New Mud Pulse Telemetry Techniques for Deepwater Applications and Improved Real-Time Data Capabilities

Abstract Increasing water depth, total well depth, synthetic mud systems and increasing measurement complexity pose unique challenges for real-time data transmission via mud pulse telemetry. In deepwater environments, where the use of synthetic oil-based mud is prevalent, low water temperature significantly increases mud viscosity which reduces the signal strength at surface and makes detection of the signal more difficult. Noise within the mud channel further hinders transmission of downhole data. With rig rates approaching $350k per day and total well depths beginning to exceed 10700 m (35,000 ft), operators cannot afford to drill ahead without good quality real-time downhole data. On recent wells in deep water conditions in the Gulf of Mexico as many as seven different measurement while drilling/logging while drilling (MWD/LWD) tools have been run concurrently. Some of these tools may include the capability to produce real-time images. There is thus an increasing demand for higher data rates coupled with more reliable telemetry to transmit all this data to the surface in real-time. Recent advances in MWD tool design, signal strength prediction, and signal recovery on the surface, using advanced digital signal processing techniques, have made it possible to double telemetry data rates while also reducing error rates in the data received at the surface.