SU878912A1 - Device for monitoring the wear of drilling bits - Google Patents

Description

(54). DEVICE FOR MONITORING THE PROCESS OF DOLOTS

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The invention relates to the field of monitoring and controlling the process of drilling a well and is intended to determine the time of trouble free operation of the bit at the bottomhole.

A device is known which, based on the static data of previously spent bits, predicts the life of the supports of the drill bit. 11The disadvantage is large errors in estimating the moment of bit lifting to the surface, associated with instability of the bit parameters and prediction function coefficients.

Devices for controlling torque on the rotary table shaft are known, which are intended to warn the operating personnel of mechanical overloads of the drill string elements and the L2J bit. Since mechanical overloads of these elements of the drill string are caused by different reasons (collapse of the borehole walls, bit transition into viscous rocks, jamming of the drill collar, downhole motor, bit, etc.), it is impossible to unambiguously judge by the level of the torque controlled by known devices. wedging of the cutters caused by the extreme wear of the bit supports. This is the main disadvantage of these devices.

It is also known to have a device for local monitoring of torque and mechanical drilling speed in order to determine the third parameter, which is the ratio of torque and speed of drilling.

15 A sharp change in the third parameter indicates an accidental wear of the drilling tool Z.

A significant drawback of such a device is the relatively low reliability of determining the moment of complete bit wear, which means that in a number of cases the complete wear of the drilling tool is not accompanied by a change in the ratio of the moment to the speed. The disadvantages should also include the need to maintain a continuous visual monitoring of the third parameter change on the part of the driller. The purpose of the invention. is to improve the accuracy of determining the moment of complete wear of the bit. The goal is achieved by the fact that a device containing torque sensors from the current mechanical drilling speed, a unit for dividing signals from sensors, a block of preventive and pre-emergency alarms, is additionally equipped with a block for predicting the unused resource of the bit supports, a threshold element, a zero-body and the prediction block of the pre-emergency situation, the inputs of which are connected to the outputs of the threshold element and the null organ, and the output to the input of the warning unit and. At the same time, the pre-alarm signaling at the same time the input of the threshold element is connected to the output of the signal splitter unit from the sensors, and the input of the null organ is connected to the output of the prediction unit of the unspent bit life time of the bit supports. FIG. 1 shows a functional diagram of the device for monitoring the failure-free testing of bits; FIG. 2 is a plot of V |) (t) M (t) V (t) f where M is the torque and V is the mechanical speed. A device for monitoring trouble-free working of bits (Fig. 1) contains a block 1 for predicting an unspent life of bit poles, a null organ 2 with an adjustable dead band, a torque sensor 3, a sensor 4 for the current mechanical drilling speed, a signal dividing unit, a threshold element 6, prediction block 7, and a warning and precate alarm block 8. Block 1 of predicting the unspent life of the operating time of the bit operates in accordance with the algorithm, Fh - P (G1 FR (t-) t is the unspent life of the time of the support of the bits of Fi, the potential resource of the supports of the bit, estimated by the data of previously spent bits; F ( t) is the consumed resource of 1 g, equal to p F (t) dt, where t is the current time of mechanical drilling,: F is the product P- (I or P Q; P) is the exponent estimated by the data of the previously worked bits. the signal of this block of the beginning of the flight of the bit (at T 0) has a maxi the minimum value and then decreases and reaches successively in time the following levels: Ut and at t TO - 3 Q at t TQ Uf "- -a at t TO + 3G; where,. TO is the expected life of the bit supports and (5 - root-mean-square deviation of the life of the bit supports: A zero-body 2 with an adjustable deadband generates a U2 signal at its output, the level of which is determined by the input signal: U2.1 at a, - U.- 0, at and U2. i. a. During the working process, the wells deepened at the outputs of the torque and mechanical speed sensors 3 and 4, the corresponding signals Uj -M (t) and U.V (t) are generated. The latter are supplied to the input terminals of the block, 5 dividing signals, which calculates the current average value of I-, -h M (t setting Vp (t) does not calibrate the signal Ug (t) -H (t). An approximate graph of this signal is shown in Fig 2a. In Fig. 26, an approximate graph of the signal at the output of the nullorgan U2 (t) is shown. When the bit is in good condition, the indicator does not exceed the threshold value% ok 6. With the onset of catastrophic wear of the bit and subsequent jamming of its support moment and over time increases and the mechanical speed decreases. driven by a sharp increase in the indicator y and the signal U (t). At ft. d, the signal reaches a threshold value selected from the condition of B. U5 () 2.5 - 3, and (o) UB (O) where and. (o) - the value of the signal U at the beginning of the voyage of the bit 5. The threshold element 6 at its output generates a signal Ux (t), the level of which is determined by the signal at the input: U (t) U, r (t) b; U (t) 1 if U (f) 1. The execution of the signals generated by block 7 is carried out by the warning and pre-alarm unit. The annual savings from the implementation of the proposed device for a single drilling rig will be 7200 rubles. Formulary of the Invention A device for monitoring bit processing, comprising torque sensors and the current mechanical drilling speed, a unit for dividing signals from sensors, warning and pre-alarm units, characterized in that, in order to improve the accuracy of

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f 2 6 the moment of complete wear of the bit, it is equipped with a prediction block of unspent life of the bit supports, a threshold element, a zero-organ and a prediction block of a pre-emergency situation, the inputs of which are connected to the output of the 1st threshold element and zero-organ, and the output - to the input of the block warning and pre-alarm signaling, while the input of the threshold element is connected to the output of the division block of signals from the sensors, and the input of the zero-organ is connected to the output of the prediction block of unspent resource time no work supports bit. Sources of information taken into account in the examination 1. Petroleum engineer, 1971, No. 9, 36-52. 2. US patent number 3782190, cl. E 21 B, 1974. 3. US Patent No. 3581564, cl. 73-151, 197J (prototype).

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Claims (1)

A device for monitoring the development of bits containing sensors of torque and current mechanical drilling speed, a unit for dividing signals from sensors, warning blocks US patent No. 3782190, id 878912 · 6 of the moment of complete wear of the bit, it is equipped with a prediction unit for the unspent resource of the operating time of the supports of the bit, a threshold element, a zero-organ and a prediction block of the emergency situation, the inputs of which are connected to the outputs of the threshold element and zero-organ, and the output - with the input of the warning block and pre-alarm, the input of the threshold element is connected to the output of the block of divisions of signals from the sensors, and the input of the zero-organ is connected to the output of the prediction unit of unspent resource time and a bit of work supports.