UA54871A - Method for cleaning drilling solution - Google Patents

Abstract

Method for cleaning drilling solution comprises of sequential cleaning from slime on a sieve, in sand-remover, hydrocyclone and slush-remover. Purified after slush-removing solution is additionally directed to the unit for chemical treatment, where solution of inorganic acid is added to it. After that the acid drilling solution thus obtained is first treated by coagulation agent, with following adding to it flocculating agent, and with following purification of the drilling solution by centrifugation, with separation to solid and liquid phases; the last one of those is, as a clarified solution, directed for next use.

Description

Description of the invention

The invention relates to the mining industry, namely to methods of cleaning mud from drilling fluids during the drilling of oil and gas exploration, industrial, production and other wells.

There is a known method of three-stage cleaning of drilling fluid, in which the entire volume of the solution is successively cleaned on a vibrating screen, in hydrocyclones and a sand and mud separator, while continuously maintaining the specified density of the solution by mixing in the circulation system the cleaned volumes of the solution of all stages of cleaning (see patent of the Russian Federation Mo 2009307, M.cl.

The disadvantage of this method is the incomplete cleaning of the solution, because it is impossible to completely separate the solid phase from the solution containing the suspension of finely dispersed structure by mechanical means alone.

Adjusting the characteristics of the solution by changing its supply for cleaning does not allow to achieve the required quality of the solution, which in turn can reduce the technical and economic indicators of drilling and the service life of the well. 19 The invention is based on the task of improving the degree of purification of the drilling fluid, in which, by adding coagulants and flocculants to the solution, the settling force acting on the drilled rock is increased, fine-dispersed ground particles are aggregated to the formation of lumpy particles, which facilitates the separation of the solid phase from the obtained clarified solution, suitable for reuse. This, in turn, increases the efficiency of cleaning the drilling mud and improves the technical and economic indicators of drilling. At the same time, the costs of building sheds for discharged drilling fluids are reduced, the volume of waste during drilling is reduced, which increases the environmental efficiency in the places of drilling layers and improves land reclamation after the end of the drilling process.

The problem is solved by the fact that in the known method of cleaning drilling fluid, which consists in sequential cleaning of mud on a vibrating screen, in a sand separator, a hydrocyclone and a mud separator, according to the 29th invention, the solution cleaned after the mud separator is additionally subjected to processing in a chemical treatment unit, where to " a solution of an inorganic acid is added to the solution, and then the resulting acidic drilling mud is first treated with a coagulant, followed by the addition of a flocculant and subsequent cleaning of the drilling mud by centrifugation with separation into solid and liquid phases, the latter of which, in the form of a clarified solution, is sent for reuse . --

In addition, as inorganic acids, solutions of hydrochloric or sulfuric acid are used, concentrations of 18-2090 rch-, respectively, and in the amount of 0.4-1.0 cm3, respectively, per 100 cm of drilling mud.

How do coagulants use aluminum or iron sulfates with a concentration of 11-11.895, respectively, and in an amount of 0.8-1.0 cm? respectively by 100 cm? drilling mud. "AND

As a flocculant, a solution of polyacrylamide with a concentration of 1.0-1.295 is used in the amount of 1.8-2.0 cm C per 100 cm of drilling mud.

The use of all essential features, including excellent ones, allows to ensure a high degree of cleaning of the drilling fluid, to obtain a clarified liquid after separation from the solid phase, which can be reused and the feeding of which into the drilling fluid easily regulates its density within wide limits, improving the technical and economic indicators of drilling . - c This is explained as follows. After the mud separator, a large number of finely dispersed particles evenly distributed throughout its volume remain in the drilling fluid, the sequential treatment of the drilling fluid with a coagulant and then with a flocculant contributes to the formation of sediment in the form of lobed particles of a branched structure with a clear surface of separation of solid and liquid phases with by obtaining in the following a more aggregated structure of the sediment in the form of lobed particles containing a minimum amount of bound water. The remaining part of the clarified solution is adsorptively bound to the surface of the sediment by forces of different strength, so it is easy to separate it by centrifugation, and its insignificant content of crushed particles allows it to be reused for a technological cycle, thus regulating the density of the drilling fluid, as well as its quality, which leads to the improvement of the technical and economic indicators of drilling, and the increase of the service life of the well.

The use of hydrochloric or sulfuric acid with the specified concentrations and in the specified quantity allows you to obtain the claimed technical result, because the action of coagulants and flocculant with a more complete - M manifestation of their properties are observed only in an acidic environment (with a pH of up to 7).

The use of aluminum or iron sulfates as coagulants with the specified concentrations and in the specified amount improves the process of thickening of dispersed particles as a result of their interaction and uniting into aggregates, therefore the formed sediment is irregularly shaped lobed particles with a loose mesh structure and sizes from a few micrometers to several millimeters » The use of a polyacrylamide solution of the specified concentration and in the specified amount as a flocculant improves the process of the formation of bladed particles due to the forces favoring the adhesion of colloidal particles, which improves their chemical precipitation and leads to faster and more complete separation from the liquid phase using a centrifuge.

A change in the concentration and quantity of the introduced components, namely, hydrochloric or sulfuric acids, aluminum or iron sulfates, and polyacrylamide solution, relative to the stated ones, leads to the fact that the obtained sediment in the form of a solid phase contains a larger amount of bound water, which causes difficulties during phase separation and does not allow to achieve the specified technical result. 65 The essence of the invention is explained by the drawing, where Fig. 1 shows the circulation technological scheme of the implementation of the method;

Fig. 2 shows a diagram of the block of chemical treatment of the drilling fluid before centrifugation.

The diagram shows (see Fig. 17) pump 1, which injects drilling fluid into well 2, vibrating screen 3, sand separator 4, hydrocyclone 5, sludge separator b, chemical treatment unit 7, centrifuge 8 connected to well 2.

Block 7 of chemical processing (see Fig. 2) contains serially installed acid tank 9, tank 10 for coagulant, tank 11 for flocculant. Each of these containers 9, 10, 11 is connected to the pipeline 12 for the supply of drilling fluid and the pipeline 13 for the supply of water. The connection with pipeline 12 for the supply of drilling fluid for containers 9, 10, 11 is made through the following systems: 70 for acid container 9 - shut-off valve 14, pump 15 acid, valve 16 return; for containers 10, 11 - shut-off valve 14, screw pump 17, electromagnetic valve 18, valve 16 reverse.

The connection of containers 9, 10, 11 and pipeline 12 to the water supply pipeline 13 is made through ball valves 19.

Containers 10, 11 are equipped with a stirrer 20 and sampling taps 21, and the acid container 9 has an acid vapor filter and is connected by a pipeline 22 for washing the acid line with a pipeline 13 for supplying water.

Pipeline 12 for supplying drilling fluid has a shut-off valve 23, a non-return valve 24 and a sampling valve 25.

The method is carried out as follows.

Drilling mud is pumped into well 2 by drilling pump 1. After vibrofiltration of drilling mud on vibroscreen C, the over-grid material is dumped into the sludge barn (not shown in the diagram), and the under-grid material enters for cleaning in sand separator 4, where it is cleaned of sand, which is then also dumped in the sludge barn. The sand-cleaned solution is sent to hydrocyclone 5. From hydrocyclone 5, the solution is fed to sludge separator b, where it is more finely cleaned of small sludge particles. After Mud Separator 6, drilling mud containing from 4 to 2595 ground particles with a density of 1020 - 195Okg/m3 is additionally subjected to chemical treatment. For which solutions are prepared in containers 9, 10, 11, respectively, in container 9 - hydrochloric or sulfuric acid, concentration 18-2095, in container 10 - a solution of aluminum or iron sulfate, concentration 11.0 - 11.895, and in container 11 - polyacrylamide solution with a concentration of 1.0 - 1.295. The required concentration of chemical reagent solutions and the density of the drilling fluid are maintained by supplying water through the -/- nozzle Ball valves 19 from the water supply pipeline 13. For fast and high-quality preparation of coagulant and flocculant solutions in containers 10 and 11, motion is given to stirrers 20, the speed of which is regulated by means of control units installed in the control cabinet (not shown in the diagram). co

After preparing solutions in containers 10, 11, the concentrations are checked, for which samples of the solutions in these containers are taken through taps 21. Valve 23 is opened and the drilling fluid flows through pipeline 12, and the contents of the containers are dosed from containers 9, 10, 11 with pumps 15, 17 9, 10, 11, while opening shut-off valves 14. The contents of containers 9, 10, 11 are dosed into pipeline 12 of drilling fluid in the amount per 100 cm? solution: hydrochloric or sulfuric acid 0.4 - 1.0 cm, respectively, aluminum or iron sulfate solution 0.8 - 1.0 cm3, polyacrylamide solution 1.8 - 2.0 cm. After chemical treatment of the drilling mud, its analysis is carried out by sampling with a crane 25. The processed drilling mud is a suspension with a branched structure in the form of lobed particles. The content of the thickened part is 95% of the original amount of solution to 49%. In the next step, the drilling mud treated in this way is sent to the centrifuge 8, where the phases are separated into solid and liquid, the latter of which is sent for reuse or to the drilling fluid circulation system of the solution, adjusting its density within wide limits and quality, or for diluting the drilling fluid before entering unit 7 of chemical processing. At the same time, the density of the clarified solution is regulated through the ball valve 19.

An example of a specific implementation. 1 After mechanical methods of cleaning the drilling fluid on the vibrating screen Z, in the sand separator 4, the hydrocyclone 5 and the mud separator, the drilling fluid with a solid phase content of 2595 and a density of 1157 kg/m? through pipeline 12 enters unit 7 of chemical processing. In containers 9, 10, 11 of block 7 of chemical processing, appropriate solutions are prepared: in container 9 - a solution of hydrochloric acid NSI, concentration 1895, density 1087 kg/m З; in a capacity of 10 - 20, a solution of iron sulfate Be5(50O,4)z, concentration 11.895 in terms of Re, density 114Okg/m?; in container 11 there is also a 1.096th polyacrylamide solution.

With pumps 15, 17, the contents of containers 9, 10, 11 are dosed into the pipeline 12 of drilling fluid in the amount per 100 cm of solution: NOSI solution - 0.4 cm, Re5(ZO,)" solution - 0.vsm, 25 polyacrylamide solution - 2.Osm3 .

P There is an intensive formation of sediment in the form of lobed particles of a larger structure.

The solution processed in this way is directed to the centrifuge 8, where, under the action of centrifugal forces, a rapid separation of the solid phase occurs, the proportion of which is 48.1905 of the original amount of the solution, the content of bound water in the sediment is a minimal amount, and the remaining part, the clarified solution, which makes up a large part of the initial amount of solution, only adsorption is connected to the surface of the sediment, therefore, after separation of the sediment, the clarified solution is sent for reuse, for example, to the system 12 for supplying drilling fluid through the ball valve 19.

Thus, the proposed method of cleaning the drilling fluid is more effective compared to the existing one, it prevents the loss of the drilling fluid into the slurry store, in addition, the reuse of the clarified solution allows to regulate the density of the drilling fluid within wide limits, its quality, improving the technical and economic indicators of drilling, increasing service life of the well.

Claims (5)

The formula of the invention 1. The method of cleaning the drilling fluid, which includes sequential cleaning from mud on a vibrating screen, in a sand separator, a hydrocyclone and a mud separator, which differs in that the solution cleaned after mud separation is additionally sent to a chemical processing unit, where a solution of inorganic acid is added to it, and then the obtained acidic drilling fluid is first treated with a coagulant, followed by the addition of a flocculant and subsequent purification of the drilling fluid by centrifugation with separation into solid and liquid phases, the latter of which, in the form of a clarified solution, is sent for reuse. 2. The method according to claim 1, which differs in that hydrochloric or sulfuric acids are used as an inorganic acid. 3. The method according to claims 1, 2, which differs in that hydrochloric or sulfuric acid is used with a concentration of 18-2095, respectively, and in the amount of 0.4-1.0 cm, respectively, per 100 cm of drilling mud. 4. The method according to claim 1, which differs in that aluminum or iron sulfates are used as coagulants. 5. The method according to claims 1, 4, which differs in that aluminum or iron sulfates are used with a concentration of 11.0-11.8 9o, respectively, and in an amount of 0.8-1.0 cm? respectively by 100 cm? drilling mud. b. The method according to claim 1, which differs in that a solution of polyacrylamide with a concentration of 1.0-1.2 95 in the amount of 1.8-2.0 cm per 100 cm is used as a flocculant? drilling mud. « «- cha (ee) « And c) - with . and? 1 sh» (ee) -I - 60 b5