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Title: Drilling Optimization Utilizing Surface Instrumentaton for Downhole Event Recognition

Technical Report ·
DOI:https://doi.org/10.2172/882932· OSTI ID:882932

This DOE project was undertaken to develop and test an instrumented data-acquisition sub that is mounted in a drill string below the top drive and used to detect downhole events. Data recorded at the surface during drilling operations would then be processed and presented to the driller to discern undesirable drilling conditions and help optimize drilling rates and maximize the life of components in the BHA. This instrumented sub was originally conceived and developed solely as a single-point collection center for rig data that would be used in a number of Noble's products. The sub was designed to collect hook load, rotary torque, rotary speed, rotary position, drill pipe pressure, mud temperature, triaxial vibration, and triaxial magnetometer data. The original design and fabrication was by Sandia National Labs under Noble's direction, which was then tested with Sandia's diagnostics-while-drilling downhole package. After initial results were analyzed, the team surmised that important information describing performance and condition of the bottom-hole assembly (BHA) was embedded in the data recorded by the instrumented sub, and began investigating the potential of using surface measurements from the sub to highlight problems occurring downhole before they could be discerned by the driller. Later, a proposal was submitted to DOE for funding to more broadly investigate use of the system for detecting downhole problems while drilling. Soon after DOE awarded this contract, the Noble team responsible for the previous developments was disbanded and their work terminated (due to factors unrelated to the sub development). This change halted the complementary work that Noble had planned to conduct during the DOE project, and necessitated that all the development work be completed by the DOE project. More effort was expended on the project to develop a field-ready prototype than was originally foreseen. The sub's design had to be significantly modified during the project based on results of field tests. The original slip ring for communication was replaced with a radio link, which makes the sub easier to move to different rigs and simplifies the set-up process. In addition, the sub's previous design would prevent it being used on oil and gas rigs due to potential explosion hazard. The sub was redesigned so that during operation all electrical components on the sub are under a blanket of nitrogen. A pressure switch is used so that, should a leak develop, the sub will shut itself down until any problems are repaired. A total of four series of field tests were conducted. The first (mentioned above) was part of the original Noble-sponsored program and in conjunction with Sandia's diagnostics-while-drilling system. Although these tests highlighted important problems, they showed significant promise for the concept, and the sub was returned to Sandia for early repairs and modifications. After the DOE project took possession of the sub, it was tested three more times in the field. The first two DOE tests had the same objective, which was to establish that the sub could function correctly on the rig and deliver usable data, and to develop procedures for setting up and operating the sub and support computer on a rig. During the first test most of the time was spent troubleshooting the sub. Several significant problems were revealed, demonstrating that the current design was not robust enough to survive typical oil field operations. The sub was then redesigned to increase its robustness and allow it to run safely in areas where explosive gases might be present. Once these changes were implemented, the sub was sent to a second shake-down field test. The new design was found to be greatly improved. The sub operated throughout the test, and quality of the data was significantly higher. Near the end of this project, a final field test was conducted with the objective of creating (or simulating) specific problem conditions and recording data to determine if signatures could be recorded and identified that, after analysis, might signify particular types of drilling activities or conditions. Tests included normal rig operations as well as dropping the string, bit stick/slip, bit bounce, and rough drilling. The sub worked very well throughout these tests, and signatures were obtained for each of the conditions. Some events, most notably stick/slip and rough drilling, exhibited unique signatures that were recorded by the instrumented sub. The final field tests were conducted in a relatively shallow well, and further testing is needed to determine the range of depths from which usable signals can be detected. However, these tests clearly demonstrated that useful data can be gathered in this manner and that much of this data, typically collected by several sensors in various locations, can be collected at a single point and that the data are of higher quality than is often the case.

Research Organization:
Maurer Technology Inc.
Sponsoring Organization:
USDOE
DOE Contract Number:
FC26-03NT41782
OSTI ID:
882932
Country of Publication:
United States
Language:
English