Supercharging device of formation pressure measurement-while-drilling instrument

Abstract

The invention discloses a supercharging device of a formation pressure measurement-while-drilling instrument. The supercharging device comprises a center shaft (1) as well as a testing connector I (2), a supercharging structure and a testing connector II (3) which are nested at the outer part of the center shaft (1) sequentially, wherein the supercharging structure comprises a casing (4) and at least one supercharging piston (5); outer walls of a large-diameter section and a small-diameter section of the supercharging piston (5) are tightly matched with an inner wall of the casing (4), and inner walls of the large-diameter section and the small-diameter section of the supercharging piston (5) are tightly matched with the center shaft (1); and the supercharging piston (5) separates the interior of the casing (4) into a low-pressure cylinder (6) and a high-pressure cylinder (7) which is filled with hydraulic oil. The supercharging device has the benefits as follows: lower slurry differential pressure inside and outside a drill column can be converted into high hydraulic pressure, power is provided for the formation pressure measurement-while-drilling instrument, the problem of larger dependence on an underground turbine generator is solved, larger hydraulic pressure can be obtained in a multistage supercharging manner, the use range is widened, and the supercharging device is simple in structure, reliable in work and long in service life.

Description

technical field [0001] The invention relates to the technical field of supercharging devices for petroleum drilling engineering, in particular to a supercharging device for a formation pressure measuring instrument while drilling. Background technique [0002] Formation (pore) pressure is one of the important basic data for oil and gas drilling engineering and reservoir geological engineering. Accurate prediction and monitoring of formation pressure is extremely important and meaningful for oil exploration, development and drilling engineering. The most direct way to accurately obtain a certain parameter or data is direct measurement. Although drilling technicians have developed various drill pipe testing techniques and cable testing techniques, the testing is carried out after the drilling is stopped. Since the formation is polluted by drilling fluid, the measured formation Pressure often has certain deviations, and formation pressure testing using traditional wireline logg...

AI Technical Summary

Problems solved by technology

The most direct way to accurately obtain a certain parameter or data is direct measurement. Although drilling technicians have developed various drill pipe testing techniques and cable testing techniques, the testing is carried out after the drilling is stopped. Since the formation is polluted by drilling fluid, the measured formation There is often a certain deviation in pressure, and it is extremely time-consuming and costly to use traditional wireline logging tools for formation pressure testing in highly deviated / horizontal wells, and there are potential risks such as difficulty in installing tools

For this reason, on the basis of the traditional wireline testing technology, drilling technicians once again proposed to test the formation pressure while drilling, that is, to use the Formation Pressure While Drilling (FPWD), which is connected to the lower In the Bottom Hole Assembly (BHA), the drilling string is run into or out of the wellbore together. Since the formation pressure measurement instrument while drilling is tested in the early stage of drilling oil and gas layers, the formation is affected by factors such as wellbore fluid during the test. The impact is small, and the measured formation pressure is more realistic, which solves a series of difficulties and problems such as large formation pressure error, long test time, high cost, hysteresis, and difficulty in running tools.

However, due to the large power required by the actuator of the formation pressure measurement instrument while drilling, the power generation power of the downhole generator in the motor pump hydraulic scheme is relatively high, and the current domestic downhole turbine generator is still difficult to meet. Chen Ping and Huang Wanzhi from the University of Petroleum proposed to use the pressure difference inside and outside the drill string to power the hydraulic system, that is, the mud-powered formation pressure measurement instrument while drilling. However, due to the relatively low pressure difference between the inside and outside of the drill string, it cannot be directly used as a hydraulic power source. Therefore, it is necessary to design a booster device that converts the pressure difference into a hydraulic power source

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