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Well Construction& Refurbishment
www.angers-soehne.com
Water - the blue gold
The world's oldest cultures developedclose to rivers and alluvial plains.The fundamental nature of thisdependence can also be seen inPersian language. There, the firstword in the dictionary is “ab”,which means “water”. Derived fromthis is the word “aba dan”, whichsignifies “civilized”.
Thus, water in its true sense of theword represents civilization. At thesame time one may argue that civi-lization cannot exist where there is no water.
Even so, 1.7 billion people are stillsaid to live without a sufficientsupply of safe drinking water today.Furthermore, the price of waterrarely ever mirrors its true valuebut mostly represents a politicalprice. In this respect one can beglad to be living in Germany oranother central European country,where problems with the drinkingwater supply are mostly unknown.
However, factors like increasedindustrialization, the spreadingof settlements, concentratedagriculture and the rising use ofbiomass, increase the pressureon our resources of drinking water.
For years these factors, in combination with complex mechanisms of control and analysis, have placed great demands on H. Anger’s Söhne as a drilling company.
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Well construction over140 years
As long as there are no watercoursesclose by, the building of a well hasalways been the only possible wayof gaining access to clean drinkingwater. Today this work is carriedout after thorough planning and byusing the most modern techniquesfor each individual well.
This process is composed of threemain components.
First of all the well is constructedusing a drilling rig. The drill's diameter decreases in a telescopingmanner, depending on the predomi-nant geological formations and
their respective depth at the well site (see illustration).
In a second production step theborehole is supported by casing or filter and the remaining annularspace between borehole walland casing is plugged.
In order to prevent undesirableinflows the borehole is sealed withcement and clay, which is backfilledinto the annular space. In the areasof the water-bearing layers to bemade use of, graded filter gravel is inserted.
Following the clean up and a thoroughdevelopment of the well, the thirdstep consists of equipping the wellwith an adequate pump and thecorresponding flow metre and control technologies (MSR).
From this point on sufficient groundwater can be produced from a high quality production facility.
The handling of this sensitive interaction of - borehole (diameter...) - filters (material, size of slots...)- gravel (grain...) and the appropriate dimensioningof the pump requires decades ofexperience and knowledge indealing with well constructions.
This is what we stand for with ourexperience of more than 140 yearsin well construction. The basis forthis is, on the one hand, the technicaldocumentation of wells we haveconstructed in the last 60 years.On the other hand, our capability is supported by our well-trainedexpert staff and the modern equip-ment and techniques Since carrying out the work in an accident free and environmen-tally sound manner is of particularconcern to us, our employeeshave been trained and tested in all safety practices.
The entire company has been certified within the framework of themanagement system SCC (SecurityCertificate Contractor).
Example well drawing
Worker installing a casing string
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The appropriate drilling method for the individual demand
Apart from the accurate planning of a new well by our respectiveclients, the most important factors for the successful implementation of your project are our well-trainedand long-serving employees ofmany years, as well as reliable andmodern equipment.
We complete wells for you accordingto all established drilling methods,depending on the geology.This includes wells using flushdrilling methods, air lift drillingmethods, dry drilling methods(cable drilling methods), as well ashammer-techniques. Depending onthe respective drilling tasks, diameters
can range between 1.50 m andapprox. 100 mm.
Basically, drilling methods canbe differentiated according to twocriteria. These two groups include,on the one hand, the methods ofpercussion drilling and, on the otherhand, those of rotary flush drilling.
Percussion DrillingThis term includes all drilling methodswhich allow a mechanical lifting ofdrill cuttings, without any circulationof scavengers such as air, water orother liquids. Percussion drillingtechniques are often used whenundisturbed samples are required.
Rotary Flush DrillingThe proceedings which fall into this category include all drillingtechniques that are characterizedby continuous lifting of cuttings bymeans of different circulating fluids.
Irrelevant thereby is the manner ofdestruction of rock (by rotation, byjarring or by a combination of both)as well as the manner of lifting:
– whether the lifting happens directly through the pipe
– or indirectly through the annular space.
Two-shift drilling operations
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The construction of every well isunique in its own way.
The interplay of given geology,resulting different compositions of water and its yield, together with the future construction itself,requires accurate planning inthe development stage.
Thereby our technical implemen-tation is not only dependent on geology, but it always fits in withthe wishes of our clients and/or therespective engineering firm as well.
Ultimately, what determines thesuccess of a project is thoroughplanning previous to the start ofconstruction as well as workinghand-in-hand of all parties involved.
For preserving the productive efficiency of the well for many yearsfollowing the construction phase,you will find in us the right partnerfor follow-up assistance.
We will attend, supervise andmaintain your well.
Well drilling rig 400kN
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Advantages of percussion drilling
In case of low lying water levels the percussion drilling techniqueis often made use of for the construc-tion of mineral water wells.
Advantages of the percussion drillingtechnique:
1. Simple and robust equipmenttechnology
2. Applicability in most soil- and rock-residuals
3. A high verticality of the boreholeeven in unfavourable formations
4. Allows a very accurate exploration of water (direct corre- lation of inflows, geology and water level layers)
5. The only reasonable procedurefor drilling of large diameter infragmented solid rock and with very deep water levels
6. No addition of mud componentsin sensitive explorations
7. Percussion drilling does not requireany circulation, therefore it is alsoapplicable in case where fluid losses would occur.
With our percussion drilling rig we are able to reach depths as fardown as 500 m, depending on therespective diameter.
Anger’s percussion drilling rig in operation
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Horizontal filter wells – a new service sector
Horizontal filter wells are used todraw ground water from higheraquifers through drilled filter strings.
As a rule, several horizontal filterstrings are produced from a vertical,impermeable shaft.
These filter strings can be arrangedradially and at different layers ofdepth, depending on the layeringand height of the aquifers.
In this way water can be produced specifically from limited horizontal layers.
In many cases the capacity of a single horizontal filter well with several strings can be much morethan that of one vertical filter well.
Ideally, one horizontal filter well can thus replace an entire verticalwell gallery.
The greatest difference betweenhorizontal and vertical wells clearlyis the alignment of their socketstrings. Whereas vertical sockets, asa rule, go through several layersof aquifers and thus may produce ground water of different qualities,horizontal sockets on the other handcan produce ground water of amuch more consistent quality.
This can have positive effects on thein-line cleaning.A horizontal filter well often repre-sents a better economical alternativecompared to a gallery of verticalwells when, e.g., large amounts of
water are to be produced from anaquifer with only limited height.
The large well cylindrical surfacehas positive effects on the ageing ofthe well and, subsequently, on thecosts of maintenance.
This, and the possible higher energyefficiency of the production tech-nology installed result in a positivecost-benefit analysis in the long run.
Additionally, the new equipmenttechnology of H. Anger’s Söhne for horizontal wells uses waterhydraulics in order to meet risingenvironmental protection demands.
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upper surface formation
horizontal filter string with gravel pack
aquifer filled with water
lowered ground water level
central shaft
horizontal filter string with gravel pack
Refurbishment of wells
Every structure is subject to the phenomena of deterioration and of wear and tear in the course ofthe years and well construction is no exception here.
If your well experiences a decline ofits original productive efficiency, inmany cases regeneration processeswill help to restore its originalpower almost entirely.
If it proves to be impossible to restore the decrease in power,stability losses or problems ofdensity via regeneration processes,the only way to preserve the well is to refurbish it.
Given the uniqueness of everysingle well, as was mentionedabove, and its possible changesthroughout the years, the companyis often confronted with the excitingquestion what can be expected withevery metre they go further down.
The advantages of a well's refurbish-ment and the involved conservationof location are obvious:
1. All of the licenses regardingbuilding and approval lawsalready exist
2. The water's composition is known
3. Measurement- and control engi- neering as well as mains exist
4. Performance data are known
5. Drilling costs will generally be minimal
6. Prompt execution
Once the decision for a partialor entire refurbishment of the well is taken, in co-operation with theclient and the respective engineer-ing firm, different possibilities ofhow to proceed do arise.
Previous to determining any furtherproduction steps, a geophysicalexploration should be carried outin order to obtain at least somebasic information to allow the refur-bishment to be planned effectively.
• repair pull-out casing• insertion casing• drill out• wash over • displacement
In case the well has already beenhighly affected by mineral depositsover a longer period of time, it isgenerally assumed that the obstructionextends through filter and gravelfar into the soil or rock layers.
In this case a change of filter gravelor measures in the original borehole would not suffice to disposeof the obstruction in the soil layers.In order to remove all deposits
leading to the loss of power, theappropriate proceeding wouldbe a wash-over of the well witha larger diameter.
When one is facing a high levelof sand encroachment in the well,changing of filters and/or filtergravel often may achieve the desiredsuccess, since the reason for thesand encroachment of the wellmay only be a wrong dimensioningat that time.
Drilling rig 500 kN
H. Anger’s Söhne Bohr- und Brunnenbau-gesellschaft mbHGutenbergstraße 3337235 Hessisch Lichtenau
Tel. +49(0)5602/9330-0Fax +49(0)5602/9330-70
