Foam drainage agent for exploiting lower palaeozoic erathem sulfur-containing natural gas and preparation method thereof

Abstract

The invention discloses a foam drainage agent for exploiting lower palaeozoic erathem sulfur-containing natural gas and a preparation method thereof. The foam drainage agent is prepared from the following components in percentage by mass: 50 to 60 percent of sulfonated AEO3, 20 to 30 percent of lauramidopropyl phosphate betaine, 5 to 10 percent of coconut oil fatty acid mono-ethanol amide, 5 to 10 percent of Chinese soapberry fruit essence, 1 to 4 percent of lignosulfonate and the balance of water; the preparation method of the foam drainage agent comprises the following steps: adding sulfonated AEO3 and lauramidopropyl phosphate betaine into a reaction kettle, carrying out primary mixing, sequentially adding coconut oil fatty acid mono-ethanol amide, Chinese soapberry fruit essence, lignosulfonate and water into a reaction kettle, and carrying out secondary mixing, so as to obtain the foam drainage agent. The foam drainage agent provided by the invention has the advantages of acid resistance, hypersalinity resistance and strong secondary foaming ability, overcomes the defects in the prior art, and solves the technical problem of foam drainage of lower palaeozoic erathem gas wells.

Description

technical field [0001] The invention relates to the field of natural gas exploitation, in particular to a foam drainage agent for the exploitation of ancient sulfur-containing natural gas and a preparation method thereof. Background technique [0002] The development of underground paleo-gas reservoirs in the Ordos Basin has gone through the stages of both vertical well evaluation and horizontal well development test. Since 2019, it has entered the integrated pilot test stage, with an annual contribution of 189 million cubic meters of production, accounting for 5.8% of production. As of April 2021, the total number of Xiagu gas wells is 93, the number of wells put into production is 89, the number of wells opened is 67 (13 vertical wells, 54 horizontal wells), the well opening rate is 74.2%, the production rate is 96%, the average The pressure is 7.39MPa, the pressure drop rate is 0.0021MPa / d, the single well production is 9,700 cubic meters per day, the liquid-gas ratio is ...

AI Technical Summary

Problems solved by technology

[0004] 1. Since the acid fracturing fluid with low pH is used, the flowback rate after the gas test is low, and the lower paleostratum contains H 2 S, the production liquid is acidic as a whole. Currently, the foaming agents used in most ancient gas wells are mainly composite foaming agents and non-ionic surfactants compounded by anionic surfactants and non-ionic surfactants. The performance is greatly affected by pH, so it is not suitable for drainage and gas recovery of ancient gas wells

[0005] 2. The lower paleoformation water and the upper paleoformation water have different characteristics. There is a high degree of salinity, which can reach 3000000mg / L, and the composition and fluid properties of the formation water are different. At present, the foaming agent used in the gas field has the highest resistance to mineralization The concentration is 200000mg / L, which leads to the foaming of traditional foaming agents in the formation water and the deterioration of the liquid-carrying ability

[0006] 3. Downhole restrictor technology is often used in Xiagu gas wells. When the foam discharge agent passes through the throttle nozzle, it will produce defoaming effect and affect the foam discharge effect.

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