Improve borehole quality and wireline running speeds

While drilling a multiwell campaign in Eden Yuturi field, East basin, Ecuador, Petroamazonas sought to improve borehole quality to enable more efficient wireline formation evaluation runs. Drilled from multiple well pads, the directional profiles include J- and S-style wells that reach TD with an 8 1/2-in production section that is 1,000–1,500 ft in length. The wells were drilled initially in the Tena formation, which was composed by claystone interval, and then into the Napo formation, a heterogeneous sequence with an unconfined compressive strength (UCS) ranging from 5,000–15,000 psi and high UCS spike, and where shale, limestone, and sandstone were encountered. To maintain borehole quality in the shale sections, flow rates and hydraulic horsepower (HSI) were controlled.

In offset wells, the operator achieved an ROP of 60–65 ft/h, and the bits reached TD in good condition. The varying formations in the 8 1/2-in section tend to break away and ledge, causing challenges with the formation evaluation wireline runs through the production section. After drilling, time-consuming wiper trips conditioned the borehole to improve wireline running speeds.

Maintain lateral stability while maximizing ROP and durability

To improve lateral stability of the base drillbit design, Smith Bits suggested a modified drill bit that employed a central Stinger conical diamond element. The Stinger element has a thick polycrystalline diamond compact composition designed for maximum strength and durability. The centrally located element removes the PDC cutters from the bit face, replacing them with technology that enables high-point loading to fracture rock more efficiently, increasing durability and ROP while maintaining lateral stability. Using the IDEAS integrated design platform, the MSiZ616 drill bit was developed from the base design used on offset wells. Surface parameters were moderated, keeping flow rate and HSI controlled while reducing rpm, minimizing borehole spiraling and avoiding washouts. In addition, the enhanced stability and obtained planned trajectories leads to good directional response.

Increased ROP by 27% to 33% on three wells, saving 1.5 days

Adding the central Stinger element on the drillbit design enabled the wireline assembly to reach TD without hanging up. The drill bit also produced a more uniform borehole shape, providing conditions conducive to efficient wireline operations. As a result, the operator saw an increase of 27% to 33% on three wells when compared with offset wells, saving 1.5 days.