Supersaturated sodium chloride cement slurry system for well cementation

Abstract

The invention relates to a supersaturated sodium chloride cement slurry system for well cementation, and belongs to the technical field of cement slurry for well cementation in petroleum drilling. The supersaturated sodium chloride cement slurry system comprises highly sulfur-resisting grade G silicate cement, a weighting agent, a salt resistant water-loss control agent, a preserving agent, a setting retarder, fresh water, sodium chloride, an enhanced channeling preventing agent and an expanding agent. The highly sulfur-resisting grade G silicate cement is used as a base, the property instability and the metastable state property of the supersaturated solution are utilized, and other raw materials are added proportionally, so that the supersaturated sodium chloride cement slurry system has good salt stain resistance and calcium contamination resistance, is simple and convenient in on-site construction, has a good well cementation effect, can meet the well cementation requirements in complex conditions such as salt-gypsum layer, high pressure deep well salt-gypsum layer and super-thick salt-gypsum layer and the like, is convenient in cementing operation, and has a remarkable oil gas water channeling prevention effect, and the density of the supersaturated sodium chloride cement slurry system can be optionally regulated in a range of 1.90-2.40g / cm<3>. The supersaturated sodium chloride cement slurry system overcomes the defect that the thickening time of the supersaturated salt water cement slurry is difficult to control, and can meet the well cementation requirements in various complex conditions.

Description

technical field [0001] The invention relates to a supersaturated sodium chloride cementing cement slurry system, belonging to the technical field of cementing slurry for petroleum drilling. Background technique [0002] The combination of thick-walled casing and cement slurry is a necessary and conventional cementing method for oil drilling. When cementing operations in salt-gypsum layers, especially deep well salt-gypsum layers and extremely thick salt-gypsum layers, the use of conventional cement slurry has the following problems: First, due to the concentration effect, the The dissolution of salt in the cement slurry will thicken or gel the cement slurry. At the same time, the dissolution of the salt layer will expand the wellbore, resulting in irregular wellbore walls and affecting drilling operations. Dissolution not only affects the hardening rate of cement slurry, but also affects its strength after hardening, and dissolution cracks will also be formed between the ce...

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Problems solved by technology

[0003] The object of the present invention is to provide an anti-salt pollution and calcium intrusion resistance, high strength and cementation performance, which can effectively avoid the erosion of thick-walled casing, prolong the service life of oil and gas wells; ensure complex salt paste The effective sealing of the casing formation in the layer well section has good cementing effect and is easy to use; it solves the problem of non-corrosion resistance, poor cementation performance, slow development of gel strength, low early strength and ineffectiveness of conventional cement slurry in the construction of complex salt-gypsum layers. A supersaturated sodium chloride cementing cement slurry system that resists the deformation of thick-walled casing caused by the external extrusion force caused by the creep of the salt formation

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