Water-based Fracturing Fluid Additives Research And Application

With the development of the oil industry, we have a higher performance requirement for the fracturing fluid, and it is particularly important to investigate the water-based fracturing fluid additive. High temperature low residue, low fluid loss and formation for fracturing high temperature permeability liquid additives is the direction of current research.Guar gum as a water-based fracturing fluid additive, due to its high content of water insoluble, difficult to control viscosity, and can not easily break down long-term preservation of biological disadvantages in engineering applications, had been gradually eliminated. In order to reduce the water insoluble matter, speed up the hydration rate, improve the shear properties of salt tolerance, we need to give a chemical modification of guar gum so that it can be widely used. In this paper, according to the disadvantages, there is a modification of guar gum: ethanol purified guar gum as raw materials for the etherification agent propylene oxide, isopropanol as dispersing agent, sodium hydroxide occur under the conditions of catalyst etherification synthesized hydroxypropyl guar. Through the modification of guar gum, the degree of molecular branching was increased, water-soluble was accelerated, water insoluble was reduced, and hydroxypropyl guar modified has some advantages of tackifying ability, enduring temperature, salt, shear high, low residue, and the formation damage is relatively small. Modified hydroxypropyl guar gum achieve even precede the performance of the domestic hydroxypropyl guar gum, the content of water insoluble matter was 2.60% lower than the mainland 3.97%, apparent viscosity was 87mPa?s, was almost equal to the domestic hydroxypropyl guar gum apparent viscosity 90mPa?s, the maximum temperature capacity was 93℃, good shear resistance , can be used as an excellent water-based fracturing fluid thickener.When the surface active agent is used as a water-based fracturing fluid additives, surface active agent has the characters of bactericidal, breaking, cleanup, and stability of clay, defoaming, foaming and so on, so the surface active agent regarded as the water-based fracturing fluid additive has been widely used. The synthesis of maleic rosin and polyoxyethylene octylphenol ether carboxylic acid sodium salt is viewed as the theoretical basis. The most suitable route of a synthesis of maleic rosin derivatives will be explored in this paper. The most suitable route is followed. Firstly, the reaction of rosin and maleic anhydride produces maleic rosin. Secondly, the reaction of maleic rosin and octylphenol ethoxylates produces maleic rosin polyoxyethylene octylphenol ether carboxylic acid diester. Finally, the reaction of maleic rosin polyoxyethylene octylphenol ether carboxylic acid diester and sodium hydroxide produces the surface active agent of maleic rosin octylphenol polyoxyethylene diester sodium salt. According to the performance requirements of surfactant as additives of water-based fracturing fluid, the synthesis surfactant is carried out performance testing of the surface tension, cmc, hlb, acid and alkali. At 21.2℃, the surface tension is relatively low, its value was 28.79mN / m. At 23℃, the foaming ratio was 40/19. The emulsification time was about 40 minutes. Since maleic anhydride sodium diester surfactants have the advantages of low surface tension, moderate foam, good stability performance, non-toxic, low-cost etc. Moreover, the maleic anhydride diester surfactant sodium in water-based fracturing fluid shows the features of emulsification, cleanup, and stability of clay, bubble. Therefore, maleic anhydride diester can be used as surfactants to improve the performance of water-based fracturing fluid additive.This article, finally, making the hydroxypropyl guar gum as the thickening agent for water-based fracturing fluid, octylphenol maleic rosin acid sodium polyoxyethylene ether surfactant as additives, added a certain percentage of fungicides, clay stabilizer, crosslinking agent glue preparation of new plant-based fracturing fluid at low temperature and water-based fracturing fluid in accordance with the performance requirements for the compatibility, temperature resistance properties, rheological properties of, gel breaking performance, the static filter lost, broken plastic surface tension performance was tested. The fracturing fluid and liquid-based cross-linking agent in accordance with the completely broken 100:0.7 crosslinked gel, gel breaking residue measured 326 mg/L, breaking the surface tension of the glue 26.06mN/m, the surface tension of the filtrate 27.76mN/m.The maximum temperature capacity was 95℃, fracturing fluid has a stable performance. Testing showed that: the new water-based fracturing fluid system with temperature, shear, gel breaking completely, and the back row of the characteristics of rapidly dissolving speed, low residue, and support the reservoir characteristics of a small crack damage, especially for the formation temperature was 95℃below. The depth of well temperature in different layers of low permeability oil and gas fracturing, they all have a good application prospect in engineering applications.