Tenders are invited for Water Well Driling Contractors, Duly Registered with the Ethiopian Ministry of Infrastructure as (Wwc) Water Works Contractors of Grade 3 and above for Drilling of Deep Borhole Bid closing date: Oct 06, 2025 10:00 AM Bid opening date: Oct 15, 2025 10:30 AM Region: Addis Ababa II. Eligibility & Scope of Works 2. Eligible bidders must also have valid registration and business licenses for the Ethiopian fiscal year 2017 E.C. (2024/25). The scope of works includes drilling through -60 m of soft formation, installation of steel surface casing with sanitary cement grout seal, continuation into fractured volcanic aquifer to -200 m depth, well completion (Option A: open-hole or Option B: cased and screened with gravel pack), well development, step-drawdown and constant-rate pumping tests, water quality testing, construction of wellhead and sanitary apron, shock chlorination and environmental discharge management, and submission of full as-built documentation. 3. Qualified firms are invited to submit sealed bids for the drilling and construction of one (1) deep production borehole at Dubti General Hospital, Afar Regional State, Ethiopia, located approximately 587 km from Addis Ababa. III. Technical Specifications & Minimum Standards 4. Drilling & Construction: a. Drilling methodology: Rotary mud drilling through unconsolidated sediments 0-3m with 24", install steel casing 16"/6mm thickness and gravitational cementation, then 3-57m with 12", install steel casing of 7.5"mm/5mm thickness transition to Down To the Hole in basalt (>60 m), pressurized neat cement grout (p 1.80g/cm³: W/C 0.50-0.54) from 0-60m, bottom-up tremie, cure >36-48 h before re-entry then continue down to the hole 60-200m with 6", installed steel casing of 5."/4mm (150m) including slotted screen of 5."/4mm (50m). b. Surface casing: All welds to be by certified welders (>3G/4G) with WPS/PQR; NDT (VT/PT) required; centralizers 3-arm every 3 m; flanged headworks pressure-rated 40 bar, c. Production casing/screens (Option B): 5"/4mm steel casing/screens (4mm thickness), m of steel screens across productive basalt fractures, gravel pack (-2.6 m³ of 2-4 mm silica), thin bentonite cap Screens: ASTM A312/A312M, collapse rating to depth, slot size 1.5mm by sieve, open area 15%; gravel pack uniformity coefficient 2.5, placed tremie bottom-up; bentonite seal 3 m d. Quality Assurance/Quality Check requirements: Verticality =3%(0- 60m); caliper log pre-completion; cement returns must equal 110% theoretical annulus volume; all cement tickets, density & temperature logs to be submitted, grout density 1.80 g/cm³, pressure-time logs, cement temperature profile, 48 h WL hold, Rossum sand test 50 mg/L. e. Pumping tests: Step-drawdown: 4 steps x 30-60,72hr (10/15/20/25 L/s). Constant-rate: 72h at >25 L/s, with 8-12 h recovery. Test pump 25 L/s @100 m head (Grundfos or equivalent), hot-rated ASTM A312/A312M, generator 75 kVA. Logs: WL, T, EC, turbidity, sand every 30 min. tests. Proof of availability (model no., datasheet, ownership/rental) must be attached, step-drawdown test and constant-rate test of 72hr at 25 L/s, extendable to 48 h if drawdown <2 m. f. Discharge management: provision of settling pit sized for =2,160 m³ discharge (25 L/s × 24 h). g. Equipment: Rig depth 220 m; compressors 900 cfm @ 25 bar (redundancy required); crane 10 t with lifting certificate; grout pump >40 bar (tested); certified welders & machines for 10 mm steel; concrete mixing mixers as per the quality and volume mention in the annex test pump as specified above. h. Certified welders + machines for a minimum of 16" casing welding. 1. High-pressure compressors >900 cfm @ 25 bar. j. Test pumping equipment equivalent to Grundfos SQ series, 25 L/s @150m head equivalent. Tender Link : https://tender.2merkato.com/tenders/68c81de80a538a0d0a000001
