Continuous sand flushing technique and continuous sand flushing device thereof

Abstract

The invention discloses a continuous sand-washing process and a continuous sand-washing device formed by, firstly, mounting control valves one by one on the upper port of a sand-washing pipe column and on the upper port of a single sand-washing pipe column. When the control valve is open, a regular sand-washing pipe column reaches down. When the sand-washing pipe column approaches or reaches the sand sediment or oil send at the bottom of a well, if extension is needed, single sand-washing pipe columns provided with control valves are connected one by one to establish sand-washing circulation channel, start a mud pump and carry out sand-washing operation; the control valve in open state allows double-way passage and offers such options as regular positive circulation operation and reverse circulation operation. Meanwhile, the control valve is started or closed manually to decouple from or couple with the single sand-washing pipe column. The invention is not subject to the restriction of sand medium and is particularly suitable for sand-washing operation by nitrogen foam under low-pressure well. The process saves the pressure-releasing time for connecting single sand-washing pipe column every time, realizes continuous sand washing, improves efficiency, prolongs the time of oil well production, and thus reduces cost and increases benefits.

Description

technical field [0001] The invention relates to an oil well sand washing process and a sand washing device in an oil field, in particular to a continuous sand washing process and a continuous sand washing device applicable to both land and sea oil well exploitation. Background technique [0002] Sand washing is a common measure taken by major oil fields to solve the problem of sand settling in wells. The sand washing media used are mainly mud and water. For low-pressure wells, because the liquid column pressure is greater than the formation pressure, the liquid will leak into the formation, making sand washing more efficient. If the water is low or the sand settlement occurs, the formation may be polluted due to the incompatibility of the liquid and the formation. In addition, due to the low viscosity of the water and the weak sand-carrying ability, it is easy to cause the sand settlement and pipe sticking at low displacement; When washing a single sand washing pipe string (...

AI Technical Summary

Problems solved by technology

[0007] 3. Due to concerns about accidents that may be caused by the non-reverse circulation of the check valve, some sites do not use the check valve, which brings the problem of longer release time of the compressed nitrogen foam fluid, such as more than 30 minutes each time. The operation time is prolonged, the operation cost is increased, and the effect of the low-density nitrogen foam operation is generally discounted

[0008] The existence of the above-mentioned deficiencies has restricted the popularization and use of the low-density nitrogen foam sand washing process

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