Stefánsson, Ari (HS Orka) | Duerholt, Ralf (Baker Hughes, a GE company) | Schroder, Jon (Baker Hughes, a GE company) | Macpherson, John (Baker Hughes, a GE company) | Hohl, Carsten (Baker Hughes, a GE company) | Kruspe, Thomas (Baker Hughes, a GE company) | Eriksen, Tor-Jan (Baker Hughes, a GE company)
The typical rating for downhole measurement-while-drilling equipment for oil and gas drilling is between 150°C and 175°C. There are currently few available drilling systems rated for operation at temperatures above 200°C. This paper describes the development, testing and field deployment of a drilling system comprised of drill bits, positive displacement motors and drilling fluids capable of drilling at operating temperatures up to 300°C. It also describes the development and testing of a 300°C capable measurement-while-drilling platform.
The development of 300°C technologies for geothermal drilling also extends tool capabilities, longevity and reliability at lower oilfield temperatures. New technologies developed in this project include 300°C drill bits, metal-to-metal motors, and drilling fluid, and an advanced hybrid electronics and downhole cooling system for a measurement-while-drilling platform. The overall approach was to remove elastomers from the drilling system and to provide a robust "drilling-ready" downhole cooling system for electronics. The project included laboratory testing, field testing and full field deployment of the drilling system. The US Department of Energy Geothermal Technologies Office partially funded the project.
The use of a sub-optimal drilling system due to the limited availability of very high temperature technology can result in unnecessarily high overall wellbore construction costs. It can lead to short runs, downhole tool failures and poor drilling rates. The paper presents results from the testing and deployment of the 300°C drilling system. It describes successful laboratory testing of individual bottom-hole-assembly components, and full-scale integration tests on an in-house research rig. The paper also describes the successful deployment of the 300°C drilling system in the exploratory geothermal well IDDP-2 as part of the Iceland Deep Drilling Project. The well reached a measured depth of 4659m, by far the deepest in Iceland. The paper includes drilling performance data and the results of post-run analysis of bits and motors used in this well, which confirm the encouraging results obtained during laboratory tests. The paper also discusses testing and performance of the 300°C rated measurement-while-drilling components – hybrid electronics, power and telemetry - and the performance of the drilling tolerant cooling system.
This is the industry's first 300°C capable drilling system, comprising metal-to-metal motors, drill bits, drilling fluid and accompanying measurement-while-drilling system. These new technologies provide opportunities for drilling oil and gas wells in previously undrillable ultra-high temperature environments.
Severe vibrations in drilling systems are one of the main limiting factors for an efficient drilling operation. An adjustment of drilling parameters is necessary to avoid the negative impact of vibrations on reliability, measurement quality, and rate of penetration. The time to drill a well is therefore directly or indirectly affected if vibrations are not properly managed; measurements must be repeated, damaged tools can lead to additional tripping time, and rate of penetration is limited by reduced power that is delivered to the bit and restrictions of operational parameters.
Complex well trajectories, a difficult drilling environment, and the extended-reach of wells are additional challenges for drilling operations. The use of a mud motor in the bottom-hole assembly (BHA) is one option to supply power directly to the bit. However, if the mud motor is not properly managed, its operation can lead to lateral vibrations. BHA design and optimization of operational parameters are options to mitigate lateral vibrations. A basic understanding of mud motor vibrations is necessary for this purpose.
To characterize mud motor-induced vibrations, a statistical evaluation of averaged vibration measurement data from several runs is conducted. Distributions of the vibrational amplitudes are analyzed, in reference to different designs of the mud motor power section. Analysis continues by reviewing a large quantity of time-based acceleration data with a sampling frequency of 1000 Hz. Special downhole tests are conducted that cover the entire range of operational parameters of the mud motor. High-frequency vibration data with distributed sensors are collected for different motor types and stabilizer configurations.
The outcome of the analysis is used to determine the ideal mud motor for a given application. Existing models for drillstring dynamics simulation are fine-tuned. Based on the models, sweet spots for operational parameters that avoid severe vibrations are derived and displayed in an innovative way.
The extensive analysis of high-frequency vibration data enables a reliable determination of operational parameters for mud motor applications that correspond to low levels of lateral vibrations. The approach enables efficient drilling with a high rate of penetration and results in increased downhole tool reliability. This ultimately leads to an optimized service delivery for drilling operations.
Geothermal energy is one of the cleanest forms of energy to satisfy the growing global demand. Many countries around the world, including the USA, have a huge potential of untapped geothermal energy. Enhanced Geothermal Systems (EGS) technology is needed to economically utilize this resource. If hot rock is sufficiently fractured with continuous channels interconnecting large volumes of rock, a very large surface area is created that enables to economically extract geothermal energy from deep in the ground. The US Department of Energy (DOE) spearheads research and innovation in tools and technologies required for a successful exploitation of such EGS reservoirs where the temperature can exceed even 3000C.
To effectively utilize EGS resources, an array of injector and producer wells must be accurately placed in the formation fracture network. This requires a directional drilling system capable of high temperature whereas most commercial services for directional drilling systems are rated at 1750C. Deeper drilling will generally become more common in the future for new reservoirs and therefore high temperature drilling technology will be equally useful to the oil and gas industry.
We will discuss the development of a 3000C directional drilling positive displacement motor. Emphasis is put on design and manufacturing challenges of the multi-lobe metal only power section.
With the assembly and successful test of two complete tools in a test well at the Baker Hughes Experimental Test Area (BETA) in Oklahoma a major mile stone has been accomplished. Additional tests on the motor test bench in Celle (Germany) have been conducted to further improve durability. The utilization of the tools in a commercial geothermal well is planned for the second half of 2014.