US 11,946,350 B2
Method for remotely shutting down downhole unit of rotary steering system from ground
Jing Bai, Sichuan (CN); Jichuan Zhang, Sichuan (CN); Dengyun Lu, Sichuan (CN); Lei Li, Sichuan (CN); Chongjun Huang, Sichuan (CN); Lichun Jia, Sichuan (CN); Chong Liao, Sichuan (CN); Liexiang Han, Sichuan (CN); Dejun Zhang, Sichuan (CN); and Gui Tang, Sichuan (CN)
Assigned to CHINA NATIONAL PETROLEUM CORPORATION, Beijing (CN); and CNPC CHUANQING DRILLING ENGINEERING COMPANY LIMITED, Sichuan (CN)
Appl. No. 17/925,599
Filed by CHINA NATIONAL PETROLEUM CORPORATION, Beijing (CN); and CNPC CHUANQING DRILLING ENGINEERING COMPANY LIMITED, Sichuan (CN)
PCT Filed May 25, 2021, PCT No. PCT/CN2021/095724
§ 371(c)(1), (2) Date Nov. 15, 2022,
PCT Pub. No. WO2021/238898, PCT Pub. Date Dec. 2, 2021.
Claims priority of application No. 202010472068.5 (CN), filed on May 29, 2020.
Prior Publication US 2023/0193729 A1, Jun. 22, 2023
Int. Cl. E21B 21/08 (2006.01); E21B 34/06 (2006.01); E21B 43/12 (2006.01); E21B 47/18 (2012.01)
CPC E21B 43/126 (2013.01) [E21B 34/066 (2013.01); E21B 47/18 (2013.01)] 14 Claims
 
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 P1 between a front end and a rear end of the drill water hole by a formula 1;
P1=Q2ρ/2μ2s2  formula 1;
wherein Q is the total displacement of the mud pump, m2/s; μ is a flow coefficient and μ=0.63; s is the equivalent area of the drill water hole, m2; P1 is the pressure difference between the front end and the rear end of the drill water hole, Pa; and ρ is fluid density, Kg/m3;
b: calculating an extension loss ΔP by a formula 2;
ΔP=P−P1  formula 2;
c: calculating a pressure P2 at the riser after turning on the downlink device by a formula 3;
P2=ΔP+ρ(1−k)2Q2/2μ2s2  formula 3;
d: since a pressure drop of a throttle valve of the downlink device is also P2 according to a pressure balance relationship, calculating an opening area S1 of the throttle valve of the downlink device by a formula 4;

OG Complex Work Unit Math
and
e: adjusting the throttle valve to a calculated opening degree according to a relationship between the opening degree and the opening area S1 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.