low rate in fracturing lfuids, which make it ideal for long fracture induction. Together with rational design of fracturing treatment in late stage, this innovative proppant can help to create fractures with effective half length up to 180 m.%常规支撑剂的密度一般比较大，严重影响着有效水力裂缝的形成，并难以应用于长缝压裂，超低密度支撑剂的使用能够增加裂缝有效长度，提高压裂井的增产效益。采用室内实验与软件模拟相结合的评价手段，对一种新型空心覆膜陶粒支撑剂（ST-I）进行酸溶解度、抗破碎率等基本性能评价，分析了其导流能力在不同闭合压力、铺砂浓度下的变化规律。同时将这种超低密度支撑剂与普通陶粒支撑剂进行性能比较，测试了其在不同压裂液黏度下的沉降特性。结果表明，该支撑剂具有较好的物理、导流性能，在压裂液中的沉降速度较普通陶粒支撑剂明显较慢，完全满足长缝压裂的基本要求。通过后期合理的压裂施工设计，能够形成有效支撑半缝长达到180 m左右的裂缝。