In recent years, China has made great progress in the exploration and development of carbonate reservoirs. Due to the development of pores and fractures and high formation temperature in carbonate reservoir, in order to ensure the transformation effect of acid fracturing, it is necessary to improve the penetration depth of acid fracturing fractures in the reservoir and improve the conductivity of acid etching fractures. Therefore, it is necessary to improve the rheological properties of acid fluid and reduce the reaction speed between acid and rock. As normal gelling agent has low viscosity not over 60 mpa.s, the ground cross-linked system came into being. Based on ideas of hydro-fracturing gelling agent and overseas crosslinking acid, we developed a new gelling system with continuous R&D.

The ground cross-linking acid system includes gelling agent, conditioner and crosslinker. At the same time, the matched additives include cleanup agent, corrosion inhibitor, demulsifier, iron stabilizer and gel breaker that forms the whole ground cross-linked acid gelling system.

The ground crosslinked acid gelling aent can be crosslinked in 10-28% hydrochloric acid with different concentrations. The crosslinking time can be controlled within 60-240 seconds, the viscosity can still be greater than 50mPa.s under the condition( shear rate 170^-1s, 140℃,in 2hrs).

In order to delay the gel-break time, capsule breaker technology is used to ensure the full release of breaker after application, the viscosity of acid solution after gel breaking is generally less than 10mps. This system has good temperature stability and shear resistance, so as to achieve low acid filtration and acid rock reaction speed and maximize the acid fracturing effect.

Technical specification

This system includes:gelling agent+crosslinker+conditioner+gel breaker.