Pollution-free well workover process for oil field

Abstract

The invention relates to a pollution-free well workover process for an oil field, which is suitable for negative-pressure well workover operation in an oil-water gas well of the oil field. At present, in the well workover operation process of the oil field, a ground pump is usually used for pumping fluids, such as clear water, and the like into the well from the mouth of the well, solid particulate matters, such as scales, sands, scrap iron and the like are taken out from the bottom of the well by adopting positive cycle or reverse cycle flushing to achieve the purposes of washing the shaft, removing sand burying and refloating downhole junks; however, in the mid-later period of waterflooding extraction of the oil field, the interlayer conflict is increased, and stratum absorption wells are increased to cause the pollution to the stratum. The invention aims at providing a well workover process which has the advantages that ground pump cycle is not needed in the operation field, no stratum pollution exists in the well workover process, the construction cost is saved, the production ageing is improved, and the pollution to the environment during working is reduced.

Description

Technical field: [0001] The patent of the invention relates to a pollution-free workover process in oilfield operations, which is suitable for negative pressure well workover operations in oil-water gas wells in oilfields. Background technique: [0002] At present, the workload of workover operations in oilfields is heavy, and well flushing is often used to clean the wellbore during the workover process. When the pipe string is brought downhole tools down to the bottom of the well for sand washing, milling, casing milling, and fishing operations, the surface pump is used to pump clean water and other fluids from the wellhead into the well, and the well is flushed by positive or reverse circulation, and carried from the bottom of the well. Scale, sand, iron filings and other solid particles are removed to achieve the purpose of cleaning the wellbore, removing sand burial, and salvaging well falling objects. However, in the middle and late stages of oilfield water injection d...

AI Technical Summary

Problems solved by technology

However, in the middle and late stages of oilfield water injection development, the contradiction between layers increases, and the number of formation leakage wells increases. The establishment of full well circulation will generate additional pressure on the formation, causing a large amount of circulating fluid to leak into the formation and pollute the formation. If the circulation is established by temporary plugging , the pollution caused is more difficult to remove. If there is a sudden leakage during the construction process, it will also lead to the accumulation of particulate matter in the buried pipe string and cause drill sticking

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