Limitations on drilling torque and penetration rates in interbedded formation

The Wolfcamp Formation in the Midland basin of West Texas contains interbedded shale and limestone that can limit drilling torque and penetration rates. The curve build section through the Spraberry Formation also presented a challenge because it required higher shale inhibition compared with the lateral.

An operator in the region needed to minimize drilling torque in a 15,285-ft- [4,659-m-] MD well while drilling the curve and 6,235-ft [1,900-m] lateral throughout the 8 1/2-in production interval. In previous wells, an inhibitive WBM was employed, but the WBM system's torque limits impaired the rig's overall ability to drill as fast as was possible using an OBM.

Performance comparable to an oil-base system

M-I SWACO recommended the HydraGlyde high-performance water-base drilling fluid system to reduce torque, drag, shale swelling, and dispersion while delivering exceptional inhibition. The HydraGlyde system delivers drillability comparable to an OBM while maintaining the characteristics of an WBM. The system also delivers a high-quality filtercake and a low-tortuosity wellbore that minimizes the risks of differential sticking.

The HydraGlyde system included approximately 1.5 lbm/bbl [5.71 g/L] of HydraCap encapsulating additive to minimize clay dispersion and to enhance wellbore integrity, 1%–2% of HydraHib shale inhibitor to provide an amine-base additive for wellbore stability, and 2%–3% of HydraSpeed ROP-enhancing primary lubricant to deliver exceptional lubricity.

The M-I SWACO team used VIRTUAL HYDRAULICS drilling fluid simulation software, which evaluates and designs critical drilling hydraulics under simulated downhole conditions by monitoring and predicting equivalent circulating density, equivalent static density, temperature, hole cleaning, and tripping profiles. This well monitoring tool helps customers avoid most hydraulics-related NPT scenarios. It complements drilling fluid performance by achieving a quality wellbore under optimal operating conditions while reducing rig time and lowering costs.

Accelerated drilling with substantial torque reduction

The 8 1/2-in production interval was drilled in 3.5 days, making it one of the operator's fastest-drilled wells in the area. Drilling torque was up to 5,000 ft.lbf less than the torque required in offset wells. The entire section was drilled to TD with one bit and exhibited a smooth wellbore that was successfully cased and cemented. The customer is using these improved drilling parameters to establish higher drilling fluid standards for future wells in the area.