Methods and systems for determining well shut-in pressures of oil and gas well drilling

A method for determining a well shut-in pressure of oil and gas well drilling, comprising:

• obtaining, by a first processor, a basic parameter of a target oil and gas well, the basic parameter including at least one of a wellbore structure parameter, a well drilling fluid performance parameter, or a casing string parameter;
• wherein the pressure calculation model is:
• P
• Cmax
• =
• min
• ⁢
• {
• P
• 1
• =
• 0.8
• (
• min
• ⁢
• {
• P
• T
• ,
• P
• R
• }
• )
• ;
• P
• 2
• =
• P
• ba
• -
• P
• be
• ;
• P
• 3
• =
• 0.8
• (
• 0.0098
• ρ
• f
• ⁢
• H
• f
• )
• ;
• }
• (
• 1
• )
• where Pcmax denotes the maximum well shut-in pressure in MPa;
• P1 denotes a minimum value of pressure limitation of a wellhead device in MPa;
• PT denotes a maximum test pressure of a support casing of the wellhead device in MPa;
• PR denotes a rated working pressure of the support casing of the wellhead device in MPa;
• P2 denotes a minimum value of pressure limitation of the casing string in MPa;
• pba denotes a maximum internal pressure strength of the casing string in MPa;
• Pbe denotes an effective internal pressure of the casing string in MPa:
• P3 denotes a minimum value of a formation rupture pressure limitation in MPa;
• ρf denotes a well drilling fluid density in g/cm3;
• Hf denotes a formation depth (vertical depth) corresponding to a position of a casing shoe in m;
• Pcmax, P1, P2, pba, Pbe, and P3 are calculated by the first processor;
• and PR, PR, ρf, and Hf are obtained by the first processor from the monitoring device;
• obtaining, by the first processor, a pressure calculation model;
• determining, by the first processor, a maximum well shut-in pressure during well drilling of the target oil and gas well based on the pressure calculation model and the basic parameter;
• determining, by the first processor, a recommended monitoring parameter and a recommended well drilling parameter based on the maximum well shut-in pressure and a wellhead pressure sequence and a bottomhole pressure sequence in a preset time period collected by a monitoring device;
• generating, by the first processor, a monitoring adjustment instruction based on the recommended monitoring parameter and sending the monitoring adjustment instruction to the monitoring device to adjust a monitoring parameter of the monitoring device to the recommended monitoring parameter, wherein the monitoring device includes a pressure monitoring device, a density detection device, a depth detection device and a length measurement device, the monitoring parameter includes a monitoring accuracy degree and a monitoring frequency of the monitoring device;
• and
• generating, by the first processor, a well drilling operation instruction based on the recommended well drilling parameter and sending the well drilling operation instruction to a second processor, the second processor being located at a terminal device, wherein the well drilling operation instruction is used to control the well drilling operation device to perform the well drilling operation with the recommended well drilling parameter, the well drilling operation device includes a drilling rig, a well drilling fluid pump and a well drilling mud mixer, the recommended well drilling parameter includes a recommended well shut-in time and a well drilling device parameter, the well drilling device parameter includes a density and a circulation speed of the well drilling fluid when the well drilling operation device works.