Method for remotely shutting down downhole unit of rotary steering system from ground

Patent metadata

Field	Value
Publication number	US-11946350-B2
Application number	US-202117925599-A
Country	US
Kind code	B2
Filing date	May 25, 2021
Priority date	May 29, 2020
Publication date	Apr 2, 2024
Grant date	Apr 2, 2024

Abstract

A method for remotely shutting down a downhole unit of a rotary steering system from ground includes steps of: a: calculating a pressure difference P1 between a front end and a rear end of the drill water hole; b: calculating an extension loss ΔP; c: calculating a pressure P2 at the riser after turning on the downlink device; d: calculating an opening area S1 of the throttle valve of the downlink device; and e: adjusting the throttle valve to a calculated opening degree; automatically targeting the function block that needs to be cut off according to a flow change detected downhole, and shutting down the downhole unit. The method can realize self-protection and continuous operation of the entire rotary steering system, reduce frequency of inspection that needs to pull back the drill when the rotary steering system is abnormal, improve drilling efficiency, and reduce costs.

First claim

What is claimed is:

1. A method for remotely shutting down a downhole unit of a rotary steering system from ground, comprising steps of:
a: setting a diversion ratio of a downlink device as k, an equivalent area of a drill water hole as s, a total displacement of a mud pump as Q, and a pressure of a riser before the downlink device is turned on as P; calculating a pressure difference P 1 between a front end and a rear end of the drill water hole by a formula 1;
P 1 =Q 2 ρ/2μ 2 s 2   formula 1;

wherein Q is the total displacement of the mud pump, m 2 /s; μ is a flow coefficient and μ=0.63; s is the equivalent area of the drill water hole, m 2 ; P 1 is the pressure difference between the front end and the rear end of the drill water hole, Pa; and ρ is fluid density, Kg/m 3 ;
b: calculating an extension loss ΔP by a formula 2;
Δ P=P−P 1   formula 2;

c: calculating a pressure P 2 at the riser after turning on the downlink device by a formula 3;
P 2 =ΔP +ρ(1− k ) 2 Q 2 /2μ 2 s 2   formula 3;

d: since a pressure drop of a throttle valve of the downlink device is also P 2 according to a pressure balance relationship, calculating an opening area S 1 of the throttle valve of the downlink device by a formula 4;

S
1

=

kQ
/

2
⁢

P
2

/
ρ

μ

;

formula
⁢

4

and
e: adjusting the throttle valve to a calculated opening degree according to a relationship between the opening degree and the opening area S 1 of the throttle valve, so that a diverting flow automatically reaches the set diversion ratio; providing a cut-off circuit to each function block of the rotary steering system; numbering each function block, and forming a preset corresponding relationship between the function block and the diverting flow of the downlink device, which is solidified in a rotary steering tool control software; if any function block is abnormal, adjusting the diverting flow of the downlink device according to the preset corresponding relationship between the function block and the diverting flow; automatically targeting a function block that needs to be cut off according to a flow change detected downhole, and shutting down the downhole unit.

2. The method for remotely shutting down the downhole unit of the rotary steering system from the ground, as recited in claim 1 , wherein in the step e, adjusting the throttle valve to the calculated opening degree comprises specific steps of: calibrating indoors to form a relationship curve between the opening degree and the opening area; and obtaining a required opening degree based on the relationship curve between the opening degree and the opening area, as well as a required opening area of the throttle valve area corresponding to the diversion ratio set in the previous step.

3. The method for remotely shutting down the downhole unit of the rotary steering system from the ground, as recited in claim 2 , wherein in the step e, the diverting flow automatically reaches the set diversion ratio through specific steps of: after the downlink device receives the set diversion ratio, calculating a required opening area of the throttle valve of the downlink device according to a calculation formula, and then obtaining a required opening degree of the throttle valve according to the relationship between the opening degree and the opening area S 1 of the throttle valve; according to a corresponding relationship between the required opening degree of the throttle valve and an analog electrical signal, outputting a current signal, so as to reach the set diversion ratio through automatic adjustment of the throttle valve of the downlink device.

4. The method for remotely shutting down the downhole unit of the rotary steering system from the ground, as recited in claim 3 , wherein in the step e, forming the preset corresponding relationship between the function block and the diverting flow comprises specific steps of: presetting 9 function blocks, and installing a controllable diode on each of the 9 function blocks; using three diverting flows of 10%, 15% and 20% with different durations to represent the 9 function blocks; wherein the 10% diverting flow lasting for 2s means to shut down a 1 #function block; the 10% diverting flow lasting for 4s means to shut down a 2 #function block; the 10% diverting flow lasting for 6s means to shut down a 3 #function block; the 15% diverting flow lasting for 2s means to shut down a 4 #function block; the 15% diverting flow lasting for 4s means to shut down a 5 #function block; the 15% diverting flow lasting for 6s means to shut down a 6 #function block; the 20% diverting flow lasting for 2s means to shut down a 7 #function block; the 20% diverting flow lasting for 4s means to shut down a 8 #function block; and the 20% diverting flow lasting for 6s means to shut down a 9 #function block.

5. The method for remotely shutting down the downhole unit of the rotary steering system from the ground, as recited in claim 3 , wherein in the step e, shutting down the downhole unit comprises specific steps of: since the rotary steering system comprises a downhole mud turbine generator and a voltage frequency changes accordingly when a mud flow through the downhole mud turbine generator changes, detecting a voltage frequency change by a rotary steering control module, so as to obtain a mud flow change; detecting a size of the diverting flow downhole and combining with an inherent coding method to complete identification of a downlink command; after receiving a shutdown command, setting a controllable diode of a corresponding function block to a cut-off state.

6. The method for remotely shutting down the downhole unit of the rotary steering system from the ground, as recited in claim 2 , wherein in the step e, forming the preset corresponding relationship between the function block and the diverting flow comprises specific steps of: presetting 9 function blocks, and installing a controllable diode on each of the 9 function blocks; using three diverting flows of 10%, 15% and 20% with different durations to represent the 9 function blocks; wherein the 10% diverting flow lasting for 2s means to shut down a 1 #function block; the 10% diverting flow lasting for 4s means to shut down a 2 #function block; the 10% diverting flow lasting for 6s means to shut down a 3 #function block; the 15% diverting flow lasting for 2s means to shut down a 4 #function block; the 15% diverting flow lasting for 4s means to shut down a 5 #function block; the 15% diverting flow lasting for 6s means to shut down a 6 #function block; the 20% diverting flow lasting for 2s means to shut down a 7 #function block; the 20% div

Assignees

• China Nat Petroleum Corp
• Cnpc Chuanqing Drilling Eng Co

Inventors

• Bai Jing
• Zhang Jichuan
• Lu Dengyun
• Li Lei
• Huang Chongjun
• Jia Lichun
• Liao Chong
• Han Liexiang
• Zhang Dejun
• Tang Gui

Classifications

• E21B43/126 Primary

  Adaptations of down-hole pump systems powered by drives outside the borehole, e.g. by a rotary or oscillating drive (powered by fluid E21B43/129) · CPC title

• E21B34/066

  electrically actuated · CPC title

• E21B47/18 Primary

  through the well fluid {, e.g. mud pressure pulse telemetry} · CPC title

• E21B7/04 Primary

  Directional drilling · CPC title

• E21B44/005

  Below-ground automatic control systems · CPC title