DwC Technology

Defyer Bits, OverDrive System with TorkDrive Tool Set Casing at Planned Depth in one trip, Mitigate Losses

New Weatherford technology allows the operator to Set casing at planned depth and thus avoid the additional drilling and casing costs associated with using contingency casing strings. In previous wells in this field, the operator encountered problems reaching total depth (TD) while running 13 3/8-in. casing conventionally in a 17 1/2-in. hole section.

It provides an effective solution for casing to reach TD and minimize delays before cementing, and allows for the reduction of hole size from 17-1/2 in. to 16 in. to reduce wellbore drilling-fluid requirements. The goal was to minimize loss circulation in the remote desert drilling location.

Weatherford’s total depth team evaluated formation strength, drilling viability, bit hydraulics, and torque and drag before installation. The recommended solution consisted of the OverDrive system with the TorkDrive compact casing running and drilling tool to deploy a 13 3/8-×16-in. casing Defyer DPA8416 drillable casing bit, and specifically designed SpiraGlider centralizers in a string of 13 3/8-in. L80, 72-lb/ft DINO VAM to the planned casing-setting depth.

A 20-in. casing string was set in the upper section to isolate severe loss circulation in the shallower hole. The operator continued drilling using the 13 3/8-in. casing string equipped with the DefyerDPA8416 drillable casing bit to the target depth.

The operator used an average rate of penetration (ROP) of 20 ft/hr (6.4 m/hr) with a maximum on-bottom torque of 10,000 ft-lb (13,558 N◦m), while controlling wellbore instability commonly caused by brittle shale cuttings. The DwC technology provided an accurate casing setting depth across the next formation at 3,618 ft (1,103 m) while maintaining wellbore stability, minimizing the number of trips across the section and reducing the size and rate of the cuttings generated.

The casing string was cemented immediately using a six-bladed conventional PDC bit. The Defyer DPA8416 drillable casing bit was drilled out to the next 12 1/4-in. section in the same trip. The Defyer drillable casing bit was drilled out in less than 8 minutes.

Weatherford’s total depth technologies were deployed, and the TorkDrive compact tool was used to run 2,368 ft (722 m) of casing and to drill 1,250 ft (381 m) with the Defyer DPA8416 bit. More than 87 connections were made during 57 hours of running and drilling operations with no lost time or safety incidents. Average casing-running speed was 8 joints per hour. Overall, the operator achieved a total depth of 3,618 ft (1,103 m) without nonproductive time (NPT) incidents.

Using Weatherford’s DwC technology with Defyer drillable casing bits and the TorkDrive tool presented the operator with many advantages. The operator was able to set the casing at the planned depth to avoid drilling hazards such as wellbore instability in the drilled formation. Weatherford’s total depth technologies also helped the operator obtain results in one trip without the NPT incidents traditionally associated with this formation type, saving the costs associated with additional drilling and casing running trips.

Additionally using the OverDrive system allowed the operator to save two in and out drillpipe trips and remove personnel from hazardous areas during casing-running operations, enhancing overall safety.

Furthermore, The TorkDrive compact tool enabled the operator to reciprocate and rotate the casing string while simultaneously circulating through tight spots and trouble zones without needing a check trip, saving significant time and costs.

By Weatherford


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