CN-121975506-A - Foam drainage agent and foam drainage rod for low-permeability dense gas well as preparation method and application of foam drainage agent and foam drainage rod

CN121975506ACN 121975506 ACN121975506 ACN 121975506ACN-121975506-A

Abstract

The invention discloses a foam discharging agent for a low-permeability compact gas well, a foam discharging rod, a preparation method and an application thereof, and relates to the technical field of natural gas development, wherein the foam discharging agent consists of 40% -60% of foaming agent, 3% -8% of foam stabilizer, 0.1% -1% of functional auxiliary agent and the balance of water, the foam discharging rod consists of 20% -30% of foam discharging agent, 55% -70% of degradable material, 2% -5% of plasticizer and 3% -10% of moisture-proof agent, and the foam discharging rod is prepared by extruding the foam discharging agent and other components in a double-screw extruder; according to the preparation method, the degradable material is adopted as the foam drainage rod main body, the foam drainage rod can be added according to different proportions to effectively meet the dissolution requirements of the foam drainage rod under different temperature requirements, the problems that the release speed of the foam drainage rod is too fast and can not be effectively controlled when the foam drainage agent is taken as the main body are effectively solved, and the purposes of economy, environmental protection, prolonged action period of the foam drainage agent and controllable degradation are achieved.

Inventors

WANG RUI
ZHANG HAN
Xiao Xuqiao
MEI ZILONG
QIN PENG
XIAN XIAOKANG
LIN BO
LIAO TIANQI
DU LIANGJUN
WANG JIE
CHEN HENG
YAN XIANGYANG
CAI DONGQING
CHEN QINGQING

Assignees

四川申和新材料科技有限公司

Dates

Publication Date: 20260505
Application Date: 20260123

Claims (10)

1. The foam discharging agent for the hypotonic dense gas well is characterized by comprising the following components in percentage by mass: 40% -60% of foaming agent 3-8% Of foam stabilizer 0.1-1% Of functional auxiliary agent The balance of water.
2. The foam discharging agent for the hypotonic dense gas well, which is characterized in that the foaming agent consists of an anionic surfactant and a nonionic surfactant, wherein the mass ratio of the anionic surfactant to the nonionic surfactant is 1:0.5-1; The anionic surfactant is one or more of alkylbenzene sulfonate, fatty alcohol polyoxyethylene ether sulfate and alpha-olefin sulfonate; the nonionic surfactant is one or more of alkylphenol ethoxylates and fatty alcohol ethoxylates.
3. The foam discharging agent for the hypotonic dense gas well, which is characterized in that the foam stabilizing agent is one or more of cocamidopropyl betaine, sodium carboxymethyl cellulose, lauric acid diethanolamide, alkyl amine oxide, saponin extract, siO 2 nano-particles, hydroxyethyl cellulose and hydroxypropyl guanidine gum; The functional auxiliary agent comprises an adsorption inhibitor, a chelating agent, a pH regulator and an antifreezing agent, wherein the mass ratio of the adsorption inhibitor to the pH regulator is (1:1-2:0.5-1:2-4); wherein the adsorption inhibitor is one or more of polyvinyl alcohol and polyvinylpyrrolidone; the chelating agent is one or more of EDTA, sodium citrate and sodium gluconate; the pH regulator is citrate; The antifreezing agent is one or more of methanol, ethanol and glycol.
4. A foam drainage rod for a low permeability dense gas well, which is characterized by comprising the foam drainage agent as claimed in claim 1 in terms of mass percent and specifically comprising the following components: Foam discharging agent 20-30% 55% -70% Of degradable material 2% -5% Of plasticizer 3-10% Of moisture-proof agent The degradable material comprises polylactic acid and at least one other degradable material except polylactic acid, and the molar ratio of the polylactic acid to the other degradable material is=1:0.5-1.
5. The foam drainage bar for a low permeability dense gas well of claim 4, wherein the degradable material is one or more of polylactic acid, polyglycolic acid, polycaprolactone, and polyvinyl alcohol; the plasticizer is one or more of citric acid esters, epoxidized soybean oil and dioctyl adipate; the moisture-proof agent is one or more of hydrophobic silicon dioxide, sodium stearate, magnesium stearate and low-molecular-weight polyethylene glycol, wherein the molecular weight of the low-molecular-weight polyethylene glycol is 300-600.
6. The method for preparing the foam drainage bar for the low-permeability dense gas well according to any one of claims 4 to 5, which is characterized by comprising the following steps: step S1, dissolving a foaming agent in deionized water and stirring uniformly; step S2, adding a foam stabilizer, a functional auxiliary agent and deionized water into the mixed solution, and continuously stirring for 30-60 min to obtain a foam discharging agent; step S3, drying the degradable material to constant weight, and uniformly mixing the foam discharging agent and the plasticizer for standby; S4, feeding the degradable material with constant weight, the foam discharging agent and the plasticizer which are uniformly mixed into a double-screw extruder for extrusion to obtain a round drainage rod; s5, controlling the diameter of the extruded round drainage rod to be 20-50 mm, cooling the round drainage rod by adopting a water cooling tank with the temperature of 10-25 ℃ at the cooling rate of 0.5-1 ℃ per second, and drawing the round drainage rod to realize cooling molding by matching with the extrusion speed; And S6, cutting the formed round drainage rod into a coarse foam drainage rod with the diameter of 10 cm-50 cm, sieving a moisture-proof agent with a sieve with the diameter of 100-200 meshes, uniformly spraying the moisture-proof agent on the surface of the coarse foam drainage rod, and drying the coarse foam drainage rod at the temperature of 50-70 ℃ for 10-20 min to obtain the water-proof agent.
7. The method for preparing the foam drainage rod for the hypotonic dense gas well, which is characterized by comprising the following steps of maintaining the screw rotating speed of 60-100 rpm for extrusion of the round drainage rod in a double-screw extruder in the step S4, preheating the double-screw extruder at 120-140 ℃, then adding a degradable material into the double-screw extruder to stir for 10-30S, continuously heating to 150-170 ℃ to continuously stir for 30-90S, then heating to 160-170 ℃, adding the uniformly mixed foam drainage agent and plasticizer into the double-screw extruder to continuously mix for 20-60S, and finally reducing the temperature to 140-150 ℃, wherein the die head pressure is 3-8 MPa, and the stable extrusion flow rate is completed within 10-30S.
8. The application method of the foam drainage bar for the low-permeability dense gas well according to any one of claims 4 to 5, which is characterized by comprising the following steps: Step S1, measuring and judging the liquid accumulation condition of a shaft based on a logging result, and designing the size, the adding amount and the throwing position of a foam drainage rod according to the liquid accumulation condition; S2, putting foam drainage bars into a designated position of a shaft; and step S3, monitoring in real time according to wellhead pressure change, water yield fluctuation and foam flowback state, determining the application effect of the foam drainage rod, and adjusting the adding amount and the throwing position of the foam drainage rod to meet the field requirement.
9. The method of claim 8, wherein the foam drainage rod is delivered by one of continuous oil pipe delivery, free-falling delivery and rod-delivering machine delivery.
10. The method of using a foam drainage bar for a low permeability dense gas well according to claim 8, wherein the foam drainage bar can be used for unconventional gas wells including dense gas, shale gas, coal bed gas.

Description

Foam drainage agent and foam drainage rod for low-permeability dense gas well as preparation method and application of foam drainage agent and foam drainage rod Technical Field The invention relates to the technical field of natural gas development, in particular to a foam discharging agent and a foam discharging rod for a low-permeability compact gas well, and a preparation method and application thereof. Background In low permeability, tight type gas wells, such as coal and rock gas wells, the bottom of the well may gradually accumulate as the production time increases. The accumulated liquid occupies a bottom hole space, the back pressure of the gas well is increased, smooth discharge of coal bed gas is prevented, the yield of the gas well is greatly reduced, even the gas well is stopped when the yield is serious, related drainage means are usually required to be introduced for treating the accumulated liquid at the bottom hole, and a liquid discharge method with higher application degree is to introduce a bubble discharge rod into the bottom hole for treating the accumulated liquid. The action principle of the foam discharging rod is that after the foam discharging rod is put into a shaft, the degradable material outside the foam discharging rod begins to degrade firstly due to the factors of ambient temperature, mineralization degree of stratum water and the like, in the process, the foam discharging agent is gradually released from outside to inside along with the slow degradation of the degradable material, meanwhile, the foam discharging agent begins to react with the contacted stratum water to perform foaming and liquid carrying effects, when the degradable material is completely degraded, the foam discharging agent is completely released, and the foam discharging agent and the foam discharging rod action effect can be adjusted and optimized according to the stratum temperature, mineralization degree and the consumption of the degradable material. Existing foam drainage agents and foam drainage bars have a number of problems in coal-to-rock gas well applications. For example, some foam discharging agents have poor temperature resistance, and under the downhole temperature environment of a coal-gas well, the surface activity and foaming performance of the foam discharging agent can be rapidly reduced, so that stable foam carrying effusion can not be effectively formed and discharged. Some foam discharging agents and foam discharging rods are insufficient in salt resistance, and the produced liquid of the coal-rock gas well usually contains a certain amount of salt, so that the molecular structure of the foam discharging agents is damaged by high salinity, and the foam stability and the drainage effect are reduced. And the conventional foam discharging agent and foam discharging rod have poor adaptability to complex geological conditions of the coal-rock gas well, and can not meet the drainage requirements of the coal-rock gas wells in different areas and with different properties. The traditional drainage mode is mainly to directly inject liquid foam drainage agent into a well shaft of a gas well, and the mode has the problem that the injection amount is difficult to control accurately. Too little injection amount can not achieve the effective drainage effect, and too much injection amount can cause resource waste and cost increase. Meanwhile, the liquid foam discharging agent is unevenly distributed in the shaft, local concentration is easy to be too high or too low, drainage efficiency is affected, professional equipment and personnel are required for frequent injection of the liquid foam discharging agent, and complexity and labor intensity of exploitation operation are increased. In addition, the release is faster when the foam discharging agent is taken as a main body, and the problem of too fast release cannot be fundamentally solved. Aiming at the problems, the patent CN114517085A discloses an ultralow surface tension foam discharging agent and a preparation method thereof, wherein the foam discharging agent has the characteristics of low surface tension, strong foaming capacity, good foam stabilizing effect, strong liquid carrying capacity and the like, and the ultralow surface Zhang Lite can meet the requirement of an ultralow-yield gas well on the foam discharging agent, but the ultralow surface tension means that the foam strength is reduced, and is unfavorable for continuous foam discharging; the patent CN106221687A discloses a gas field foam drainage rod and a preparation method thereof, the foam drainage rod is an amphoteric foam drainage rod, the foam drainage rod has the characteristics of high foaming capacity and no influence of high mineralization degree, methanol and condensate, but the patent only optimizes problems in terms of water quality, does not consider the problem of liquid accumulation in the production process of a gas well, meanwhile, the foam drainage rod does not te