Multi-stage packer dropped pipe string and its tripping method

Abstract

The invention relates to a multilevel packer releasing pipe column and a dismantling method thereof. The process pipe column includes a pitching releasing tool, multiple groups of pipe column units, afixing ball base, a sieving pipe and a pipe plug. Every two pipe column units are connected in series through a sliding-sleeve type step-by-step deblocking releasing tool; when pipe columns need to be dismantled, a fishing anchor is put into a fish top of the pitching releasing tool, the inner wall of the fish top is clamped, and meanwhile, a central pipe is sealed; steel balls are put into oil tubes for keeping down the pressure, each level of sliding-sleeve type step-by-step deblocking releasing tools are unlocked and started step by step for pressure relief, the pipe columns are lifted up,and then the sliding-sleeve type step-by-step deblocking releasing tools are extended to provide an enough deblocking stroke for a packer at the higher level, so that the packer at the higher level is deblocked alone, and the deblocking load is reduced. When the pipe columns are stuck during dismantling, the pipe columns are lifted up, and releasing is achieved by the sliding-sleeve type step-by-step releasing tools; thus, the pipe columns at the upper portion are dismantled, then the fishing anchor is put in to fish out the pipe columns at the lower portion, large-scale overhaul operation isavoided, and the reliability of a multilevel packer releasing pipe column dismantling process is improved.

Description

technical field [0001] The invention relates to a downhole construction method for oil and gas field operations, in particular to a construction method for a multi-stage packer drop-off pipe string in the field of oil production, in particular to a multi-stage packer drop-out pipe string and a tripping method thereof. Background technique [0002] Most of the blocks in the oilfield belong to multi-layer, heterogeneous, complex fault-block reservoirs. Due to the many layers of oil layers, the distribution of oil, gas and water, and the corresponding relationship between oil and water wells are complicated. Entering the stage of high water cut development, in order to reduce the water content of the produced crude oil and achieve stable and high production in the oil field, various methods of finding water are usually used to find out the water producing layer, and the corresponding multi-stage packer is used to plug the pipe string. Water, the currently commonly used multi-st...

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Problems solved by technology

[0002] Most of the blocks in the oilfield belong to multi-layer, heterogeneous, complex fault-block reservoirs. Due to the many layers of oil layers, the distribution of oil, gas and water, and the corresponding relationship between oil and water wells are complicated. Entering the stage of high water cut development, in order to reduce the water content of the produced crude oil and achieve stable and high production in the oil field, various methods of finding water are usually used to find out the water producing layer, and the corresponding multi-stage packer is used to plug the pipe string. Water, the currently commonly used multi-stage packer string is mainly composed of tubing, packer, centralizer, pitching ball, pressing ball seat, etc. In the field application, there are multiple stages in the string. The packer is unsealed at the same time, and the unsealed load is relatively large; if the pipe string is stuck due to sand production, scaling, etc., the unsealed load will be greater, and unsealed failure will occur, resulting in major repairs and increasing oilfield production costs. The deficiency is more obvious in deep wells and highly deviated wells. Therefore, in order to improve the reliability of multi-stage packer lost strings and reduce the risk of overhaul operations, it is urgent to study the safety of multi-stage packer lost strings. Useful ways

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