#centralizerforcasing

Continuous access to underground energy resources such as oil, gas and geothermal energy requires drillers to carry out a safer drilling and extraction process. Drilling is one of the integral steps to sustain global energy requirements. An important piece of equipment to accomplish safer drilling are Centralizers. Widely used to position the casing uniformly inside the wellbore, this oilfield equipment ensure that the casing is centralized in the wellbore so as to offer a more uniform distribution of cement slurry around the casing. They also keep the casing from hitting the wellbore walls. As a result of casing centralization, a continuous annular clearance around the casing allows the cement to completely seal the casing to the borehole wall. API RP 10D-2 recommends the appropriate positioning of the centralizers in the wellbore.

Opportunities for Centralizer Manufacturers

An estimate says that globally 10 million centralizers are fabricated and utilized every year. The casing centralizer market alone was estimated to be worth USD 430 million in 2018 and is projected to be valued at USD 670 Million by 2025, expanding at a CAGR of 6.8%. This presents immense opportunities for centralizer manufacturers and suppliers. However, for centralizer manufacturers, business limitations such as geography have always been a big obstacle. An industry worth $430 million is handicapped due to the absence of a global marketplace, that is both transparent and digital. Both the operators and service companies face problems in a manner that they have to choose from the right type of centralizers from the right kind of manufacturers. While you can easily find verified centralizers manufacturers on different portals, let us look at the types of centralizers widely used across the oil and gas industry.

Types of Casing Centralizers

Bow Spring

Bow-spring centralizers are manufactured from a set of flexible springs attached to two collars. A restoring force is generated by the flexible bows that provide the separation between the casing and wellbore. Considering the fact that the outer diameter of the bows is generally larger than the well diameter, bow springs are appropriate for utilization in washout areas. While a particular application dictates the shape, size, and the number of bows, performance requirements such as starting force, restoring force, and testing for these centralizers are outlined in API Spec 10D.

The bow-spring category can be further classified into non-welded and welded centralizers. It has been observed that the non-welded type operates well under compressive loads. They find usage in standard applications where no rotation is needed or lowering the drag force is not a condition. However, these centralizers are not tailored according to hole/pipe size combinations so they come less expensive than other types of centralizers. Bow-spring centralizers can easily pass through narrow hole sections and expand in the focused locations, owing to the flexibility of bows. However, the effectiveness of Bow spring centralizer is subject to the restoring force. In cases when the casing is heavy or the wellbore is highly deviated, they may not support the casing very well.

Rigid Centralizers

Rigid centralizers are fabricated using solid steel bars or cast iron, with a fixed blade height. These centralizers are sized to fit a specific casing or hole size. Rigid Centralizers are rugged and operate well even in deviated wellbores, regardless of the side force. They offer an assured standoff and function as bearings during the pipe rotation. However, limitation comes because the centralizers are smaller than the wellbore, and hence they will not provide a good centralization as well as the bow-spring type centralizers in vertical wells.

Semi-Rigid Centralizers

Semi-rigid centralizers provide desirable features found in both the bow-spring and the rigid centralizers and are manufactured by double-crested bows. In semi-rigid centralizers, the spring characteristic of the bows allows them to compress so as to get through tight spots and severe doglegs. The semi-rigid centralizers demonstrate specific features usually related to rigid centralizers. These features are found because of the double-crested bow which delivers restoring forces exceeding the standards outlined by API.

Mold-On Centralizers

Fabricated using carbon fiber ceramic materials, the mold-on centralizer blades find application directly for the casing surface. The blade length, angle, and spacing can be tailored to suit specific well applications, particularly for close tolerance annulus. The non-metallic composite can also diminish the friction in extended reach laterals to avoid cases of casing buckling. 

With experience of 4 decades in the field of oilfield equipment & Cementing activity, Eneroil Offshore has created range of centralizers to be the perfect cementing equipment for all kind of well cementing job across the globe.

Based on the current challenges of well operations, Eneroil's application engineers have designed cementing equipment that suits larger variety of well applications and this range includes Welded, Non-welded, Rigid, Semi-rigid, Roller Centralizers, Bow type centralizer along with our latest masterpiece - Single Piece centralizer & Thermoplastic centralizer.