Justification of the volume and cost of engineering-geological surveys. I T O G O laboratory work

Experience in designing water wells in the Moscow region

(Toolkit)
(Authors D.V. Kasatkin and G.A. Prokopovich are the developers of the collection GESN-2001-04.)

This manual discusses the methodology for compiling a bill of quantities for drawing up estimates for drilling water wells. The manual is intended for specialists involved in pricing in the field of drilling operations. It will also be useful when conducting an examination of water well drilling projects.

A project for drilling a well, as a rule, is an integral part of a project for the construction of a water intake unit. The cost takes up no more than 10% of the total cost of design work. In this regard, very little attention is paid to the issue of well design in the special and regulatory literature. At the same time, drilling water wells is a highly specific type of work, which is performed by a fairly limited circle of specialists.

This work is intended for a wide range of specialists who, due to the nature of their activities, are faced with the design of drilling water wells. It can also be useful when conducting examinations of drilling projects, for estimators, and for students of construction and drilling specialties.

Drawing up a project for drilling a well is based on the general construction regulatory framework. However, due to its specificity, the design cannot fit into the framework proposed by the builders, since the problem under consideration is closely related to the development of subsoil, the protection of groundwater, and the increased social significance of the extracted minerals.

Methodology for compiling statements of quantities of work and drawing up estimates by type of work

The methodology for compiling statements of quantities and estimates for drilling work during the construction of water wells is tied to the 4th collection of GESN-2001 “Wells”.

Working drawings for a well, attached to the project, are called a geological and technical section or a geological and technical work order (GTN). This document, as a rule, reflects many technological details that are superfluous when drawing up bills of quantities or estimates.

The section discusses in great detail the issue of the technological cycle of rotary drilling, with calculations of equipment and materials for the work.

A statement of quantities of work and materials is presented.

The methodology discusses some issues of compiling a statement of quantities and estimates for liquidation plugging of non-self-discharging water intake wells.

The estimate and regulatory framework does not contain separate prices for this type of work. Therefore, when drawing up estimates, it is necessary to link the technological cycle to existing prices. We also note that this work examines the implementation of liquidation plugging in relation to the practice that has developed in the Moscow region. As a rule, the “Rules for liquidation plugging of drill wells for various purposes, backfilling of mine workings and abandoned wells to prevent pollution and depletion of groundwater”, approved by the Ministry of Geology of the USSR and the Ministry of Health of the USSR in 1966-67, act as a regulatory technological document.

Examples of drawing up estimates for work in wells

This section provides examples of drawing up estimates for various works in wells on a certain average section for wells of various depths and designs.

Drilling.

The section describes the rules for drawing up well designs, technological modes, methods for calculating cementation of casing pipes, as well as local estimates. The wells are 100 m deep (design 1-1¸ 1-5), 122 m (design 2-1¸ 2-5), 172 m (design 3-1¸ 3-4), 240 m (design 4-1¸ 4-3).

For drilling an artesian well with a depth of 100 m, respectively, and according to structures (with a capacity of 6, 16, 40, 65, 120 m 3 / hour), 122 m (6, 16, 40, 65, 120 m 3 / hour), 172 m (40 , 65, 120 m 3 /hour), 240 m (16, 40, 65) 17 estimates in total.

For example, design 2-3 is presented.

In Fig. 1 presents the geological and technical work order (well design), the procedure for carrying out work and the specification of materials.

Drilling of the designed wells into the Podolsko-Myachkovsky aquifer is provided for using a rotary method using a machine of the URB 3-AZ, 1BA-15V type. The design depth of the wells is 122.0 m. The operating diameter is 219 - 426 mm.

The conditions for the work are described on the design geological and technical section.

Well drilling is designed without core sampling. Geological control along the wellbore is carried out by sampling cuttings every 3-5 m of penetration and additionally when changing layers.

Drilling of rocks (interval 0.0 - 57.0 m) is carried out using colloidal clay solution, drilling through aquifers (interval 57.0 - 122.0 m) is carried out with flushing with clean water.

A clay solution with a density ofr= 1.15-1.20 g/cm 3, viscosity 20-25 sec according to SPV-5, water loss 5-15 cm 3 in 30 minutes, sand content up to 4%. When opening rocks in zones of disturbances prone to landslides, the parameters of the washing liquid must be within the following limits: densityr=1.30-1.35 g/cm 3 , viscosity 21-30 sec according to SPV-5, water loss 5-10 cm 3 in 30 minutes, sand content up to 2%.

When drilling a well, a single-stage cementing method is used using two separation plugs. Cementation is carried out with Portland cement using cement mixing machines and cementing units of type 1AC-20 and 3AC-30. For pumping and pushing cement mortar, special cementing units of the TsA-1.4-1-150 type are used.

Electricity is provided from existing networks, water is imported.

If there is a water supply source near the work site (watercourse, pond, mine well, quaternary well, etc.), to provide water for the drilling process, it is necessary to provide for the laying of a temporary water supply from the source to the work site.

An interval of 0-10 m is passed with a bit (cone reamer)Æ 590 mm with subsequent installation of a guide columnÆ 530 mm. The annulus of the column is cemented from the shoe to the wellhead. The cement plug is drilled out with a bitÆ 490 mm.

Drilling to a depth of 27.0 m is carried out with a tricone bitÆ 490 mm, then the passed interval is secured with a casing stringÆ 426 mm. The annulus of the column is cemented from the shoe to the wellhead. The cement plug is drilled out with a bitÆ 395 mm.

Drilling to a depth of 57.0 m is carried out with a tricone bitÆ 395 mm, then the passed interval is secured with a casing stringÆ 324 mm. The annulus of the column is cemented from the shoe to the wellhead. The cement plug is drilled out with a bitÆ 295 mm.

After cementing work, the casing strings are tested for leaks by creating internal excess pressure.

The well is drilled with a tricone bit to a design depth of 122.0 mÆ 295 mm with flushing with clean water.

The filter has an above-filter part, a working filter part and a settling tank. The design of the filter column (the position of the working and blind parts) is specified based on the actual section.

The well is washed with clean water (short-term pumping with an airlift or submersible pump), after which experimental pumping is carried out with mandatory water sampling to determine the physicochemical and bacteriological composition of the water.

Work procedure and specification of materials.

Typical design (2-3)

Work procedure

The design of the well, 122 m deep, was developed for the rotary drilling method using a 1BA-15V type rig.

Exploited aquifer: Podolsko-Myachkovsky Middle Carboniferous (C 2 pd-mc).

Rock penetration is carried out using colloidal clay solution in the interval of 0-57 m, drilling in the interval of 57-122 m is carried out with flushing with clean water.

Pipe columns are being cementedÆ 530, 426 and 324 mm with lifting of cement mortar from the shoe to the wellhead.

To clarify the geological section and the most water inflow zones in the well, geophysical work is carried out including measurements of PS, CS for each column, gamma ray logging (along the entire wellbore), caliper logging, and resistivity logging.

Filter columnÆ 219 mm is installed from 0 to 122 m with perforation at the level of aquifers.

Filter duty cycle up to 20%. The position of the working and blind parts of the filter is specified based on the GIS results.

After installing the filter column, the well is washed with clean water (short-term pumping with a submersible pump), after which experimental operational pumping is carried out. Pumping is carried out continuously at two levels. The first reduction with a flow rate 25-30% higher than designed. The second reduction is carried out with a flow rate equal to the design one. Pumping is considered completed after 16 hours after the dynamic level has stabilized and the water has completely clarified. At the end of pumping, water samples are taken for complete physical, chemical and bacteriological analyses. Pumping duration is 6 days. An ECV type pump can be used for pumping.

The well is an exploration and production one, and therefore the geological section, depth, well design, flow rate and water level position are adjusted during the drilling process.

Well design

Specification of materials

LOCAL ESTIMATE No.
For drilling an artesian well 120 m deep

An object: Artesian well 122 m deep with a productivity of 40 cubic meters per hour (typical design 2-3)

Base: Drawings No.

Estimated cost : 552.17 thousand rubles.

Well depth: 122 m

Compiled in 2001 prices.

Well abandonment.

The methodology for abandoning a well is described in the “Rules for sanitary sealing (grouting) of water wells”; the full text of the Rules is included in this manual. For liquidation plugging of an artesian well 100 m deep (design 1-1 ¸ 1-5), 122 m (design 2-1 ¸ 2-5), 172 m (design 3-1 ¸ 3-4), 240 m (design 4-1 ¸ 4-3).

Geological and technical crew for liquidation plugging EXAMPLE OF ESTIMATE 02

Types of work on liquidation plugging and conditions for their production EXAMPLE OF ESTIMATE 03

An example of a local estimate for well abandonment EXAMPLE OF ESTIMATE 04

LOCAL ESTIMATE No.
For liquidation plugging of an artesian well 122 m deep

An object:Liquidation well plugging (Design 2-3)

Base: Drawings No.

Estimated cost: 93.66 thousand rubles.

Well depth: 122 m

Compiled in 2001 prices.

LOCAL ESTIMATE No.
To clean the wellbore and drill out the blocked part of the wellbore to a depth of 122 m

An object:Artisan well 122m deep (Design 2-3)

Base: Drawings No.

Estimated cost: 90.75 thousand rubles.

Well depth: 122 m

Compiled in 2001 prices.

LOCAL ESTIMATE No.
Fishing work in a well 122 m deep

An object:Artisan well 122 m deep (Structures 2-1 - 2-5)

Base: Drawings No.

Estimated cost: 22.08 thousand rubles.

Well depth: 122m

Compiled in 2001 prices.

To replace a filter column in a well

To replace a filter column in a well 100 m deep (design 1-1¸ 1-5), 122 m (design 2-1¸ 2-5), 172 m (design 3-1¸ 3-4), 240 m (design 4-1¸ 4-3) total of 17 estimates

For 1-time reagent treatment of an artesian well 100 m deep (design 1-1¸ 1-5), 122 m (design 2-1¸ 2-5), 172 m (design 3-1¸ 3-4), 240 m (design 4-1¸ 4-3) total of 17 estimates

For cleaning the wellbore and drilling out the blocked part of the wellbore with a depth of 100 m (design 1-1¸ 1-5), 122 m (design 2-1¸ 2-5), 172 m (design 3-1¸ 3-4), 240 m (design 4-1¸ 4-3).

For fishing work

in wells 100 m deep, 122 m ( EXAMPLE OF LOCAL ESTIMATE 5), 172 m, 240 m.

LOCAL ESTIMATE No.
Fishing work in a well 122 m deep

An object:Artisan well 122 m deep (Design 2-3)

Base: Drawings No.

Estimated cost: 22.08 thousand rubles.

Well depth: 122 m

Compiled in 2001 prices.

Typical design (2-3)

TYPES OF WORK ON LIQUIDATION CAMPING AND CONDITIONS OF THEIR PRODUCTION

Sanitary sealing of the well is carried out in accordance with the current “Rules for liquidation plugging of drill wells for various purposes, backfilling of mine workings and abandoned wells to prevent pollution and depletion of groundwater.”

The work is carried out in two stages: I - preparation, II - sealing.

I.

1. Installation of the drilling rig above the wellhead.

2. Dismantling the ECV pump -

3. Conducting borehole geophysical surveys (actual depth, condition of production and filter columns) -

4. Drilling out rubble in a well (10 m).

5. Cleaning the walls of the production filter column in the range of 0-122 m from corrosion, build-up and siltation.

6. Removing the filter column d=219 mm, installed in the interval 0-122 m.

7. Flushing the wellbore with a solution of bleach with a dose of active chlorine of at least 125 mg/l by mixing and replacing the water in the well in an amount of 3 volumes of the wellbore. Contact chlorine with water for at least 4 hours.

Well volume: V CKB = 0.785(d 1 2 h 1 +d 2 2 h 2 +...+d n 2 h n)

Volume of solution: Vp 1 =V CKB´ 3 ´ l,l.

Amount of bleach: P 1 = Vp 1´ 0,5

Duration of disinfection is 1 day.

8. Pumping water from the well using an airlift until the water quality is stabilized - clarification, chloride content, stability of the composition. Duration of pumping - 3 days.

9. Disinfection of building materials that will be poured into the well is carried out with a solution of bleach with a dose of active chlorine of at least 100 mg/l of water by dousing the building materials and mixing with shovels.

Volume of building materials: V page mat. = V gravel + V sand

Volume of solution: Vp 2 = V page mat. ´ 4 ´ 1.5. Amount of bleach: P 2 = Vp 2´ 0,5

10. The required amount of water is calculated using the formula: V water = V r 1 + V r 2 + V water for cement

II

1. The wellbore in the interval of the exploited aquifer is filled with washed and disinfected material (gravel, crushed stone) from 122 m to 55 m, then to a height of 3 m (55-52 m) it is filled with washed and disinfected sand (with compaction).

2. Installation of a cement bridge in the interval of 52-47 m (cement mortar composition 1:0.5). (WTC - 3 days).

7. After the cement mortar has hardened, a hole of size 1 is dug around the wellbore´ 1 ´ 1=1 m 3, which is filled with cement mortar of composition 1:3.

8. The well number and grouting date are stamped on the cement slab.

9. Upon completion of the work, a report on the sanitary sealing of the well is drawn up.

WELL CHARACTERISTICS

1. Location:

2. Well number:

3. The organization that carried out the drilling:

4. Year of construction:

5. Absolute elevation of the wellhead:

6. Well depth: 122 m.

7. Exploited aquifer: Podolsko-Myachkovsky v. Middle Carboniferous (C 2 pd-mc)

8. Static level during drilling:

9. Well productivity during drilling:

10 Static level at the time of examination:

11. Well productivity at the time of inspection:

Reagent treatments

This section describes reagents for restoring well production, equipment and technology for reagent treatment of wells.

In total, the manual contains 21 drawings and 89 local estimates.