Methods of restoring the delivery of drainage wells

Conclusions

• 1. During the operation of a drainage system, the reduction in well productivity is governed by chemical-silting processes, the rate of which is determined, in many respects, by the design of the permeable portion of the well.

• 2. Use of the pneumatic-impulse treatment of wells with an interrepair period of not more than 6 months is possible in wells that have been in service for not longer than 3–4 years.

• 3. In wells that have been in service for 5–10 years, treatment by the detonation of a blasting fuse ensures the restoration of productivity up to 65–45% of the initial yield. A rational interrepair period is 8 months.

• 4. Solution of silting formation in a well that has been in service for not more than 6–7 years is ensured by-concentrated hydrochloric acid and solutions of powdered reagents. The recommended interrepair period as a function of the design of the water-receiving portion of the well is 18–24 months.

• 5. Use of combined methods of treatment is expedient in wells that have been in service for more than 7–8 years where interrepair periods of 24–30 months have been observed.

• 6. Experience acquired with the massive restoration of the productivity of drainage wells in a flood-control system in an area within the region of the Kuibyshev Reservoir can be used in developing measures to stabilize the effect of vertical drainage of terrace dams and flood-protection systems under similar hydrogeologic conditions.