Method for determining formation pressure in oil producer equipped with submerged electric-driven pump

FIELD: oil and gas industry.

SUBSTANCE: invention refers to the oil-extracting industry and can be used on oil deposits for measuring formation pressure for controlling and managing the oil extraction process. The method involves measuring the formation pressure in an oil producer equipped with a submerged electric-driven pump. A calculation process involves using a fluid influx point from the formation to the well via a known uniform-density damping fluid when commissioning the well after the damping procedure by formula.

EFFECT: reducing a surveyed well downtime, increasing the accuracy and reliability of determining the foundation pressure, and facilitating the implementation when commissioning the well after damping.

2 dwg

 

The invention relates to the oil industry and can be used in oil fields for measuring formation pressure to control oil production.

Known "Method of determining reservoir pressure in an oil well", which is to stop the well, removing using depth gauge curve recovery pressure measuring downhole pressure to stop well with the subsequent interpretation of the curve of pressure recovery. (Patent RF №2167289 from 19.01.1999,, IPC E21B 47/06).

The disadvantage of this method is that it is necessary to stop the well, also this method is intended for wellhead and compressor wells.

Known "Method of determining reservoir pressure oil reservoirs", which includes the determination of the carrying supply of oil to the well, which determine the formation pressure. Also determine cumulative production fluid from the well, the accumulated amount of injection of the displacing agent and the accumulated value of his selection from the production well. Reservoir pressure is determined from the calculation formula. (See Patent No. 2107161 from 29.07.1996, IPC E21B 47/06).

The disadvantage of this method is the complexity of the task due to the additional cost of collecting a large amount of information on each well.

From the local "Method hydrodynamic studies in the borehole, equipped installation of electrical submersible pump with adjustable-frequency drive, performed on a mobile vehicle. To control and automatic registration of digital estuarine well parameters used hardware-software complex. (See Patent No. 2370635 from 18.09.2007, IPC E21B 43/00).

The disadvantage of this method is the complexity of the task by attracting additional transportation and material resources.

Reservoir pressure is established in the process of recovery when off well until complete stabilization. This time is from 6 hours to several days, and the oil is not produced.

The need for periodic measurement of pressure in a large number of wells leads to a noticeable loss in oil production. In addition, the required technical operations descent devices into the well reservoir pressure.

Known studies on the measurement of formation pressure in wells equipped with submersible pumps showed that practice the calculation of reservoir pressure gives large errors. This is due to the uncertainty of determining the average specific weight of the mixture of fluids in the well.

The objective of the invention is to reduce downtime wells in the study, improving the accuracy and reliability the determination results of reservoir pressure and simplifying its implementation at the conclusion of the wells in the operation mode after the killing.

The technical result of the invention is achieved by use of the start point of the flow of fluid from the reservoir to the well, with a predetermined, uniform density, fluid damping, when the output well at mode after plugging in the formula:

Ppl=ρW.gl.g(Hpepf.-Hn.ppandtaboutKand),(1)

where ρW.CH.is the density of the kill fluid, kg/m3;

g - free fall acceleration, m/s2;

Hperf.- the depth of the upper holes of the perforation, m;

HN. tributary- the value of the dynamic level in the well when the output mode after plugging corresponding to the transition from the linear plot changes to a curved, which characterizes the beginning of the flow from the reservoir, m

In Fig.1 shows a curve of the output wells on the mode and curve density changes of the fluid in the annular space.

In Fig.2 - determination of the dynamic level graphical method.

In primavista well on mode, when lowered almost to the bottom submersible pump, carries out registration of changes of level in the annular space. Since the beginning of the output dynamic level begins to decrease, initially (before flow from the reservoir), the law changes the dynamic level is straightforward. The transition point from the linear law changes curved to match the flow of fluid from the reservoir. Flow from the reservoir is subject to the condition that the bottomhole pressure is less than or equal to Plast pressure. The density of the fluid in the annulus to a dynamic level corresponding to the beginning of the flow from the reservoir does not change and is equal to the density of the fluid damping. The pressure in the annular space is equal to 0 or close to 0. To determine the formation pressure, the equation (1).

The density of the kill fluid, the depth of the perforations and the acceleration of free fall are known quantities. Therefore, determination of reservoir pressure is reduced to finding the value of the dynamic level in the well when the output mode after plugging corresponding to the transition from the linear plot changes to a curved, which characterizes the beginning of the inflow from the reservoir. To determine the point HN. tributaryyou can approximate method.

Method of determination is to find the points of intersection between two straight, first direct is a straightforward extension of the plot changes the dynamic level and the first two points with a curved change the dynamic level (second line). At the intersection, we get the value of the dynamic level in the well when the output mode after plugging corresponding to the transition from the linear plot changes to a curved, which characterizes the beginning of the inflow from the reservoir. This method can be graphical and analytical. Graphical method of determination shown in Fig.2.

The analytical method involves the preparation of two linear equations and finding their common point (the intersection point). In the first case, the resulting point 1 (H1; t1) and 2 (H2; t2second 3 (H3; t34 (H4; t4). The equation will take the form:

where

H1H2H3H4- dynamic level in points 1, 2, 3, 4, respectively, m,

t1, t2, t3, t4- the time corresponding to the dynamic level H1H2H3H4, h,

H1(t), H2(t) - equation of lines, connecting points 1-2 and 3-4, respectively.

Making mathematical transformations, we obtain the system of equations:

where

H1H2H H4- dynamic level in points 1, 2, 3, 4, respectively, m,

t1, t2, t3, t4- the time corresponding to the dynamic level H1H2H3H4, h,

H1(t), H2(t) - equation of lines, connecting points 1-2 and 3-4, respectively.

To find the total points must equal equation and to find the time. Time tH. ductis:

where

H1H2H3H4- dynamic level in points 1, 2, 3, 4, respectively, m

t1, t2, t3, t4the time corresponding to the dynamic level H1H2H3H4the hour

H1(t), H2(t) - equation of lines, connecting points 1-2 and 3-4, respectively.

The obtained values of t by the formula (5) substituted in any equation of the system (4), we get Hp. tributary. After finding the Hp. tributarycalculation of reservoir pressure on the known density of the fluid damping by the formula (1).

The method of determining reservoir pressure in an oil well equipped with a submersible electric pump, characterized in that the calculation uses the starting point of the fluid flowing from the reservoir to the well, with a predetermined, uniform density, fluid damping, when the output well at mode after plugging in the formula
P PLW.CH.·g·(Hperf.-HN. tributary),
where ρW.CH.is the density of the kill fluid, kg/m3;
g - free fall acceleration, m/s2;
Hperf.- the depth of the upper holes of the perforation, m;
HN. tributary- the value of the dynamic level in the well when the output mode after plugging corresponding to the transition from the linear plot changes to a curved, which characterizes the beginning of the flow from the reservoir, m



 

Same patents:

FIELD: mining.

SUBSTANCE: according to the method, a casing string with temperature sensors attached to its outer surface is lowered to a well and cement is pumped to an annular gap between the casing string and well walls. During a cement filling and hardening process, temperature measurements are made and thermal conductivity of surrounding mine rocks of the well is determined as per the measured relationship between temperature and time.

EFFECT: possibility of simultaneous reception of information on properties of a relatively thick layer of rocks around the well and information on thermal conductivity of rocks for the whole cemented interval of depths.

3 cl, 2 dwg, 1 tbl

FIELD: oil and gas industry.

SUBSTANCE: device includes a mechanical oscillating system with constant magnets fixed on it and a converter of mechanical oscillations to electrical ones. A mechanical oscillating system is made in the form of a cylindrical bimetallic spiral, one end of which is rigidly fixed, and the other one is free, and the converter of mechanical oscillations to electrical ones is made in the form of a system of interacting electromagnetic fields of constant magnets rigidly fixed on a cylindrical bimetallic spiral and coils of a drive and pickup of oscillations providing for transverse oscillations of the cylindrical bimetallic spiral.

EFFECT: enhancing reliability of a device and improving its design.

2 dwg

FIELD: oil and gas industry.

SUBSTANCE: invention is related to the area of wells completion and testing in oil industry and intended for calculation of parameters for the well bottomhole and bottomhole area. The method where in process of string movement in the well pressure is measured by two sensors, at that one sensor is installed over the packer while the second one is installed below the packer. According to results of pressure measurement fluid density is determined and then flowing bottomhole pressure is determined on the basis of fluid density, gravity constant, preset rate of drilling string motion, cross-sectional area of the drilling string, formation pressure, and productivity index of the well.

EFFECT: potential determination of parameters for the well bottomhole and bottomhole area during round-trip operations with further calculation of liquid influx/reflux at the bottomhole and calculation of skin factor, permeability or thickness of the reservoir.

13 cl, 5 dwg

FIELD: oil-and-gas industry.

SUBSTANCE: evaluation of fluid inflow fraction from every productive zone of multi-zone productive well comprises determination of pressure at wellhead. Integrated indicator curve (IPR1) is obtained to describe the relationship between pressure and fluid yield from first productive zone and integrated indicator curve (IPR2) is obtained to describe the relationship between pressure and fluid yield from second productive zone. Value for integrated indicator curve at the point of mixing (IPRm) is obtained with the help of IPR1 and IPR2. Initial fluid inflow fraction from first productive zone at mixing points and initial fluid inflow fraction from second productive zone are defined. First total curve of outflow (TPR1) is obtained describing the relationship between fluid pressure and yield, fluid flowing from mixing point to wellhead. First portion of fluid inflow from first productive zone (Q11) and first portion of fluid inflow from second productive zone (Q21) are defined at mixing point with the help of IPRm and TPR1. Machine-readable carrier accessible for processor comprise program including instructions for above listed jobs.

EFFECT: more efficient evaluation of the portion of influx from productive seam.

20 cl, 5 dwg

FIELD: measurement equipment.

SUBSTANCE: system (100) of sensors for measurement of a technological parameter of a fluid medium in a well location, comprising a resonator (110) of a parameter, which is located in a well (106), having resonance frequency that varies depending on the technological parameter of the fluid medium and which in response generates a resonant acoustic signal on the resonance frequency that indicates the technological parameter. Besides, the system comprises an acoustic sensor (118), arranged in the location near above the surface, spaced from the parameter resonator, a measurement circuit (102), connected with the acoustic sensor, and an acoustic source connected with a pipe in the location near above the surface and spaced from the parameter resonator placed in the well. At the same time the acoustic sensor is made as capable of receiving the resonant acoustic signal, transmitted from the parameter resonator, the measurement circuit is arranged as capable of formation of an output signal of the technological parameter, corresponding to the technological parameter of the fluid medium, in response to the received resonant acoustic signal, and the acoustic source is arranged as capable of transmission of the acoustic signal into the well.

EFFECT: provision of measurement of well fluid medium properties in real-time mode both in process of drilling and in process of well operation.

20 cl, 6 dwg

FIELD: oil and gas industry.

SUBSTANCE: the method is realized in two stages. At the first stage to the lower horizontal producer a flow string is run in to the beginning of a slotted filter. A heat insulated filter is set in the upper horizontal injector above the slotted filter. In the upper horizontal injector temperature tests are made in the interval from the well head up to the packer. Steam is injected to the lower horizontal producer and temperature tests are made simultaneously in the upper horizontal injector. Upon completion of steam injection to the lower well the final temperature test is made in the upper well. At the second stage fresh water is injected to the upper horizontal injector and a heat insulated flow string is run in with a thermal packer and shank. The packer is set before the slotted filter and control temperature test is made in tubular annulus in the interval from the well head up to the packer. Steam is injected to the upper horizontal injector though the heat insulated flow string, through the packer and shank to the beginning of the slotted filter. At that, periodically, upon commencement of injection, temperature tests are made in tubular annulus in the interval from the well head up to the packer. Upon completion of steam injection the final temperature test is performed in the upper horizontal injector. When required, tests in the lower producer and operational procedures for the wells are interchanged.

EFFECT: improving authenticity of the obtained results during identification of intervals with cross flows behind the casing for wells operated in deposits of viscous and superviscous oil.

FIELD: mining.

SUBSTANCE: proposed device comprises housing to accommodate the set of pressure and temperature gages, moisture metre and flow metre, electronics unit connected by logging cable, on one side, with surface control station and. On opposite side, with said gages, coupling unit with cable joint head and centring skid. Instrumentation module is secured at said housing by leverage, said module including inclination metre and extra gages, at least, moisture metre and flow metre connected with electronics unit. This module can reciprocate along the gravity vector between casing pipe and housing. It is located at casing pipe profile lower part by centring skid and coupling unit. It is equipped with housing turn drive and instrumentation module to turn them from gravity vector set by inclination metre via electronic unit.

EFFECT: registration borehole fluid interface boundaries and flow rate of every separate phase in conditionally horizontal wells.

4 cl, 3 dwg

FIELD: oil and gas industry.

SUBSTANCE: bubble-point pressure determination method includes measurement of bottomhole pressure at different oil production rates and registration of bottomhole pressure change curves upon returning the well to production in linear and nonlinear oil influx modes above or below bubble point pressure. At that wellhead pressure change curves and dynamic level changes in annular space are recorded additionally. By measurement results average density is calculated at each moment of time for the mixture column at annular space and the curve of average density changes in time at annular space is plotted. The free gas release is fixed when a gas separator releases it to the annular space. The value of bubble point pressure is determined by comparison of the mixture density change curve with pressure changes at pump suction at a certain period of time.

EFFECT: improvement of accuracy measurement of bubble point pressure.

1 tbl, 1 ex, 3 dwg

FIELD: oil and gas industry.

SUBSTANCE: invention is related to a method of well production optimisation. Intervals are selected in a deviated offshoot and drill-stem testing and borehole treatment is deployed. Then each interval is isolated in order to perform the required testing. The obtained testing data are evaluated in order to define respective recovery measures, which are implemented later by means of the drill-stem testing and borehole treatment.

EFFECT: provision of testing and treatment for the plenty of intervals in a horizontal hole during one running to the borehole.

11 cl, 6 dwg

FIELD: oil and gas industry.

SUBSTANCE: method lies in measurement of the maximum dynamic head depth for the known well-killing fluid with homogeneous density when bringing the well on to stable production after killing according to the following formula Pbthpkf.·g·(Hperf-HDHmax), where ρkf - density of the well-killing fluid, kg/m3; g - acceleration of free fall, m/s2; Hperf - height of the upper perforated openings, m; HDHmax - maximum dynamic head depth in the well when bringing the well on to stable production after killing, m.

EFFECT: reducing downtime during well surveys, improving accuracy and reliability while determining the bottomhole pressure and simplifying of the bottomhole pressure measurement when bringing the well on to stable production after killing.

3 dwg

FIELD: well boring, particularly for measuring pressure in well during drilling thereof.

SUBSTANCE: device has body with central flushing orifice and grooves. Arranged in the grooves are electrical circuits and positive pressure transducers isolated by pressure-resistant shell. The first pressure transducer is connected with central flushing orifice in tube, another one - with annular tube space. The device is provided with power source and two differential amplifiers with outputs connected to summing unit inputs. Supply diagonal units are linked correspondingly with power source inputs. The first units of measuring diagonals of the first and the second pressure transducers are connected correspondingly with inverting and non-inverting inputs of the first differential amplifier. The second units of measuring diagonals of the first and the second pressure transducers are linked correspondingly to inverting and non-inverting inputs of the second differential amplifier. The first and the second pressure transducers may be arranged in the body at 0°-45° and 153°-180° angles to vertical device axis correspondingly or may be inversely arranged. The body may be formed of titanic alloy.

EFFECT: increased measuring reliability.

4 cl, 2 dwg

FIELD: survey of boreholes or wells, particularly in borehole geophysical instrument requiring additional thermal stabilization.

SUBSTANCE: mounting with members to be thermostated is arranged inside heat absorbing device. Heat absorbing device is made as a set of heat absorbers, each of which is made as hollow heat-conductive cylinder filled with heat absorbing material. Heat insulator is formed as cylindrical heat-protective shell with outer and inner ring-shaped ribs and adapted for receiving heat absorbers. Heat-conductive mounting have heat absorbing plugs connected to ends thereof. Each heat-absorbing plug is made as hollow heat-conductive cylinder filled with heat absorbing material. Surfaces of heat-protective case, heat-protective cylindrical shell, heat absorbers and heat absorbing plugs facing thermostating members are covered with heat absorbing coating. Surfaces thereof facing borehole are covered with heat-reflecting coating.

EFFECT: increased duration of working thermostating cycle and simplified structure of thermostat.

6 cl, 2 dwg

FIELD: survey of boreholes or wells, particularly for tracing pressure distribution along well bore and for diagnosing various situations in well bore.

SUBSTANCE: method involves temporarily blocking part or full fluid flow by quick-acting valve gate along with continuously recording pressure in point spaced a small distance from the valve gate in upstream direction; determining friction losses with the use of Darcy-Weisbach equation; plotting diagram depicting pressure as a function of distance on the base of above time diagram and on the base of acoustic speed in real fluid with the use of the following relation: ΔL=0.5aΔt, which correlates time Δt with distance ΔL. To estimate acoustic speed in fluid one may use correlations which determine relation between hydraulic impact value, fluid pressure, fluid velocity and acoustic speed in the fluid and which are known from Joukowski formula. Acoustic speed also may be estimated on the base of time determination between pressure change peaks depicted on time diagram and caused by equipment, flow sectional area and other parts located along well bore, discharge line and pipeline in predetermined points. Acoustic speed may be determined on the base of changes in time diagrams in at least two different points along pipeline and by comparison of above time diagrams. Combined well temperature and pressure diagram may also be obtained, wherein above temperature distribution along well bore depth is measured with the use of optical fiber. Above method may be used to determine and localize influx points in well bore, discharge line and pipeline or to determine and localize losses from well. Method may also be used to determine and localize collapse of discharge lines or presence of deposits, namely hydrates, solid hydrocarbons, pyrobitumen or sand. Above method may be used to determine effective diameters of well bore, discharge line or pipeline in different sections thereof, or to determine which gas lift valves are in working state and to localize and determine working characteristic values of pipeline equipment utilized for oil and/or gas production.

EFFECT: increased efficiency of well survey.

12 cl, 11 dwg, 2 ex

FIELD: survey of boreholes or wells, particularly devices for differential pressure measurement equipment during balanced or unbalanced well boring.

SUBSTANCE: method involves determining excessive pressure inside drilling string and in annular space is static mode with the use of excessive pressure sensors, wherein the sensors communicate with flushing orifice and hole annuity through pressure supply channels; taking greater or lesser excessive pressure as actual pressure; determining difference between greater and lesser pressure values and estimating above difference in dynamic regime in pressure supply channel having lesser static pressure if greater excessive pressure is chosen as the actual pressure value or in pressure supply channel having greater static pressure value if lesser excessive pressure is chosen as the actual pressure.

EFFECT: increased sensitivity of differential pressure sensor and measurement reliability.

1 dwg

FIELD: oil and gas industry, particularly to stimulate oil production.

SUBSTANCE: oil production is performed along with controlling of oil production parameters and speed of submersible pump electromotor rotation to maintain optimal values of oil production process parameters. Liquid level in well is chosen as the main oil production process parameter. Volume of liquid to be produced is chosen as parameter to be optimized. Control operation is carried out in several stages in automatic mode. At the first stage initial liquid level in well corresponding to calculated level, which provides maximal liquid inflow into well, is specified in pump motor control unit and pump operational mode is selected so that volume of liquid extracted from well is equal to volume of liquid flowing into well for the predetermined time period. Then liquid level corresponding to above situation is recorded and stored in memory. At the second stage predetermined initial liquid level in well is determined and then influx flow and extracted flow are equalized by pump mode of operation. Obtained value of extracted flow is compared with that at previous stage. If above value exceeds that obtained at previous stage predetermined liquid level is also increased and influx flow and extracted flow are equalized by pump mode of operation to increase predetermined liquid level in well in several stages up to corresponding extracted flow volume reduction. After that one backward step is executed, predetermined extracted liquid level corresponding to above step is taken as optimal level and above level is maintained during well operation. If extracted liquid volume decreases at the second stage predetermined liquid level change direction is performed in reverse order and then all above operations are repeated beginning from the second stage. Device for above method realization comprises electromotor to activate pumping jack, which is connected with submersible pump, extractable liquid volume sensors, well liquid pressure sensors connected to electromotor control unit. The control unit comprises serially connected memory means, frequency regulator and voltage changer. Control device is also provided with acoustic depth finding sensor, which determines liquid level in well and is installed at well head. The acoustic depth finding sensor is connected to one frequency regulator input. Extracted liquid volume sensor is connected to one input of memory means having the second input connected to command operator's console. Well liquid pressure sensor is connected to the second input of frequency regulator having output connected to electromotor through voltage changer.

EFFECT: increased oil output.

1 dwg

FIELD: mining, particularly oil and gas well testing.

SUBSTANCE: method involves lowering sample taking device suspended to wire or logging cable to take two or more deep fluid, gas or fluid and gas mixture samples in air-tight manner simultaneously, wherein the sample taking device comprises at least two sample taking chambers; communicating well space with sample taking chamber interiors by closing or opening the chambers with the use of hydraulic drive, which is actuated since sample taking sample taking device was lowered in well, wherein lowering, lifting operations, as well as operation for sample taking device retaining at sampling point are carried out along with measurement of pressure, temperature and sample taking device location depth. The sample taking chambers are opened or closed synchronously or alternatively. Hydraulic drive is operated by electromagnetic valve under control of electronic programmable controller, which controls valve opening and closing in accordance with preset time period or well pressure value. In the case of cable communication line usage the valve is controlled by control signal given from land-based unit. Sample taking device comprises electronic module, hydraulic drive assembly, one or several sample taking chambers, temperature and pressure sensors and programmable controller, which operates electromagnetic valve of hydraulic drive assembly, magnetic collar locator, natural radioactivity recording unit. All information fixed by sensors is digitized and stored in nonvolatile memory means. Sample taking device also has sensor system, which detects sample taking chamber valves opening and closing independently for each sample taking chamber. All measured parameters are digitized and stored in electronic module memory or is supplied to land surface in the case of cable communication line usage.

EFFECT: possibility to take sealed samples simultaneously in one well point or in several points located at different depths, possibility to perform continuous depth, temperature and pressure measurements inside the well in sampling point and along well bore, provision of independent control of each sample taking chamber.

9 cl, 3 dwg

FIELD: oil production well operation survey, particularly to control productive formation pressure along with information transmission via wireless communication channel.

SUBSTANCE: method involves lowering subsurface pressure gage connected to flow string and to well sucker-rod, wherein the subsurface pressure gage comprises pressure sensor and information transmission device, which transmits information via wireless communication channel; measuring pressure and transmitting information to day surface via wireless electromagnetic communication channel with the use of decompressor having variable base, wherein base length is defined by distance from productive formation roof to end of well sucker-rod filter and magnitude of temperature flow string length change adjusted for geometrical factor equal to 1 - 1.01. Device for above method realization comprises subsurface pressure gage provided with electromagnetic wave transmitter, which transmits electromagnetic waves generated by electric signal sent by decompressor electrically linked to well sucker-rod. The decompressor has variable base and is terminated in electrode located in lower variable base part. The electrode is electrically connected to casing pipe through centrator. Pressure sensor is arranged in electrode body and connected to electronic circuit. Device may be provided with additional pressure sensors connected with each other and forming pressure sensor string. Number of pressure sensors in the array is equal to number of production strings. Pressure sensors may be located opposite to corresponding productive formation center. Pressure sensors may be connected with each other through electric insulators adapted to receive multiple-strand electric cable passing inside the insulators. The pressure sensors may have electrodes electrically linked to casing pipe through centrator.

EFFECT: reduced time of pressure measurement and data transmission.

7 cl, 1 dwg

FIELD: testing the nature of borehole walls and formation testing particularly for obtaining fluid samples or testing fluids, in boreholes or wells.

SUBSTANCE: device comprises tubular body to be secured inside drilling string arranged in well bore. The tubular body is provided with one or several extensions created along body axis and forming expanded axial part. Probe is arranged in expanded axial body part zone having minimal cross-section. The probe may be moved between extended and retracted positions. In extended position probe may touch well wall to gather information from formation. To protect probe during drilling operation probe in brought into retracted position. Drive adapted to move the probe between extended and retracted positions is installed on the body.

EFFECT: increased accuracy of well and formation testing.

38 cl, 29 dwg

FIELD: survey of boreholes or wells, particularly measuring temperature or pressure in running wells.

SUBSTANCE: device comprises land-based assembly and submersed assembly including pressure transducer made as pressure unit linked to measuring resistor with output connected to land-based assembly inlet through diode and communication line. Land-based assembly includes power source, computing unit, digital indicator, the first analog-digital power source voltage converter, and the second analog-digital power source voltage converter. Land-based assembly input is linked to input of the first analog-digital converter having output linked to the first input of the computing unit. Land-based assembly input is also connected with the first output of power source having the second output linked with ground through resistor and with input of the second analog-digital converter. Output of the second analog-digital converter is connected to the second input of computing unit. The first output of computing unit is connected to digital indicator. The second output thereof is linked to power source input.

EFFECT: increased operational reliability.

1 dwg

FIELD: well survey, particularly geothermal well survey.

SUBSTANCE: temperature probe assembly comprises temperature sensors installed in upper or lower assembly part and uniformly distributed around a circle having radius r>R3/2, where R3 is probe assembly radius. Circle center coincides with probe assembly axis. Assembly also has safety lamp made as a pipe with orifices. Summary orifice area is not less than pipe cross-sectional area. The probe assembly may be provided with two centralizers arranged in upper and lower parts thereof. In some variants temperature sensor is arranged along assembly axis in upper or lower part thereof, probe assembly has safety lamp made as a pipe with orifices, wherein summary orifice area is not less than pipe cross-sectional area, and pressing device. The pressing device includes two springs arranged in upper and lower probe assembly parts. Temperature sensor is 1-2 mm under or over safety lamp end plane correspondingly. In other variants safety lamp has beveled end and is pressed to pipe string by short generator thereof. Probe assembly variants including temperature sensors and two centrators in upper and lower parts are also disclosed. The temperature sensors are arranged on each spring of upper centrator in upper part thereof or each spring of lower centrator in lower part thereof is provided with one temperature sensor spaced a distance from pipe string or production string axes. The distance is determined from equation. In just other variants probe assembly has centrators arranged in upper and lower parts thereof and temperature sensors carried by substrate formed of resilient material and arranged in lower probe assembly part between springs of lower centrator or in upper probe assembly part between upper centrator springs. Each spring is provided with limiting strip to restrict substrate and temperature sensor displacement with respect to probe assembly axis. Temperature sensors are located in upper or lower probe assembly parts in dependence of downhole instrument movement direction during well survey performance.

EFFECT: increased accuracy of continuous temperature measurement along generator defined by temperature sensor movement due to elimination of liquid mixing in front of temperature sensor.

12 cl, 7 dwg

Up!