Inclinometer while drilling is generally used in oil drilling, coal exploration, offshore oil drilling and other oil fields, most of the current inclinometer is wired inclinometer while drilling. Inclinometer while drilling is generally used in oil drilling, coal exploration, offshore oil drilling and other oil fields, most of the current inclinometer is wired while drilling, and on the basis of this developed a new MWD wireless inclinometer while drilling. The main difference between it and the wired inclinometer while drilling is that the transmission mode of downhole measurement data is different. It is widely used in the borehole trajectory measurement construction of difficult directional Wells, especially for high-inclination Wells and horizontal Wells, and it is composed of guided drilling systems with guided dynamic drilling tools and offshore oil drilling.
During the drilling process, the data detected by the inclination instrument mounted on the BHA is continuously transmitted to the surface in real time, so that the wellbore trajectory can be controlled more accurately and the inclination time can be saved. This measuring instrument is often referred to as the inclinometer while drilling (traditionally MWD). According to the structure characteristics of the measuring instrument and the transmission mode of the measuring parameters, it can be divided into wired inclinometer and wireless inclinometer while drilling.
While drilling inclinometer is generally used in oil drilling, coal exploration, Marine oil drilling oil field, such as the current most of the inclinometer is wired inclinometer with drilling, and on the basis of the development of a new type of MWDS wireless inclinometer with drilling, it has to do with wired inclinometer with drilling the main difference is that of underground transmission of measured data in a different way, it is widely used in borehole trajectory measurement construction of highly difficult directional Wells, especially in highly deviated Wells and horizontal Wells, and is composed of steering drilling system with guiding power drilling tools and offshore oil drilling.
There are three main transmission methods for MWD wireless inclinometer while drilling
1. Positive pulse method
The position of the needle valve of the positive mud pulse generator relative to the hole can change the cross-sectional area of the mud flow path here, thus causing the mud pressure to rise inside the drill string. The needle valve movement is realized by measuring data encoded by the probe pipe through the modulator control circuit. Changes in riser pressure are continuously detected at the surface and translated into different measurements through decoding.
2. Negative pulse method
Mud pulse generator need to assemble in special non-magnetic drill collar, open the discharge valve of the mud negative pulse generator, can make the mud inside the drill string by the discharge valve and the discharge orifice flow on the non-magnetic drill collar to borehole annulus, causing the inside of the drill string mud pressure is reduced, the action of discharge valve is encoded by test tube measurement data by modulator control circuit.Changes in riser pressure are continuously detected at the surface and translated into different measurements through decoding
3. Continuous wave method
Continuous generator rotor in mud sine or cosine pressure under the action of wave, encoded by underground test tube measurement data through the modulator system control relative to the angular displacement of the rotor stator make the sine or cosine phase displacement appears on the pressure wave in time, on the ground continuously detect these changes in phase displacement, and through decoding into different measurement data.
In wireless drilling field construction, improving the signal-to-noise ratio of signal transmission is the key to successfully obtain the parameters while drilling. In the whole process, we should pay attention to various factors affecting the signal-to-noise ratio, and take measures to improve the signal-to-noise ratio to ensure the smooth progress of construction. During the use of the instrument, it is necessary to ensure the maintenance, assembly and combination of accessories of the instrument itself, but also to combine the drilling fluid performance, equipment operation and drilling parameters. Therefore, to ensure the normal use of mud pulse wireless drilling instrument, so that downhole data quickly and accurately transmitted to the surface, to provide protection for directional application.