Low-density mixed material suitable for shallow loose sandstone formation, and preparation method of low-density mixed material

Abstract

The invention discloses a low-density mixed material suitable for shallow loose sandstone formation. The low-density mixed material is prepared from the following raw materials in 100 parts by mass: 10-20 parts of floating beads, 30-40 parts of micro-silicon, 25-35 parts of fly ash and 15-25 parts of slag. Based on the low-density mixed material, the invention further provides cement paste. The cement paste is prepared from the following components in parts by weight in a mixed mode: 100 parts of G-grade Portland cement, 55-75 parts of the low-density mixed material, 7-15 parts of a fluid lossagent, 0.5-2 parts of a retarder, 0.5-3 parts of an early strength agent, 1-4 parts of a dispersing agent, and 100-150 parts of fresh water. According to different construction requirements, the density of the low-density mixed material can be adjusted at will within the range of 1.40-1.70 g / cm<3>, the low-density mixed material has good cement paste compressive strength, good stability and goodtwo-interface cementation well-cementing quality at the low temperature, and the well-cementing requirements of the shallow loose sandstone formation can be met.

Description

technical field [0001] The invention belongs to the technical field of cement slurry for oil drilling and well cementing, and in particular relates to a low-density mixed material suitable for shallow loose sandstone formations and a preparation method. Background technique [0002] Shallow unconsolidated formations usually face problems such as formation leakage easily, shallow geological disasters, low compressive strength of cement stone, poor bonding quality of the two interfaces and other production technology problems. In order to avoid these problems, cementing is one of the key links. The quality of cementing largely depends on the performance of cement slurry. For shallow loose formations, low-density cement slurry system is usually used for cementing construction. Low-density cement slurry has the advantages of short setting time and good stability, which can greatly improve Construction safety and cementing quality of shallow wells that are prone to leakage. Ther...

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Problems solved by technology

[0003] Aiming at the production technical problems such as low compressive strength of cement stone and poor bonding quality of the two interfaces faced by well cementing in shallow unconsolidated formations, the present invention provides a low-density mixed material suitable for shallow unconsolidated sandstone formations. According to different construction requirements, The low-density mixed material density of the present invention can be at 1.40-1.70g / cm 3 The cementing slurry density can be adjusted arbitrarily within the range, and it has good compressive strength, stability, rheology and cementing quality of the two interfaces at low temperature, which can meet the cementing requirements of shallow loose sandstone formations

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