Diverting agents

The common acidification effect is not ideal due to the high heterogeneity of the reservoir. In order to solve this problem, we synthesized the diverting agent UZV-180 for acidizing fluids. It will turn the spent acid into the gel-like liquid by increasing its viscosity, forcing the subsequent fresh acidizing fluids to turn from a relatively high permeability zone to the low permeability zone. The gel-like liquid will automatically break thoroughly once meet the hydrocarbons then return to the ground. Finally, achieve the purpose of uniform acidification.

The recommended dosage of UZV-180 is 3.0~8.0% (30~80 kg/m3). Adding the recommended dosage evenly into acid circulating in the preparation acid process. This product has good compatibility with a variety of other additives, no special requirements on the order of addition.

Secondary additives such as corrosion and asphaltene inhibitors should be co-injected with the VES containing fluid to protect the well and mitigate secondary issues which can occur as a result of reservoir acidizing. Performance testing of the fully formulated fluid should be performed to ensure no negative impact on the acid-depletion viscosification mechanism.

This product should be stored in ventilated and dry warehouse. No contact with acid, alkali and other chemicals. Keep away from heat.

This product should be handled with care during transportation. Avoid moisture and damage.

Has a shelf life of 12 months from the date of manufacture.

This product is of no hazard and can be transported as general chemcials.

1. A acid solution was prepared as diverted acidizing fluid recipe.

2. Spent Acid Preparation of HCl Diverted Fluid:Spent acid can be prepared by two methods.

（1）Added excess calcium carbonate to 100 ml of HCl diverted fluid, reacted to the pH value around 3 to 4, and removed excess calcium carbonate by centrifugation.

（2）Simulation of 20% hydrochloric spent acid with 30% calcium chloride solution.

3. Rheological Test:

The residual acid was transferred to a Huck rheometer, and the temperature was raised from 86°F to a specified temperature. The temperature gradient was 5.4°F/min, and the shear rate was 100s-1.

Recipe 1#：95ml(30%CaCL2)+3ml(UZV-180)+0.4ml(UZ CI-180V), add 2-4 drops of HCL to pH between 2-4.The rheological curve is shown in the figure 1.

Fig 1  Rheological curve of recipe 1

Recipe 2#：94ml(30%CaCL2)+4ml(UZV-180)+0.4ml(UZ CI-180V), add 2-4 drops of HCL to pH between 2-4.The rheological curve is shown in the figure 2.

Fig 2  Rheological curve of recipe 2

Recipel 3#：94ml(30%CaCL2)+4ml(UZV-180)+0.4ml(UZ CI-180V), add 2-4 drops of HCL to pH between 2-4.The rheological curve is shown in the figure 3.

Fig 3  Rheological curve of recipe 3

Recipe 4#：94ml(30%CaCL2)+4ml(UZV-150)+0.4ml(UZ CI-180V), add 2-4 drops of HCL to pH between 2-4.The rheological curve is shown in the figure 4.

Fig 4  Rheological curve of recipe 4

Recipe 5#：51.7ml（36%HCL）+8ml VES(UZV-180)+1.8ml Corrosion inhibitor(UZ CI-180V)+4ml Corrosion intensifier (CII-100)+1ml Ferric ion stabilizer (FS-100)+33.5ml Water, add excess calcium carbonate to pH between 2-4.The rheological curve is shown in the figure 5.

Fig 5  Rheological curve of recipe 5