Drill collars are heavy steel tubes used in the drilling process to provide weight on the drill bit, stabilize the drill string, and transmit torque to the bit. Non-magnetic drill collars (NMDCs) are drill collars made from non-magnetic materials such as titanium or non-magnetic steel alloys. They are used in drilling operations where magnetic interference from conventional magnetic drill collars may interfere with sensitive measuring instruments such as magnetic resonance imaging (MRI) and electromagnetic logging tools.
Functions of Non-Magnetic Drill Collars:
1. Weight and Stability: The primary function of NMDCs is to provide additional weight and stability to the drill string. The weight helps to push the drill bit into the formation, while the stability prevents the drill string from deviating from the desired path.
2. Corrosion Resistance: NMDCs are made from non-magnetic materials, which also have excellent corrosion resistance properties. This makes them ideal for use in drilling operations in corrosive environments.
3. Magnetic Interference: Non-magnetic drill collars are used in drilling operations where magnetic interference may interfere with sensitive measuring instruments, such as MRI and electromagnetic logging tools.
Selection of Non-Magnetic Drill Collars:
When selecting NMDCs, the following factors should be considered:
1. Material: The material used for NMDCs should have good strength, durability, and corrosion resistance. Some commonly used materials include titanium, aluminum, and non-magnetic steel alloys.
2. Weight: The weight of the NMDC should be sufficient to provide the necessary weight and stability to the drill string.
3. Length: The length of the NMDC should be such that it provides adequate weight and stability to the drill string while minimizing the overall length of the drill string.
4. Connection Type: The connection type of the NMDC should be compatible with the other components of the drill string, such as drill bits and drill pipes.
5. Cost: The cost of the NMDC should be considered as they are typically more expensive than conventional magnetic drill collars. However, the cost of using NMDCs may be justified in drilling operations where magnetic interference may cause significant problems.
Overall, non-magnetic drill collars are an essential tool in modern drilling operations, especially in situations where magnetic interference could disrupt sensitive measuring instruments. The proper selection and use of NMDCs can help to ensure a safe and efficient drilling operation.
China Vigor's Drill collars are extra-heavy integral tools used to concentrate weight onto the drill bit for drilling and keep the drill string in tension. Mill test certificate conformance to API Spec. 7-1, NS-1, DS-1, and Customer requirements. We also manufacture Slick Non-magnetic Drill collars and Spiral Non-magnetic Drill collars, they function as housing for the MWD tools and provide weight for drilling string in directional drilling.
China Vigor's Drill Collar materials include AISI 4145H, AISI4145H modified steel, and Non-magnetic (P550 equivalent, P530 equivalent) Drill collars type are Spiral Drill collar, Slick, Flex, and Slip and /or Elevator Recess.
Features and Benefits:
1. API stress relief groove pin connection; API Bore back Box Connection.
2. Cold Rolling Thread roots—to improve the fatigue resistance of the connection.
3. Phosphate-coated connections- to prevent corrosion and galling upon initial make-up.
4. A hardness range of 285 to 341 BHN and a Charpy impact value of 40 ft-lbs are guaranteed at evenly distributed 16 points in any sections at room temperature;
Special Features:
1. Spiral Grooving- to avoid differential pressures sticking in the hole.
2. Stress Relief Groove & Bore Back Box
3. Hardbanding if required.
4. Slip and Elevator Recess-to improve downhole handling efficiency and safety.
China Vigor Drilling Oil Tools and Equipment Company Limited was established in the year 2008. Vigor is one of the first batches of companies that introduced Chinese downhole tools to the international market. Vigor understands how important quality means for the oil and gas industry, and how meaningful it is for saving the cost of the products, especially during this difficult and unprecedented time for the global world.
