Study on mechanical properties of titanium alloy drill pipe and application technology

With the increasing intensity of oil and gas field exploration and development, oil and gas wells are also drilling into deeper and more complex formations. Conventional steel drilling tools can no longer meet the requirements of ultra-deep, high-temperature and high-pressure wells. The paper first analyzes the advantages of titanium alloy drill pipe based on basic performance of titanium alloy drill pipe. The experimental results show that the basic properties of titanium alloy drill pipes meet the operating standards of the petroleum industry. Then the buckling performance of titanium alloy drill pipe and steel drill pipe is compared, the calculation results show that the buckling performance of titanium alloy drill tools is slightly lower than that of steel drill tools. Secondly, the maximum allowable buildup rate of titanium alloy drill pipe and steel drill tool is studied. The research shows that under the same condition of the drill pipe outer diameter, titanium alloy drill pipe can be used for a smaller curvature radius and greater buildup rate. This advantage of titanium alloy drill pipe makes it more suitable for short radius and ultra-short radius wells. Finally, taking a shale gas horizontal well as an example, with the goal of reducing drill string friction and ensuring drill string stability, a comparative study on the application of titanium alloy drill pipe and steel drill pipe is carried out. The results show that titanium alloy drill pipe has a wider application in the field, and is suitable for operations under various complex working conditions.

FKV-Bohrrohre mit strukturintegrierter Sensorik/Vibration damping and process monitoring in BTA deep hole drilling using fiber composites – FRP drill tubes with structure-integrated sensors

Bei BTA-Tiefbohrprozessen kommt es aufgrund der großen Werkzeuglängen häufig zu Torsionsschwingungen des Werkzeugsystems aus Bohrkopf und Bohrrohr. Im Vergleich zu konventionellen Stahl-Bohrrohren reduzieren Bohrrohre aus faserverstärktem Kunststoff diese Schwingungen durch ihr materialspezifisches Dämpfungspotenzial und erhöhen damit die Prozesssicherheit und verringern den Werkzeugverschleiß. Die Einbindung von Sensorfasern direkt in das Laminat erlaubt zudem eine Prozessüberwachung.   In BTA deep hole drilling, torsional vibrations of the tool system consisting of a drill head and a drill tube often occur due to the long tool lengths. Compared to conventional steel drill tubes, drill tubes made of fiber-reinforced plastic reduce these vibrations through their material-specific damping behavior and thus increase the process reliability and reduce the tool wear. The integration of sensor fibers directly into the laminate also allows a monitoring of the drilling process.

Methodology for Studying the Wear of Drill Pipe Threads during Repeated Making up and Holding under Load

Purpose of reseach is to develop a methodology for studying the wear of drill pipe threads during repeated making up and holding under load. Methods. For the research, stand “IRS-1” was used. This stand is a device for creating a torque of up to 80 kNm and transferring it to a made-up pipe. It is equipped with a make-up torque sensor and a control system that performs make-up until the specified tightening torque is achieved or periodically applies the torque to the made-up thread pair. The test procedure for IRS-1 stand consists of the following sequence of actions: before starting the tests, the threaded protectors are removed; the threads on the nipple and sleeve are cleaned of the preservative grease and traces of corrosion by dry wiping and subsequent degreasing; the thread on the nipple is measured according to the measurement chart using a gauge. The gauge is made on the basis of the threaded surface impression and is a plate with cutouts in the form of a cross-section of four threads. The gap between the gauge and the thread is measured using a set of probes from 0.01 to 0.09 mm in increments of 0.01 mm, over 0.1 mm to 0.45 mm in increments of 0.05 mm, over 0.5 mm to 1 mm in increments of 0.1 mm. Results. A new tribotechnical stand of IRS-1 model was designed and created, which allows implementing various techniques for studying the wear of drill pipe threads during repeated making-up and holding under load. An important feature of the designed stand is a make-up torque sensor and a control system that perform make-up until the specified tightening torque is achieved or periodically applies the torque to the made-up threaded pair. The maximum torque generated by the stand is 80 kNm. A particular technique was developed. The technique includes the requirements of the API 7G-2 standard and has shown its effectiveness in the study of thread wear of steel drill pipes. To implement the technique, a special gauge was developed on the basis of the threaded surface impression and is a plate with cutouts in the form of a cross-section of four threads. Within this technique, a measurement chart with two selected measurement areas was developed. An algorithm for making up a pipe at a uniform speed was created. The algorithm includes three stages. There was developed an algorithm of measurements using reference marks, providing measurements at four points in each selected area. Conclusion. The results obtained can be used to create resource-saving technologies for processing ingot, powder, and nanocomposite materials with different dispersion of phase and structural components that are operated under extreme conditions and states.

Estimate of potentialities for product machinability improvement by high-speed steel tool with modified cutting part

There are presented results of the comparative operation of two high-speed steel drill types: common ones and those with the working part modified by low-temperature plasma effect. A possibility to improve product machinability according to the criterion of productivity at the expense of the durability period increase of modified drills is shown. There are formulated requirements to the results of low-temperature plasma modification ensuring tool life increase.