Product Overview
The Convex Mill convex nose pilot positioning milling shoe is a convex protruding front-end pilot tool specially developed for coiled tubing downhole plug, metal junk and fish milling grinding remedial workover operations.
The front working end of the convex mill adopts an inner-high outer-low convex protruding pilot profile design; the raised central convex nose segment acts as a stable positioning pilot during milling grinding operations, which can keep the milling shoe centered and prevent lateral sliding or offset, ensuring smooth uniform grinding movement; the rear wide flat working face provides full-area coverage grinding capacity to completely grind down target plugs, bridge plugs or fallen metal junk obstacles. The convex outer contour surface of the tool body forms an active cuttings diversion structure: the convex slope surface continuously pushes all milled cuttings and rock debris away from the central axis of the milling shoe, eliminating cuttings accumulation dead zones at the tool center and significantly improving overall milling grinding efficiency. Each flow port distributed on the tool body is precisely optimized through full-flow field computational fluid dynamics (CFD) simulation analysis; the optimized flow hole layout effectively suppresses vortex turbulence phenomenon inside the fluid flow passage, improves the uniformity of wellbore circulating fluid flow field distribution, and significantly enhances the flushing and cleaning effect of circulating fluid on milled debris and cuttings at the bottom of the well. Multiple interchangeable tungsten carbide hard alloy cutting chip specifications are available for free selection to adapt to different downhole rock hardness and junk fragment hardness construction demands.
The Convex 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 convex nose pilot milling shoe down along the wellbore until the front convex pilot nose contacts the target plug or metal junk obstacle, apply rotary torque and continuous circulating well fluid to realize three-in-one functions of pilot central positioning, full-area plug/junk grinding and cuttings diversion 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, tungsten carbide cutting chip hardness grade and base material corrosion resistance grade customization are available upon customer technical drawing submission.
Complete Technical Specification Table
| PN Part Number | Outer Diameter OD | Make-Up Length | Working Condition Grade | Bottom Connection Thread |
|---|---|---|---|---|
| Custom PN Series | 2-7/8" | Custom Length | STD Standard | Custom Coiled Tubing Thread |
| Custom PN Series | 3" | Custom Length | STD Standard | Custom Coiled Tubing Thread |
| Custom PN Series | 4" | Custom Length | STD Standard | Custom Coiled Tubing Thread |
| Custom PN Series | 5-1/2" | Custom Length | STD Standard | Custom Coiled Tubing Thread |
Note: Custom outer diameter, tungsten carbide cutting chip hardness grade and base material corrosion resistance grade modification convex nose pilot 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; three types of cutting chip structures (standard crushed carbide grains / piranha serrated cutting chips / integral high-performance cutting inserts) can be freely matched on the milling cutting surface according to different downhole rock and junk hardness construction demands.
Core Features & Advantages
Inner-High Outer-Low Convex Protruding Front End Pilot Positioning Design: The front working end of the convex mill adopts unique inner-high outer-low convex protruding pilot profile, the raised central convex nose segment acts as a stable positioning pilot during milling grinding operations, which can keep the milling shoe centered and prevent lateral sliding or offset, ensuring smooth uniform grinding movement; the rear wide flat working face provides full-area coverage grinding capacity to completely grind down target plugs, bridge plugs or fallen metal junk obstacles.
Convex Outer Contour Active Cuttings Diversion Structure Design: The convex outer contour surface of the tool body forms an active cuttings diversion structure, the convex slope surface continuously pushes all milled cuttings and rock debris away from the central axis of the milling shoe, eliminating cuttings accumulation dead zones at the tool center and significantly improving overall milling grinding efficiency.
CFD Computational Fluid Dynamics Optimized Flow Port Layout Design: The position and inner diameter size of each flow port distributed on the tool body are precisely optimized through full-flow field computational fluid dynamics simulation analysis; the optimized flow hole layout effectively suppresses vortex turbulence phenomenon inside the fluid flow passage, improves the uniformity of wellbore circulating fluid flow field distribution, and significantly enhances the flushing and cleaning effect of circulating fluid on milled debris and cuttings at the bottom of the well.
Multiple Interchangeable Tungsten Carbide Hard Alloy Cutting Chip Grade Configuration: Three types of interchangeable cutting hard alloy chip structures are freely selectable for all convex mill models: standard crushed carbide grains, piranha serrated cutting chips and additional integral high-performance cutting inserts, which can flexibly match different downhole rock hardness and junk fragment hardness construction demands.
Full Outer Diameter Size Range Coverage: The applicable outer diameter size range of the convex nose pilot 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 convex nose pilot 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 convex nose pilot milling shoe down along the wellbore until the front convex pilot nose contacts the target plug or metal junk obstacle, apply rotary torque and continuous circulating well fluid to realize three-in-one functions of pilot central positioning, full-area plug/junk grinding and cuttings diversion 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 convex contour cuttings debris cleaning and flow port passage blockage flushing inspection are required, no complex disassembly, internal tungsten carbide cutting chip replacement or spring preload adjustment maintenance procedures, greatly reducing daily maintenance labor and spare parts inventory cost.
Application Scenarios
1. Coiled tubing downhole plug, metal junk and fish milling grinding heavy-load intervention treatments, including composite bridge plug, solid cement plug, small fallen metal junk fragment and other plug-type downhole obstacle milling and removal remedial workover construction operations
2. Conventional sweet crude oilfield convex nose pilot positioning milling shoe plug and metal junk milling grinding 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 rotary milling cutting load safety protection for coiled tubing bottom-hole assemblies in onshore and offshore oilfield composite bridge plug / cement plug milling grinding remedial workover intervention projects
Standard Delivery Package
Complete convex nose pilot positioning milling shoe integral alloy steel pre-assembled unit including main tool cylinder body, front inner-high outer-low convex protruding pilot nose and rear wide flat grinding working face with multi-type interchangeable tungsten carbide cutting chip layout
Spare interchangeable tungsten carbide hard alloy cutting chip maintenance kit with three types of cutting structure specifications (standard crushed carbide grains / piranha serrated cutting chips / integral high-performance cutting inserts) for on-site milling cutting surface worn cutting chip replacement
Full factory inspection test report including repeated rotary milling cutting load fatigue resistance test, integral tensile load test, convex pilot nose central positioning stability calibration test and convex contour cuttings diversion debris flushing efficiency test data
Product dimension drawing and official installation & operation instruction manual, with detailed on-site composite bridge plug / cement plug milling grinding 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 tungsten carbide cutting chip hardness grade and cutting structure type according to different downhole rock and junk hardness construction demands
Quality Warranty & After-Sales Service
Warranty Coverage: 12 months after factory shipment or 2000 cumulative rotary milling cutting load cycles, whichever condition is reached first
Full factory inspection: Each finished convex nose pilot positioning milling shoe passes integral tensile load test, repeated rotary milling cutting load fatigue test, convex pilot nose central positioning stability calibration test and convex contour cuttings diversion debris flushing efficiency test before factory delivery
Free professional technical support: Our oilfield downhole tool engineering team provides coiled tubing composite bridge plug / cement plug milling grinding remedial workover tool string matching, outer diameter & working condition grade (STD / H₂S) selection and tungsten carbide cutting chip hardness grade & cutting structure type selection consultation free of charge
Long-term spare parts supply: All interchangeable tungsten carbide hard alloy cutting chip wear accessories are stocked with competitive factory bulk pricing
Custom development service: Support custom outer diameters, customized tungsten carbide cutting chip hardness grade specifications, base material corrosion resistance grade modification, bottom coiled tubing connection thread profiles and special size convex nose pilot positioning milling shoes based on customer technical drawings
FAQ
Q1: What is the core function of a Convex Mill (Convex Nose Pilot Positioning Milling Shoe)?
The Convex Mill is a convex protruding front-end pilot milling shoe dedicated to coiled tubing downhole plug, metal junk and fish milling grinding remedial workover operations. The front inner-high outer-low convex protruding pilot nose realizes stable accurate central positioning during milling grinding operations to avoid lateral sliding or offset, the rear wide flat working face provides full-area coverage grinding capacity for target plugs or junk obstacles. The convex outer contour surface actively pushes all milled cuttings and debris away from the central axis of the milling shoe to eliminate central cuttings accumulation dead zones and improve overall milling grinding efficiency. Each flow port is precisely optimized through computational fluid dynamics (CFD) simulation analysis to reduce internal vortex turbulence and enhance well fluid circulation flushing cleaning effect. Three types of interchangeable tungsten carbide hard alloy cutting chip structures are freely selectable to adapt to different downhole rock hardness and junk fragment 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 downhole composite bridge plug, cement plug and fallen metal junk milling grinding remedial workover construction operations.
Q2: What three core structural advantages does this Convex Mill Convex Nose Pilot Milling Shoe own?
1. Inner-high outer-low convex protruding front end pilot positioning design, the front working end of the convex mill adopts unique inner-high outer-low convex protruding pilot profile, the raised central convex nose segment acts as a stable positioning pilot during milling grinding operations, which can keep the milling shoe centered and prevent lateral sliding or offset, ensuring smooth uniform grinding movement; the rear wide flat working face provides full-area coverage grinding capacity to completely grind down target plugs, bridge plugs or fallen metal junk obstacles; 2. Convex outer contour active cuttings diversion structure design, the convex outer contour surface of the tool body forms an active cuttings diversion structure, the convex slope surface continuously pushes all milled cuttings and rock debris away from the central axis of the milling shoe, eliminating cuttings accumulation dead zones at the tool center and significantly improving overall milling grinding efficiency; 3. CFD computational fluid dynamics optimized flow port layout design & ultra-simplified wellsite operation logic, the position and inner diameter size of each flow port distributed on the tool body are precisely optimized through full-flow field computational fluid dynamics simulation analysis; the optimized flow hole layout effectively suppresses vortex turbulence phenomenon inside the fluid flow path, improves the uniformity of wellbore circulating fluid flow field distribution, and significantly enhances the flushing and cleaning effect of circulating fluid on milled debris and cuttings at the bottom of the well; the convex nose pilot milling shoe has no complex internal movable friction components, spring energy storage assemblies or differential pressure release mechanisms, only need to run the convex nose pilot milling shoe down along the wellbore until the front convex pilot nose contacts the target plug or metal junk obstacle, apply rotary torque and continuous circulating well fluid to realize three-in-one functions of pilot central positioning, full-area plug/junk grinding and cuttings diversion 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 multiple interchangeable tungsten carbide cutting chip grade configuration and full outer diameter size range coverage to further expand application scope and match various downhole working condition demands.
Q3: What outer diameter sizes and configurable options do these Convex Mill Convex Nose Pilot Milling Shoes support?
Our standard applicable outer diameter size range covers 2-7/8", 3", 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 composite bridge plug / cement plug milling remedial workover tools. Custom tungsten carbide cutting chip hardness grade specifications, cutting structure type 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 convex nose pilot milling shoes with special outer diameters or customized tungsten carbide cutting chip hardness grade specifications, cutting structure type, 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 convex nose pilot positioning milling shoes, concave recessed milling shoes, five-blade five-wing milling shoes, flat bottom milling shoes, combination flat blade 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 rotary milling cutting load fatigue, convex pilot nose central positioning stability calibration and convex contour cuttings diversion debris flushing 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 tungsten carbide cutting chip hardness grade and cutting structure type, 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 composite bridge plug / cement plug milling grinding 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 tungsten carbide cutting chip hardness grade & cutting structure type confirmation according to different downhole rock and junk hardness construction demands during order placement.
