FR2647849A1 - METHOD OF CHARACTERIZING A LAYER OF FIELD - Google Patents

Abstract

The invention relates to a method for characterizing a layer of land, and in particular for determining its stratigraphy. A drilling is carried out in this land, during the drilling a certain number of raw parameters are recorded, including at least the depth reached, according to a predetermined sampling protocol, these parameters are digitized, the parameters thus digitized are introduced into a database. volatile facts contained in a memory of a processing unit also containing a permanent fact base, a rule base and an inference engine, for at least certain sampling cycles, an inference cycle of the engine of inference using the volatile fact base, the permanent fact base and the rule base to deduce the type of ground traversed by the borehole, we add to the permanent fact base at least the type of ground thus inferred associated with its depth , and we reset the volatile fact base.

Description

The present invention relates to a method of

  characterization of a land layer.

  Such processes are already known in which drilling is carried out and a certain number of parameters of this drilling are noted, such as the pressure of the perforation fluid, the torque, the thrust exerted on the tool, the speed of the drilling. the speed of rotation of the tool, or the vibrations of the stem, either as a function of time or

depth function.

  From these parameters or combinations of these parameters, a specialist can attribute certain characteristics to the terrain traversed, for example defining the parameters of an injection that will be carried out later, or even having a relatively precise idea

the type of this land.

  Such an analysis can not, however, be carried out in real time on the actual site of the drilling, so that if these results are useful in themselves for the characterization of the terrain, and especially for the knowledge of its stratigraphy, they can not be used in particular for the actual conduct of the drilling, whether by the driller or

  by an automaton which would be substituted for it.

  The present invention aims to overcome these disadvantages.

  To this end, the subject of the invention is a method for characterizing a layer of terrain and in particular for determining its stratigraphy, characterized in that a drilling is carried out in this terrain, which is taken up during drilling a number of raw parameters including at least the depth reached, according to a predetermined sampling protocol, that these parameters are digitized, that the parameters thus digitized are introduced into a volatile base of facts contained in a memory of a processing unit also containing a permanent fact base, a rule base and an inference engine, that for at least some sampling cycles an inference engine inference cycle is started using the database of facts volatile, the basis of permanent facts and the basis of rules to deduce the type of terrain traversed by the drilling, that we add to the basis of facts permanent at least the type of terrain inferred i associated with its depth,

  and reset the volatile base of facts.

  Of course, we already know many expert systems using a knowledge base, a rule base, and a

  inference engine to simulate the expertise of a specialist.

  It should be noted, however, that one of the essential characteristics of the invention consists in successively carrying out a series of 2-cycles of inference using as a basis of knowledge, on the one hand a number of permanent facts and on the other hand facts volatiles that are kept in the knowledge base only one cycle time and which

  are at least some of the raw parameters sampled.

  On the other hand, according to another essential characteristic, the permanent part of the knowledge base, namely the permanent fact base, is enriched with each cycle of inference of the terrain inferred from this cycle, so that, during the Next cycle, the knowledge base includes all the stratigraphy of the terrain

  finding above the current depth of the borehole.

  Sampling of drilling parameters can be done either at predetermined time intervals or at intervals of

predetermined depths.

  The advantage of sampling over time is to allow good control of drilling operations, including during

  phases of rod change, and during maneuvers.

  On the other hand, the disadvantage is that the quantity of data to be stored is not a priori bounded above and can

  therefore become extremely important.

  On the other hand, sampling according to

  depth makes it possible to better restore the acquired information in space.

  We have already seen that in the permanent base of facts, the types of terrain previously traversed by the drilling are stored associated

at their depth.

  According to another important feature of the invention, all the facts of the permanent fact base are associated with

a depth interval.

  This means that all permanent facts are affirmed, and therefore true over an entire depth interval, whereas volatile facts are only true for depth.

  corresponding to the current inference cycle.

  It is furthermore possible to introduce into the volatile fact base, in addition to the raw parameters, at least one composite parameter.

  obtained by digital processing of some of the raw parameters.

  Output editing, that is to say at least the terrain traversed by drilling, and possibly some of the raw or compound parameters, can be done for example on a screen or a printer. But the outputs can also be used in

  real time, for example by a PLC in order to optimize drilling.

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  Outputs can also trigger some

  alarms or possibly interrupt the drilling.

  A particular embodiment of the invention will now be described by way of nonlimiting example with reference to the appended diagrammatic drawings, in which: FIG. 1 is an overall view of a drilling machine making it possible to implement the FIG. 2 is a flowchart of the operations performed by the processing unit, and FIG. 4 shows a result obtained using the method. FIG. . The machine 1 of Figure 1 comprises a drill head 2 providing in a known manner the rotary drive of the drill string 3 and the injection of drilling fluid into these rods. A tool for

  Drill 4 is mounted at the lower part of the drill string 3.

  The drilling head 2 is connected to a device for measuring the depth of the drilling and the speed of advance by a cable 5 passing over a return pulley 6. Between the drill head 2 and the drill string 3 is inserted an electronic measuring device 7 connected by a non

  represented at a processing unit 8.

  The device 7 may be of the type described in the French patent application N 89.01624 or, er. variant, be replaced by a bolt of hydraulic pressure sensors connected to the hydraulic circuits

of the machine 1.

  By way of example, the measuring device 7 can record the pressure of the perforation fluid, the torque, the

  thrust on the tool as well as the vibrations of the drill string.

  These parameters, as well as the speed of advance are

  measured at each depth step, for example all Smm.

  Referring now to FIG. 2, it can be seen that the ground 9 in which the drilling is carried out exerts certain forces on the drilling tool 4. These efforts are taken up by the drilling machine 1 which prints the tool with a tool certain thrust and a couple of rotation, and which

  further provides the perforation fluid under pressure.

  This results in a certain number of drilling parameters which are detected by the sensors of the connected device 7, via an acquisition box 10 where the sampling and digitization are carried out at the processing unit. 8, which is

  connected to any input / output means 11 such as a printer.

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  Referring now to FIG. 3, it can be seen that the processing unit 8 begins at 12 to initialize the permanent fact base prior to the beginning of drilling. This initialization is carried out

  either from a memory, or directly by the operator.

  Then we see that the program runs in two nested cycles. The first cycle is performed all n no input,

  while the outer cycle is carried out over the entire depth of the borehole.

  The first cycle consists first of reading the data supplied by the acquisition cabinet at 13, then processing this data to convert them to raw parameters at 14, and then possibly combining some of these raw parameters to obtain parameters.

compounds in 15.

  Compound parameters can be either algebraic combinations of some of the raw parameters, or values

  smoothed out of these parameters on the n not.

  Not all, the volatile fact base is reset to 16, then the raw parameters and parameters are entered

  selected compounds that constitute the volatile facts in question.

  In 17, the inference engine of the processing unit performs an inference cycle from which it deduces, in particular, the type of terrain

which has just been crossed.

  In 18 the permanent facts base is updated by adding the type of terrain found as well as the depth, and the results

are published in 19.

  It is therefore found that the volatile fact base contains values of raw parameters and composite parameters that are only valid for one inference cycle, namely the cycle that occurs.

  unfurls at the depth reached by drilling.

  On the other hand, the permanent fact base includes at least all the lands found at the previous inference cycles associated with their depth. Table 1 below defines a particular configuration that was used during a drilling that led to the results.

shown in Figure 4.

  The gross parameters are those mentioned above, the torque and the thrust and the restraint exerted on the tool being measured as pressures in the circuits

hydraulic machine 1.

  The definition of the composite parameters aims at obtaining the parameter P13 which is the smoothed value over ten steps of the square of the value

  absolute difference in thrust between two successive steps.

  Outputs consist of graphical printing of pressure and thrust parameters as well as parameter P13, and graphical and alphanumeric printing of terrain traversed as it is

determined by the expert system.

  Table 2 shows the facts of the permanent fact base. Facts of the type AFF - "type of terrain" mean that it is necessary to display, that is to say to edit on the printer or on

the screen, this type of terrain.

  Finally Table 3 sets out the rules of the base used.

  We see that these rules are of the type: Si i and Si j and Si k oo ... ,, .. e .., ... Then 1 and Then m and Then n ee, e ....., in which i, j, k ...., l, m, n ... are either facts of the facts base

  permanent, facts of the volatile facts base.

  It is furthermore noted that each rule may be assigned a decisive priority order, in the case where two rules can be implemented simultaneously (that is, in the case where the firstfruits of each are all true). , the order in which these rules must be

implemented.

  The skilled person can, from the description which

  precedes and in this example, write the computer software allowing

  to obtain the result shown in Figure 4.

  This figure represents, in terms of depth, the pressure of the perforation fluid, the thrust exerted on the tool, the parameter P13 and the types of ground successively encountered in

course of drilling.

  Various variations and modifications can of course

  be made to the foregoing description without departing from the scope

nor the spirit of the invention.

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  This process can be used in various fields of civil engineering, such as soil recognition, injection control

  automatic or determining the anchorage level of piles and tie rods.

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TABLE 1

DEFINITION OF DRILLING PARAMETERS

NAME MAXIMUM VALUE UNIT

  PO DEPTH 0.005 m Pi PRESSURE 35 bar P2 TORQUE 150 bar P3 PUSH 150 bar P4 ADVANCE 1200 m / h P5 ROTATION 500 Hz P6 RETENTION 150 bar P7 VIBRATION 250 g P8 TIME 8 s

DEFINITION OF COMPOUND PARAMETERS

NAME DEFINITION

P9 P10

PIO P3

ABS Fold (P10-P9)

F12 P1I * P11

P13 Smoothing of P12 on 10 steps

DEFINITION OF OUTPUTS

NAME UNIT SCALE

  1 G Pi PRESSING Bar 10 2 G P3 PUSHED bar 100

3 S P13 100

4 X EXPERT SYSTEM

Vertical scale 1/100.

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TABLE 2

BASIC FACTS

DONE N 01: AFF <> ALLUVIONS

FACT N 02: AFF - ALLUVIONS

DONE N 03: AFF - CLAY

DONE N 04: AFF = LIMESTONE

  DONE N 05: AFF - REFURBISHED CAREER

  DONE N 06: AFF - MARNE AND CAILLASSES

DONE N 07: AFF <> REMBLAI

DONE N 08: AFF - REMBLAI

  DID N 09: AFF - SAND OF BEAUCHAMP

DONE N 10: PI - 0

DONE N 11: P1> 0

FACT # 12: P13 <1

FACT # 13: P13> 1

FACT # 14: P8 <1

FACT # 15: P8> 1

DONE N 16: PROF <2

DONE N 17: PROF <10

DONE N 18: PROF> 10

DONE N 19: PROF <20

DONE N 20: PROF> 20

  DONE N 21: SITE - PARIS ** true on all drilling **

DONE N 22: LAND <> LIMESTONE

DONE N 23: TERRAIN - DEBRIS

  DONE N 24: FIELD - COMPACT TRAINING

DONE N 25: TERRAIN - REMBLAI

DONE N 26: SANDY GROUNDS

  DONE N 27: FIELD FIND - ALLUVIONS * PROF> 5

  DONE N 28: TERRAIN FINDS - SAND OF BEAUCHAMP

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TABLE 3

RULES OF THE BASIS

  Rule number 1 (order of priority - 1): If Pl - 0 And If PROF <20 Then TERRAIN <> SAND And Then FIELD <> CALCARY And Then TERRAIN = DEBRIS Rule number 2 (order of priority - 1): If FIELD - DEBRIS And Si P13 <1 Then AFF - ALLUVIONS Rule number 3 (order of priority - 1): If DEBRIS FIELD And Si P13 <1 Then AFF - BACKGROUND Rule number 4 (order of priority - 1): If Pl> 0 ALors TERRAIN - COMPACT TRAINING Rule number 5 (order of priority - 1): If FIELD - COMPACT TRAINING And Si P8> 1

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  Then AFF - MARNES AND CAILLASSES Rule number 6 (order of priority = 1) If PROF> 20 And If P1 - O Then AFF = CAREER REMBLAYED l0 Rule number 7 (order of priority - 1): If P8 <1 And IF FIELD - COMPACT TRAINING And If PROF <10 Then AFF - BEAUCHAMP SAND Rule number 8 (order of priority - 1): If P8 <1 And IF FIELD = COMPACT FORMATION And If PROF> 10 Then AFF - LIMESTONE Rule number 9 (order of priority - 3) If FIELD FOUND - ALLUVIONS * PROF> 5 And If AFF - FILLING Then AFF <> FILLING And Then AFF = ALLUVIONS Rule number 10 (order of priority = 3) If PROF <2 And If AFF - ALLUVIONS Then AFF <> ALLUVIONS And then AFF - REMBLAI

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  Rule number 11 (order of priority - 3) If AFF - ALLWUVIONS And If TERRAIN FINDS - SAND OF BEAUCHAMP Then AFF <> ALLUVIONS And Then AFF - SAND OF BEAUCHAMP

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Claims (5)

  1. A method of characterizing a layer of ground, and in particular of determining its stratigraphy, characterized in that a drilling is carried out in this ground, that a number of raw parameters are observed during drilling. of which at least the depth reached, according to a predetermined sampling protocol, that these parameters are digitized, that the parameters thus digitized are introduced into a volatile fact base contained in a memory of a processing unit also containing a permanent fact base, a rule base and an inference engine, that for at least some sampling cycles an inference engine inference cycle is triggered using the volatile fact base, the permanent fact base and the rule base to deduce the type of terrain traversed by the borehole, which is added to the permanent base of facts at least the type of ground thus inferred associated with its depth, and reset the volatile base of facts. 2. Method according to claim 1, characterized in that the sampling is carried out at predetermined time intervals. 3. Method according to claim 1, characterized in that the sampling is carried out at predetermined depth intervals.   4. Method according to any one of claims I to   3, characterized by the fact that all the facts of the permanent facts base   are associated with a depth interval.   5. Method according to any one of claims I to   4, characterized in that, in addition to the raw parameters, at least one compound parameter is introduced into the volatile base of facts.   by digital processing of some of the raw parameters.