A thermal recovery well sealing agent, sealing slurry and sealing method

Abstract

The invention relates to a thermal production well cementing agent, cementing slurry and a cementing method, and belongs to the technical field of oilfield development. The thermal production well cementing agent consists of the following components in parts by weight: 50-100 parts of oil well cement, 0-50 parts of slag micropowder, 2-5 parts of bentonite, 30-70 parts of a stabilizer and 5-8 parts of a blocking agent. The cementing slurry prepared from the thermal production well cementing agent and water can realize restore of small casings in casing damage wells of thermal production wells, blocking of leakage strata, and secondary-cementing integrated safety construction, and has a good adaption performance to large-pore loosen strata and breakthrough flow channels of thermal production wells, can solve various complicated technical problems of high-temperature resistant cementing and blocking of thermal production wells, and can meet the requirements of large-dose site construction.

Description

technical field [0001] The invention belongs to the technical field of oil field development, and in particular relates to a thermal recovery well sealing agent, a thermal recovery well sealing slurry, and a sealing method using the thermal recovery well sealing slurry. Background technique [0002] At present, heavy oil thermal recovery mainly adopts steam injection methods, such as steam flooding, steam huff and puff, steam-assisted gravity drainage, etc. The wellbore temperature is high during thermal recovery of heavy oil. For example, the gas injection temperature of steam huff and puff wells reaches about 300°C, the local well temperature of steam flooding production wells is also about 200°C, and the temperature of deep wells above 4500m is above 150°C. Such a high temperature must have a great impact on cementing. Oil well casing damage has become a frequently encountered technical problem in the oilfield production process. For example, during the steam stimulation...

AI Technical Summary

Problems solved by technology

However, there are many limitations in the implementation of these technologies: when implemented by mechanical means, 1) the plugging and casing repairing are implemented separately, that is, the layer to be plugged is blocked first, and then the small casing repairing operation is carried out, the process is complicated, The cycle is long and the cost is high; 2) The cementing slurry in the integrated operation cannot be returned to the ground due to its poor retention performance, which has potential safety hazards, and the implementation of remedial operations will increase operating costs

However, the application of chemical plugging agent for plugging and cementing has solved the technical problems of plugging and cementing integration to a certain extent, but there are problems of high cost and unstable restoration success rate, which restrict the high efficiency and efficiency of thermal recovery wells. It has been developed for a long time, and the use of chemical sealants has certain requirements on the formation temperature, and it is not too inapplicable under high temperature environmental conditions, such as the chemical composite resin seal for oil well casing repair disclosed in the prior art CN 102516963 B Solid agent, the sum of the weight percentages of each component is 100%; the weight percentage of each component is: prepolymerized condensation product of phenol and formaldehyde: 60-75%, F-46 epoxy phenolic resin 10-20%, epoxy resin 6101 5-30%, ethylenediamine 1-5%, triethanolamine 1-5%, acetic anhydride 0.5-2%, dibutyl phthalate 1-3%, ethylene glycol 2-5%, poly 2-5% vinyl alcohol, 0.1-0.2% ultra-fine acrylic staple fiber, but the applicable formation temperature of this chemical composite resin sealant is only up to 110°C

[0004] In order to overcome the shortcomings of the above-mentioned prior art, the present invention has developed a thermal recovery well sealing agent, which can realize thermal recovery well casing repair, sealing of lost formations and secondary cementing, and return the residual slurry to the ground. It solves the serious problem of casing damage in heavy oil thermal recovery wells, avoids the inconvenience caused by mechanical or chemical methods to repair casing damage, and at the same time meets the technical requirements of field configuration and adjustable initial setting time; it can also resist up to 300 ℃ temperature, suitable for the development of thermal recovery wells

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