US 12,411,030 B2
Forward and reverse bidirectional flow rate measurement method for subsea chemical agent injection device
Haodong Chen, Haikou (CN); Xiaowei Ma, Shanghai (CN); Chunmin Zeng, Haikou (CN); Guangfu Li, Shanghai (CN); Anchao Wei, Haikou (CN); Yanzhi Pan, Shanghai (CN); Ming Luo, Haikou (CN); Tan Xiao, Haikou (CN); Donglei Jiang, Haikou (CN); and Huan Diao, Haikou (CN)
Assigned to CNOOC (CHINA) CO., LTD, Tianjin (CN); CNOOC CHINA LIMITED, HAINAN BRANCH, Haikou (CN); and HAHAIMO SUBSEA TECHNOLOGY (SHANGHAI) CO., LTD., Shanghai (CN)
Appl. No. 19/112,278
Filed by CNOOC (CHINA) CO., LTD, Tianjin (CN); CNOOC CHINA LIMITED, HAINAN BRANCH, Haikou (CN); and HAIMO SUBSEA TECHNOLOGY (SHANGHAI) CO., LTD., Shanghai (CN)
PCT Filed Aug. 27, 2024, PCT No. PCT/CN2024/114663
§ 371(c)(1), (2) Date Mar. 17, 2025,
PCT Pub. No. WO2025/021225, PCT Pub. Date Jan. 30, 2025.
Claims priority of application No. 202311271924.0 (CN), filed on Sep. 28, 2023.
Prior Publication US 2025/0258026 A1, Aug. 14, 2025
Int. Cl. G01F 1/36 (2006.01); F17D 3/12 (2006.01); F17D 3/18 (2006.01)
CPC G01F 1/363 (2013.01) [F17D 3/18 (2013.01); F17D 3/12 (2013.01)] 9 Claims
OG exemplary drawing
 
1. A forward and reverse bidirectional flow rate measurement method for a subsea chemical agent injection device, comprising a device body, wherein the device body comprises an agent input connector, a pressure reduction member, a needle valve assembly, and an agent output connector that are sequentially communicated through a flow channel;
step 1: keeping an opening V of the needle valve assembly fixed, taking the agent input connector and the agent output connector as inlets to inject agents with different calibrated flow rates Q into the device body for forward and reverse bidirectional calibration, and synchronously obtaining first differential pressures DP1 before and after a chemical agent flows through the pressure reduction member, and second differential pressures DP2 before and after the chemical agent flows through the needle valve assembly during a period; and
obtaining a forward calibration array and a reverse calibration array for the opening V;
step 2: fitting relationships between flow rates and differential pressures in forward and reverse directions at the same opening V according to Formula 1:

OG Complex Work Unit Math
in the formula:
QA is a forward flow rate; KA is a forward flow coefficient; CA is a forward calibration coefficient; DPnA is either DP1A or DP2A, DP1A is a forward first differential pressure, and DP2A is a forward second differential pressure; and
QB is a reverse flow rate; KB is a reverse flow coefficient; CB is a reverse calibration coefficient; DPnB is either DP1B or DP2B, DP1B is a reverse first differential pressure, and DP2B is a reverse second differential pressure;
step 3: adjusting the needle valve assembly to different openings V, and repeating the steps 1 and 2 to obtain forward and reverse flow coefficients, as well as forward and reverse calibration coefficients at the different openings V, respectively;
a forward opening VA, the forward flow coefficient KA, and the forward calibration coefficient CA correspond to each other and form a forward fitting array; and
a reverse opening VB, the reverse flow coefficient KB, and the reverse calibration coefficient CB correspond to each other and form a reverse fitting array;
step 4: fitting relationships between flow coefficients and needle valve openings according to Formula 2:

OG Complex Work Unit Math
step 5: establishing a formula of flow rate, opening, and differential pressure according to Formula 3:

OG Complex Work Unit Math
in the formula:
CA is an average of a plurality of forward calibration coefficients CA; and
CB is an average of a plurality of reverse calibration coefficients CB;
step 6: connecting the device body to a production system and injecting the chemical agent;
when a pressure of the chemical agent shows a decline trend from the pressure reduction member to the needle valve assembly, the chemical agent is determined to flow in a forward direction; and a real-time forward opening of the needle valve assembly is controlled to VA′, a real-time forward first differential pressure DP1A′ and a real-time forward second differential pressure DP2A′ are obtained, and a real-time forward flow rate QA′ is then calculated according to Formula 4:
QA′=f(VA′)*√DPNA+CA,  Formula 4;
in the formula, DPnA′ is either DP1A′ or DP2A′; and
when the pressure of the chemical agent shows an increase trend from the pressure reduction member to the needle valve assembly, the chemical agent is determined to flow in a reverse direction; and a real-time reverse opening of the needle valve assembly is controlled to VB′, a real-time reverse first differential pressure DP1B′ and a real-time reverse second differential pressure DP2B′ are obtained, and a real-time reverse flow rate QB′ is then calculated according to Formula 5:
QB′=f(VB′)*√DPnB′+CB,  Formula 5.