IADC BIT AND BHA DULL GRADING 2026

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IADC BIT AND BHA DULL GRADING 2026 – เราใช้เวอร์ชั่น 1987 มานานแล้ว ตอนนี้ IADC ออกเวอร์ชั่นใหม่มาเมื่อต้นปี 2026 แต่ยังไม่แพร่หลายกัน

เวรอ์ชั่น 1987 ผมเคยทำสรุปไว้ให้แล้ว

IADC bit dull grading เราทำกันอย่างไร

โหลดเวอร์ชั่นใหม่ได้จากข้างล่างนี่เหลยครับ หรือ คลิ๊กที่รูปก็ได้

Download – IADC Bit and BHA Dull Grading Manual

IADC BIT AND BHA DULL GRADING 2026

ข้างล่างนี่เฉพาะสายแข็งเลย ผมขี้เกียจแปล สายแข็งย่อมแปลเองได้อยู่แล้ว ถ้าแปลไม่ได้ก็ไม่ใช่สายแข็งล่ะเนอะ

จะสรุปย่อให้ว่าเวอร์ชั่นใหม่ปรับปรุงอะไรบ้าง

1. Moving from Aggregate Codes to Cutter-by-Cutter Precision
2. Introducing Standardized BHA & Tool Dull Grading
3. Drilling Forensics: Linking “Effect” Directly to “Cause”
4. Rig-Site Best Practices: Visual Documentation & Photo Protocols
5. Modern Data Management & Interoperability
6. Real-World Case Studies: Key Operational Takeaways

Moving from Aggregate Codes to Cutter-by-Cutter Precision

The legacy system assigned a single average wear number (0–8) across the inner and outer rows. However, modern PDC bits rarely fail uniformly across a row; localized damage dictates run life.

Key Updates for Fixed Cutter Bits

• Cutter-by-Cutter Granularity: When cutter data is available, bits are evaluated cutter by cutter using a 4-step workflow:
  1. Positional Data: Recorded by Blade Number, Pocket Number (e.g., 101 for inner cutter on Blade 1), and Bit Zone (Cone [C], Nose [N], Shoulder [S], Gauge [G]).
  2. Damage Severity: Quantified by percentage area loss (% Loss), correlated with the legacy 0–8 scale via defined radius ratios (e.g., 50% loss = Grade 4; 100% loss = Grade 8).
  3. Diamond Face Damage Classification: Expanded qualitative damage codes distinguishing specific failure mechanisms:
     • Chamfer Wear (CW), Cutter Wear (WC), Spalled Cutter (SC), Broken Cutter (BC).
     • Shop-Grade Specific Diagnostics: Beach Marks (BM) (impact fatigue), Island Spall (IS), Crack Face (CF), Tangential Break (TB), Delaminated Cutter (DC).
  4. Substrate Damage Classification: Separate grading for the tungsten carbide substrate:
     • Eroded Substrate (ERS), Corroded Substrate (CRS), Eroded/Corroded Substrate (ECS), Heat Checked Substrate (HCS).

Expanded Cutting Tool Profiles

• Shaped Cutters: Standardized protocols for non-planar cutters—including Scribe, Concave, Convex, and Rolling cutters. (Note: as damage severity reaches catastrophic levels like BC-8 or LC-8, wear profiles converge to resemble standard flat cutters).
• Impregnated (Impreg) Bits: Evaluation based on volumetric blade consumption (0–8 scale normal to the blade profile) rather than individual diamond loss, reflecting the self-sharpening matrix abrasion mechanism.

Hammer Bits, Core Heads, & Hybrid Bits: Tailored tables accommodating core cutter rings, roller cone/PDC combinations, and unique hammer bit dulls such as “Cat Eye” (CE) wear.

Introducing Standardized BHA & Tool Dull Grading

Historically, when a BHA tripped out due to a downhole issue, failure descriptions were inconsistent and siloed across service company proprietary sheets. The 2026 Manual establishes a unified industry nomenclature for BHA components.

Positive Displacement Motors (PDMs)

Motors are evaluated across 5 distinct sections:

1. Top Sub
2. Power Section
3. Transmission Section
4. Bearing Section
5. Stabilization

Standardized failure codes catalog both structural and functional failure modes, such as Connection Back-Off (BO), Washout (WO), Cracks (CK), Belled Connection (BEC), Elastomer Chunking (CH), Debonding (DB), Blisters (BL), Excessive Bearing End Play (EB), and Locked Up Bit Box (LB).

Rotary Steerable Systems (RSS) & Stabilizers

• RSS Grading: Separates the tool into the Biasing Unit (Pads/Ribs), Electronics Unit, and Power Unit, tracking functional failures (e.g., Inability to Steer [IT], Tool Face Control [TFC], Downlink Acceptance [AD/CDL]) alongside physical damages (Pad Missing [PM], Abrasion Wear [AW], Clogged Tool [CLT]).
• Stabilizer Wear Patterns as Forensic Signatures:
  • Lower Shoulder Wear: Indicates mechanical interference caused by borehole spiraling over long intervals (often misdiagnosed as swelling formations).
  • Eccentric (One-Sided) Wear: The classic signature of forward BHA whirl, where one face continuously rubs against the borehole wall.

Uniform Severe Wear (All Sides): Driven by violent backward whirl, where high contact forces cause the stabilizer to bounce and jump backwards off the wellbore wall.

Drilling Forensics: Linking “Effect” Directly to “Cause”

Drilling forensics investigates the relationship between applied drilling forces (causes) and physical downhole observations (effects). The manual outlines how physical failure modes diagnose root causes:

Observed Damage / Feature, Failure Mode / Physics, Primary Suspected Cause

• Plastic Hinge, Compression / bending shear failure, Tangential overload, severe stick-slip, or excessive WOB exceeding structural limits
• Beach Marks radiating inward, Stress waves from impact point, Impact from outside = Bit whirl; Impact from bottom = Bit bounce / axial vibration
• 45° Crossing Cracks, Combined bending & alternating torsional stress, High Frequency Torsional Oscillations (HFTO) (150–400 Hz)
• Flaking Diamond Table, Tensile failure on reverse side, Reverse rotation / back-spinning downhole

Deep Gouging / Worn Flush Blades, High normal impact force, Backward whirl (cannot be solved by harder facing alone)

Rig-Site Best Practices: Visual Documentation & Photo Protocols

• To support engineering redesigns and automated machine learning grading, photos must capture precise physical evidence rather than generic views:
• Eliminate On-Camera Flash Glare: Direct flash on metallic components creates blinding white hot-spots that obscure micro-cracks, wear scars, and cutter chamfers. Turn flash off and illuminate the surface with a separate flashlight held at a 45-degree angle.
• Pre-Run Baselines are Critical: Always photograph refurbished bits and rerun BHA components before running in hole. Differentiating pre-existing pocket erosion or manufacturing gauge grind from in-hole wear is essential for root cause analysis.
• Standardized Blade Indexing:
• Looking at the bit face, Blade 1 is the blade originating closest to the center (often stamped with the bit serial number), with blade counts incrementing clockwise in the direction of drilling.
• On photos, position Blade 1 at 3 o’clock.
• Mandatory Photo Portfolio:
• Top / Face View (perpendicular, Blade 1 at 3 o’clock).
• 0° Blade Face View (capturing primary cutter faces, chipping, and spalling).
• 45° Angle Blade View (capturing body, shoulder, and cutter profiles).
• 80° Backup Cutter View (capturing secondary elements and substrates).
• Gauge Ring Verification (using a “Go” ring and measuring 1/16-inch offsets on the opposing side).

Modern Data Management & Interoperability

Dull grading data can no longer live on paper tour sheets or static PDF daily drilling reports. The manual sets guidelines for integrating wear data into open digital ecosystems:

• Standard Schemas (JSON / XML): Standardizing structured cutter-by-cutter and BHA failure data formats mapped directly into schemas like WITSML, IADC DDR Plus™, D-WIS, and OSDU.
• Data Quality Dimensions: Ensuring field data adheres to core quality principles—Accuracy, Completeness, Traceability, Timeliness, and Granularity.

• Industry Data Sharing & Governance: Establishing neutral, access-controlled data exchanges where operators and OEMs can benchmark performance, train computer vision AI models, and share failure insights while safeguarding intellectual property.

Real-World Case Studies: Key Operational Takeaways

The manual highlights three industry case studies that illustrate why deeper forensics changes operational responses:

1. The Cored Bit (Motor Stator Chunking): A bit pulled with a cored center and secondary ring-out was initially assumed to be caused by excessive WOB. Integrating surface telemetry showed a 400 psi standpipe pressure spike without motor torque increases. Forensics revealed the motor stator chunked near its end-of-life, sending rubber pieces downhole that plugged the bit’s center nozzles. The resulting thermal starvation and loss of hydraulic cleaning caused the cone cutters to fail.
2. Casing Shoe Drill-Out Damage: Gauge trimmers suffered severe spalling during shoe-track drill out on a bent motor. High-speed downhole sensors (~1,000 Hz) confirmed off-bottom lateral vibrations of 35–40 g while circulating and washing through plugs. Mitigations: minimize off-bottom rotating hours inside casing, optimize motor bend angles, and utilize impact arrestors behind gauge cutters.

• The UTAH FORGE Geothermal Wear Paradox: Drilling ultra-hard granite (30,000–40,000 psi UCS), cutters repeatedly failed from thermal spalling once wear flats formed. Conventional instinct suggested decreasing RPM and WOB. However, forensics demonstrated that cutter wear is a function of total sliding distance, not WOB. By increasing WOB from 30–45 klbs to 65–70 klbs with an aggressive cutter design, depth of cut (DOC) increased significantly. Because the bit drilled deeper per revolution, cutters traveled less cumulative distance to drill the interval, delaying the onset of critical wear flats. The result was an 80% increase in ROP and a 65% increase in footage.

IADC BIT AND BHA DULL GRADING 2026

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