CN-122022403-A - Quantitative design method for intermittent dosing parameters of gas well

Abstract

The invention discloses a quantitative design method for intermittent dosing parameters of a gas well, and relates to the technical field of foam drainage and gas production of the gas well. According to the method, through collecting basic parameters of a gas well and physical property parameters of produced liquid, a quantitative calculation formula of critical liquid accumulation amount and a dosing period is deduced based on Li Min critical liquid carrying model and a foam liquid carrying lower limit equation, and single dosing amount is calculated by combining standard dosing concentration, so that quantitative design of intermittent dosing parameters is realized. Because the liquid phase which can not be taken away only by aiming at the gas phase liquid carrying flow, the dosage of the medicament is reasonably reduced while quantitative calculation basis is provided for on-site medicament adding parameter optimization.

Inventors

• LIU XIAOLIANG
• An Yizhe
• TIAN SHUN
• ZHAO XIANG
• MAO CHENG
• YAO HUIJUAN
• CHEN HONGJUN
• Hou Peiyuan

Assignees

• 克拉玛依职业技术学院

Dates

Publication Date

20260512

Application Date

20260413

Claims (2)

1. 1. The quantitative design method of intermittent dosing parameters of a gas well is characterized by being used for optimizing the dosing period and dosing amount of a foaming agent in a foam drainage and gas production process, and comprises the following steps: Step 1, acquiring basic parameters of a target gas well, including daily gas production, shaft temperature, shaft pressure, oil pipe inner diameter and daily liquid production, and calculating actual liquid carrying gas velocity v gr in the shaft according to the basic parameters, wherein a calculation formula is as follows: v gr = (V g × Z × T) / (2.5×10 8 × A × P) Wherein V gr is the actual liquid-carrying gas velocity, the unit is m/s, V g is the daily gas production, the unit is m 3 /d, Z is a compression factor, the dimension is zero, T is the absolute temperature of a shaft, the unit is K, A is the sectional area of the shaft, calculated by the inner diameter of an acquired oil pipe, the unit is m 2 , P is the pressure of the shaft, the unit is MPa, and 2.5X10 8 is the engineering unit conversion comprehensive coefficient; Step 2, calculating a gas well critical liquid carrying gas speed v c based on a Li Min critical liquid carrying model, and determining a lowest foam liquid carrying gas speed v fc by combining a foam liquid carrying lower limit equation, wherein v c is the gas well critical liquid carrying gas speed in m/s, and v fc is the lowest foam liquid carrying gas speed in m/s; Step 3, verifying calculation conditions, namely, the actual liquid carrying gas speed v gr needs to meet v fc ＜v gr ＜v c , if v gr ＞v c , judging that the well does not need auxiliary liquid carrying measures, terminating the method, and if v gr ≤v fc , after adjusting the type of the foaming agent under the adaptive working condition, re-executing the calculation of v fc in step 2 and the condition verification of the step, and carrying out subsequent calculation after meeting the condition of v fc ＜v gr ＜v c ; Step 4, respectively calculating the liquid holdup H L in the shaft when the foaming agent is not added and the liquid holdup H L ́ in the shaft after the foaming agent is added according to a liquid holdup calculation formula by using the calculated v c and v fc , wherein the liquid holdup H L and the liquid holdup H L ́ are dimensionless parameters, and the calculation formula is as follows: H L = Q lin / (v c × A × 86400) H L ´ = Q lin / (v fc × A × 86400) Wherein Q lin is the daily liquid production of the target gas well, the unit is m 3 /d;H L , the liquid holdup in the shaft is dimensionless when no foaming agent is added, H L ́ is the liquid holdup in the shaft after the foaming agent is added, the dimensionless is not found, and 86400 is the time conversion coefficient of seconds and days; Step 5, calculating the flow carrying capacity Q gr in the shaft when the foaming agent is not added and the flow carrying capacity Q lf of foam in the shaft after the foaming agent is added, wherein the calculation formula is as follows: Q gr = H L × v gr × A × 86400 Q lf = H L ´ × v gr × A × 86400 Wherein Q gr is the flow carrying capacity in the shaft when no foaming agent is added, the unit is m 3 /d;Q lf , and the unit is m 3 /d; Step 6, calculating a critical fluid volume V crit and a time t acc from accumulation of the wellbore fluid to the critical fluid volume, wherein the calculation formula is as follows: V crit = （Q lf - Q lin ）× t eff /1440 t acc = V crit / (Q lin - Q gr ) × 24 Wherein V crit is the critical fluid accumulation of the shaft, the unit is m 3 ;t eff , the effective fluid carrying time of the foaming agent is the effective fluid carrying time after the foaming agent contacts the fluid accumulation of the shaft, the unit is h, t acc is the time of accumulating the fluid accumulation of the shaft to the critical fluid accumulation, the unit is h, and 1440 is the time conversion coefficient of days and minutes; Step 7, the dosing period t dose is the sum of t acc and t eff , and the calculation formula is as follows: t dose = t acc + t eff Wherein t dose is a dosing period of intermittent dosing of the foaming agent of the target gas well, and the unit is h; Step 8, calculating a single dosing amount V according to the critical accumulated liquid amount V crit calculated in the step 6 and the set dosing mass concentration c, wherein the calculation formula is as follows: V = V crit × c × 1000 / C 0 Wherein V is the single dosing amount, the unit is L, C is the dosing mass concentration, the unit is g/L, C 0 is the mass concentration of the foamer mother liquor prepared on site, the unit is g/L, and 1000 is the volume conversion coefficient of cubic meters and liter; And determining the foaming agent dosing period and the single dosing amount of the foaming agent in the foam drainage and gas production process of the target gas well according to the dosing period t dose and the single dosing amount V obtained through calculation.
2. 2. The quantitative design method for intermittent dosing parameters of a gas well according to claim 1, wherein the effective liquid carrying time period t eff of the foaming agent is measured through an indoor liquid carrying experiment or a field experiment.

Description

Quantitative design method for intermittent dosing parameters of gas well Technical Field The invention belongs to the technical field of foam drainage gas production of gas wells, and particularly relates to a quantitative design method of intermittent dosing parameters of a gas well, which is suitable for foam drainage gas production process optimization of a low-pressure low-yield gas well. Background In the gas field development process, as formation energy is continuously attenuated, the problem of wellbore hydrops is increasingly prominent, so that the yield of a gas well is reduced and even the production is stopped by flooding. The foam drainage gas production process has the advantages of simple construction, low cost, quick effect and the like, is widely applied to various large gas fields, and intermittent dosing is the most widely applied foaming agent dosing mode on site. The design rationality of the dosing period and the dosing amount directly determines the process implementation effect and the production economy. Currently, related patent technologies are researched aiming at gas well dosing technologies, for example, chinese patent CN 105927195A discloses an intelligent dosing method of a gas well based on oil jacket pressure difference, chinese patent CN 104632156A discloses an intelligent dosing method of a cluster gas well combined with effusion diagnosis, and Chinese patent CN 204082096U and Chinese patent CN 103754815A respectively optimize flow control and metering regulation structures of a gas well dosing device. However, the research and development of the hardware of the dosing device and an automatic control system are focused on in the prior art, the research on the quantitative design method of intermittent dosing core parameters is insufficient, the on-site dosing parameter formulation is still highly dependent on engineering experience, the critical liquid carrying theory and the liquid accumulation rule of a well bore are not combined, and a quantitative calculation method of the dosing parameters of the system is established, so that the problems of medicament waste, unstable liquid carrying effect and poor suitability of gas wells under different working conditions exist. Based on the method, the invention provides a quantitative design method for intermittent dosing parameters of a gas well, so as to solve the defects in the prior art. Disclosure of Invention The invention aims to provide a quantitative design method for intermittent dosing parameters of a gas well, which is used for realizing quantitative calculation of intermittent dosing core parameters of a foaming agent and overcoming blindness of traditional empirical dosing by integrating multiphase flow theory, foam liquid carrying characteristics and on-site gas well parameters and deducing quantitative formulas of critical liquid accumulation amount and dosing period. In order to achieve the above purpose, the present invention adopts the following technical scheme: 1. collecting basic parameters of a target gas well Collecting gas well production data, including the inner diameter of an oil pipe (used for calculating the cross section area A of a shaft), daily gas yield V g (unit m 3/d), daily liquid yield Q lin (unit m 3/d), shaft temperature T (unit ℃ and shaft pressure P (unit MPa); Testing the physical parameters of the produced liquid, namely testing the surface tension sigma (unit N/m) of the produced liquid when no foaming agent is added by a surface tensiometer, the surface tension sigma' (unit N/m) of the produced liquid after the foaming agent is added, and testing the density rho l (unit kg/m 3) of the liquid phase by a densitometer; Calculate the gas phase density ρ g (unit kg/m 3): Calculating a natural gas compression factor Z by adopting a Gopal method which is common in industry, namely calculating relative pressure P r = P/Pc and relative temperature T r = T/Tc according to shaft temperature T (unit K) and pressure P (unit MPa), wherein P c is natural gas critical pressure, 4.6 MPa is taken, T c is natural gas critical temperature, and 190.6K is taken; In a non-supercritical state, adopting a modified ideal gas state equation to calculate ρ g：ρg = (P×M)/(Z×R×T), wherein M is the natural gas molar mass, 0.01604 kg/mol is taken, R is a universal gas constant, and 8.314J/(mol.K) is taken; in the supercritical state, calculating by adopting a critical density conversion formula ρg：ρg = ρc × (P/Pr) × (Tr/T)（ρc= 162.7 kg/m3）. The actual liquid carrying gas velocity v gr in the shaft is calculated by adopting a formula after the critical liquid carrying gas volume formula is deformed, vgr = (Vg × Z × T) / (2.5×108 × A × P) The method comprises the steps of taking actual liquid-carrying gas velocity as V gr, taking the actual liquid-carrying gas velocity as m/s, taking the daily gas production as V g, taking the daily gas production as m 3/d, taking Z as a compression factor, taking no dimension, taki