Method for processing MWD (Measurement While Drilling) underground continuous wave signal
A signal processing and signal technology, applied in seismic signal processing, seismology for logging records, earth-moving drilling, etc., can solve the problem of not representing the real situation of ΔP signal transmission
Active Publication Date: 2013-05-08
BC P INC CHINA NAT PETROLEUM CORP +2
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Therefore, the traditional analysis method that "infinite transmission along the drill string" does not represent the real situation of ΔP signal transmission
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[0014] figure 1 It is a simulation diagram of the downhole MWD system structure and signal transmission channel. This system is composed of a finite length drill collar and a semi-infinite length drill string. The continuous wave signal will be attenuated due to irreversible thermodynamic loss during the transmission process of the drill collar and the drill string; however, in the signal processing mode discussed so far, its loss factor can be regarded as a constant, and its dynamic response is irrelevant.
[0015] according to figure 1 As shown, the drill bit is located at , the mud pulse generator is located at The length of the drill collar is L c , the cross-sectional area is A c , the cross-sectional area of the drill string is A p . figure 1 It also shows the difference of the three cross-sectional areas in the system, marked with 1, 2, and 3.
[0016] figure 2 A in A shows the initial state of the signal generation: the ΔP signal is sent out at the pulse g...
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The invention discloses a method for processing MWD (Measurement While Drilling) underground continuous wave signals, which solves the problem that the original processing method does not consider the influence of signal reflection, superposition, echo, etc. The method comprises the following steps of: firstly, establishing a simulated diagram of underground MWD system structure; and then, respectively processing signals by dividing into two conditions according to the proportional relationship between the drill bit nozzle area and the drill bit section area, wherein the first condition is that the drill bit is an open end reflector and the impedance of a drill pipe and that of a drill column are not matched, and the second condition is that the drill bit is a closed end and a solid reflecting surface, and the cross section of the drill pipe and that of the drill column are not matched. Based on the specific signal processing algorithm provided by the invention, the inferences of reflection, supersosition and echo contained in signaled received on ground can be removed, the original delta P signals can be recovered, and furthermore, the MWD information can be acquired by analyzingdelta P signals.
Description
technical field [0001] The invention relates to a deconvolution processing method based on continuous wave measurement signals in the measurement-while-drilling or logging-while-drilling of petroleum, mining, geological exploration and the like. The invention herein is related to the measurement-while-drilling system and is closely related to the propagation of downhole data during the measurement-while-drilling process. . Background technique [0002] In the process of MWD continuous wave signal processing, it is generally considered that the "downhole signal" is emitted by the pulse generator installed near the end of the MWD drill collar of the downhole instrument string. Two corresponding signals are generated on both sides of the continuous wave signal generator, which we call ΔP signals, and they propagate to the surface and downhole respectively. [0003] In a downhole MWD collar, drilling fluid flows through an MWD pulse generator, which may be a positive pulse, a ...
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IPC IPC(8): E21B47/18G01V1/48
Inventor 苏义脑盛利民窦修荣李林邓乐陈伟松边海龙石荣
Owner BC P INC CHINA NAT PETROLEUM CORP