CN102094631A

Movatterモバイル変換

Info

Publication number: CN102094631A
Application number: CN2011100367407A
Authority: CN
Inventors: 冯建宇; 张耀辉
Original assignee: BEIJING LIUHE GREATNESS TECHNOLOGY CO LTD
Current assignee: BEIJING LIUHE GREATNESS TECHNOLOGY CO LTD
Priority date: 2011-02-12
Filing date: 2011-02-12
Publication date: 2011-06-15

Abstract

The invention discloses a method for positioning an underground sleeve by measuring the gradient of a geomagnetic field. The direction and distance of the sleeve are accurately positioned by measuring the gradient of the geomagnetic field around a ferromagnetic drilling sleeve. A three-axis magnetic field meter of a magnetic field measuring instrument can measure the vectors of the geomagnetic field, which comprise magnetic field intensity and direction; and the measuring accuracy of the magnetic field intensity is not less than 1uT. The measuring instrument acquires underground attitude data, is taken out and is connected with ground software; the software constructs a nonlinear equation set of geomagnetic field gradient change through the acquired magnetic field intensity of n known points; and a position at which the sleeve is lost can be calculated by an optimization algorithm. By the method, the lost sleeve can be accurately positioned, so that a broken well on a shallow layer can be repaired; and the method is simple, is easy to operate, and has considerable economic benefit.

Description

A kind of by measuring the method for gradient location, earth's magnetic field down-hole casing

Technical field

The present invention relates to drilling engineering deviational survey fields such as oil, directed tunnel and geological prospecting, relate in particular to a kind of method that in workover treatment, is used for determining the sleeve pipe lost owing to crustal movement.

Background technology

Daqing oil field gets out first mouthful of oil well from nineteen fifty-nine in high estrade oil field to begin, and is the oil district of China's maximum till now always, has produced crude oil since 1976 per year always more than 5,000 ten thousand tons.These years the exploitation of underground oil is made the disorder of grand celebration subsurface pressure, crustal movement is active.Daqing oil field has thousands of mouthfuls of oil well casings to be extruded distortion even fracture, makes and can't continue recover petroleum.Some fracture location can be proceeded exploitation near the well on the face of land by repairing, and saves a large amount of manpower and materials than new well-digging, is very necessary so find the sleeve pipe reparation of losing.Do not have effective method that the sleeve pipe of losing is positioned in the industry at present, make that the oil well of fracture can't effectively be handled.It is that magnetic field is not directly perceived that the problem that sleeve pipe mainly exists is lost in the down-hole, location, and how the earth's magnetic field around the sleeve pipe specifically changes can't quantitative description, experimental results show that Changing Pattern difference in different directions, also is non-linear even change on the same direction.The earth's magnetic field of different regions is variant, even areal changes in time, the earth's magnetic field all can change.In addition, because hardware reason, different sensors records data and may there are differences in identical magnetic field.

Summary of the invention

In order to solve the problem that can't position the sleeve pipe of losing in the existing drilling well industry, the invention provides a kind of method of losing sleeve pipe that is used to locate, can accurately navigate to the sleeve pipe of fracture by this method, save cost.

The present invention solves the scheme that its technical problem adopts: by measuring ferromagnetism well casing field gradients peripherally, the accurately direction and the distance at locating sleeve place.The three-axle magnetic field meter of magnetic-field measurement instrument is the vector that can measure the earth's magnetic field, comprises magnetic field intensity and direction, and the magnetic field intensity accuracy of measurement is not less than 1uT.By attitude data under the measuring apparatus production wells, take out instrument and be connected with software on ground, software passes through the magnetic field intensity at n the known point place of being gathered, and is configured to the Nonlinear System of Equations of an earth's magnetic field change of gradient.Can calculate the position (X that loses sleeve pipe through optimization algorithm₀, Y₀, Z₀) and attitude (β is the angle on dipole moment and the z axle positive direction for Φ, β) parameter; Φ is the projection of dipole moment on XOY plane and the angle of X-axis positive direction.Main performing step:

(1) instrument of magnetic-field measurement is put into the down-hole, treat to gather magnetic field data behind the instrument stabilizer;

(2) instrument is taken out from the down-hole, be connected with ground processing software and read magnetic field data group A;

(3) actual measurement magnetic field strength date group A, shell material property calculation go out direction and the distance of sleeve pipe with respect to survey mark near the geomagnetic field intensity of ground processing software by known local position, the sleeve pipe.

The invention has the beneficial effects as follows and can accurately locate the sleeve pipe of losing, the disconnected well of reparation shallow-layer is become a reality, and method is simple, and is easy to operate, and economic benefit is considerable.

Description of drawings

The present invention is further described below in conjunction with drawings and Examples.

Fig. 1 is the flow chart of localization method of the present invention.

Fig. 2 is the magnetic-field measurement instrument structure chart that the present invention uses.

Among Fig. 2,1. upper binding head, 2. damper, 3. three-axle magnetic field meter, 4. orientation lever.

The specific embodiment

Fig. 1 is the flow chart of localization method of the present invention, and ground processing software at first realizes the preliminary treatment to initial data, and the constitution optimization object function, uses optimization algorithm to solve optimal solution then.Concrete implementation step is as follows:

1. image data preliminary treatment:

The image data preliminary treatment comprises: interference, the sensor orthogonality that suppresses the earth's magnetic field proofreaied and correct, regional initial alignment.

(1) suppressing the earth's magnetic field disturbs

By magnetic mark Positioning Principle as can be known, calculate position and the attitude parameter of losing sleeve pipe, just must measure the magnetic field intensity in magnetic field that sleeve pipe produces, and in the environment of no magnetic screen actual measurement to the magnetic field that produces except the target permanent magnet also comprise environmental magnetic field, environmental magnetic field is made up of earth's magnetic field and other electromagnetic interference, and wherein the earth's magnetic field is a Main Ingredients and Appearance.Therefore need to eliminate earlier the interference in earth's magnetic field in location Calculation, the magnetic induction intensity that the sleeve pipe that will lose from measured value produces is separated.

Because static collection value has comprised the information of environmental magnetic field, under approximate situation, the dynamic acquisition value has also comprised the information of environmental magnetic field except the space magnetic field information that comprises the sleeve pipe of losing, therefore the difference of the two has suppressed the interference in earth's magnetic field basically, subtract each other by the average of several groups of dynamic acquisition values and the average of static collection value in this software, its difference is to have removed the Magnetic Field collection value of losing sleeve pipe that disturb in the earth's magnetic field.

(2) revise sensor orthogonality error

Because the three-axis sensor module is a home built, can not guarantee the desirable quadrature of 3 axial magnetic sensors in the manufacturing process, therefore need carry out the quadrature correction to each sensor assembly.If global space rectangular coordinate system o-xyz, the sensor of three directions of a number axial magnetic sensor module be oriented to ox ', oy ', oz '.

If ox ', oy ', the angle of oz ' and oz axle is respectively θ x, θ y, θ z, its in the plane projection and the angle of ox axle be respectively φ x, φ y, φ z.The measured value of 3 axle sensor modules then

,,

3 component B with magnetic field intensity under the global coordinate system_x, B_y, B_zFollowing relation is arranged:

Ground processing software is revised sensor orthogonality error correction by above-mentioned formula.

(3) zone location

Because what localization method adopted is the nonlinear optimization algorithm, if the initial value of substitution algorithm is more near result of calculation, the spent time of location algorithm will be reduced, improve the efficient of location algorithm, therefore carry out simple zone location by the collection value after handled early stage, can obtain one and approach pinpoint zone position information.Down-hole magnetic field gradient array is used the place, 9 summits of nine palace lattice | B|'s and as discriminant function, just can determine that losing the projection of sleeve pipe on magnetic field gradient plane, down-hole is to drop on | B| with maximum one nine palace lattice in.

2. realize based on the software of non-linear least square localization method.

The nonlinear least square method formula:

This method is that the quadratic sum minimum with error is a kind of method for parameter estimation that criterion is estimated the nonlinear Static model parameter.If the model of nonlinear system is

, y is system's output in the formula, x is input,

θ is a parameter, the non-linear nonlinear model that is meant parameter θ here.The form f of model is known when estimated parameter, obtains data (x through N experiment₁, y₁), (x₂, y₂) ..., (x_n, y_n).The criterion of estimated parameter (or being called object function) is elected the error sum of squares of model as.Nonlinear least square method is exactly to ask the estimates of parameters that Q is reached capacity to become.Because f's is non-linear, need to adopt complicated optimization algorithm to find the solution, adopt searching algorithm, select the several parameters value by certain rule, the object function that calculates them respectively reaches minimum parameter value.So proceed, till can not selecting better parameter.

Because what localization method adopted is the nonlinear optimization algorithm, this algorithm is design alteration with each parameter to be estimated, with the error function relevant with design variable as object function, in the design formulas of error function in the location algorithm shown in 4.3.F in the formula_Ix, F_Iy, F_IzRepresent the x axle of i sensor, y axle, the error function value that the z axle calculates.x_Ix, y_Ix,z_IxRepresent 3 coordinates of the x axle sensor of i sensor assembly, x_Iy, y_Iy,z_IyRepresent 3 coordinates of the y axle sensor of i sensor assembly, by that analogy.What wherein coordinate figure needed the reference sensor origin of coordinates is provided with the table and the deviant of sensor coordinates initial point, its numerical value be three of each sensor assemblies initial point and each sensor with respect to the vector of this side-play amount with.

Wherein

Be respectively respective shaft to sensor to the distance of losing sleeve pipe.

In Fig. 2, the magnetic-field measurement instrument structure chart that the present invention uses adopts screwed connection to form by upper binding head (1), damper (2), three-axle magnetic field meter (3), orientation lever (4), and wherein the high corner of orientation lever (5) is consistent with three-axle magnetic field meter (3) tool face azimuth.Damper (2) provides protection for three-axle magnetic field meter (3), avoids it to be subjected to vibration and causes damaging.Orientation lever (5) is used for determining the tool-face zero angle of instrument of the present invention.

More than the embodiment of the inventive method and system is described in detail, and set forth concrete operation method, whole flow chart as shown in Figure 2.Owing to there are differences in different earth's magnetic fields, region,, even all there are differences on the same day in evening in the morning even in same local Various Seasonal.Directly to check in the reference table workload in orientation by downhole data huge so make, and be difficult to realize.Through a large amount of experiment this method is the most practical, the method that is easy to realize.The method is suitable for the location of shallow faults sleeve pipe in addition, if fracture place is too dark, the magnetic field of fracture place and the magnetic field on ground differ greatly, and is difficult to realize the scene reproduction.For one of ordinary skill in the art, according to the thought of the inventive method, the part that all can change in specific embodiments and applications, in sum, this description should not be construed as the restriction that invention is used to this method.

Claims

1. one kind is passed through to measure the method that the earth's magnetic field gradient is located down-hole casing, it is characterized in that: by measuring ferromagnetism well casing field gradients peripherally, the direction and the distance at accurate locating sleeve place, mainly performing step:

2. described a kind of by measuring the method that sleeve pipe is lost in down-hole, gradient location, earth's magnetic field according to claim 1, it is characterized in that: the three-axle magnetic field meter of magnetic-field measurement instrument can be measured the vector in earth's magnetic field, comprise magnetic field intensity and direction, the magnetic field intensity accuracy of measurement is not less than 1uT.