The clean sand-carrying fluid produced by the company is also designed and developed by the company, with the complete formulation and production and testing equipment. The research and development of product technology are accomplished by joint effort of professionals from Shengli Highland Petroleum Engineering Services Co., Ltd. and Shandong Nalong Hi-Tech Petroleum Technology Co., Ltd., where they applied the water solution gelling multi-stage polymerization technology to the production and improvements of products. The clean sand-carrying fluid system can satisfy the company’s clean fracturing fluid standard only by adding with designed crosslinker. This system has the following technical characteristics:
(1)The clean sand-carrying fluid system is an anionic surfactant. As sulfonic acid group is introduced, its resistance to temperature and salt is increased. In addition, the anionic surfactant is of the same properties as the formation, so it is not absorbed by formation, hence reducing the damage to formation in immediate vicinity of wellbore.
(2)The clean sand-carrying fluid system has fast dissolution rate and dissolves uniformly, with the viscosifying time at 10min, so it is suitable for field preparation and use.
(3)This clean sand-carrying fluid system is not much affected by biodegradation factors, so it is suitable for long-time storage. As a natural organic polymer, guar gum is easily biodegradable.
(4)This clean sand-carrying fluid system has such characteristics as low viscosity, high strength and high sand-carrying capacity, with settling velocity not more than 0.02m/min (according to the standard requirements, it should not be more than 0.1m/min).
(5)It has extensive sources of raw materials, which would not be affected by international market, with stable cost price.
(6)Low residue level (≤ 70mg/L; guar gum ≥ 200mg/L);
(7)Small formation damage rate (≤5%; for guar gum, 10%∼50%)
(8)Characteristics of gel breaking
1.Gel breaking at low temperature of <20°C;
2.Cross-linked gel is different from VES and is not degraded when mixed with hydrocarbons;
3.The gel breaking liquid is surface-active, easily for flow back;
4.The hydration viscosity of gel breaking liquid is less than 1.4mPa•s.