RU2798233C1 - Method of operational optimal control of the process of drilling of oil and gas wells - Google Patents

Abstract

FIELD: drilling oil and gas wells.

SUBSTANCE: invention can be used for automatic operational optimal process control using a drilling machine. A method for optimal adaptive control of the process of drilling oil and gas wells is claimed consisting of regulating the axial load on the bit, the model of the mechanical drilling speed is corrected based on the bottom rock, said model represents the interaction of the rock at the bottom of the well with the work of the bit, obtaining results of downhole measurements of the mechanical speed every 0.3 m of rock drilling as a result of the work of the bit at the bottom, updating the drilling speed model, determining the optimal axial load on bit according to the updated drilling speed model, transferring the value of the optimal axial load on bit to the surface equipment control system, drilling the next 0.3 meters of rock with a new load on the bit and multiple repetition of the operations of obtaining, updating, determining, transferring and drilling during the operation of the well. At the same time, the control is carried out according to the updated model of the drilling process, built on the basis of the McLaren series for the sine function based on the mathematical expression given in the claim materials. Moreover, the model has a mathematical maximum in terms of the axial load parameter, which makes it possible to calculate the optimal bit load according to the criterion of maximum mechanical speed.

EFFECT: increase in the accuracy of drilling mode control and an increase in the mechanical speed of well drilling due to control optimization according to a new mathematical model with one adjustable parameter.

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Description

The invention relates to the field of drilling oil and gas wells and can be used for operational optimal process control.

A known method of controlling the drilling process according to patent SU 1231946, E21B 44/00 dated 11/27/1995, including the use of a drilling process model, which is an exponential trend of the penetration rate, which is obtained as a result of six or more experimental drilling data in the formation interval of the same drillability, followed by their approximation by the least squares method. Further, the coefficients of the drilling model are substituted into the criterion "minimum cost of a meter of penetration", which contains the expression of the dependence of the drilling time t on the axial load on the bit G, its rotation frequency n and the flow rate of the drilling fluid Q in the form of a polynomial of the first degree, and the minimum of the criterion is searched for by the penalty function method . The obtained optimal parameters are set on the drilling rig and further drilling regulation is carried out at the optimal settings G, n and Q. The model is updated every 0.3 meters of penetration. At the same time, the drilling time is calculated before changing the bit, and the boundaries of formations with the same drillability are determined from the confidence interval of the mechanical velocity trend. The model contains parameters representing the geology of the formation surrounding the wellbore. The downhole equipment system contains measuring devices located above the bit on the drill string. The drilling conditions measurements comprise a formation estimation measurement. Automatic tuning allows you to perform automatic optimal control of the well deepening process, which can be used to predict the optimal values of bit performance in heterogeneous formations.

Disadvantages: control is carried out in manual, not automatic mode; the method requires preliminary six or more experiments to obtain an exponential trend of ROP; when changing the breed, new experiments are required; the model in the form of an exponential trend does not have an extremum; the polynomial of the first degree may not provide the required modeling accuracy.

There is a known method for optimal adaptive control of the drilling process (patent 2595027 RU C1, 20.08.2016), in which the drilling process model is adjusted, containing the axial load on the bit G, its rotation frequency n and the flow rate of the drilling fluid Q, representing the interaction of conditions in the bottom hole with drill string bit and drilling fluid, getting multiple downhole measurements of drilling conditions every 0.3 meters during operation in the well, updating the drilling process model based on the results of downhole measurements of drilling conditions and surface equipment operating data received from the surface equipment control system , determining a set of optimal drilling parameters based on the updated model of the drilling process, transmitting data on optimal drilling parameters to the surface equipment control system and repeatedly repeating the operations of obtaining, updating, determining and transmitting during operation in the well.

Disadvantage: the method involves the use of a model containing three control parameters G, n and Q , while the parameters n and Q are not regulated by the control system.

The objective of the invention is to optimize the method of adaptive automatic control of the process of drilling oil and gas wells according to a new mathematical model with one adjustable parameter.

The technical result is an increase in the accuracy of drilling mode control and an increase in the mechanical speed of well drilling due to control optimization according to a new mathematical model with one adjustable parameter.

The technical result is achieved by adaptive control of the drilling process, in which the drilling process model representing the interaction of the rock at the bottom of the well with the drill string bit is constantly updated every 0.3 meters of penetration based on the results of downhole measurements of drilling speed and axial load on bit (i.e. e. the model is adjusted to the rock at the bottomhole), the optimal axial load on bit is determined based on the updated model of the drilling process, the transmission of data on the optimal drilling parameter to the drilling drive, the drilling of the next 0.3 meters of penetration at the optimal load on bit and repeated repetition of operations receiving, updating, determining, transmitting and drilling during the operation of the well, characterized in that the control is carried out according to the mathematical model of the drilling process, built on the basis of the McLaren series for the sine function of the form

where υm - ROP, m/h; k _υ - dimensional coefficient of drillability of the rock, representing the reservoir model; G - axial load on the bit, N; C _G - dimensional constant. The model has a mathematical extremum in the G parameter, which makes it possible to calculate the optimal WOB.

The method involves multiple updating of the model coefficients k _υ and C _G based on the results of downhole measurements, calculation of the optimal weights on bit according to the "maximum mechanical speed" criterion, their transfer to the drilling rig drive and drilling on the calculated parameter.

Management is carried out according to the objective function

where υm - ROP, m/h;

k _υ - dimensional coefficient of rock drillability;

G - axial load on the bit, N;

C _G - dimensional constant.

The method of optimal adaptive drilling control is implemented as follows:

1. At the beginning of drilling, according to the data specified by the project (or from the experience of the driller), according to model (1), the optimal value of G _opt is calculated to achieve the criterion "maximum mechanical speed υm = max".

2. The optimal parameter G _opt is set on the drilling equipment and 0.3 m of penetration is drilled.

3. The value of the mechanical velocity υm obtained during drilling is measured and transmitted via the feedback channel to the control system of the surface equipment of the well.

4. The values of the coefficients k _υ and C _G of the model (1) are recalculated, thereby the model adapts to the rock at the bottomhole.

5. For the model with new coefficients, G _opt is calculated to achieve the maximum of function (1), a new G _opt is installed on the drilling rig, the next 0.3 meters of penetration are drilled with the measurement of the obtained drilling speed, etc.

Thus, by optimizing the control according to a new mathematical model with one adjustable parameter, an increase in the accuracy of controlling the drilling mode and an increase in the mechanical speed of the well drilling are achieved.

Claims (3)

A method for optimal adaptive control of the process of drilling oil and gas wells by regulating the axial load on the bit, in which the rock at the bottom is corrected for the model of the mechanical drilling speed, which represents the interaction of the rock at the bottom of the well with the work of the bit, obtaining results of downhole measurements of the mechanical drilling speed every 0.3 m formation as a result of the work of the bit at the bottomhole, updating the drilling speed model, determining the optimal axial load on bit according to the updated drilling speed model, transferring the value of the optimal axial load on bit to the surface equipment control system, drilling the next 0.3 meters of rock with a new load on bit and repeated repetition of the operations of obtaining, updating, determining, transmitting and drilling during the operation of the well, characterized in that the control is carried out according to the updated model of the drilling process, built on the basis of the McLaren series for the sine function of the form

, where υ _m - ROP, m/h; k _υ - dimensional coefficient of drillability of the rock, representing the reservoir model; G - axial load on the bit, N; C _G is a dimensional constant, while the updated model has a mathematical maximum in the G parameter, which allows calculating the optimal weight on bit according to the “maximum mechanical speed” criterion.