A multi-layer and multi-grain composite pre-packed screen suitable for sand control of silt and fine sand

Abstract

The invention relates to a multi-layer multi-size fraction composite prefilling sieve tube suitable for sand prevention of silty-fine sand. The multi-size fraction composite prefilling sieve tube suitable for the sand prevention of the silty-fine sand comprises a base tube, an internal wire winding layer, a multi-size fraction composite filling layer, an external wire winding layer and an externalprotection cover in sequence from inside to outside, wherein the outer surface of the base tube is sleeved with the internal wire winding layer, the outer portion of the internal wire winding layer is sleeved with the multi-size fraction composite filling layer, the multi-size fraction composite filling layer is composed of three layers, gravels fill the gaps between the layers, the thickness ofeach layer is different from that of other layers, and the grain sizes of the gravels of different gaps between different layers are different; the outer portion of the multi-size fraction composite filling layer is sleeved with the external wire winding layer, and the external protection cover serves as the outermost layer. Compared with existing methods of gavel filling sand prevention and mechanical sieve tube sand prevention, the multi-layer multi-size fraction composite prefilling sieve tube has the advantages that the sand prevention layer is thick, the useful life is long, the sand prevention layer function and the circulation function can both provided, and the sand prevention effect and oil-gas well high yield are kept. The multi-layer multi-size fraction composite prefilling sieve tube suitable for the sand prevention of the silty-fine sand is suitable for the sand prevention of petroleum, natural gas and natural gas hydrate silty-fine sand.

Description

technical field [0001] The invention relates to a multi-layer and multi-grain composite pre-filled screen suitable for silt and fine sand sand control, belonging to the technical field of downhole drilling and production tools for oil, natural gas and natural gas hydrate. Background technique [0002] Unconsolidated sandstone oil and gas reservoirs are widely distributed in my country and the world, and their reserves and production are currently dominant. One of the main thorny problems in the development of unconsolidated sandstone oil and gas reservoirs is sand production in oil and gas wells, resulting in damage to production equipment and a significant reduction in production. In natural gas hydrate reservoirs, most of the cement in reservoir rock particles is hydrate, which loses cementation after decomposition and produces a large amount of sand. For the above-mentioned sand production problems in oil and gas reservoirs, sand control measures need to be taken in norm...

AI Technical Summary

Problems solved by technology

[0005] (1) Single-layer single-grain filling, single-size gravel, formation sand is easy to invade, block and reduce production;

[0006] (2) The gravel pre-packing layer is thin, the sand-retaining effect is poor, and the validity period is short;

[0007] (3) The selection and design of gravel size is difficult to take into account the sand retaining effect and maintain high flowability, and it is difficult to meet the sand control requirements of silt fine sand and super silt fine sand

The base pipe with high conductivity can ensure that the fine sand that passes through the gravel layer can be produced through the base pipe. Although the sand control pipe has high conductivity, for oil and natural gas unconsolidated sandstone reservoir silt and fine sand (grain size 50 μm), Especially the ultra-fine sand (grain size reaches 10-15μm) in natural gas hydrate reservoirs, it is difficult to meet the sand control requirements of silt and ultra-fine sand

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