RU2524708C1 - Method of bore mud processing - Google Patents

Abstract

FIELD: mining.

SUBSTANCE: bore mud is mixed with sand at the ratio of 1:(0.75-5) to add hydrochloric acid in amount of 0.02-2.246 gram-molecules per 1 kg of mud to mix pH of 5 to 8, mix being mixed and dried thereafter. As a result, inert construction material or man-caused soil is produced from wastes. To select more accurate recipe, bore mud is subjected to analysis for content of clay particles and pH level.

EFFECT: simple and reliable process.

6 cl, 2 tbl

Description

The invention relates to the field of processing drilling waste, in particular to the disposal of drill cuttings to produce building materials and industrial soils from them.

Industrial waste from the construction of wells, which are usually accumulated and stored directly on the territory of the drilling site - in sludge pits, consists of drilling wastewater (BSW), spent drilling fluids (OBR) and drill cuttings (BS). Oil and petroleum products, chemical reagents of varying degrees of toxicity, soluble mineral salts and other dangerous substances that pose a serious danger to the environment may be present in drilling waste. Therefore, environmental protection issues are of particular importance, namely the timely elimination of sludge pits with BSW, OBR and BS or the disposal of drilling waste without storage in barns.

There are a large number of drilling waste processing schemes to produce useful products. The analysis of existing schemes is described in sufficient detail in the article by Yagafarova G.G., Barakhnina V.B. "Disposal of environmentally hazardous drilling waste." Oil and Gas Business, 2006 (http://www.ogbus.ru/authors/Yagafarova/Yagafarova_2.pdf).

There is a known method of utilizing drilling well waste, according to which drill cuttings, spent technological solution and wastewater are mixed with mineral additives - loam and / or sand or a sand-clay fraction until a homogeneous mass is applied to the inside surface of the barn of a gas-flare installation - HFC. The HFC barn further burns off the exhaust gas. In the flame of HFCs, thermal firing and sintering of the aforementioned homogeneous mass deposited on the inner surface of the HFC barn is carried out to obtain a finished inert and durable building material in the form of ceramic, balanced in composition from waste polluting the environment (RU 2425815, 08/10/2011).

The material obtained according to the known method, can be used in the arrangement of well sites, wells and infield roads. However, it is quite expensive.

A known method of utilization of drill cuttings, including the curing of waste drilling fluids, implemented using special compositions or additives. The neutralizing effect is achieved by converting spent drilling fluids or drill cuttings into an inert consolidated mass, into the structure of which the main pollutants are bound. As consolidants, substances and compositions containing components of fertilizers and nutrient nutrient elements are used (Bulatov A.I. et al. Actual problems of environmental protection when drilling wells. Oil industry, 1988, No. 6, pp. 5-8).

However, the development of this technology is associated with certain difficulties due to the lack of special equipment.

The closest in technical essence is the method of processing drill cuttings, in which drill cuttings are cleaned, squeezed out on a four-stage cleaning system, placed in a trench built in the body of the embankment of the well site. After cleaning and drying to a moisture content of 30%, drill cuttings are allowed for use as soil in the construction of the body of the embankment of the well site, for the installation of anti-filter screens. A mixture of sludge and sand in a ratio of 1: 4 or 1: 5 was proposed as sandy loam for the construction of self-supporting structures (RU 2439098, 01/10/2012).

However, the method is characterized by a sufficiently high water consumption for cleaning sludge, and the resulting product is unsuitable for use as a building material.

The objective of the present invention is to develop a simple and economical method of disposal of drill cuttings, which provides useful products suitable for use as an inert building material and industrial soil, including in the Far North.

The problem is solved by the described method, which includes mixing drill cuttings with sand in a mass ratio of 1: (0.75-5), mixing the components and drying to obtain material, while hydrochloric acid is additionally mixed in the amount of 0.02-2.246 mol per 1 kg of sludge, ensuring the pH of the mixture from 5 to 8.

Preferably, the amount of clay impurities is determined previously in the drill cuttings and when their content is below 14% by weight. mixing sludge with sand is carried out in a mass ratio of 1: 5, and when the content of clay impurities is above 16% of the mass. mixing sludge with sand is preferably carried out in a mass ratio of 1: 4.

The method provides that the mixing serves drill cuttings with a moisture content of 60-90% of the mass. and quartz sand with a particle size of not more than 5 mm.

The drying operation is carried out to obtain a material having a moisture content of not more than 15-18% of the mass. with a yield strength of 10-15% of the mass. and density 1.70-1.83 g / cm.

The material obtained in the amount of the above set of features is used in the construction and strengthening of roads, cluster sites, landfills, foundations of landfills for household and industrial waste, other industrial facilities or as an anthropogenic soil.

In the scope of the features of the independent claim, a technical result is achieved consisting in the development of a simple and cheap method for the disposal of sludge with obtaining useful products.

To clarify the possibility of using the obtained mixtures as a building material or technogenic soil, laboratory studies of mixtures were carried out: clay particles in the drill cuttings were determined by swelling, yield strength was determined in accordance with GOST 5180-84, and solids content was determined in accordance with GOST 18164- 72, determination of humidity - according to GOST 5180-84, determination of maximum density - according to GOST 5180-84, determination of particle size modulus - GOST 12536-79.

As a result of the tests, the quantitative ratios of the mixed components, on which the physicomechanical characteristics of the target product depend, are experimentally determined.

The research results are given in table. one.

Table 1

Name Components Products Drilling waste, (mass. Part) Sand, (mass. Part) Hydrochloric acid, (mol / kg sludge) Technogrunt-S Brand-1 one 0.75-1 0.02-2.246 Technogenic soil Technogrunt-S Brand-2 one 1-4 0.02-2.246 Technogenic soil Technogrunt-S Brand-3 one four 0.02-2.246 Construction material Technogrunt-S Brand-4 one 5 0.02-2.246 Construction material

It should be noted that a preliminary determination of clay impurities and the pH level in the feedstock allows for a more accurate mixture formulation, leading to high-quality products. Carrying out these operations allows us to obtain four varieties of the target product in the future, two of which can be used as an inert building material used in the construction and strengthening of roads, bush sites, embankments, flare bars, foundations of landfills for household and industrial waste, and other industrial facilities, and the two remaining ones are for the restoration of disturbed lands, spent quarries, ravines, karst and other voids, etc. subject to local conditions.

The introduction of hydrochloric acid within the stated limits provides the PH mixture necessary to obtain the target product with the best physico-mechanical characteristics.

Material obtained from sludge with a clay impurity content of less than 15%, having a moisture content of not more than 15% of the mass. with a yield strength of 12-15% of the mass. and the maximum density of 1.79 g / cm, assigned to the brand Tekhnogrunt-S Mark-3, and the material obtained from sludge with clay impurities more than 15%, with a moisture content of at least 12% of the mass. with a yield strength of 10-12% of the mass. and the maximum density of 1.83 g / cm, assigned mark Technogrunt-S Mark-4.

The following are specific examples of the invention.

Example 1

Drilled cuttings are selected from the sludge barn, which is an aqueous suspension (water amount 60-90%), the solid particles of which are represented by the products of the destruction of the rocks of the face and the walls of the well, the products of the abrasion of the drill and casing and clay minerals.

A) Determination of clay particles in drill cuttings by swelling. The essence of the method is to determine the magnitude of the increment of the volume of clay particles for at least 24 hours from the moment of sedimentation and to calculate the content of clay particles by the average value of the increment of volume.

A sample weighing 200 g is taken from an average sample of sludge weighing 1 kg, dried to a constant weight at a temperature of (105 ± 5) ° C. The slurry is sieved through a sieve with mesh No. 063. Determine the content of grains with a size of less than 0.63 mm G ₀₆₃ . The sludge passing through the sieve is poured in equal portions through the funnel into two glass measuring cylinders when tapped on the cylinders until the volume of the sludge in the compacted state reaches 10 ml. Then the sludge in each cylinder is loosened, 30-50 ml of distilled water is poured, thoroughly mixed with a glass rod with a rubber tip until the smears of clay on the cylinder walls completely disappear. After that, 5 ml of a 5% solution of calcium chloride are poured into each cylinder as a coagulant, mix thoroughly and add distilled water to a mark of 50 or 100 ml on a glass rod (to wash clay off it). After settling for at least 24 hours, but not more than 30 hours, the volume occupied by the sand is measured.

The increment in volume K during the swelling of clay particles for each 1 ml of the initial volume is calculated to the second decimal place by the formula:

$$K=\frac{V-V_0}{V_0},(\mathrm{one})$$

Where

V ₀ is the initial volume of sludge, ml;

V is the volume of sludge after swelling, ml.

The increase in volume during swelling is defined as the arithmetic mean of the two results.

The K value (Table 2) determines the content of clay particles in the sludge.

The content of clay particles in the sludge is calculated by the formula:

Where

A _0.63 - the content of clay particles in the grains of the sludge with a size of less than 0.63 mm,% by weight;

- the content in the sludge of grains with a size of less than 0.63 mm,% by weight.

table 2 Volume increment K The content of clay particles in grains with a particle size of less than 0.63 mm,% 1,50 17.0 1.45 16,43 1.40 15.87 1.35 15.35 1.30 14.74 1.25 14.17 1.20 13.85 1.15 13.03 1.10 12.46 1.05 11.90 1.00 11.33 0.95 10.76 0.90 10,20 0.85 9.63 0.80 9.06

The analysis results showed that the investigated batch of sludge has a clay content of 10% by weight.

B) 250 kg of sludge from this batch is mixed with 750 kg of quartz sand with a particle size of 3-5 mm with an initial moisture content of 18-20%. Hydrochloric acid is introduced into the resulting mixture at the rate of 2.0 mol per 1 kg of sludge, providing a pH of 5. After mixing, the resulting mixture is dried under natural conditions until a specified moisture content is achieved.

The resulting product has the following indicators: humidity 13% by mass., Density 1.78, clay content 2.9% by mass.

Example 2

The method is carried out in the same manner as in example 1. However, the analysis of this sample of sludge showed the content of clay particles equal to 17 wt.%. 200 kg of drill cuttings are mixed with 800 kg of silica sand with a moisture content of 12-15% and hydrochloric acid is fed for mixing at the rate of 0.02 mol per 1 kg of cuttings. Provide a pH of the mixed mixture, equal to 8. The resulting product has the following indicators: humidity 10% wt., Density 1.83 g / cm, clay content 4.5% of the mass.

Example 3

The method is carried out as described above. Analysis of this sample of sludge showed a clay particle content of 15 wt.%. The starting components are mixed at the rate of 200 kg of sludge, 1000 kg of sand with a moisture content of 20-22% and 73 kg of HCl (1.0 mol of hydrochloric acid per 1 kg of sludge). The resulting mixture with a pH of 7.0 is stirred and dried. The material has the following indicators: humidity 15% by weight, density 1.8 g / cm, clay content 5.7%.

Example 4

The method is carried out as in example 1, but without preliminary determination of clay impurities in the sludge, while 100 kg of sludge is mixed with 75 kg of sand, after which hydrochloric acid is added to pH 6. The resulting material is used as an industrial soil.

Similarly, tests were conducted of the claimed method for processing sludge from various drilling rigs. The test results showed that the claimed method can be carried out processing of drill cuttings of various compositions.

The resulting products are recommended for use as an inert building material or man-made soil.

Claims (6)

1. A method of processing drill cuttings, including mixing drill cuttings with sand, mixing the components and drying to obtain material, characterized in that hydrochloric acid is additionally mixed in the amount of 0.02-2.246 mol per 1 kg of cuttings, ensuring a pH of 5 to 8, while mixing the sludge with sand is carried out in a mass ratio of 1: (0.75-5). 2. The method according to claim 1, characterized in that previously in the drill cuttings determine the amount of clay impurities and when their content is below 14% of the mass. mixing sludge with sand is carried out in a mass ratio of 1: 5. 3. The method according to claim 1, characterized in that preliminary in the drill cuttings determine the amount of clay impurities and when the content of clay impurities is above 16% of the mass. mixing sludge with sand is preferably carried out in a mass ratio of 1: 4. 4. The method according to claim 1, characterized in that the mixing serves slurry with a moisture content of 60-90% of the mass. 5. The method according to claim 1, characterized in that the mixing serves quartz sand with a particle size of not more than 5 mm 6. The method according to claim 1, characterized in that the drying is carried out to obtain a material having a moisture content of not more than 15% of the mass. with a yield strength of 10-15% of the mass. and density 1.70-1.83 g / cm.