Drilling Performance Improvements in Gas Shale Plays using a Novel Drilling Agitator Device

Abstract

High friction of the drill string against the wellbore has become a concern in the process of drilling, irrespective of whether it is a vertical, directional or horizontal application. This source of additional torque and drag will lead to low rates of penetration, poor tool face control, short runs, severe drill string and bit wear, and at the same time, could cause problems while running casing, liners and completions. In directional and horizontal applications, this high friction could also lead to high well tortuosity, which will limit the amount of step out and can even impair productivity. The implementation of a unique tool, referred to as a Drilling Agitator Tool (DAT), has demonstrated clear improvement in drilling performance by reducing stick slip and torque at the drill string. This has enabled reduction in drag and thus improved weight transfer to the bit when drilling through highly interbedded formations, directional applications or long horizontal sections. It has also shown greater accuracy in maintaining tool face control once the static friction was minimized. This DAT relies on three main mechanisms: a power section, a valve and bearing section, and an excitation section. The tool operation vibrates the drill string with a low frequency and low amplitude axial vibration. This paper illustrates case studies from the Haynesville, Fayetteville and Barnett Shale Plays, where the DAT has proven to help reduce torque and Stick-Slip when run on rotary in vertical applications, as well as Motor assemblies through directional and horizontal sections. These improvements in drilling performance have resulted in longer runs and faster rates of penetration compared to offset wells, thus reducing the number of bits and improving the economics in drilling these shale plays.

Performance Analysis of a Fluidic Axial Oscillation Tool for Friction Reduction with the Absence of a Throttling Plate

“…Therefore, the frequency of pulses is double the oscillation frequency of the fluidic oscillator. In order to sufficiently generate benign oscillations and to minimize the impact on the Measurements While Drilling (MWD) and Logging While Drilling (LWD) tools, the pulse frequency is encouraged to be limited to10 per second [1]. According to the study of Zhang et al [22], increasing the diameter of the piston rod will significantly reduce the backward stroke end velocity of the piston, thus decreasing the amplitude Figure 7 provides the variation of measured displacement D with time T for different supply volume flow rates Q V .…”

“…Drilling a structurally complex well, irrespective of whether it is a horizontal well, a directional well, an extended reach well, or a multilateral well, has become commonplace in the oil and natural gas industry, as companies seek to drill deeper and further optimize the oil and gas production in the target field [1][2][3]. As a result, the high frictional resistance of a drill-string against the borehole rock has become a concern in the drilling process [4][5][6].…”

“…This source of additional torque and drag will lead to a low rate of penetration (ROP), the wear of drilling tools, short runs, wellbore instability, and complex stress of the drill string, etc. [1]. In particular, wellbore instability sometimes leads to the pipe becoming stuck, which may require plugging and side tracking, significantly driving up the cost of reservoir development [7].…”

Dynamic Analysis of Bottom Hole Assembly With External Vibrating Force Excitation

“…Franklin and Aref [16] illustrated several case studies of the VARD tool. In the fields of Haynesville, Fayetteville and Barnett Shale Plays, the test results proved t hat the VARD tool was effective in reducing torque and controlling stick-slip in vert ical applications, a nd directional drilling with down-hole motors.…”

Vibration characteristics analysis and experimental study of new drilling oscillator

“…These methods are mostly restricted in suitable conditions, and speed-up effect is not obvious. [4][5][6][7] Among these methods, the downhole vibration tools, such as fluid hammer, hydraulic impactor, and hydro-oscillator, have a good effect on drill string friction reducing and bit ROP increasing. [8][9][10] For the complicated downhole conditions, the existing researches mainly obtain related parameters through experimental tests.…”