The recent industry downturn has driven a demand for predictable, repeatable drilling performance and precise well placement, enabling increasing confidence in forecasting the commercial viability of geological assets. This in turn has led to a need for real-time downhole data of a quality and quantity sufficient to have a substantial impact on the ability to visualize downhole conditions.
Real-time data can be streamed through high-speed wired drillpipe (WDP) telemetry allowing operators to make more data-driven decisions with clarity and confidence. The IntelliServ WDP includes a data connection by incorporating a coaxial cable along the length of the drillstring from the rig to sensors near the drillbit. This high-speed data network, using inductive coils located in the drillstring connections, enables bi-directional data transmission between downhole tools and the surface at speeds up to 57,000 bits per second (bps).
The data transmitted include high-frequency direction and inclination, temperature, pressure, and three axes vibration sensors. These sensors are not restricted to the near-bit location. There also are along-string measurement sensors at regular intervals along the drillstring allowing visibility of, for example, annular pressure, which provides indications of hole-cleaning efficiency and allows the mitigation of problems such as pack-offs.
Automation platform
When combined with NOV’s programmable automation platform NOVOS, this near-instantaneous transmission of downhole data allows for the fine-tuning of several critical operations. For example, constant vibration measurements near the bit enable a refinement of the taggingbottom procedure, which in the past has been a source of the challenging dynamic conditions that can lead to drillbit damage and downhole tool failure.
Significant time is saved by high-speed communication with MWD/LWD tools and rotary steerable systems, eliminating much of the lost time it has traditionally taken to communicate with these tools.
In addition to the benefits of the standalone WDP network, the platform also plays a crucial role in being able to drill automatically. NOV’s control systems provide the driller with joystick control of the rig and the drilling process. The driller has multiple responsibilities, including the safety of the crew, which does not allow for undivided attention on the efficiency of the drilling process.
This challenge has been addressed with the NOVOS automation platform. Bringing together downhole sensors, the rig control system with the IntelliServ downhole network connecting them, has enabled an advanced closed-loop automated drilling system. In addition, an open architecture philosophy and a software development kit allows third parties to write algorithms to control the system, which can, for example, enhance drilling through downhole automated drill-off tests that constantly analyze the efficacy of different combinations of drilling parameters.
One NOVOS application being used is the Equivalent Fluid Density viewer, which was designed to manage wellbore stability by utilizing the along-string measurement’s for measuring annular pressure. This provides the operator with the ability to view the cuttings transportation along the wellbore and identify any zones that are accumulating cuttings or creating potential cutting beds. The network also can be used to communicate with third-party downhole tools and sensors. Controlling the drilling process using downhole data allows for a borehole quality that is very difficult to achieve using the traditional inferred measurements at surface.
Geosteering
Typically within the industry when drilling out of the production sweet spot, it is technically possible to directionally drill back into the production zone within one 9-m (30-ft) single pipe. However, this would create a high dogleg in the wellbore and increase wellbore tortuosity. It is more practical to complete this within one 27-m (90-ft) stand.
When looking at the average potential loss of production over 27 m, it could be well over $200,000 over the life of the well. Maximizing potential production demands precise well placement, requiring geosteering, which in turn demands interpretation of geological data during the drilling process.
The use of WDP allows data from logging sensors to be streamed to surface providing, in real time, an image quality only previously seen in memory mode, which allows for much greater clarity for those with well placement responsibility. Geosteering without WDP is almost like driving in the dark without headlights. Geosteering with WDP is like driving with headlights on and ensures the operator can stay within the target zone by being able to steer in real time.
When using mud pulse telemetry, it is typically 2 bps to 12 bps and has a time delay in downlinking data to the surface. With WDP, there is real-time communication at internet speeds of 57,000 bps. This enables users to proactively mitigate risks by providing accurate geosteering, which helps avoid potential production loss.
This type of accuracy is even more important as horizontal lateral lengths in the U.S. unconventional market continue to get longer. From 2016 to now, there has been a 40% increase in horizontal lateral length from 1,767 m (5,800 ft) to 2,438 m (8,000 ft). At this pace, it could average 4,572 m (15,000 ft) by the year 2020. NOV is enabling and powering the industry to ensure that operators have the advanced technology needed to achieve these longer laterals. The industry once again is proving that the adoption of advanced technology can enable companies to improve the efficiencies required to drill a way out of a downturn.
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