Polymer injection block oil-water well production and injection increase technology

Abstract

The invention discloses a polymer injection block oil-water well production and injection increase technology. The technology comprises the steps of washing a well using clean water in large discharge capacity through an inverse well-flushing method, and flushing grit, dirt and polymers around a shaft and a blasthole out of the ground from a well bottom; connecting pipelines in a positive circulation mode, opening the gates of an oil tube and a casing, and putting a newly prepared blockage relieving agent at the bottom of the well until the upper bound of an oil layer; closing the gate of the casing, and squeezing the surplus blockage relieving agent into the oil tube; squeezing the clean water into the casing, and squeezing the blockage relieving agent in a tube column into a stratum; then closing the well for reaction for 48 hours; squeezing hydrochloric acid with the hydrogen chloride content of 12% and hydrofluoric acid with the hydrogen fluoride content of 2% into the casing in sequence after the well is opened; squeezing the clean water into the casing to push the blockage relieving agent to the far-end of the stratum and make the blockage relieving agent react with deep polymers; finally conducting normal production after a 48-hour closing-well reaction. The polymer injection block oil-water well production and injection increase technology effectively removes blocking stuffs of immediate vicinity of wellbore of the polymer injection block oil-water well, recovers the yield, greatly increases the treating radius of the blockage relieving agent, is safe and reliable, and avoids the safety loophole of producing oxygen, chlorine and the like by superoxide .

Description

technical field [0001] The invention relates to an oil recovery technology in an oil field, in particular to a technology for increasing production and injection of an oil-water well in a polymer injection area. Background technique [0002] Tertiary oil recovery is one of the important development methods in Shengli Oilfield. Polymer injection work has been carried out in more than 40 development units, involving more than 3,000 oil and water wells, and good development results have been achieved. However, after polymer injection in oil and water wells, blockage of polymers in the near-well area and in sand filter pipes generally occurs, resulting in a sharp drop in the fluid production of oil wells and a sharp drop in the injection rate of water wells. Here comes the puzzle. Based on the analysis of well washing and sand flushing on site, the clogging objects are complex, including polymer aggregates, reservoir sediment and various scale samples. The complex clogging obje...

AI Technical Summary

Problems solved by technology

At present, the plugging removal of such under-injection wells is mainly based on acidification and filling. Due to the lack of pertinence, single process and poor effect, it is difficult to solve on-site problems. It is urgent to carry out relevant process technology research to solve the problem of water injection in polymer injection wells

[0003] Conventional acidification, filling and other processes carry out plugging removal work, the effect is poor, and the validity period is short; using chlorine dioxide, hydrogen peroxide and other strong oxidants as plugging agents has a certain effect, but the safety is poor, and it is not suitable for storage and transportation and on-site construction

Cannot meet safety and environmental protection requirements

The reported plugging removal technology for this type of well can be divided into two categories. The first type uses strong oxidants such as chlorine dioxide and hydrogen peroxide to remove plugging construction. However, due to its strong corrosiveness, the formation action distance short, and at the same time, explosive gas will be produced during storage, transportation and construction, which has caused great difficulties and potential safety hazards in the construction process; Hao Zhanyuan et al. Underground production of chlorine dioxide; Zhao Yingqiu et al. (CN 1247734C, CN102925128A) invented a composite plugging removal process, which mainly consists of a mixture of calcium peroxide and peroxy tert-butanol for polymer plugging removal; Hu Xinsuo et al. (CN 1480628) Invented a plugging removal method of injecting hydrolysis catalyst ADS into the formation; Lin Aiguo and others invented a plugging removal agent formula mainly composed of double-base solidification cracking agent, dispersant, self-generated gas foaming energy-enhancing diffusing agent

The traditional technology uses plugging remover to treat the area near the wellbore, and at the same time cooperates with acid, landfill and other processes to remove plugging, but various existing technologies have the disadvantages of small formation range and poor plugging removal effect

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