A high-pressure well cementing process

Abstract

The invention discloses a technique for cementation of a high-pressure well. The technique includes: adjusting density of drilling fluid, and pressure-stabilizing an oil-gas reservoir; lowering a sleeve, and circulating the drilling fluid; calculating thickening time h for quick setting and performance coefficient SPN of quick-setting cement grout and thickening time h for slow setting of slow-setting cement grout, preparing the quick-setting cement grout according to the thickening time h for quick setting and the performance coefficient SPN, and preparing the slow-setting cement grout according to the thickening time h for slow setting; confirming density and using amount of the drilling fluid, weighted spacer fluid, flushing fluid, the slow-setting cement grout and the quick-setting cement grout to enable pressure applied on the oil-gas reservoir by a grout column to be higher than a sum of pressure applied on the oil-gas reservoir by a fluid column of the drilling fluid and a pressure-stabilizing added value during drifting when the quick-setting cement grout loses weight; pushing the drilling fluid, the weighted spacer fluid, the flushing fluid, the slow-setting cement grout and the quick-setting cement grout into a well cementation annulus.

Description

technical field [0001] The invention relates to the technical field of oil and gas development, in particular to a high-pressure well cementing process. Background technique [0002] As the development of oilfields gradually faces deep layers, the number of high-pressure wells in deep low-permeability reservoirs is increasing year by year, which is characterized by high formation pore pressure and tight formation lithology. The on-site performance is "high pressure is suppressed when the well is shut down, and there is no pressure when the well is opened", so it is difficult to implement effective pressure stabilization for such high-pressure wells. If effective pressure stabilization is not implemented without well control risk before cementing, oil and gas will be mixed into the drilling fluid, and this part of oil and gas will form an oil film on the well wall that is not easy to be washed off, thus hindering the cement and well wall. The tight cementation results in poo...

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