Well cementation cement system for in-situ combustion

Abstract

The invention discloses a well cementation cement system for in-situ combustion. The well cementation cement system for the in-situ combustion comprises, by weight, 50 parts of G-class oil well cement, 50 parts of aluminate cement, 20 parts of coal ash, 20 parts of quartz sand, 14 parts of micro silicon, 1.4 parts of sodium lignin sulfonate, 0-15 parts of iron ore powder, 0.6-1 part of retarder and 1.6-2 parts of fluid loss agents; the retarder adopts one of calcium hydrophosphate, sodium citrate and D-sodium gluconate or a composition of the calcium hydrophosphate, the sodium citrate and the D-sodium gluconate, and the fluid loss agents adopt one of polyvinyl alcohol, AM/AA/AMPS copolymers and sodium polystyrene sulfonate or a composition of the polyvinyl alcohol, the AM/AA/AMPS copolymers and the sodium polystyrene sulfonate. According to the well cementation cement system for the in-situ combustion, the requirements that the in-situ combustion reaches to temperature up to 600 DEG C to 700 DEG C in oil thermal recovery can be met, the advantages of being high in compression resistance strength, low in permeability and good in set cement stability and homogeneity at 600 DEG C to 700 DEG C are achieved, and the site construction requirements can be met.

Description

technical field [0001] The invention relates to a cement system for oilfield drilling and cementing, in particular to a cementing cement system for burning oil layers, and belongs to the technical field of drilling and production. Background technique [0002] At present, heavy oil recovery in oil fields is mainly based on thermal oil recovery. During thermal oil recovery, the temperature of the incinerated oil layer is as high as 600°C to 700°C. During the exploitation of the incinerated oil layer, the wellbore will be subjected to repeated periodic high temperatures, which will lead to the decline of the compressive strength of the cement sheath at high temperatures, the increase of the permeability, and the stability of the cement stone. And the homogeneity is destroyed, and the production life of the heavy oil thermal recovery well is directly shortened after the wellbore is damaged, which makes the oil recovery efficiency drop. [0003] There are certain difficulties i...

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Problems solved by technology

During thermal oil recovery, the temperature of the incinerated oil layer is as high as 600°C to 700°C. During the exploitation of the incinerated oil layer, the wellbore will be subjected to repeated periodic high temperatures, which will lead to the decline of the compressive strength of the cement sheath at high temperatures, the increase of the permeability, and the stability of the cement stone. And the homogeneity is destroyed, and the production life of the heavy oil thermal recovery well is directly shortened after the wellbore is damaged, which reduces the oil recovery efficiency

[0003] There are certain difficulties in the formulation design of cementing cement slurry for thermal recovery well combustion oil layers. The existing conventional cement slurry formulations are difficult to meet the ultra-high temperature resistance conditions of thermal recovery well combustion oil formations. The currently developed aluminophosphate cementing cement The slurry system is easily polluted by Portland cement, which leads to harsh construction conditions on site. Therefore, it is necessary to develop a cementing slurry system with strong on-site adaptability and easy and safe construction for the cementing of incinerated oil layers.

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