Abstract

Drill pipe capable of transmitting high-bandwidth downhole data and surface control signals has been developed and successfully tested. The system incorporates a high-speed data cable protected in a high-pressure conduit that runs the length of the joint. The cable terminates at induction coils that are installed in protecting grooves machined in the secondary torque shoulders of double-shoulder tool joints at each end of the pipe. The system is virtually transparent to standard rig procedures and offers robust, reliable operation.

The new system has successfully demonstrated error-free, data transmission rates of up to 2,000,000 bits/sec. The bi-directional system can transmit real time MWD/LWD data, as well as, send commands or signals from the surface to operate downhole tools and sensors. Full-length prototype joints have been used extensively to drill and transmit data in test wells. Results of these tests, along with plans for field-testing in actual drilling environments, are presented.

Potential drilling enhancements include improved bit life, optimized casing point selection, enhanced kick detection and control, and elimination of wireline log runs and survey time to retrieve MWD/LWD data. Telemetry drill pipe can expand the potential for Underbalanced Drilling (UBD) techniques and improve the safety of UBD operations. The paper presents overviews of new concepts and technologies that can take advantage of the high-bandwidth, two-way communication capabilities of the system. Seismic-While-Drilling with the ability to look ahead of the bit, enhanced well control systems with sensors distributed along the drill string and drill string dynamics monitoring systems represent areas for innovation with the telemetry drill pipe.

Telemetry drill pipe can improve well and field productivity by providing more complete, real-time logging information and reduce drilling time and costs and enhance well control by providing real-time downhole drilling data and early kick detection.

Introduction

The process of locating and extracting energy resources from deep within the earth is challenging. Reservoirs must be located using advanced techniques, geologic formations must be penetrated and dangerous over-pressured zones must be navigated and controlled.

Precise well bore placement is essential to maximize well productivity and profitability. Hydrocarbon reservoirs can be entered incorrectly, experience formation damage that adversely affects production, overshot or even missed completely. Inaccurate drilling and imprecise downhole information can result in millions of dollars of lost and delayed production. Even more tragic is the potential for injury or loss of life due to improper drilling practices associated with inaccurate well data.

As early as 1939, technology had been proposed to link serial drill string components to provide a network for the transmission of power and data from the bottom of the hole to the drilling platform on the surface.¹

Drill String Connectivity Solution

The core technology behind the telemetry drill pipe system is a passive communications link than connects discrete components together. This link consists of a ring-shaped transducer that can transmit data to another component without direct electrical contact. The ring shape is ideal for data transmission across thread tool joints since radial orientation is not required for effective communication. The non-contact feature of the coupler permits it to be encased and protected within the tool joints or connections, and thereby avoids the pitfalls inherent in previous electrical connector concepts.

The system incorporates a data cable traveling the length of each drill pipe section or subassembly. The cable is protected within the pipe and tool joint, and does not interfere with mudflow or the deployment of downhole tools through the drill string. The data cable is specifically engineered to transmit high-speed data with low power loss. At either end of each section of drill pipe or drill stem component, a non-contact line coupler is employed to ensure that the data signal can be passed along to the next component.