Method for subsurface injection conformance improvement using micro calcium carbonate particles

A method of improving subsurface injection conformance and sweep efficiency using extremely small calcium carbonate particles having a median particle size of about 1 μm to no more than 140 μm to shut off an injected fluid flow into thief zones within a subsurface reservoir and to divert the injected fluid to desired hydrocarbon, geothermal or carbon storage zones, the method comprising:

• evaluating and diagnosing of the subsurface reservoir and the thief zones, thereby estimating and defining pore size and fracture width of the thief zone;
• engineering and designing of a treatment plan for sealing pores and fractures of the thief zone, thereby determining the required calcium carbonate particle size, spectrum and concentration of the treatment plan;
• introducing the calcium carbonate particles according to the treatment plan into the thief zones to create seals over the thief zones, wherein at least a portion of the calcium carbonate particles is non-spherical;
• computing and estimating of a permeability of the created seals over the thief zone thereby predicting and defining post-treatment permeability;
• and
• determining injection conformance improvement, injected fluid rate distribution over different zones, and estimating oil or geothermal production rate increase, and a ratio of an injection rate to a withdrawal rate.