Product Overview
The Flat Bottom Mill is a flat-face self-sharpening multi-carbide milling shoe specially developed for coiled tubing through-tubing fishing, plug milling and junk wasover remedial workover operations.
This flat bottom milling shoe adopts multi-layer hard alloy cutting particle insert welding layout design on the flat end working surface; multiple layers of high-hardness wear-resistant hard alloy cutting grain inserts are uniformly welded to the flat bottom contact face, the alloy cutting blades feature automatic self-renewing structural design: as the outermost cutting layer wears and abrades during milling, new sharp cutting edges will continuously expose and replace the worn cutting segments, permanently maintaining stable optimal high-efficiency grinding performance without frequent tripping out of the well to replace worn milling tools. Each axial flow water channel machined on the tool body is equipped with dual bidirectional cutting edge structural design on both inner side walls of the flow groove; the bidirectional cutting tooth profiles can perform secondary crushing and fine shearing treatment on downhole fallen metal junk fragments, rock cuttings and milled plug debris during continuous milling process, further reducing debris particle size to lower resistance and facilitate full circulating fluid transport of cuttings upward to the well surface. Multiple interchangeable hard alloy grain insert grade specifications are available for free selection to adapt to different downhole formation rock hardness and junk material hardness construction demands.
The Flat Bottom Mill has no complex internal movable friction components, spring energy storage assemblies or differential pressure release mechanisms, with extremely simplified wellsite operation flow and low maintenance cost; construction crews only need to run the flat bottom milling shoe down along the wellbore until the flat bottom cutting face contacts the target composite bridge plug / cement plug / fallen metal junk, apply rotary torque and continuous circulating well fluid to realize continuous plug milling, secondary debris crushing and cuttings circulation flushing work, no additional auxiliary operation steps such as drop ball delivery or shear pin impact jarring are needed, shortening wellsite operation time and reducing human error risks.
The standardized product lineup covers outer diameter sizes ranging from 2-7/8" to 5-1/2", with complete outer diameter specification series to match different wellbore inner diameter constraint conditions and different plug milling construction demands. Custom outer diameter, hard alloy cutting grain insert hardness grade and base material corrosion resistance grade customization are available upon customer technical drawing submission.
Complete Technical Specification Table
| Product Model PN | Outer Diameter OD | Applicable Size Range | Working Condition Grade | Bottom Connection Thread |
|---|---|---|---|---|
| Custom PN Series | 2-7/8" | 2-7/8" plug / wellbore | STD Standard | Custom Coiled Tubing Thread |
| Custom PN Series | 3-1/2" | 3-1/2" plug / wellbore | STD Standard | Custom Coiled Tubing Thread |
| Custom PN Series | 4" | 4" plug / wellbore | STD Standard | Custom Coiled Tubing Thread |
| Custom PN Series | 5-1/2" | 5-1/2" plug / wellbore | STD Standard | Custom Coiled Tubing Thread |
Note: Custom outer diameter, hard alloy cutting grain insert hardness grade and base material corrosion resistance grade modification flat bottom milling shoes are available via engineering consultation. Two working condition grades (STD standard carbon steel / H₂S sour service anti-corrosion alloy) are optional for each outer diameter size, and the working condition grade needs to be clearly confirmed according to the downhole wellbore fluid H₂S concentration corrosive environment during order placement; multiple different hardness alloy grain insert specifications can be freely selected to match different downhole rock and junk hardness conditions.
Core Features & Advantages
Multi-Layer Welded Hard Alloy Cutting Particle Insert Flat Bottom Layout Design: Multiple layers of high-hardness wear-resistant hard alloy cutting grain inserts are uniformly welded to the flat end working contact face of the milling shoe, the alloy cutting blades feature automatic self-renewing structural design; as the outermost cutting layer wears and abrades during milling, new sharp cutting edges will continuously expose and replace the worn cutting segments, permanently maintaining stable optimal high-efficiency grinding performance without frequent tripping out of the well to replace worn milling tools.
Dual Bidirectional Cutting Edge Flow Water Channel Structural Design: Each axial flow water channel machined on the tool body is equipped with dual bidirectional cutting edge structural design on both inner side walls of the flow groove; the bidirectional cutting tooth profiles can perform secondary crushing and fine shearing treatment on downhole fallen metal junk fragments, rock cuttings and milled plug debris during continuous milling process, further reducing debris particle size to lower fluid circulation resistance and facilitate full circulating fluid transport of cuttings upward to the well surface.
Multiple Interchangeable Hard Alloy Grain Insert Grade Configuration: Various different hardness hard alloy cutting grain insert specifications are optional for free selection to adapt to different downhole formation rock hardness and junk material hardness construction demands, realizing flexible matching of milling cutting force and wear resistance performance according to actual downhole working conditions.
Full Outer Diameter Size Range Coverage: The applicable outer diameter size range of the flat bottom milling shoe covers 2-7/8" to 5-1/2", with complete outer diameter specification series to match different wellbore inner diameter constraint conditions and different composite bridge plug / cement plug milling construction demands.
Ultra-Simplified Wellsite Operation Logic: The flat bottom milling shoe has no complex internal movable friction components, spring energy storage assemblies or differential pressure release mechanisms, the operation flow is highly streamlined: only need to run the flat bottom milling shoe down along the wellbore until the flat bottom cutting face contacts the target composite bridge plug / cement plug / fallen metal junk, apply rotary torque and continuous circulating well fluid to realize continuous plug milling, secondary debris crushing and cuttings circulation flushing work, no complex auxiliary operation steps such as drop ball delivery or shear pin impact jarring are needed to shorten wellsite operation time and reduce human error risks.
Low Routine Maintenance Design: The integral monolithic alloy steel tool body eliminates vulnerable split assembly movable wear parts; after each plug milling operation, only simple surface flat bottom alloy cutting grain debris cleaning and flow water channel blockage flushing inspection are required, no complex disassembly, internal hard alloy cutting grain insert replacement or spring preload adjustment maintenance procedures, greatly reducing daily maintenance labor and spare parts inventory cost.
Application Scenarios
1. Coiled tubing through-tubing fishing, plug milling and junk wasover heavy-load intervention treatments, including composite bridge plug, solid cement plug, small fallen metal junk fragment and other downhole obstacle milling and removal remedial workover construction operations
2. Conventional sweet crude oilfield multi-layer self-sharpening alloy flat bottom milling shoe through-tubing plug milling and junk wasover remedial workover service (STD Standard carbon steel working condition grade)
3. High-sulfur H₂S containing corrosive downhole wellbore construction project composite bridge plug / cement plug milling heavy workover projects requiring H₂S sour service anti-sulfide stress cracking high-corrosion-resistant alloy material grade
4. Long-term continuous repeated milling cutting load safety protection for coiled tubing bottom-hole assemblies in onshore and offshore oilfield through-tubing plug milling and junk wasover remedial workover intervention projects
Standard Delivery Package
Complete flat bottom milling shoe integral alloy steel pre-assembled unit including integral tool cylinder body, flat bottom multi-layer welded hard alloy cutting grain insert working face and dual bidirectional cutting edge axial flow water channels
Spare interchangeable hard alloy cutting grain insert maintenance kit with multiple hardness specifications for on-site worn cutting grain layer replacement
Full factory inspection test report including repeated milling cutting load fatigue resistance test, integral tensile load test, flat bottom alloy cutting grain self-renewing wear performance calibration test and dual bidirectional cutting edge secondary debris crushing efficiency test data
Product dimension drawing and official installation & operation instruction manual, with detailed on-site through-tubing plug milling and junk wasover operation guidance, with clear reminder to select STD standard carbon steel grade or H₂S sour service anti-corrosion alloy grade according to downhole wellbore fluid H₂S concentration corrosive environment during order placement, and confirm required hard alloy cutting grain insert hardness grade to match different downhole rock and junk hardness construction conditions
Quality Warranty & After-Sales Service
Warranty Coverage: 12 months after factory shipment or 2000 cumulative milling cutting load cycles, whichever condition is reached first
Full factory inspection: Each finished flat bottom milling shoe passes integral tensile load test, repeated milling cutting load fatigue test, flat bottom alloy cutting grain self-renewing wear performance calibration test and dual bidirectional cutting edge secondary debris crushing efficiency test before factory delivery
Free professional technical support: Our oilfield downhole tool engineering team provides coiled tubing through-tubing plug milling and junk wasover remedial workover tool string matching, outer diameter & working condition grade (STD / H₂S) selection and hard alloy cutting grain insert hardness grade selection consultation free of charge
Long-term spare parts supply: All interchangeable hard alloy cutting grain insert wear accessories are stocked with competitive factory bulk pricing
Custom development service: Support custom outer diameters, customized hard alloy cutting grain insert hardness grade specifications, base material corrosion resistance grade modification, bottom coiled tubing connection thread profiles and special size flat bottom milling shoes based on customer technical drawings
FAQ
Q1: What is the core function of a Flat Bottom Mill (Flat-Face Self-Sharpening Multi-Carbide Milling Shoe)?
The Flat Bottom Mill is a flat-face multi-layer self-sharpening hard alloy milling shoe dedicated to coiled tubing through-tubing fishing, plug milling and junk wasover remedial workover operations. Multi-layer hard alloy cutting grain inserts are welded on the flat bottom working face, the self-renewing alloy cutting blade structure enables new sharp cutting edges to continuously expose and replace worn cutting segments during milling, permanently maintaining optimal high-efficiency grinding performance. Each axial flow water channel is equipped with dual bidirectional cutting edge design on both inner side walls of the flow groove, which can perform secondary crushing and fine shearing treatment on downhole fallen metal junk fragments and rock cuttings to reduce debris particle size and facilitate circulating cuttings return to surface. Multiple interchangeable hard alloy cutting grain insert hardness grade specifications are optional to adapt to different downhole formation rock hardness and junk material hardness construction demands. The applicable outer diameter size range covers 2-7/8" to 5-1/2". Two independent working condition material grade options are provided: STD standard carbon steel grade for conventional non-corrosive wellbore environments without high-concentration H₂S corrosive medium; H₂S sour service high-corrosion-resistant alloy grade for high-sulfur H₂S containing corrosive downhole wellbore construction conditions. No complex internal movable friction components or spring assemblies are equipped, operation flow is highly simplified, widely applied for coiled tubing through-tubing composite bridge plug, cement plug and fallen metal junk milling and wasover remedial workover construction operations.
Q2: What three core structural advantages does this Flat Bottom Mill Flat-Face Milling Shoe own?
1. Multi-layer welded hard alloy cutting particle insert flat bottom layout design, multiple layers of high-hardness wear-resistant hard alloy cutting grain inserts are uniformly welded to the flat end working contact face of the milling shoe, the alloy cutting blades feature automatic self-renewing structural design; as the outermost cutting layer wears and abrades during milling, new sharp cutting edges will continuously expose and replace the worn cutting segments, permanently maintaining stable optimal high-efficiency grinding performance without frequent tripping out of the well to replace worn milling tools; 2. Dual bidirectional cutting edge flow water channel structural design, each axial flow water channel machined on the tool body is equipped with dual bidirectional cutting edge structural design on both inner side walls of the flow groove; the bidirectional cutting tooth profiles can perform secondary crushing and fine shearing treatment on downhole fallen metal junk fragments, rock cuttings and milled plug debris during continuous milling process, further reducing debris particle size to lower fluid circulation resistance and facilitate full circulating fluid transport of cuttings upward to the well surface; 3. Multiple interchangeable hard alloy grain insert grade configuration & ultra-simplified wellsite operation logic, various different hardness hard alloy cutting grain insert specifications are optional for free selection to adapt to different downhole formation rock hardness and junk material hardness construction demands; the flat bottom milling shoe has no complex internal movable friction components, spring energy storage assemblies or differential pressure release mechanisms, only need to run the flat bottom milling shoe down along the wellbore until the flat bottom cutting face contacts the target composite bridge plug / cement plug / fallen metal junk, apply rotary torque and continuous circulating well fluid to realize continuous plug milling, secondary debris crushing and cuttings circulation flushing work, no complex auxiliary operation steps such as drop ball delivery or shear pin impact jarring are needed to shorten wellsite operation time and reduce human error risks; the product also features full outer diameter size range coverage and low routine maintenance design to further optimize on-site construction efficiency and reduce post-operation maintenance workload.
Q3: What outer diameter sizes and configurable options do these Flat Bottom Mill Flat-Face Milling Shoes support?
Our standard applicable outer diameter size range covers 2-7/8", 3-1/2", 4" and 5-1/2". Each OD size supports two independent working condition material grade versions for free matching selection: STD standard carbon steel working condition grade and H₂S sour service high-corrosion-resistant alloy working condition grade. All models support custom coiled tubing bottom connection threads compatible with global mainstream coiled tubing connector assemblies and other supporting downhole through-tubing plug milling and junk wasover remedial workover tools. Custom hard alloy cutting grain insert hardness grade specifications and base material corrosion resistance grade specifications are available upon customer downhole wellbore fluid H₂S concentration corrosive environment and downhole rock/junk hardness construction demands.
Q4: What is the standard production lead time for bulk purchase orders?
All standard PN part numbers are kept in factory inventory, goods can be delivered within 7–15 working days. Customized flat bottom milling shoes with special outer diameters or customized hard alloy cutting grain insert hardness grade specifications, base material corrosion resistance grade specifications & bottom connection thread profiles require 20–35 working days production cycle, subject to total order quantity and customization scope.
Get Custom Datasheet & Factory Quote
We are a professional OEM & ODM manufacturer focused on full series coiled tubing heavy workover and washing downhole service tools, covering flat bottom milling shoes, five-blade five-wing milling shoes, magnetic fishing rods, magnetic junk retrieval magnets, venturi junk baskets, flow activated releasable fishing overshots, flow activated releasable fishing spears, flow activated releasable JDC running/pulling tools, flow activated releasable GS fishing tools, bi-direction mechanical accelerators, bi-direction hydraulic accelerators, bi-direction hydraulic jars, up-stroke hydraulic jars, bi-direction mechanical jars, up-stroke mechanical jars, wireline grabs, wireline spears and all other supporting downhole fishing, jarring, anchoring and washing service tools. Every finished product undergoes strict factory tensile load, repeated milling cutting load fatigue, flat bottom alloy cutting grain self-renewing wear performance calibration and dual bidirectional cutting edge secondary debris crushing efficiency testing, with complete material inspection certification attached to each shipment. Please share your detailed technical requirements, including target outer diameter size, required working condition grade (STD standard carbon steel / H₂S sour service anti-corrosion alloy), required hard alloy cutting grain insert hardness grade, downhole wellbore fluid H₂S concentration corrosive environment construction conditions, working environment and all customized specification demands. Our dedicated oilfield downhole tool engineering team will send complete detailed technical datasheets and competitive factory wholesale quotations within 24 business hours, and provide professional on-site through-tubing plug milling and junk wasover operation guidance, with clear confirmation reminder for working condition grade selection (STD standard carbon steel for non-corrosive well / H₂S sour service anti-corrosion alloy for high-sulfur corrosive well) and hard alloy cutting grain insert hardness grade confirmation according to downhole rock and junk hardness construction demands during order placement.
