RU2198142C1 - Method of neutralizing boring sludge contained in spent drilling mud - Google Patents

Abstract

FIELD: drilling fluids. SUBSTANCE: method consists in separating solid and liquid phases of drilling mud by adding aluminosilicates hydrolyzed to pH value 9-12. Resulting solid phase precipitate is loaded into mixer wherein it is mixed with also added there liquifying powder complexing agent containing following components, wt.%: Portland cement, 20-30; burnt lime, 10-15; calcium carbonate, 10-20; phosphogypsum, 10-40; and dolomite, 10-20; 0.2 to 1.0 weight parts of complexing agent being added per 1 weight part of precipitate to be treated. EFFECT: avoided use of sludge-storage facilities. 2 cl, 1 dwg, 3 tbl

Description

 The invention relates to a technology for the rehabilitation of drill cuttings saturating spent drilling fluids.

 When drilling, a drilling fluid is supplied into the well under pressure, containing, as a rule, bentonite clay, plasticizers, stabilizers, surfactants and other substances that contribute to the drilling process and increase its efficiency. The spent drilling fluid is saturated with drilled rock, which is the main component of drill cuttings, and enters the surface. Then, the spent solution is in some cases separated using sieves into solid and liquid phases. The liquid phase can be reused in the drilling process, and the solid (gruel) phase with a moisture content of more than 70% is sent to the sludge storehouse (barn), see, for example, F. A. Shamshev "Technology and technique for exploratory drilling," p. , 113-115, M., 1973.

 A known method of disposal of waste drilling fluid located in the sludge storage, including the separation of the received drilling fluid into a solid phase, with a moisture content of 35-45%, which after processing after a while (10-20 hours) solidifies, and the liquid phase; processing the contents of the sludge storage facility is carried out by introducing aluminosilicates hydrolyzed to pH 9-12, see RU 2150437, C 02 F 11/00, 07/28/98.

 This method is adopted as a prototype of the present invention; it provides a sufficiently high degree of neutralization of sludge pollutants, simplifies and cheapens its disposal.

 However, the disadvantage of this method is the fact that it provides for the mandatory presence of a sludge storage for processing sludge. At the same time, atmospheric precipitation, foreign bodies, soil, etc. also fall into the sludge store and accumulate in it. foreign substances.

 This makes it difficult to reclaim sludge storages, since the volume of the contaminated mass contained in them increases, which requires an increase in the mass of necessary means for its neutralization; in addition, large areas are alienated for the construction of sludge storages and harm the environment as pollutant concentrators.

 The present invention is based on the solution of the problem of creating a method of disposal of drill cuttings contained in the spent drilling fluid, which would not require the creation of sludge storages (barns).

According to the invention, this problem is solved due to the fact that in the method of neutralizing drill cuttings contained in the spent drilling fluid, comprising separating the solid and liquid phases of the drilling fluid by introducing aluminosilicates hydrolyzed to pH 9-12, the precipitate obtained from the solid phase is separated into the mixer, in which it is mixed with a lithifying powder complexing agent also supplied to the mixer, containing the following components, wt.%:
Portland cement - 20-30
Quicklime - 10-15
Calcium Carbonate - 10-20
Phosphogypsum - 10-40
Dolomite - 10-20
with 1 weight. including processed in the mixer, the precipitate of the solid phase serves 0.2-1.0 weight. including lithifying powder concentrate; lithifying powder concentrate may additionally contain clay in an amount of 10-30 wt.%; the lithifying powder concentrate may additionally also contain gypsum in an amount of 2-15 wt.% and calcium chloride in an amount of 1-3 wt.%.

 The applicant has not identified sources containing information about technical solutions identical to the present invention, which allows us to conclude that it meets the criterion of "novelty."

 The implementation of the distinguishing features of the invention leads to a very important new technical effect: eliminating the need for the construction of sludge storages, the neutralization of drill cuttings occurs directly at the drilling rig, which ensures pitless drilling of oil and other wells.

 The applicant has not found any sources of information containing information about the impact of the claimed distinctive features on the technical result achieved as a result of their implementation. This, according to the applicant, indicates that this technical solution meets the criterion of "inventive step".

 The invention is illustrated by a diagram illustrating the implementation of the method.

From the drilling rig 1, the spent drilling fluid containing drill cuttings enters the tank 2, which also serves a suspension of aluminosilicates hydrolyzed to pH 9-12. The contents of the tank 2 are then pumped into a vertical sump 3, where intensive separation of the solid 4 and liquid 5 phases of the spent drilling fluid occurs; the liquid phase is fed for reuse in the rig after adjusting its composition; solid phase - drill cuttings containing 65-75% of water, enters the mixer 6. In a specific example, a screw mixer is used; the use of a paddle mixer is also possible. In the mixer 6 also serves lithitizing powder concentrate (LPC). In example 1, LPK contains, wt.%:
Portland cement - 20
Quicklime ground lime - 10
Ground calcium carbonate - 10
Phosphogypsum - 40
Ground Dolomite - 20
while in this example, 1 weight. including processed in the mixer, the precipitate of the solid phase was supplied 0.95 weight. h. forestry complex.

 The mixture was stirred for 2 minutes until a uniform plastic state; then the resulting material is fed to a vehicle, for example, a dump truck and was delivered to the place of disposal (laying in the structural layer of the base or in the formed technogenic array). The setting time of the material is 3-5 hours. The lithification process is more intense during the first 3-5 days, and then slows down and continues for several months (similar, for example, to the hardening process of cement mortars and concrete).

 Physico-mechanical properties of the material after 28 days of hardening are given in table. 1.

In example 2 of the implementation of the method used LPK, which contained, wt.%:
Portland cement - 30
Ground quicklime - 12
Ground calcium carbonate - 15
Phosphogypsum - 20
Ground Dolomite - 10
Cambrian clay powder - 13
For 1 weight. including drill cuttings was fed 0.25 weight. h. forestry complex. The introduction of clay into the LPC is due to the absence of clay in a specific example in the original drilling fluid.

Physico-mechanical properties of the material are given in table. 2. In example 3 used LPK, which contained, wt.%:
Portland cement - 25
Ground quicklime - 15
Ground calcium carbonate - 20
Phosphogypsum - 10
Ground Dolomite - 15
Gypsum - 13
Calcium Chloride - 2
For 1 weight. including drill cuttings was fed 0.5 weight. h. forestry complex. Gypsum and calcium chloride provide an additional acceleration of the process of lithification of drill cuttings and reduce the time of onset to 2-2.5 hours.

 Physico-mechanical properties of the material are given in table. 3.

 To implement the invention, inexpensive and non-deficient materials are used, and conventional equipment, in particular mixers (mortar mixers, etc.), is used to prepare the mixture. These circumstances allow us to conclude that the invention meets the criterion of "Industrial applicability".

Claims (3)

1. A method of neutralizing drill cuttings contained in the spent drilling fluid, comprising separating the solid and liquid phases of the drilling fluid by introducing aluminosilicates hydrolyzed to pH 9-12, characterized in that the precipitate obtained from the separation of the solid phase is fed to a mixer, in which it is mixed with a lithifying powder complexing agent also supplied to the mixer, containing the following components, wt.%:
Portland cement - 20-30
Quicklime - 10-15
Calcium Carbonate - 10-20
Phosphogypsum - 10-40
Dolomite - 10-20
at the same time for 1 weight.h. processed in the mixer, the precipitate of the solid phase serves 0.2-1.0 weight. including lithifying powder concentrate.  2. The method according to claim 1, characterized in that the lithifying powder concentrate additionally contains clay in an amount of 10-30 wt.%.  3. The method according to claim 1 or 2, characterized in that the lithifying powder concentrate additionally contains gypsum in an amount of 2-15 wt.% And calcium chloride in an amount of 1-3 wt.%.

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