SU1076569A1 - Method of eliminating absorption of drilling muds and cements - Google Patents

Abstract

METHOD OF ELIMINATING THE ABSORPTION OF DRILLING OR CEMENTAL SOLUTIONS by washing in the absorption zone of inert materials, characterized in that, in order to increase the efficiency of the method by forming an absorbent filtering surface in the channels of the developed filtering surface, inert materials are injected by pumping 10-15 ° C oh suspension of filtroperlita.

Description

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O) QD The invention relates to methods for eliminating drilling and cement mortars that provide blockage of fractures and channels of absorbing formations when drilling wells for various purposes and can be used in the oil and gas industry, geology and mining. Methods are known for isolating absorption zones by injecting into the absorbing compositions into the absorption zone in order to form an insulating bridge in it, in particular, by injecting into the well and forcing the cement mortar 1 into the cracks and channels of the absorbing reservoir. the presence of intense acquisitions. In these cases, the formation of stable insulating bridges is not achieved, because the cement slurry, due to its inherent rheological properties, freely escapes through the fractures and channels of the formation, does not linger in them, and thus the insulation of the cracks and channels in the zone does not occur. absorption. There is also known a method to eliminate absorption of drilling or cement mortars by washing in the absorption zone of inert materials, in particular perlite (2. However, the use of perlite as a precoat hinders the work on the elimination of absorption due to the fact that perlite floats in water. In addition , the efficiency of eliminating absorption is also reduced due to the fact that inert materials do not form a developed filtering surface, and they accumulate and accumulate in separate channels. This is achieved by the fact that, according to the method for eliminating absorption of drilling mud or cement mortar by washing inert materials in the absorption zone, all-in-one is carried out by pumping 10-15 / o of a suspension of filtroperlite. conditions of the well, fulfilling the functions of the alluvial layer, the filtroperlite forms a spatial network structure in the near-wall zone of the slag layer with a certain mechanical strength. This is facilitated by the angular shape of the open-pore particles of filter-perlite. Coupling at the ends and edges of the grain of the filter-perlite can withstand a significant pressure drop, this results in the compaction of the bulk grating with trapped solid particles of cement or drilling mud and the formation of a strong web in the absorbing zone. In terms of physico-technical indices, filterperlite meets the basic requirements of TU 480-1-79-74: bulk density is not more than 150 kg / m, the amount of floating particles in water is not more than 12%; filtration permeability to water not less than 1.0 darcy; the dry residue of the water extract after evaporation is not of a very small bulk mass, the filter-perlite practically does not float in water, but forms a suspension in it, the solid particles of which eventually settle and form a filter grid. This important property of filter-perlite is used when a large and developed surface is washed up in the absorption zone by pumping 10-15% aqueous suspension of filter-perlite into the well. To this end, the calculated volume of dry filtering powder is packaged in mixers SME-20 or 2AC-20 and sealed with water using cementing units. The table lists the properties of the aqueous suspension of filter perperlite.

Filtration of the perforation is carried out until the circulation of its aqueous suspension in the well is restored. The mode of injection of the suspension in this case is chosen so that the filter permeable, falling into the cracks and channels of the absorbing horizon, settled in them. The equilibrium between the pressure created in the wellbore by the column of filtroperlite suspension and the reservoir pressure of the absorbing horizon is ensured by the low density of the suspension.

Conducted testing method. In the process of drilling a well at a depth of 1447 m

complete loss of circulation of the flushing fluid is observed. Absorbances are eliminated by washing the filterperlite in the zone absorbed at a depth of 1,447 m and subsequent cementing of this zone. At the same time, 1.5 tons (10 m) of filtroperlite and 7 tons of cement cement were consumed. Before the start of the isolation works, the cement and cement are loaded into separate mixers. The drill string is installed 10-15 m above the absorption zone. A 10.5 m aqueous suspension of filtroperlite with a density of 1.05 g / cm is pumped into drill pipes.

the fluid in the annulus while raising to the mouth of the well. The preparation of the slurry and its injection is carried out using a cementing unit and a blender.

The test of the proposed cnocciba of the elimination of absorption by washing the filtroperlite into the absorption zone was successful, the absorption of the washing liquid was eliminated.

The application of the method in isolating absorption zones in one well can save up to 10 thousand rubles.

Claims (1)

METHOD FOR LIQUIDATION OF ABSORPTION OF DRILLING OR CEMENT MORTARS by washing inert materials in the absorption zone, characterized in that, in order to increase the efficiency of the method by forming a developed filtering surface in the channels of the absorbing layer, washing of inert materials is carried out by pumping a 10-15% suspension of filter perlite. smiling