(12) Patent Application Publication (10) Pub. No.: US 2010/ A1

Transcription

1 US 2010O212962A1 (19) United States (12) Patent Application Publication (10) Pub. No.: US 2010/ A1 ROsten et al. (43) Pub. Date: (54) ASSEMBLY FOR DRILLING AND LOGGING, (30) Foeign Application Pioity Data METHOD FOR DRILLING AND LOGGING AND DEVICE FOR ELECTRO PULSE Feb. 9, 2007 (NO) O769 DRILLING Publication Classification (76) Inventos: Tage Rosten, Tondheim (NO); Tond Bolas, Sandnes (NO) (51) Int. Cl. E2IB 47/12 ( ) Coespondence Addess: WENDEROTH, LIND & PONACK, L.L.P. (52) U.S. Cl / th Steet, N.W., Suite 400 East Washington, DC (US) (57) ABSTRACT (21) Appl. No.: 12/526,574 Assembly fo dilling and logging, compising a device fo (22) PCT Filed: Feb. 7, 2008 electo pulse dilling (EPD device), at least one device to eceive acoustic signals geneated by the EPD device, distin (86). PCT No.: PCT/NO08/OOO42 guished in that the assembly futhe compises at least one device to eceive electomagnetic signals geneated by the S371 (c)(1), EPD device. Method fo dilling and logging, and device fo (2), (4) Date: Nov. 9, 2009 electo pulse dilling.

2 Patent Application Publication Sheet 1 of 3 US 2010/ A1 Fig. 1

3 Patent Application Publication Sheet 2 of 3 US 2010/ A1

4 Patent Application Publication Sheet 3 of 3 US 2010/ A1 L?) Yi s x OS Cy) N. CY) X CS XC DXC St. st CY) CO CO n. s Xo, st X Cy CY) s CY) cy s Cy) Cy) Yi X () \t Cy)

5 ASSEMBLY FOR DRILLING AND LOGGING, METHOD FOR DRILLING AND LOGGING AND DEVICE FOR ELECTRO PULSE DRILLING FIELD OF THE INVENTION The pesent invention elates to dilling and logging, paticulaly fo exploiting hydocabons fom undegound fomations Moe specifically, the pesent invention elates to an assembly fo dilling and logging, a method fo dilling and logging and a device fo electo pulse dilling paticulaly feasible fo woking the method. BACKGROUND OF THE INVENTION AND PRIOR ART 0003 Most deposits of gas and/o liquid hydocabons ae found hidden inside the undegound in stata of ock sedi ments. Dilling into the undegound to be able to poduce hydocabon fluids fom a hydocabon-containing foma tion, is vey costly. To incease the possibility fo the well to hit a hydocabon containing esevoi, the undegound is mapped as much as possible befoe dilling. Seismic tech niques, and to a lesse extent electomagnetic techniques ae used fo said mapping But also duing dilling thee is geat inteest in having infomation on the undegound in ode to have bette planning and contol of the dilling opeation so that assumed o identified hydocabon esevois can be poduced. Advan tageously, said infomation is as detailed and coect as pos sible, fo impoved planning and contol of the dilling opea tion Dilling is usually pefomed with a dill sting that is otated fom the suface. An altenative method is to use a down-hole moto nea the dilling bit, fo otation theeof. The moto can fo example be diven by the ciculating dill ing mud A thid method fo dilling is electo pulse dilling, so-called EPD Electo Pulse Dilling. When electo pulse dilling, poweful electic pulses ae used to beak up the fomation, instead of a pue mechanical teatment as used by the taditional dilling pocesses. Moe specifically, at least two electodes that ae sepaated with an insulating mateial ae used, one electode being chaged to a high electical potential, while the othe electode is gounded. At suffi ciently high chaging, a poweful spak will be fomed as the electodes ae shot-cicuited by the cuent going the way of lowest esistance fom the chaged electode to the gounded electode. A dill bit fo electo pulse dilling compises at least said two types of electodes, in diffeent configuations, and may in addition compise one o seveal additional elec todes that duing opeation will take potential between said electodes, so-called floating electodes. Thee is a equie ment fo high Voltage, typically seveal kilovolts, and high cuent to delive sufficient enegy to beak up the fomation ahead of the dilling bit whee the electodes ae aanged. To have sufficient effect, at powe-full electic supply is equied, typically compising a numbe of elements fo chaging and Subsequent dischaging of the electical enegy, which ele ments typically ae in the fom of condenses. Dependent on the fomation and the opeational paametes, the electical spak will fom a pessue wave in the dilling fluid ahead of the dilling bit, o fom a plasma channel in o at the foma tion, in both cicumstances esulting in beaking up of the fomation Electo pulse dilling is descibed in seveal patent applications, of which thee to ae descibed below In patent publication U.S. Pat. No. 4,741,405 a device is descibed fo focused electo pulse dilling, com pising multiple electodes. The dill bit includes at least a fist electode that is positively coupled to a pulse-foming line, a second electode that is coupled to the gound poten tial, and a numbe of thid electodes that ae aanged nea the fist and the second electode, the thid electodes being floating electodes. By chaging the fist electode, at the coect conditions a spak will be fomed between the fist electode and one of the thid electodes, futhe to a next of the thid electodes, until the spak finally goes ove to the gounded second electode. The dill bit is against the foma tion Suounded by a woking fluid, and the spaks fom a pessue wave in the woking fluid diected at the mateial to be dilled out. It is assumed that in the woking fluid plasma channels ae fomed, esulting in pessue waves, which again have sufficient enegy to beakdown the mateial to be dilled out. By a Sophisticated Switched coupling of the pulse-fom ing lines between an electic Supply and selected fist elec todes in the dill bit, a focusing of the pessue wave can be achieved, such that the dill can be contolled and diected. The high-voltage powe can be deliveed to the pulse-foming lines eithe down-hole o fom the suface. A numbe of means to this end ae descibed, amongst them use of a Max-geneato as high-voltage souce. Futhe, it is descibed fo example in column 4, lines that the elec to pulse dill as Such can be used as a souce fo seismic impulses to detemine the position of the dilling bit and theeby the position of the well-boe. Moe specifically, pes Sue waves geneated by the dill bit ae used as seismic impulses that can be eceived by a netwok of seismic eceival units positioned on the suface close to the well-boe. Seismic time-distance data can be eal-time pocessed, and a continu ous pesentation of the well-boe position and deviations fom a nomal can be pojected by use of a dedicated unit. The deviations can then be used to coect and diect the dilling device by geneating contol signals fom the Suface. In the patent publication thee is only a shot desciption of seismic time? distance analysis to detemine the position, nothing is mentioned about mapping fomation popeties based on the eceived seismic data o othe data In patent publication RU C2 electo pulse dilling is descibed in the fom of otational dilling with a mechanical tool, with high-voltage electic pulses taveling ove the bottom of the well-boe to educe the fomation stength. Theeby a moe effective dilling is achieved. (0010. In patent publication WO 03/ A1 electo pulse dilling is descibed in the fom of plasma channel dilling. Moe specifically, an appaatus and a method ae descibed, using a pulsed high-voltage geneato coupled to an electode assembly placed at a mateial emoval station fo the appaatus, which means down into a well-boe, the appa atus being adapted to geneate electical pulses to fom a plasma channel epetitively pe second within o on a Suface of a mateial, so that mateial is emoved by apid expansion of each plasma channel that factues and fagments the mate ial body pulses pe second ae used, typically 5-25 pulses pe second, lasting 1-50 mico seconds, and ise time below 150, typically below 100 nanoseconds, with high-volt

6 age in the ange kv and effect with top value MW. Voltage is limited is to about 50 kv to avoid too com pehensive equiements as to insulation. Holes can be dilled with diametes up to 100 mm. Dilling in a dy well-boe is also possible, see page 6, line 22, but pefeably a dilling fluid of low electic conductivity is used, such as wate, which is pefeable fo emoval of fagments. The electodes ae concentically aanged, with gound outemost. The publi cation povides a good and compehensive desciption of physical paametes in connection with electo pulse dilling. The significance of the dielectical popeties of fluid and fomation ahead the dilling bit is descibed elative to diffe ent opeating paametes. Inte alia, it is descibed that at elative high voltage, the electical beak-down will take place in the fomation instead of in fluid Suounding the dilling bit. The FIGS. 6 and 7 illustate beak-down of the insulating dielecticum (eithe the fomation that is dilled out o fluid Suounding the dilling bit) as function of Voltage o Voltage field, and time fo dischaging. Likewise, the signifi cance of distance between the electodes is illustated and descibed. On page 16, lines 7-21, fo opeating paametes esulting in the electical beak-down in the fomation instead of in a fluid, it is explained how the plasma channels gadually will beak down the fomation ove the whole aea of the dilling bit in the diection of dilling, because the plasma channel seeks to go the way of lowest esistance, which way theeby will be the fomation. The plasma channel fomation will ove time otate 360 aound the dilling bit face, wheeby mateial ahead of the full dilling bit is boken down and thee is no need to otate the dill bit with electodes pe se. Futhe, it is descibed that the pulse geneato pefeably can geneate a high-voltage pulse with a wave-fom nea the citical damped esponse fom the cicuit fomed when the plasma channel is poduced. Fomation of a plasma channel esults in beak-down of the dielectical esistance, why next plasma channel fomation should wait until the dielectical esistance is eestablished. In the publication thee is no dis cussion of electo pulse dilling and simultaneous logging of any kind Measuement while dilling, MWD, means to col lect data on pessue, tempeatue and path of dilling in thee dimensions duing o in connection with dilling. Measue ments while dilling to map the fomation itself is usually temed logging-while dilling, LWD, which includes mea Suement of paametes as esistance, poosity, acoustic velocity and gamma adiation. In Patent Publication U.S. Pat. No. 5,881,310 a close desciption of LWD and MDW is found. In said publication it is descibed that the dilling sting and dill bit can be used as a souce fo acoustic signals, but electo lo pulse dilling is not mentioned In Patent Publication WO 2004/ A1 a method and an appaatus ae descibed fo detemining the popeties of undegound esevois by using an electomag netic tansmitte and a seismic tansmitte with in Substance identical location on the gound o seabed, which tansmittes geneate signals that ae eceived by an electomagnetic eceive and a seismic eceive, said eceives having in Sub stance identical location on the gound o seabed, sepaated fom the tansmittes. Pefeably low acoustic and electo magnetic fequencies ae used, in the ange 0.1 to 20 Hz, to have each. By analyzing and compaing diffeent compo nents of electomagnetic field and acoustic esponse, paticu laly efacted components, data indicating pesence of a hydocabon esevoi can be identified and analyzed. (0013. In Patent Application WO 02/14906 A1 a method and an appaatus is descibed fo detemining popeties of undegound esevois. An electomagnetic field is applied fom the seabed by use of a dipole antenna-tansmitte, which field is detected by using a dipole antenna-eceive. Measue ments ae taken with the antenna-eceive both in-line and paallel and the diffeence between the two sets of measue ments give indication of inteest. Dependent on the angle of incidence and State of polaization an incident electomag netic wave to a laye of high esistance may excite a ducted o guided wave mode in the laye. Such high-esistive laye can be a hydocabon-containing laye. The ducted wave modus popagate lateally along the laye and leaks enegy back to the ovebuden and eceives positioned on the seabed. The ducted wave-modus is excited only fo an incident wave with tansvese magnetic (TM) polaization, which means mag netic field pependicula to plane of incident, and at angles of incidence close to the Bewste angle and the citical angle (the angle of total eflection). Fo electomagnetic waves with tansvese electic polaization (TE) the ducted mode will not be excited. The tansmitte geneates both TE and TM waves, but by vaying the oientation of the tansmitte, optionally using othogonally oiented eceiveantennas, the two modes of waves can be eceived at diffeent sensitivity The above-mentioned methods fo mapping the undegound ae compehensive and expensive. Often the signals ae noisy due to intefeence and inteaction, inte alia, with othe souces, long path of the signal, and poblems with weak contact with the seabed and distubing effects of suounding seawate. Thee is a demand fo bette technol ogy fo logging, paticulaly at simultaneous dilling, and paticulaly so that compehensive quantities of data of pef eably independent data can be collected. Thee is also demand fo a device fo electo pulse dilling that is paticu laly feasible fo simultaneous electo pulse dilling and gen eation of signals fo logging The objective of the pesent invention is to meet the above demands. SUMMARY OF THE INVENTION With the pesent invention an assembly fo dilling and logging is povided, compising a device fo electo pulse dilling (EPD device) and at least one device fo eceiving acoustic signals geneated by the EPD device, distinguished in that the assembly futhe compises at least one device fo eceiving electomagnetic signals geneated by the EPD device. With acoustic signal is meant any type of elastic o seismic signal geneated by the EPD device. By electomag netic signals is meant any type of electic, electomagnetic and magnetic signals geneated by the EPD device With a device fo electo pulse dilling is meant any device fo electo pulse dilling, fo example those intoduc toily descibed, but moe pefeably a device fo electo pulse dilling in accodance with the pesent invention, which will be futhe descibed below. The devices to eceive acous tic and electomagnetic signals espectively, geneated by the EPD device ae of any peviously known type, and with placement feasible to eceive said signals The assembly accoding to the invention pefeably compises acoustic eceives measuing thee displacement vectos and one pessue component, the eceives being aanged in one o moe positions chosen amongst: on a seabed, on a gound Suface, in wate ove the seabed, in one o moe sepaate well-boes, in the well-boe whee the EPD

7 device is used. Theeby the shea and pessue components of the acoustic waves can be detemined. Conveniently, thee axial piezoelectic eceives, hydophones and geophones can be used The assembly accoding to the invention pefeably compises electomagnetic eceives, aanged in one o moe positions chosen amongst: on a seabed, on a gound Suface, in wate above the seabed, in one o moe sepaate well-boes, in the well-boe whee the EPD device is used. With the tem electomagnetic eceive is meant electic field eceives, electomagnetic eceives and magnetic field eceives. Elec tic field eceives compise fo example diffeent types of electode antennas, such as silve-silve-chloide-, cabon filled electodes, fibe optic sensos, dipole antennas and dielectic plate antennas. Electomagnetic eceives compise fo example ing antennas and coils with o without feo magnetic coe, and induction coil magneto-metes. Magnetic field eceives can be divided into two main goups: 1) mag neto-metes fo H-1 mt and 2) Gauss metes fo HD.1 mt. Magnetometes can be divided into two Subgoups: a) vecto, fo example seach coil, fluxgate, Squid, magneto-esistive and fibe optic magnetometes, and b) scala, fo example optic pumped and poton pecision magnetometes. Gauss metes ae fo example Hall effect-magneto-esistive, mag neto-diode, and magneto-tansisto Gauss metes. The eceives can pefeably be aanged in pais and thee and thee to measue all components of the electomagnetic field. Most pefeed ae silve-silve-chloide dipole electodes o coils withfeomagnetic coe fo measuement of electic and magnetic field stength on the Suface, espectively, because of simple poduction, low cost and good measuements. I well-boes ing antennas, such as loop antennas o cicula antennas ae most pefeed fo electomagnetic measue ment, fo coesponding easons. The above-mentioned eceives ae pefeably placed togethe in goups, so that seveal types of measuement can be made fom the same position, which simplifies analysis of the measues data. Fu the, many goups of eceives ae advantageously aanged, paticulaly on the seabed, to povide seveal sets of measue ments and good positional accuacy. The eceives geneate advantageously electical, acoustic, adio, electomagnetic o optical signal that ae deliveed in the fom of aw data o pocessed data via cable o by othe means to a suface posi tion, pefeably eadable and pocessable in eal-time. In the well-boe whee the EPD device is used, eceives ae pef eably aanged in pais, fo example close to each othe along a dill Sting and in addition diametically opposite about a dill sting, fo easie to identify and emove unwanted sig nals, and detemining the position of inteesting eflexes o signals. The measuement devices measue stings of data ove time at a fequency of measuement adapted elative to the fequency of the geneated waves The assembly accoding to the invention pefeably compises a device coupled to the eceives fo ecoding, stoage and pocessing of data fom the eceives connected to the EPD device o eadable fo an opeato of the EPD device, fo contol of the electo pulse dilling based on mea Sued and/o pocessed data, eithe manually o automati cally The assembly accoding to the invention pefeably compises an EPD device with adjustable effect, so that the plasma geneation selectable can be povided eithe in a dill ing fluid ahead of the dill bit, o into o on a fomation suface in font of the dill bit. This is of significance not only fo the dilling pocess and the contol theeof, but also fo the gen eation of diffeent types of data. Thee ae easons to expect that plasma channel fomation in o on the fomation will give diffeent electomagnetic and acoustic signatue than plasma channel fomation in a dilling fluid. The plasma channel fomation in a dilling fluid gives a pessue wave and an electomagnetic wave which because of eflection at the inte face to the fomation ae assumed to have lowe penetation into the fomation, and a diffeent content of shea and tans vese components fo the geneated wave fields, than plasma channel fomation into (and possibly onto) the fomation. Futhe, the output effect fo plasma channel fomation in a dilling fluid will be lowe, and the physical mechanism fo the way in which the fomation is fagmented will be diffe ent The assembly accoding to the invention pefeably compises a devise fo electo pulse dilling with at least thee electodes fo chaging to high-voltage (chaging electodes) and Subsequent dischaging, aanged angulaly sepaate within the cicumfeence, at least one electode coupled to gound, as the electodes ae aanged in a dilling face of a dilling bit, with insulation between electodes, with indi vidually Switch-able connection of chaging electodes to an effectic-selectable high-voltage souce. With at least thee chaging electodes, pefeably aanged evenly aound the cicumfeence, and with a selectable effect fo the high-volt age souce that can be contolled to povide plasma channel fomation eithe into o onto the fomation o within a dilling fluid, both impoved contol of the device fo electo pulse dilling and geneation of diffeent types of acoustic and electomagnetic signals ae achieved. The fequency of the geneated wave field can be contolled by the switching The invention also povides a method fo electo pulse dilling and logging, compising intoducing a device fo electo pulse dilling in a well-boe, eithe in the end of a dill sting o in the end of a cable o a coiled tubing, distin guished by electo pulse dilling the fomation while simul taneously geneating electomagnetic and acoustic signals; to eceive acoustic signals with at least one device fo eceiving Such signals, to eceive electomagnetic signals with at least one device to eceive Such signals, and to use the eceived data, eithe diectly o in pocessed fom, to contol the elec to pulse dilling Eventually, the invention povides a device fo elec to pulse dilling, distinguished in that it compises at least thee electodes fo chaging to high-voltage (chaging elec todes) and Subsequent dischaging, aanged angulaly in sepaated sectos within the cicumfeence, and at least one electode coupled to gound, the electodes being aanged in a dilling face in a dilling bit, with insulation between elec todes, with individual Switch-able coupling of chaging elec todes to a high-voltage souce fo which the effect can be selected The pesent invention has benefits by the souce fo signals fo logging simultaneously being the device fo dill ing, and the geneated signals tavel a shote way than if they wee geneated at the Suface, which povides lowe damping and less occuence of distubing signals. Futhe, fom one Souce independent signal can be povided in the fom of acoustic and electomagnetic signals, and the electomag netic and acoustic signals can be geneated by diffeent ope ating paametes and povide independent sets of measue ments. Theeby, at a elative low cost a lage quantity of data of identical and/o independent measuements can be po

8 vided, which povides data of good statistical significance. It is possible to wok the invention by using only peviously known equipment. FIGURES The pesent invention is illustated with thee fig ues, moe specifically 0027 FIG. 1 that illustates an assembly accoding to the invention, 0028 FIGS. 2A and 2B that illustate the device fo electo pulse dilling accoding to the invention, and 0029 FIG. 3 that is a coss-section illustating aange ment of eceiving devices and the EPD device of the assembly and the method accoding to the invention. DETAILED DESCRIPTION 0030 FIG. 1 illustates an assembly 1 accoding to the invention, compising a device 2 fo electo pulse dilling (EPD device), at least one device 3 to eceive acoustic signals geneated by the EPD device, and at least one device 4 to eceive electomagnetic signals geneated by the EPD device. The devices 3, 4 to eceive acoustic and electomagnetic signals, espectively, ae opeatively coupled to a unit 2a that eceives and pocesses the signals, fo use eithe manually o automatically to contol the electo pulse dilling based on the measued data. Theeby the electo pulse dilling can be con tolled to hit and penetate a hydocabon esevoi, as the measued data can povide infomation on the location of the dill elative to said esevoi. To achieve the best functional ity it is equied with an EPD device that is paticulaly feasible to povide measuement data of sufficient quality to delimit and detemine a hydocabon esevoi. Such EPD device is povided with the invention and is illustated on the FIGS. 2A and 2B. 0031) Moe specifically, FIG. 2A illustates a device 2 fo electo pulse dilling, compising thee electodes 2B fo chaging to a high-voltage (chaging electodes) and Subse quent dischaging, aanged in angulaly sepaated sectos within the cicumfeence and at least one electode 2c coupled to gound, the electodes being aanged in a dilling face 2d of a dill bit, with insulation between electodes, with individually switch-able coupling of chaging electodes to a effect-adjustable high-voltage souce 2e. Thee chaging electodes 2b ae illustated, aanged 120 sepaated within the cicumfeence of the dilling face 2d. This is sufficient to be able to focus the electo pulse dilling in any diection, by altenately chaging chaging-electodes to have the electo pulse dill deviating in the desied angle. Howeve, to incease the diamete of the well-boe and dilling face aea, and stee-ability, it can be pefeable with fou chaging elec todes o moe, aanged within the cicumfeence of the dilling face, as illustated on FIG.2B. The dill bit fo electo pulse dilling illustated on FIG. 2B compises in total 8 chaging electodes and two concentic gounded electodes. The dilling face also compises insulation 2f between the electodes, and openings 2g fo ciculation of dilling fluid. The electodes ae coupled with pulse-foming lines 2h to an electic Supply 2e, which again is coupled to a unit 2a fo eceival and pocessing of data fom eceives fo electomag netic and acoustic signals geneated by the EPD device, as appaent fom FIG. 2A. The figues ae not dawn to scale and all efeence signs ae not intoduced, to impove claity. The electic Supply 2e can delive chaging that povides plasma channel foming only in o on the fomation and chaging that povides plasma channel fomation only into the dilling fluid ahead of the dill bit, and be adjusted fo aimed focusing of the dilling effect. Said focusing is achieved by choosing chag ing electodes o sections o goups of chaging electodes so that the dilling effect is angulaly focused in the desied diection, by the electo pulse dill not dilling at even ate ove the dilling face. Fo example when dilling in sandstone, and with 5 cm between the electodes, a chaging up to at least 250 kv is equied fo plasma channel fomation to take place into o on the sandstone instead of into a dilling fluid of wate, accoding to FIG. 6 of Patent Publication WO 03/ By focused dilling in sandstone a chaging is theefoe elected to be below 250 kv, and electodes povid ing desied deviation of the dilling diection. In the intoduc toily descibed patent application WO 03/ , futhe guidance is found on appopiate opeating paametes, efe in paticula to the FIGS. 6-8 and accompanying text in the desciption. The electic Supply can conveniently be an adapted Max geneato. The pulse-foming lines can conve niently be Blumlein pulse-foming lines. The chage Voltage can pefeably be adjustable fom 0 to at least 300 kv, most pefeably so that plasma channel fomation can take place in any type of fomation that is dilled though at the actual distance between the electodes. The insulation between the electodes is conveniently in the fom of a ceamic mateial. Futhe guidance on pulse-foming lines, electic Supply, chage Voltage and effect of electode sepaation can be found in Patent Publications WO 03/ and U.S. Pat. No. 4,741, FIG.3 is a coss-section illustating the aangement of eceiving devices and the EPD device of the assembly and the method accoding to the invention. A substantial numbe of eceiving devices 3, 4 ae illustated, which eceiving devices in geneal ae a goup of eceiving devices chosen amongst acoustic and electomagnetic eceiving device. Moe specifically, the eceiving devices 3, 4 ae aanged in the sea 5 above a seabed 6, on said seabed 6, in geological stata 7, 8, and 9 downwad fom the seabed in sepaate well-boes and in the well-boe 13 whee the EPD device is used. Unde a cap 10 gas 11 and oil 12 ae found. With the EPD device 2 the well-boe 13 is dilled futhe so that the well-boe 13 hits said gas and oil, fo subsequently to poduce the gas and oil though the well-boe The EPD device will duing opeation geneate acoustic and electomagnetic waves, of fequency dete mined by the Switching and dischaging fequency, and enegy and component contents dependent on the dischaging effect and modus fo plasma channel fomation (in a dilling fluid, o in o on a fomation). Moe specifically the acoustic waves will compise both pessue and shea components, and the electomagnetic waves will compise TE and TM components. The EPD device will initially send out a shot esponse with andom shape limited in time and as a continu ous fequency spectum of acoustic and electomagnetic waves, which esults in time-domain data. Tansmission of long peiodic signals in time fom the EPD device esults in pinciple in discontinuous fequency specta, esulting in fe quency-domain data. In pinciple it is the objective to use all types of data that can be geneated by the EPD device, both time-domain data and fequency-domain data The eceives fo acoustic and electomagnetic sig nals will eceive a compehensive set of signals with diect, eflected, efacted, deviated and excited components.

9 Amongst the signals it will in paticula be sought fo com ponents giving infomation Suitable to delimit and detemine the popeties of inteesting Zones in the esevoi. Acoustic shea components, fomed diectly by the EPD device o by eflections, will to a limited extent popagate though fluid containing esevois, because fluids do not tansfe shea waves. Fluid-containing Zones, in paticula Zones containing oil and gas, will typically have a esistivity that deviates fom the Suounding aeas and the ovebuden. Electomagnetic TM components can, dependent on the angle of incidence, excite a channeled wave modus in a laye of high esistivity, as descibed in Patent Publication WO 02/14906A1. Advan tageously, many eceives ae used, with diffeent placements to povide good accuacy fo detemining positions by path time analysis. The tansmitte (EPD device) and eceives must be synchonized in eal-time, fo example with GPS, and the tansfe function of the sende and the eceives must be measued o estimated. Fo eceives that stoe the signals peliminaily, time must be logged togethe with eceived data, in ode to coect any time deviation. Futhe, measue ments may advantageously be taken up ove a dilling inte val, in ode to have components fomed that ae paticulaly feasible fo detemining the popeties of the inteesting Zones. Advantageously, many measuements ae taken to obtain data that can be pocessed by aveaging and filteing away noise and undesied signal components as appopiate. Analysis and pocessing of the measued data is a compe hensive and challenging opeation. Data can be analyzed by using existing techniques, as fo example descibed in the Patent Publications WO O2/14906 A1 and WO 2004/ A1, and techniques being developed When dilling a well it can be pefeable to use conventional dilling technology fo the uppe pats of the well boe, having lage diamete than achievable with electo pulse dilling, but shifting to electo pulse dilling when the well-boe is close to an identified esevoi. To take up foces geneated by the EPD device, and to ensue good access deeply into deviating well-boes, the EPD device can be aanged as a bottom hole assembly at the end of a dill Sting. 1. Assembly fo dilling and logging, compising a device fo electo pulse dilling (EPD device), at least one device to eceive acoustic signals geneated by the EPD device, chaacteized in that the assembly futhe compises at least one device to eceive electomagnetic signals gen eated by the EPD device. 2. Assembly accoding to claim 1, chaacteized in that it compises acoustic eceives mea Suing thee displacement vectos and one pessue com ponent, the eceives being aanged in one o moe positions chosen amongst: on a seabed, on a gound Suface, in wate above is the seabed, in one o moe sepaate well-boes, in the well-boe whee the EPD device is used. 3. Assembly accoding to claim 1, chaacteized in that it compises electomagnetic eceiv es, aanged in one o moe positions chosen amongst: on a seabed, on a gound Suface, in wate above the seabed, in one o moe sepaate well-boes, in the well boe whee the EPD device is used. 4. Assembly accoding to claim 1, chaacteized in that it compises silve-silve-chloide dipole electodes and coils with feomagnetic coe fo measuing electic and magnetic signals espectively, on the suface o a seabed. 5. Assembly accoding to claim 1, chaacteized in that it compises loop antennas fo mea Suing electomagnetic signals in a well-boe. 6. Assembly accoding to claim 1, chaacteized in that it compises a device coupled to the eceives fo ecoding, stoing and pocessing of the data fom the eceives, coupled to the EPD device o eadable fo an opeato fo the EPD device, fo contol of the electo pulse dilling based on the measues and/o pocessed data, eithe manually o automatically. 7. Assembly accoding to claim 1, chaacteized in that it compises a EPD device with adjust able pefomance, so that plasma fomation selectable can be povided eithe in a dilling fluid ahead of the dilling bit, o into o onto a fomation face ahead of the dilling bit. 8. Assembly accoding to claim 1, chaacteized in that it compises a device fo electo pulse dilling with at least thee electodes fo chaging to a high-voltage (chaging electodes) and Subsequent dis chaging, aanged angulaly sepaate within the ci cumfeence, and with at least one electode coupled to gound, the electodes being aanged in a dilling face of a dill-bit, with insulation between the electodes, with individually switch-able coupling of the chaging electodes to an effect-adjustable electic high-voltage Supply. 9. Method fo electo pulse dilling and logging, compis ing to bing a device fo electo pulse dilling into a well-boe, eithe in the end of a dill sting o in the end of a cable o coiled tubing, chaacteized by electo pulse dilling the fomation by simultaneously geneating electomagnetic and acoustic signals; to eceive acoustic signals with at least one device to eceive such signals; to eceive electomag netic signals with at least one device to eceive Such signals; to use the eceived data, eithe diectly o in pocessed fom, to contol the electo pulse dilling. 10. Device fo electo pulse dilling, chaacteized in that it compises at least thee electodes fo chaging to a high Voltage (chaging electodes) and Subsequent dischaging, aanged in angulaly sepaated sectos within the cicumfeence, and at least one elec tode coupled to gound, the electodes being aanged in the dilling face of a dill bit, with insulation between the electodes, with individually switch-able coupling of chaging electodes to an effect adjustable high-voltage SOUC.