RU1838599C - Method to control process of diamond core drilling - Google Patents

Abstract

Purpose: automation of the process of managing the drilling of exploration wells. SUMMARY OF THE INVENTION: During the drilling process, the technological conditions are constantly measured: mechanical drilling speed UF, axial load, rotational speed of the drill bit n, pressure P and flow rate Q of flushing fluid. The theoretical flow rate QT of the washing liquid is determined analytically From - m (j Vm / n - k), at P Pred .. Q Qmin, where k, J, m are experimentally determined constants. Set the actual flow rate of the flushing fluid Q - From. The maximum permissible value of the flushing fluid pressure Ppred is set. and the minimum allowable value of its flow rate Qmin. The values of the actual pressure of the flushing fluid P are compared with Pred. If the P-value is exceeded, Q is reduced to normalize P. At the same time, the value of the reduced flushing fluid flow rate is compared with Qmin. When Qmin is exceeded, the reduced flow rates stop the drilling process. 1 ill.

Description

The invention relates to methods for monitoring and controlling the drilling of exploration wells, in particular to methods for controlling a diamond core drilling process.

The aim of the invention is to increase the efficiency of the drilling process by establishing optimal flushing fluid flow rates in order to maintain a rational thermophysical mode of operation of the diamond core and a mode of cleaning the bottom of the hole from drill cuttings.

This goal is achieved due to the fact that with the method of controlling the diamond core drilling process, including measuring the parameters of the drilling process (mechanical drilling speed Um, axial load P, frequency

rotation of the drill bit n, the flow rate of the flushing fluid Q and the power consumption for drilling N) the maximum effective flow rate of the flushing fluid is set, and if the actual value of the flushing fluid pressure exceeds the permissible value, the fluid flow rate is reduced to the normal pressure value, and then, while maintaining in an emergency, the drilling process automatically stops. At the same time, the flow rate of flushing fluid is set in the range of acceptable values equal to the theoretical one determined by the analytical method, taking into account the current values of the mechanical drilling speed and the rotational speed of the drill bit during the established technological process, recognizing

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in terms of axial load and power consumption.

The effective operation of a diamond rock-cutting tool is possible if the process of diamond destruction is maintained at a constant level and the products of rock destruction (sludge) are removed from the slab unhindered. These processes are closely related to the flushing regime, which has a complex, conflicting effect on the drilling process. Thus, according to theoretical and experimental studies, with an increase in the flow rate of the flushing liquid, the wear of the diamond rock-cutting tool decreases, while at the same time in the medium and low abrasive rocks the diamonds are polished, their outflow from the matrix body is reduced, which leads to loss of crown performance . In addition, the increased flow rate of the flushing fluid leads to a number of negative phenomena when drilling fractured rocks; intensification of core core self-spells, its increased wear, matrix destruction by rock fragments, hydraulic support of the core pipe. Reducing the flow rate of flushing liquid ™ reduces the effect of these negative phenomena, but can lead to the development of the process of intense thermophysical wear of diamonds and the matrix, although when polishing crowns this can help restore their performance. With this dependence, the efficiency of the drilling process from the flow rate of the flushing fluid is obvious. There is an obvious need to control the drilling process in order to maintain normal working conditions of the diamond crown, the core formation process and eliminate abnormal phenomena - polishing diamonds, thermophysical wear of crowns, hydraulic supports and core self-wedges.

Management of the proposed method is carried out in accordance with the following dependence obtained experimentally

R rpred

From m (j Vm / n - k), npw

where is the theoretical flow rate of flushing fluid;

Vm is the mechanical drilling speed;

n is the rotational speed of the drill;

k, j, m are constants determined experimentally.

The choice of these constants (coefficients) provides the necessary thermophysical mode of operation of the diamond crown and the mode of cleaning the bottom of the well from drill cuttings, while the lowest flow rate of flushing liquid is realized.

which makes it possible to reduce the negative effect of hydraulic support, as well as to reduce the effect of flushing on core safety.

Monitoring the fulfillment of the conditions of R Pred. and About Qmin aims to prevent emergency situations. If one of the conditions is not met, the system takes measures to restore the parameters in the working area by reducing the flow rate of the flushing fluid and then returning to the optimal flow rate. If it is not possible to eliminate the situation if one of the conditions is not met or both conditions are not fulfilled simultaneously, the drilling process automatically stops while avoiding emergency collapse.

Various methods of controlling flushing of a well during diamond core drilling were investigated, however, they failed to detect signs and criteria for controlling flushing by the maximum effective flow rate of flushing fluid, determined by analytical

a method taking into account the permissible pressure of the flushing fluid in the well, the current values of the mechanical drilling speed and the rotational speed of the drill bit at a steady process recognized by the magnitude of the axial load and power consumption. The described is the basis for the conclusion that the proposed technical solution meets the criterion of substantial

difference. The achievement of a positive effect became possible due to the fact that when the proposed method is implemented, the number of core sub-wedges is reduced, in addition, an illiquid sub-wedge is recognized.

at which the drilling process stops, the time of inefficient drilling is reduced. The working conditions of the diamond crown are also improved, resulting in an increase in penetration by

crown, a constant analysis of the presence of a pre-emergency situation is carried out with the drilling process stopped if it cannot be eliminated, which reduces the psychophysical load on the drilling personnel.

All this proves the possibility of achieving a positive effect in the implementation of the proposed technical solution.

The technical nature and principle of operation of the proposed method for controlling the flow rate of flushing fluid are illustrated in the flowchart in the drawing.

I The block diagram of a device for implementing the fifth method for controlling a diamond drilling process has blocks 1-3 — the start of the control cycle, block 4 — setting the initial output of the actual parameter values beyond the limit values, block 5 — checking the drilling condition, block 6 | - output of information messages about the values of P and Q, block 7 - calculation of theoretical Q, blocks 8 and 9 - check that theoretical values are exceeded, the blocks 10 and 11 - flow rate correction, block 12 - actual flow rate setting, block 13 - output determination the actual value of the parameters beyond the critical ones, block 1J4 is the end of the control cycle, block 15 is the correction of the theoretical flow rate, block 16 is the output of the theoretical value of f-beyond the minimum, block 17 is the flow rate setting.

1 The proposed method for controlling the diamond drilling process is carried out as follows. The initial flow rate of flushing fluid is set by unit 2, after a time delay of unit 3, an analysis of the actual state of the process is carried out to determine whether the parameter limits are exceeded. After this, block 5 analyzes the process step, in the case of drilling, an information message is sent by block 6 about the current parameters of the drilling mode, blocks 8 and 9 analyze this value beyond the control limits and set the flow rate of 10 and 11 rinsing liquid in case of exit for limitation, and block 12 in a normal process. After 3JTHX operations, the control loop closes. The next branch of the flowchart begins with block 13, to which control of block 4 is transferred if the current parameter values exceed the limit value, block 13 estimates the parameter values and, if they exceed critical values, transfers control to block 14 at the end of the flight. In block 15, the theoretical value of the flow rate of the flushing fluid is reduced and then checked by block 16 to ensure that this parameter is not output for the minimum value. If block 17 does not exit, sets the actual flow equal to theoretical and closes the control cycle. If the theoretical flow rate goes beyond the lower limit, the actual flow rate remains the same.

This method of controlling the drilling process allows optimally (in the sense of increasing penetration to the crown and maintaining the mechanical drilling speed at the same time) and quickly set new values for the flow rate of drilling fluid under actual drilling conditions of exploration wells; when changing rocks, take into account the condition the use of a rock cutting tool 0, increase the efficiency of rock destruction at the bottom of the well, control the occurrence of pre-emergency situations, eliminates the influence of the subjective factor on the technological 5 well drilling process.

Using this method provides an increase in penetration on the crown, an increase in the mechanical speed of drilling, as well as a decrease in the psychophysical loads on the drilling personnel, i.e. improvement of working conditions.

Claims (1)

Claims A method for controlling a diamond core drilling process, including measuring the mechanical drilling speed, axial load, drill rotational speed, flushing fluid pressure and flow rate, and drilling power consumption, changing flushing fluid 0 flow rate, axial load-1 and drilling rotational speed shells, characterized in that, in order to increase the efficiency of the drilling process by establishing optimal flow rates of flushing fluid 5 to maintain a rational thermophysical mode of operation of the diamond crown and the mode of cleaning the bottom of the well from drill cuttings, reducing self-jamming of the core and the influence of hydraulic support, analytically determine the theoretical flow rate of the flushing fluid in accordance with the expression P PnpeA QT m (J -Vm / n-k, for where QT is the theoretical flushing rate liquids k, j, m - constants determined experimentally; 0 Vm - mechanical drilling speed; p is the rotational speed of the drill; P-actual rinse pressure; Rpred. the maximum permissible value of the washing fluid pressure; Q is the actual value of the flow rate of the flushing fluid; QMHH is the minimum allowable flow rate for flushing fluid. set the maximum permissible value of the pressure of the flushing fluid and the minimum permissible value of the flow rate, set the flow rate of the flushing fluid supplied to the well to be equal to the theoretical value and compare the value of the actual pressure of the flushing fluid with its maximum permissible value; the flow rate of the flushing fluid to normalize the pressure, the value of the reduced flow rate is compared with its minimum a valid value and if the value of the minimum allowable flow exceeds the value of the reduced flow, the drilling process is stopped.