Pressurized workover device and pressurized workover method for low pressure oil and water wells

Abstract

The invention relates to a pressure workover device and a pressure workover method for a low-pressure oil-water well. A blowout preventer group is installed on the upper flange of the wellhead spool through bolts. There is a single ram BOP, the lower part of the single ram BOP is equipped with a four-way, the upper part of the single ram BOP is installed with a double ram slip BOP, and the double ram slip BOP is installed An annular blowout preventer is installed on the top, and a hexagonal grid platform is arranged on the outer periphery of the middle section of the annular blowout preventer. A sunken collection box is installed below the hexagonal grid platform. The bottom of the sunken collection box passes through four rectangularly distributed The outriggers are supported on the ground, and the bottom edge of the sunken collection box is connected with a discharge elbow. The middle and lower part of the annular blowout preventer is located in the central cylinder. Both ends of the lower beam are respectively equipped with lifting hydraulic cylinders, and the two lifting hydraulic cylinders pass through the sleeve vertically upwards respectively to connect with the upper beam. Pre-connect the blowout preventer group before operation, install the hot workover device, and pull out the tubing string. The invention can improve the wellhead environment, has low height, is convenient for overall relocation, and greatly shortens installation time.

Description

technical field [0001] The invention relates to an oilfield operation tool, in particular to a workover device for a low-pressure oil-water well under pressure; the invention also relates to a workover method for a low-pressure oil-water well under pressure, belonging to the technical field of workover under pressure. Background technique [0002] The wellhead device of the oil-water well includes the wellhead spool and various blowout preventers installed above the wellhead spool, and the oil pipe extends along the center of each blowout preventer. At present, the downhole pressure of oil and water wells in oil fields can be classified into three types: high, medium and low, among which low pressure wells account for a relatively high proportion. However, most of the workover devices for oil and water wells in oil fields are high-pressure operation devices, which have the following deficiencies: [0003] 1. In order to realize high-pressure sealing construction, multiple s...

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Problems solved by technology

[0003] 1. In order to realize high-pressure sealing construction, multiple semi-sealed BOPs, full-sealed BOPs or annular BOPs are usually installed. There are many structural components, and the height is mostly above 5m. The overall height is too high, the installation is complicated, and the operation is inconvenient. , poor safety, and the relocation of the whole machine is inflexible and low in efficiency. For low-pressure wells, there is a problem of inefficiency of "big horse-drawn carts". At present, there is no small-scale workover device for low-pressure wells with a height of no more than 2m in the oil field

[0004] 2. When the well pressure is low and there will be no oil pipe topping phenomenon, in order to improve the construction progress, the annular blowout preventer is usually used to seal the oil pipe annulus when lifting and lowering the oil pipe, resulting in a short service life of the annular blowout preventer rubber core. The rubber core of the blowout preventer is frequently replaced, and the purchase cost is high

[0005] 3. During the routine operation of oil-water wells with pressurized workover and small overflow wells, the overflow between the outer periphery of the tubing and the blowout preventer due to the lack of sealing, and the overflow of liquid in the tubing will bring serious pollution to the well site; During the process of lifting the oil pipe, when the oil pipe is blocked or there is no oil drain device at the lower part, when the connecting thread of the oil pipe is removed, the liquid in the oil pipe will flow down quickly, and the dirty oil and water will fall and splash on the flange of the blowout preventer plane, causing environmental pollution at the wellhead, deterioration of the construction environment, and affecting the physical and mental health of operators

Existing high-pressure operation devices do not have the function of overflow collection. Under the circumstances of increasing environmental protection requirements, how to realize the function of not affecting the operation speed and avoiding the well site from being polluted by overflow has always been a problem that plagues underground operations.

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