CN-117887436-B - Hydrothermal synthesis type long-term anti-fading low-density well cementation material in ultra-high temperature environment and preparation method thereof

CN117887436BCN 117887436 BCN117887436 BCN 117887436BCN-117887436-B

Abstract

The invention provides A hydrothermal synthesis type long-term anti-fading low-density well cementation material under ultrA-high temperature environment and A preparation method thereof, wherein the well cementation material can generate substances with certain strength by utilizing hydration reaction of the raw materials at high temperature through introducing calcium oxide, silicon oxide and various calcium aluminates into the formulA of the material, meanwhile, in A high-temperature environment, three kinds of calcium aluminate meeting A certain proportion can generate hydrated calcium aluminosilicate (C-A-S-H) with long-term high-temperature resistance with calcium oxide and silicon oxide, so that the long-term high-temperature resistance of the well cementation material is ensured. Through the method, the well cementation material which does not have strength degradation under the long-term high-temperature condition (at 240 ℃ for 90 d) is prepared, and the problem of strength degradation at high temperature in cement paste for deep wells in the prior art is effectively solved.

Inventors

PANG XUEYU
WANG CHUANGCHUANG
CHENG GUODONG
SUN JINSHENG
LV KAIHE

Assignees

中国石油大学(华东)

Dates

Publication Date: 20260505
Application Date: 20240108

Claims (3)

1. The hydro-thermal synthesis type long-term anti-fading low-density well cementation material under the ultra-high temperature environment is characterized by comprising the following raw materials, by weight, 13-38 parts of retarder, 185-280 parts of solid reactant, 6-11 parts of stabilizer, 6-11 parts of fluid loss agent, 1-4 parts of dispersing agent, 0.7-1.1 part of defoamer and 89-129 parts of water; The solid reactant comprises the following raw materials, by weight, 26-110 parts of calcium hydroxide, 100 parts of silica sand and 39.1-87 parts of a calcium aluminate mixture, wherein the solid reactant satisfies the element molar ratio of Ca/Si/Al to be 4:4:1 or 2:2:1, and the mass of the retarder is 7-14% of the total mass of the solid reactant; the calcium aluminate mixture comprises, by mass, 22-27%, 34-48% and 28-37% of monocalcium aluminate, calcium dialuminate and dicalcium aluminosilicate; The retarder is a high-temperature-resistant retarder HX-36L, the stabilizer is a high-temperature-resistant suspension stabilizer O-SP, the fluid loss agent is a high-temperature-resistant fluid loss agent HX-12L, and the dispersant is a dispersant USD-1.
2. The preparation method of the long-term anti-fading low-density well cementing material under the ultra-high temperature environment according to claim 1 is characterized by comprising the following steps of uniformly mixing 13-38 parts of retarder, 185-280 parts of solid reactant, 6-11 parts of stabilizer, 6-11 parts of filtrate reducer, 1-4 parts of dispersing agent, 0.7-1.1 parts of defoaming agent and 89-129 parts of water, and curing for 90 days at 240 ℃ and 50MPa to obtain the well cementing material; The solid reactant comprises the following raw materials, by weight, 26-110 parts of calcium hydroxide, 100 parts of silica sand and 39.1-87 parts of a calcium aluminate mixture, wherein the mass of the retarder is 7-14% of the total mass of the solid reactant; the calcium aluminate mixture comprises, by mass, 22-27%, 34-48% and 28-37% of monocalcium aluminate, calcium dialuminate and dicalcium aluminosilicate.
3. The method of claim 2, wherein the slurry has a density of 1.65g/cm 3 after mixing all the materials uniformly.

Description

Hydrothermal synthesis type long-term anti-fading low-density well cementation material in ultra-high temperature environment and preparation method thereof Technical Field The invention relates to the technical field of oil and gas exploitation, in particular to a hydro-thermal synthesis type long-term anti-fading low-density well cementation material in an ultra-high temperature environment and a preparation method thereof. Background In recent years, deep oil and gas resources have become an important point for resource development. With the continuous development of deep oil and gas resources, the number of oil and gas wells with the bottom hole static temperature exceeding 200 ℃ is also continuously increased. At temperatures above 110 ℃ downhole, the semi-crystalline calcium silicate hydrate (C-S-H) in the portland cement-based hydration product gradually converts to a crystalline phase, resulting in a decrease in compressive strength and an increase in permeability. As the bottom hole temperature further increases, the mechanical properties of the set cement will further deteriorate. This behavior of portland cement at high temperatures is known as strength decay of the cement. In the past, siO 2 -rich materials (mainly silica fume) have often been added to cement slurries to prevent deterioration of the strength of the set cement at high temperatures. Recent research results indicate that this approach only alleviates strength degradation over a short curing time, but does not completely prevent strength degradation over a long period of time (over 30 days) above 200 ℃. Therefore, in order to improve the quality of well cementation in deep wells and the integrity of the well wall, there is an urgent need to find or develop a new material that does not undergo strength degradation at high temperatures. The deep well often has a low-pressure easy-leakage area, the phenomenon that slurry is easy to leak into a reservoir is caused by using conventional density cement slurry, and besides, the damage to the pressure of a shaft and a tubular column can be reduced by using the low-density cement slurry, so that the low-density well cementation liquid with long-term high temperature resistance is required in the easy-leakage area of the deep well. However, the conventional low-density cement slurry system is more serious in strength degradation at high temperature and almost cannot be applied. In view of the above, there is a need to design an improved long-term anti-fading low-density cementing material by hydrothermal synthesis under ultra-high temperature environment and a preparation method thereof, so as to solve the above problems. Disclosure of Invention The invention aims to provide a hydrothermal synthesis type long-term anti-fading low-density well cementation material in an ultra-high temperature environment and a preparation method thereof. In order to achieve the aim of the invention, on the one hand, the invention provides a hydro-thermal synthesis type long-term anti-fading low-density well cementation material under an ultra-high temperature environment, which comprises the following raw materials, by weight, 13-38 parts of retarder, 185-280 parts of solid reactant, 6-11 parts of stabilizer, 6-11 parts of fluid loss agent, 1-4 parts of dispersing agent, 0.7-1.1 parts of defoamer and 89-129 parts of water; The solid reactant comprises the following raw materials, by weight, 26-110 parts of calcium hydroxide, 100 parts of silica sand and 39.1-87 parts of a calcium aluminate mixture, wherein the mass of the retarder is 7-14% of the total mass of the solid reactant; the calcium aluminate mixture comprises, by mass, 22-27%, 34-48% and 28-37% of monocalcium aluminate, calcium dialuminate and dicalcium aluminosilicate. In one embodiment of the present invention, the retarder is a high temperature resistant retarder HX-36L. In one embodiment of the invention, the stabilizer is a high temperature resistant suspension stabilizer O-SP. In one embodiment of the invention, the fluid loss additive is a high temperature resistant fluid loss additive HX-12L. In one embodiment of the invention, the dispersant is dispersant USD-1. On the other hand, the invention also provides a preparation method of the hydro-thermal synthesis type long-term anti-fading low-density well cementation material under the ultra-high temperature environment, which comprises the following steps of uniformly mixing 13-38 parts of retarder, 185-280 parts of solid reactant, 6-11 parts of stabilizer, 6-11 parts of fluid loss agent, 1-4 parts of dispersing agent, 0.7-1.1 parts of defoamer and 89-129 parts of water, and curing for 90 days under the conditions of 240 ℃ and 50MPa to obtain the well cementation material; The solid reactant comprises the following raw materials, by weight, 26-110 parts of calcium hydroxide, 100 parts of silica sand and 39.1-87 parts of a calcium aluminate mixture, wherein the mass of the retarder is 7-14% of