Method for integral status assessment of bottomhole formation zone

FIELD: oil and gas industry.

SUBSTANCE: method for integral status assessment of bottomhole formation zone includes operation of the well in steady conditions before hydrodynamic research, hydrodynamic research by repressuring method, determination of bottomhole pressure and continued fluid influx to the well from formation after its shutdown and processing of measurement results. At that during processing of measurement results current formation pressure is determined by multiplication method, approximation of the measurement results is made including division of actual pressure buildup curve (APBC) into separate sections at coefficient of determination less than 0.99. Then selection of approximate equations is made for the selected sections and division of the whole research period into intervals with uniform time increments. Values of bottomhole pressure are calculated for the specified intervals. The approximated APBC is processed by determined pressure moments with determination of formation pressure and nondimensional diagnostic property. The obtained formation pressure is compared with the pressure obtained by multiplication method. When the values differ per more than 0.3 MPa, approximation procedure shall be made with use of other approximate equations. Then against results of formation pressure determination by multiplication method the degree of bottomhole pressure buildup is assessed and well production index is determined for the conditions. In order to specify position of the processed section the log-log plot is plotted. The actual and approximated APBC is processed by tangent method with determination of parameters for the remote formation section. The results of actual and approximated APBC processing by tangent method are compared. When permeability coefficients for the remote formation section are different as related to actual and approximated curves, then approximation procedure is performed with use of other approximate equations. Then skin factor is determined for APBC with almost full pressure buildup, at least equal to 99%, and for APBC without pressure buildup. Status of the bottomhole formation zone is assessed against values of diagnostic property and skin factor. When APBC cannot be processed by tangent method, processing is made by differential or integral methods considering influx after the operations, with preliminary made procedure of approximate buildup curves for equidistant time values. Parameters are determined for the remote formation zone using several methods considering influx after the operations, in case of their status deterioration dimensions and properties of the remote formation zone are determined using permeability values determiner at earlier stage for the remote formation zone. Status of the bottomhole and remote formation zones is assessed against values of diagnostic property, permeability, hydraulic conductivity, piezoconductivity and dimensions of the bottomhole formation zone.

EFFECT: improving determination accuracy for indices characterising status of the bottomhole formation zone.

11 dwg

 

The invention relates to the oil industry and can find application in the development of the productive formation and the determination of the parameters of the productive reservoir.

A known method for determining filtration parameters of bottom-hole formation zone and the detection of defects in the construction of the well, including commercial seismic exploration. Namely perform hydrodynamic perturbation pressure in the studied layer by periodic or non-periodic time changes of flow rate, record the time dependence of the flow rate and pressure. The pressure and flow rate measured at the wellhead, pressure is simultaneously tubing (tubing) and in the annular space. Receive frequency dependence relationship of the amplitude of pressure to flow rate and phase shift between them. They calculate the ratio between the amplitudes and the phase shift component of the frequency spectrum (harmonics) of pressure to the flow rate, refer to the bottom of the borehole, i.e. the complex impedance of the bottomhole zone. The formulas obtained from the view of structural volumes well the equivalent electrical circuit that includes two successive coaxial line and focused capacity at the point of their connection to the respective measurement points of pressure to calculate flow parameters of PLA is used for non-periodic view of the impact of the frequency dependence of the impedance of the receive time dependence of the pressure or flow rate, refer to the bottom of the borehole. Significant difference of the values of the complex impedance of the bottomhole zone, calculated according to the pressure, make a conclusion about the presence of hydrodynamic disturbances of the structural integrity of the borehole at points remote from the bottom (see RF patent №2445455 from 20.03.2012).

The disadvantage of this method is the lack of reliability assessment bottom-hole formation zone due to the fact that a known manner determined filter parameters. In addition, the method is time consuming due to long-term measurements of change of flow rate with time.

The closest way to the same destination to the claimed invention on the totality of symptoms is the way the study wells, including well operation at steady state before conducting hydrodynamic studies, hydrodynamic studies of well method of recovery pressure, determination of downhole pressure and continuing the flow of fluid from the reservoir into the well after it is stopped, the processing of measurement results. When fixing the curve of pressure recovery (ARC) for the first 10 min measurements produce every 30 s during the first hour - every 1 min during the first five hours every 10 min during the first three days every 1 h during the second day - every h, during the third day - every 10 hours and then every 24 hours the Pressure is measured with an accuracy of 0.01 MPa. Record at least two ARCS through the time interval of operation of the wells, sufficient for the manifestation of changes in the properties of PZ. Rebuild the ARCS in the curves of pressure drop in logarithmic coordinates is the logarithm of the pressure as a function of logarithm of time. Find the point of overlapping curves. Recalculate the coordinates of the output points and determine the depth of contamination PZ. Perform cleaning PZ layer. Again fix the ARCS with the above measurements and accuracy. Rebuild the ARCS in the curve of pressure drop in the above logarithmic coordinates. Compare the curve with the latest curve to events processing PZ. Find the point of overlapping curves. Recalculate the coordinates of the output points and determine the depth cleaning (see RF patent №2407887 from 27.12.2010). This method is adopted for the prototype.

The characteristics of the prototype, coinciding with the essential features of the proposed method - operate well at steady state before conducting hydrodynamic studies; hydrodynamic study well the recovery method of pressure; determining downhole pressure and continuing the flow of fluid from the reservoir into the well after it is stopped, the processing of the results is of ameres.

The disadvantages of this method adopted for the prototype is the low accuracy of determination of the size of the area with improved properties due to the use of the graphical method; lack of reliability assessment bottom-hole formation zone due to the fact that a known manner to determine the value of the size of the area only with improved properties. In the known method, there are high demands for the removal of ARCS, it is more time-consuming. In addition, requires the measurement of several ARCS, which involves considerable material and labor costs.

The problem to which the invention is directed is to increase the reliability assessment of bottomhole formation zone, the simplification method.

The technical result that can be obtained by carrying out the proposed method is more accurate determination of the parameters characterizing the state of the bottom-hole formation zone.

The task was solved due to the fact that in the known method, including exploitation of the well at steady state before conducting hydrodynamic studies, hydrodynamic studies of well method of recovery pressure, determination of downhole pressure and continuing the flow of fluid from the reservoir into the well after it is stopped, the processing of measurement results according to the ACLs to the invention, when processing the results of measurements determine the current reservoir pressure method works, conduct approximation of these results, including when the coefficient of determination less than 0,99 division actual curve recovery pressure on some areas, the selection of the approximating equations for selected areas, divide the entire period of study at intervals with a constant time step of the calculation for these values of downhole pressure, process approximated by a curve of the pressure recovery method deterministic moments of pressure with the determination of reservoir pressure and dimensionless diagnostic sign, compare pressure with pressure, a certain method works, if they differ by more than 0.3 MPa perform the approximation procedure using other approximating equations then determine the formation pressure method works assess the degree of recovery of downhole pressure obtained in the study wells and determine the productivity of wells by mode, to clarify provisions of cultivated land to build bilogarithmic schedule, handle the actual and approximated curves of the recovery pressure is Ecodom tangent defining the parameters of the remote zone, compare the results of processing the actual and approximated curves restore pressure tangent method, the differences in the coefficients of permeability remote zone actual and approximated curves more than 10% when k>0.1 µm2; more than 15% at 0.1>k>0.01 µm2; more than 20% when k<0.01 µm2perform the approximation procedure using other approximating equations then determine the skin factor for the curve of the pressure recovery with almost complete at least 99% pressure recovery and nedoustanovlennoy recovery curves pressure, if selected during the process of land by a linear dependence with a determination coefficient not lower than 0,96, in other cases, the value of the skin factor S is estimated by the correlation between diagnostic sign of d and S, to assess the condition of bottom-hole formation zone by the values of the diagnostic indicator and the skin factor for recovery curves pressure, the processing of which by the tangent method cannot be performed, proceed to process the differential or integral methods taking into account polarity, after performing the approximation procedure recovery curves annular buffer and pressures for equidistant time values, define the settings for the remote zone of the reservoir in which ispolzovanie several methods taking into account polarity, in the case of the deterioration in the condition of the bottom-hole formation zone determines the size and properties of the bottom-hole formation zone, using the previously defined values of permeability remote zone, assess the condition of the wellbore and remote areas of the reservoir by the values of the diagnostic sign permeability, hydroconductivity, piezoconductivity and sizes of bottom-hole formation zone.

The characteristics of the proposed technical solution, distinctive features of the prototype - processing of results of measurements determine the current reservoir pressure method works; make the approximation of these results, including when the coefficient of determination less than 0,99 division actual curve recovery pressure on some areas, the selection of the approximating equations for selected areas, divide the entire period of study at intervals with a constant time step of the calculation for these values of downhole pressure; handle approximated curve of the pressure recovery method deterministic moments of pressure with the determination of reservoir pressure and dimensionless diagnostic characteristic; comparing the received pressure with pressure, a certain method works, if if they differ by more than 0.3 MPa, perform the approximation procedure with IP is the use of other approximating equations; the results determine the formation pressure method works assess the degree of recovery of downhole pressure obtained in the study wells and determine the productivity of wells by mode; to clarify the provisions of the treated area build bilogarithmic schedule; perform the processing of the actual and approximated curves pressure restoration by the method of the tangent with the definition of parameters in the remote zone of the formation; compare the processing results of the actual and approximated curves restore pressure tangent method, the differences in the coefficients of permeability remote zone actual and approximated curves more than 10% when k>0.1 µm2; more than 15% at 0.1>k>0.01 µm2; more than 20% when k<0.01 µm2perform the approximation procedure using other approximating equations; determine the skin factor for the curve of the pressure recovery with almost complete at least 99% pressure recovery and nedoustanovlennoy recovery curves pressure, if selected during the process of land by a linear dependence with a determination coefficient not lower than 0,96, in other cases, the value of the skin factor S is estimated by the correlation between diagnostic sign of d and S; evaluate what bisabolol the reservoir area by the values of the diagnostic indicator and the skin factor; for recovery curves pressure, the processing of which by the tangent method cannot be performed, proceed to process the differential or integral methods is based on polarity, after performing the approximation procedure recovery curves annular buffer and pressures for equidistant time values; determine the parameters of the remote zone using several methods taking into account polarity; in the case of the deterioration in the condition of the bottom-hole formation zone determines the size and properties of the bottom-hole formation zone, using the previously defined values of permeability remote zone; assess the condition of the wellbore and remote areas of the reservoir by the values of the diagnostic sign permeability, hydroconductivity, piezoconductivity and sizes of bottom-hole formation zone.

Distinctive features in conjunction with the known can increase the accuracy of determining the parameters characterizing the state of the bottom-hole formation zone, and to simplify the evaluation method. Improving the accuracy of definition of indicators will provide high reliability assessment of the bottomhole zone of the formation.

The definition of indicators characterizing the state of the bottom-hole formation zone, is carried out in various ways, depending on the quality of the ARC.

There are several basic methodology the assessment of bottomhole formation zone (PPP). It is established that each of the methods is characterized by certain features and conditions effective use, failure of which may lead to erroneous results.

A common way of assessing the status of the PPP based on the definition of the skin factor when processing recovery curves pressure (ARC) tangent method, you can apply for the ARC, almost complete (99%) recovery of downhole pressure to the reservoir size and unambiguous allocation of straight-line plot. In case of incomplete recovery of the pressure value of the skin factor can be determined with reasonable accuracy, if the ARCS in semi-logarithmic coordinates is allocated the final section, approximated by a linear dependence with the value of the determination coefficient not lower than 0,96.

Method deterministic moments is applicable for processing the ARCS, including equidistant nonlinear increasing values of hydrostatic pressure. If this condition requires the procedure of approximation of the original data. The approximation is reasonable to spend on a separate (local) specific locations on the ARC, the final plots use a logarithmic dependence. Successfully processed ARCS deterministic method of moments allows to obtain not only the quality, but quantitative characteristic of the bottomhole zone, which is an advantage of the method.

To handle some of the ARCS may be applied a method of Pollard, primarily for conditions of fractured porous reservoir and at a sufficiently precise determination of reservoir pressure.

A significant number of ARCS, up to 50% and more in quality does not meet the requirements, which may be processed by any method of obtaining reliable results. In such cases, the integrated use of processing methods to the ARCS.

The inventive method is illustrated in the drawings, figure 1-11.

Figure 1 shows the processing of the ARCS method works.

Figure 2 - graph of the second derivative of the pressure (VPD).

Figure 3 is a piecewise approximation of the ARC.

Figure 4 - results of processing the ARCS deterministic method of moments (DMD).

Figure 5 - diagnostic bilogarithmic graph.

Figure 6 - ARCS in semi-logarithmic coordinates.

7 is approximated ARCS in semi-logarithmic coordinates.

On Fig - correlation between permeabilities on the indicator diagram (ID), and ARC.

Figure 9 - correlation between dcfand Scffor objects of development in carbonate reservoirs pore type (layers BSH).

Figure 10 - relationship between the d cfand Scffor objects of development in carbonate reservoirs fractured-porous type (layers of T-FM).

Figure 11 - relationship between the dcfand Scffor development objects in terrigenous reservoirs.

The method of complex assessment of the state of bottom-hole formation zone includes the operation of the well at steady state before conducting hydrodynamic studies, hydrodynamic studies of well method of recovery pressure, determination of downhole pressure and continuing the flow of fluid from the reservoir into the well after it is stopped, processing of results of measurements.

Processing of results of measurements carried out in the following sequence.

1. The actual processing of data by the method works by identifying the current reservoir pressure.

2. Approximation of the actual data, including, if the coefficient of determination less than 0,99 division actual ARCS into separate sections; the selection of the approximating equations (logarithmic or other) for the selected areas; dividing the total period of study for 20-30 intervals with a constant time step; the calculation for these values of downhole pressure.

3. Processing of the approximated ARC method deterministic moments of pressure with the determination of reservoir pressure and BizRate the aqueous diagnostic sign. Compare pressure with pressure, a certain method works in claim 1. If they differ by no more than 0.3 MPa, the processing method determined moments of pressure (DMD) is believed to be reliable. Otherwise you need to go back to clause 2 and to perform the approximation procedure using other approximating equations.

4. Assessment of the degree of recovery of downhole pressure obtained in the study wells, the results of determination of reservoir pressure method works.

5. Determination of the coefficient of the productivity of wells by mode (as the ratio of the flow rate at the steady state mode to the stop to the difference between the reservoir pressure, defined in claims 1 and 3, and downhole pressure during steady mode (stop before wells)).

6. The diagnostic procedure to verify the situation of cultivated land with building bilogarithmic graph.

7. Processing the actual and approximated curves tangent method for determining the parameters of the remote zone. Comparison of processing results of the actual and approximated the ARC tangent method. In case of differences of coefficients of permeability remote zone actual and approximated curves more than 10% when k>0.1 m is m 2; more than 15% at 0.1>k>0.01 µm2; more than 20% when k<0.01 µm2perform the approximation procedure using other approximating equations. The slight discrepancy of the values obtained confirms the required accuracy of the performed approximation procedure.

8. The definition of the skin factor for ARCS with almost complete (99%) pressure recovery and nedoustanovlennoy ARCS, if selected during the process of land by a linear dependence with a determination coefficient not lower than 0,96. In other cases, the value of the skin factor (S) can be estimated by the dependence between diagnostic sign (d) and S.

Figure 9-11 shows graphs of the dependence of dimensionless diagnostic sign of d from the values of the skin factor S for the three selected groups of objects of development,

The graphs in the coordinate "d-S" there is a strong dependence between these two parameters.

When processing using the method of DMD recovery curves pressure obtained from the research production wells operating Bashkir carbonate deposits of oil fields, the status of the PPP should be considered degraded if the values of the diagnostic sign more than 2.6.

It seems appropriate to evaluate the status of the PPP for the ARCS in the tournaisian-Famennian carbonate from which Azaniah worsened, if the obtained value is dimensionless diagnostic sign of more than 2.7.

The status of the PPP in terrigenous reservoirs should be considered degraded if more than 2.4 d.

9. Assessment of PPP by the values of the diagnostic indicator and the skin factor.

10. For ARCS, the processing of which by the tangent method cannot be executed, the processing methods is based on polarity (differential, integral). You must perform the approximation procedure recovery curves annular buffer and pressures for equidistant time values.

11. Determination of the parameters of the remote zone using several methods taking into account polarity (such as averages).

12. In the case of the deterioration of the PPP (using DMD and others), is the definition of the dimensions and properties of the bottom-hole formation zone, using defined in clause 8 of the permeability value of the remote zone.

The value of d remains constant regardless of the filtration properties of homogeneous reservoir properties reservoir oil, formation thickness, radius of the well and the power line, the flow rate of the well to stop that allows you to take d as a diagnostic sign in interpreting the ARC. Taking into account measurement errors and other factors, which result is to a certain range of values of d, the following scheme [Ibragimov LH, Mishchenko, ETC, Cheloyants D.K. Intensification of oil production. - M.: Nauka, 2000. - 414 S.]:

1) d<a 2.0 is filtered Newtonian fluids in fractured porous reservoir or filtering of non-Newtonian fluid (viscous-elastic oil) in a homogeneous reservoir;

2) 2,0≤d≤2,2 - filtering occurs Newtonian fluid in a homogeneous reservoir;

3) d>2,2 - filtering occurs Newtonian fluid in a heterogeneous aquifer (around the well has an annular zone of reduced permeability).

Integrated data processing research wells gives grounds to assume that the deterministic calculation of moments of pressure and diagnostic criterion d should be relatively stable for all models filtering.

For the homogeneous reservoir after calculation of the moments of the pressure water permeability and bezopastnosti are determined by the formulas:

ε=khμ=4q0M15M02

T=rK2x=32M1M0

According to the results of processing the ARCS method of deterministic points of pressure are determined by the dimensions and properties of the critical area according to the following algorithm (for d≥2,2) [Ibragimov LH, Mishchenko, ETC, Cheloyants D.K. Intensification of oil production. - M.: Nauka, 2000. - 414 S.]:

The definition of dmaxand tmax(accordingly, the maximum value d, and the corresponding value of time t on the graph constructed in the processing method DMD).

Determination of coefficient heterogeneity, α, is equal to the ratio of permeability (kUZP), hydroconductivity (εUZPand piezoconductivity (χUZP) Transducer to the values of these same parameters characterizing the near-wellbore area of the formation.

When you do this:

α=1,22·dmaxwhen 2,2<dmax≤2,6

α=3,17+of 10.25(dmax-2,6) with 2,6<dmax≤3,0

α=7,27+13,89·(dmax-3,0) with a 3.0<dmax<∞

Determining the travel time of the wave perturbations through PPP

tPPPvalue =0.01·α·tmax

The definition of εUZP, kUZPand χUZP:

εPCP=εYCPα;kPCP=k YCPα;xPCP=xYCPα

Define (estimate) dimensions PPP

rPCP=rPCP1+rPCP22,

where

rPCP1=πxCPt0,

rPCP2=2,5xPCPt0

13. The generalization of the results.

The proposed method of integrated assessment allows reliable quality and, in some cases, quantitative estimates of the PPP according to research wells in different geological and physical conditions, including : the incomplete recovery of downhole pressure to the reservoir size.

As an example of application of the method of complex assessment of the PPP process the survey data well 617 Envisage field, the performance of which is given in table 1.

Table 1
Performance SKU
DepositBB
RaisePalacherla
Study date27.08.2007
The flow rate before stopping, m3/d6,87
The thickness of the layer, m7

0,16
Oil viscosity, MPa·s1,16
The volume ratio of oil1,21
The volumetric compression ratio of oil, 10-101/PA12,86
The volumetric compression ratio of oil, 10-101/PA0,91
Porosity, det
Water content, %0,73

The results of measuring downhole pressure during the study wells are presented in table 2.

Table 2
The pressure measurements
no PP12345678910
t min0551301753404602170355042805110
RS, MPa6,557,719,029,5410,9911,63trend of 15.8716,16 16,2316,33

Determination of reservoir pressure method works.

ARC SCV in the coordinate "P·t - t" is presented in figure 1. According to the results of processing the ARC pressure was 16,71 MPa.

With the purpose of approximation of a differential analysis of the ARC. A graph of the second derivative of the pressure (VPD) in time are presented in figure 2.

The second derivative of the pressure at the initial plot is monotonically increasing nature, then almost stable, which allows you to select on the ARC two areas for further piecewise approximation (figure 3).

In accordance with the selected at approximation equations calculated bottomhole pressures for equally spaced time points (table 3).

4
Table 3
The results of the calculation pressure
no PPt minP, MPa
106,55
225510,2932
351012,0625
76513,0975
5102013,8318
6127514,4014

7153014,8668
8178515,2603
9204015,6012
10229515,9075
11255015,9644
12280516,0158
13306016,0628
14331516,1060
15357016,1626
16382516,1948
174080 16,2249
18433516,2532
19459016,2799
20484516,3051
21510016,3291

According to the data presented in table 3, was processed by the method of DMD. The results are shown in figure 4.

Obtained by processing the ARCS method DMD pressure equal 16,711 MPa, practically coincides with a certain method works value, which confirms the reliability of the performed procedures approximation.

The diagnostic value of the characteristic indicates a deteriorated condition of the PPP.

With a formation pressure equal 16,71 MPa, the value of the coefficient of productivity is 0.68 m3/(day·MPa).

In bilogarithmic coordinates zero slope is characterized by the plot, including the final four points (figure 5).

For determination of filtration characteristics of the reservoir in a remote area processed ARC tangent method (Fig.6).

As a result of processing the received value of the permeability of the transducer of 0.002 μm2.

Also the implementation of the treatment approximated the ARC tangent method (Fig.7).

Obtained by treatment of the approximated ARC the value of the coefficient of permeability (0,002 µ) coincides with the value of this ratio when processing actual ARCS, which confirms the reliability of the performed procedures approximation.

The graph (Fig.7) in semi-logarithmic coordinates clearly distinguishes the final section, approximated by a linear dependence with the value of the coefficient of determination 0,995 that, in accordance with the prior findings, to determine the skin factor, despite the partial recovery of downhole pressure to the reservoir. According to the results of calculations of the value of the skin factor is 2.6, which allows to assess the state of the PPP as degraded.

According to the results of processing the ARCS method DMD of the PPP is also expected to be degraded; the results of determining the dimensions and properties of the PPP are shown in table 4.

Table 4
The results of determination of the properties of PPP
The maximum value of the diagnostic sign3,15
The permeability of the transducer μm20,002
Coefficient t heterogeneity 7,05
The permeability of the PPP, μm20,0003
The radius of the PPP, m5,6

Processing the ARCS on the proposed method allows to obtain a large amount of information about the state of the reservoir system and can be used for a comprehensive evaluation of geological and technical measures at the wells.

To assess the validity of the results obtained in the analysis of ARCS, processed data more than 20 indicator research wells. It is known that the processing indicator diagrams (ID)obtained during well testing under steady-state conditions, is determined by the permeability of the formation, which is the averaged characteristics of the drainage area of the reservoir. If the collector is in the range of the studied wells is zonally inhomogeneous, then the permeability can be considered as effective, defined by the formula:

kef=lnrK/rc1kYCPln rK/rPCP+1kPCPlnrPCP/rwith a,(1)

Certain changes in the condition of critical and more remote areas of the reservoir after stopping the wells to remove the ARCS should be reflected on obtained when processing the results, therefore, almost complete coincidence of the permeability determined by the indicator diagram (ID) and the processing of the ARCS, i.e. the effective permeability may not be.

On Fig results of processing recovery curves pressure determining the permeability of the UZP and the PPP, the effective permeability by the formula (1) and the processing results of indicator diagrams.

Analysis of the obtained data allows to draw a conclusion about some of the differences between effective permeability, defined as a result of processing the ARCS in accordance with the proposed method, and permeability, defined on indicator diagrams for most wells. At the same time quite unique dependence between pronica what Rostami confirms the reliability of the results of processing the ARCS in accordance with the proposed method.

High reliability of the evaluation results of the PPP is an advantage of the proposed method of comprehensive evaluation in comparison with known methods. Furthermore, the method is simple and less labor-intensive, because a comprehensive assessment of the condition of the well in this way a sufficient one-stop well at removing ARCS.

The method of complex assessment of the bottomhole zone of the formation, including the operation of the well at steady state before conducting hydrodynamic studies, hydrodynamic studies of well method of recovery pressure, determination of downhole pressure and continuing the flow of fluid from the reservoir into the well after it is stopped, the processing of measurement results, wherein when processing the results of measurements determine the current reservoir pressure method works, conduct approximation of these results, including when the coefficient of determination less than 0,99 division actual curve recovery pressure on some areas, the selection of the approximating equations for selected areas, divide the entire period of study at intervals with a constant time step of the calculation for these values of downhole pressure, process approximated curve recovery pressure metadatamanager moments of pressure with the determination of reservoir pressure and dimensionless diagnostic sign compare pressure with pressure, a certain method works, if they differ by more than 0.3 MPa, perform the approximation procedure using other approximating equations then determine the formation pressure method works assess the degree of recovery of downhole pressure obtained in the study wells and determine the productivity of wells by mode, to clarify provisions of cultivated land to build bilogarithmic schedule, handle the actual and approximated curves pressure restoration by the method of the tangent with the definition of parameters in the remote zone of the reservoir, compare the results of processing the actual and approximated curves restore pressure tangent method, the differences in the coefficients permeability remote zone actual and approximated curves more than 10% when k>0.1 µm2; more than 15% at 0.1>k>0.01 µm2; more than 20% when k<0.01 µm2perform the approximation procedure using other approximating equations then determine the skin factor for the curve of the pressure recovery with almost complete at least 99% pressure recovery and nedoustanovlennoy recovery curves pressure, if the shock is slow when processing area by a linear dependence with a determination coefficient not lower than 0,96, in other cases, the value of the skin factor S is estimated by the correlation between diagnostic sign of d and S, to assess the condition of bottom-hole formation zone by the values of the diagnostic indicator and the skin factor for recovery curves pressure, the processing of which by the tangent method cannot be performed, proceed to process the differential or integral methods is based on polarity, after performing the approximation procedure recovery curves annular buffer and pressures for equidistant time values, determine the parameters of the remote zone using several methods taking into account polarity, in the case of the deterioration in the condition of the bottom-hole formation zone determines the size and properties of the bottom-hole formation zone using the previously defined values of permeability remote zone, assess the condition of the wellbore and remote areas of the reservoir by the values of the diagnostic sign permeability, hydroconductivity, piezoconductivity and sizes of bottom-hole formation zone.



 

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2 dwg

FIELD: oil-and-gas industry.

SUBSTANCE: proposed method comprises drilling the wildcat well and recording of data signal from drilling zone. Note here that said data signal represents electromagnetic radiation caused by bed material destruction by drill bit to compare obtained spectrum of signals with premade spectra of destruction of materials containing the known amount of hydrocarbon stock. In case said spectra are alike hydrocarbons are considered available in the bed. Besides, signal originating in drill bit volume is recorded by radio antenna located on the surface while said rill bit is isolated from casing pipe.

EFFECT: simplified and valid process and device.

3 cl, 1 dwg

FIELD: oil and gas industry.

SUBSTANCE: method includes well survey using impulse neutron spectrometric surveying, determination of rock fractional analysis, including porosity and instant oil saturation coefficient (Kos). Core samples are prepared preliminary from collectors opened by key wells; by results of their survey instant water saturation (Kws), coefficients of relative permeability to oil and water (K'opr K'wpr), exponential values of relative permeability to water and oil (nw no), clayiness index (Kcl), porosity factor (Kp), petrophysical parameters (a, b) for relations of residual water saturation factor and ratio clay volume to porosity, residual oil saturation factor (Kor); then residual water saturation factor is calculated according to the formula Kwr=a*(Kcl/Kp)+b, thereafter water cut factor (Kwc) is calculated and against the latter expected composition of influx is evaluated.

EFFECT: improving quality and reliability of log data interpretation.

3 dwg

FIELD: oil and gas industry.

SUBSTANCE: in order to determine properties of carbohydrate formation and fluids produced in extraction process according to the method acoustic signal is registered at least once and the above signal represents response of the well-formation system to acoustic pressure pulses. Source of pressure pulses is an electric submersible pump located inside the well. Acoustic signal is registered by at least one sensor located in bottomhole chamber of the well; the sensor measures at least one quantitative physical parameter of the well-formation system characterising process of acoustic signal propagation in the well. Mathematical model is created for acoustic pressure pulses in bottomhole chamber and data obtained by modelling are compared with data obtained by registration of acoustic signal representing response of the well-formation system. Formation parametres are adjusted in mathematical model to ensure compliance of at least one quantitative physical parameter of the well-formation system obtained by modelling with the same quantitative physical parameter obtained by registration; thereafter properties of formation and produced fluids are determined as parametres ensuring compliance.

EFFECT: determining characteristics of bottomhole area parametres and obtaining better characteristics of formation at the border of formation and well.

19 cl, 3 dwg

FIELD: oil-and-gas industry.

SUBSTANCE: proposed method comprises lab and geophysical studies of rock porosity, permeability, oil saturation and oil displacement and determination of pressure gradient field over the deposit area. Note here that collector and filtration-capacitive properties are defined in expanded pressure range and linear speed to make 1*10-4 MPa/m and 1*10-4 m/days. Defined are statistic porous hydrodynamic and energy structure of rock including reserves of hydrocarbons in the filed of pressure gradients while said factor is calculated as the portion of threshold deposit volume per one producing well.

EFFECT: higher accuracy, reliability and accelerated determination.

1 ex, 3 tbl, 3 dwg

FIELD: oil and gas industry.

SUBSTANCE: method involves creation of steady-state abnormal pressure in the chosen source well at the productive formation interval, fan-type recording of interval time of propagation of steady-state pressure mode in the same formation to wells of receivers distributed along the network on the deposit surface area, subsequent repetition of fan-type recording of interval time of propagation of steady-state pressure using the largest number of wells as the abnormal pressure source, which participate in fan-type recording with further processing of the obtained two-index data of interval time as to tomographic modification of methods of integral geometry that is adapted to kinematic equations of movement of flow of fluids in non-homogeneous medium using optimised principles.

EFFECT: receiving reliable information on spatial distribution of alternating effective permeability having the nature of carrying capacity of formation fluids under action of steady-state pressure along the surface area.

FIELD: mining.

SUBSTANCE: proposed method comprises tripping the video camera in hole with turbid medium on logging cable over tubing. Logging zone is isolated by packer and web in tubing suspension wherein suspended rock is settled by gravity. Visualised logging is executed in column of laminated optically clear fluid by displacement of video camera inside tubing suspension. Logging results are used to estimate operating conditions of the hole. If required, extra web is used to confine the logging zone. In compliance with first version, logging device comprises tubing suspension with packer separating the logging zone from hole behind-the-packer chamber, logging cable, video camera suspended from logging cable inside the suspension. Web is hooked to video camera to fit in suspension seat and to be detached at camera tripping in hole along suspension to logging zone. Web and seat in suspension are furnished with locking elements. Web has a central hole with gland for logging cable to slide there over and can have filter cells. Said web features OD smaller than tubing ID. Video camera is equipped with centring skid. Logging cable is coated with polyamide shell over logging length. In compliance with second version, logging device comprises tubing suspension with packer separating the logging zone from hole behind-the-packer chamber, logging cable, video camera suspended from logging cable inside the suspension. Web is secured to video camera to slide by its edges over suspension wall. Video camera is equipped with centring skid. Gland seals are arranged over web edges. Said web can be made of filter material. Said web features OD smaller than tubing ID.

EFFECT: lower costs, accelerated analysis.

15 cl, 2 dwg

FIELD: oil and gas industry.

SUBSTANCE: method involves separation of oil-gas-water fluid contained in a measuring cylinder using chemical reagents for oil and water with gas emission, measurement of height of liquid column, hydrostatic pressure, emptying of the measuring cylinder, measuring current values of differential pressure and levels of oil-gas-water fluid, oil-water fluid, oil, calculation of oil and water density. At that, volume content of water is calculated by a mathematic formula, and weight content of water is calculated as difference between the value of differential pressure of water in the measuring cylinder and the value of differential pressure of oil-water fluid in the measuring cylinder.

EFFECT: increased measurement accuracy for determination of parameters of oil-gas-water mix.

1 dwg

FIELD: oil and gas industry.

SUBSTANCE: invention is related to method and a device for pressure and/or temperature control in one or few annular spaces of well casing in natural deposit without disturbance of well sealing or structure. The device includes a Wireless Sensor Unit (WSU) located outside of the section of non-magnetic casing and including an ambient pressure and/or temperature measuring sensor; at that, WSU can be mounted or positioned at any height of well bore, and power for WSU can be supplied by energy collection. At that, induction signal frequency is within 10-1000 Hz for deep penetration through non-magnetic casing. Sensor Electronics Unit (SEU) is located inside of well bore casing and used for WSU power supply and communication; at that, SEU is mounted on a drill pipe or structure of an equipped well with the use of a pipe with thread, which allows adjusting its height position; at that, SEU converts DC power supplied by cable from surface into AC electromagnetic field providing power supply for WSU located outside of casing. At that, SEU and WSU use electromagnetic modulation for data communication between those components.

EFFECT: accurate pressure and/or temperature control in one or few annular spaces of well casing.

35 cl, 6 dwg

FIELD: oil and gas industry.

SUBSTANCE: bore core is selected in the well and surveyed, the oil saturation factor is determined for the bore core, an integrated well log survey is performed and the oil saturation factor is determined according to the survey results, a relative factor is determined as a ratio of the core oil saturation factor to the oil saturation factor of the well log survey, log curves for wells are analysed in the terrigenous section of the productive formation, reservoir beds are identified with induction logging apparent resistivity less than 3 Ohm/m, among the identified reservoir beds the beds are selected with the mineral composition of the core and mud having minerals reducing specific resistivity and high content of current-carrying elements against the log survey data, the true oil saturation factor is determined for the identified beds by multiplying the oil saturation factor of the well log survey by the relative factor and the obtained result is compared with oil saturation factor values for low oil-saturated and oil-saturated reservoir beds and the respective bed is referred to the low oil-saturated and the oil-saturated reservoir beds.

EFFECT: improving accuracy of the oil-saturated bed in the well log.

3 tbl

FIELD: electricity.

SUBSTANCE: method for automated calibration of temperature measurement in hydrogen-rich media with high temperature in the system using a fibre-optic distributed temperature sensor includes the following stages: a. in a measurement mode when flash burn energy of the primary light emission source is delivered to the sensing fibre, and b. in a correction mode when selection of the secondary light emission source is made and pulses of the above secondary source are delivered to the sensing fibre. At that at the first stage backscattered Stokes and anti-Stokes components of Raman emission are collected and temperature values are calculated using intensities of the backscattered Stokes and anti-Stokes components of Raman emission. At the second stage the backscattered Stokes and anti-Stokes components of Raman emission are collected from the secondary light emission source; this Stokes component of Raman emission is used for correction of a profile for anti-Stokes component of Raman emission collected from the primary light emission source during the measurement mode; corrected temperature value is calculated based on the corrected profile of anti-Stokes component of Raman emission. At that the used distributed temperature sensor is an optical fibre with a pure silicate core (PSC). At that the primary light emission source is a source with a wave length of 1,064 nm and the secondary light emission source is a source with a wave length of 980 nm.

EFFECT: ensuring potential operation of the fibre-optic sensor in conditions with higher temperature and increase of its operational reliability during the whole service life of this sensor.

3 cl, 7 dwg

FIELD: oil and gas industry.

SUBSTANCE: suggested invention relates to the filed of directional well drilling, in particular, to methods of control for directional drilling. The invention suggests the method for drilling trajectory control for the second well passing in direct vicinity to the first well, which includes passing of the first electrode connected to the first conducting wire through the casing string; placement of the return grounded electrode in the surface soil; generation of time-dependent electric current in the first conducting wire and the first electrode and the second conducting wire passing towards the return grounded electrode; formation of an electromagnetic field around the casing string of the first well induced by passing of time-dependent electric current in the first conducting wire; drilling of the second well against the drilling trajectory parallel to the first well; measurement of the electromagnetic field formed around the casing string of the first well from the drilling rig in the second well; and control of the second well trajectory with use of the measured electromagnetic field. At that the first electrode passes to an uncased borehole section, beyond the farthest end of the casing string so that the first conducting wire passes along the whole length of the casing string in the first well. Besides, distance between the first electrode and the casing string end should be sufficient for prevention of current passing from the first electrode upwards, through the casing string of the first well towards the return grounded electrode.

EFFECT: improving accuracy of the drilling trajectory control and levelling of one well in regard to another well.

10 cl, 7 dwg

FIELD: mining.

SUBSTANCE: method consists in irradiation of rocks by fast neutron flow, radial probing of gas recovery reservoir by multi-probe modification of neutron method and/or complex of different-depth neutron methods and registration of data as well-logging records. Note here that measurement results are compared to reveal temporary cavity from availability on inversion in probe depth readings compared to larger-depth readings describing given gas recovery reservoir.

EFFECT: higher reliability and efficiency of detection.

7 dwg

FIELD: oil and gas industry.

SUBSTANCE: invention is related to survey of wells having large horizontal wellbores and it can be applied for delivery of tools. The device contains a logging cable with a propulsor made of a set of weights and the tool fixed at the end of the logging cable. The logging cable has a diameter as low as practicable in conditions of its breaking strength. Weights of the propulsor are made as balls, ellipsoids or short cylinders with spherical butt-ends having axial openings provided that weight move freely in regard to the logging cable axis. Weights of the propulsor are made with a diameter as big as practicable in conditions of their free movement in the well.

EFFECT: technical result lies in increase of transportation length (depth) for survey tools to horizontal wellbores up to 1000 m and more, reduction of friction against pipe walls, improvement in reliability and accident-free operation of the device.

4 cl, 2 dwg

FIELD: oil and gas industry.

SUBSTANCE: method envisages running-in of the flow string to the well and injection of the working fluid to pipes with measurement of its flow rate and an injection pressure at the well head. Before running-in the flow string is equipped with a multi-set packer with a liner and at running-in of the flow string the packer is set over the roof of the first production interval in the direction of the horizontal well (HW) drilling. The injection pressure for the working fluid is recorded at the well head when it stabilises, then the parker is broken and the flow string is run in further and the parker is set over the roof of the next production interval in the direction of the HW drilling. Then the working fluid is injected again. When the well-head injection pressure stabilises it is maintained equal to the injection pressure for the previous survey and the flow rate of the working fluid is recorded; at that breaking of the packer, running-in of the flow string, setting of the packer over roofs production intervals is repeated several times depending on quantity of production intervals in the horizontal well. At that the injection pressure of the working fluid during each survey is maintained constant and equal to the injection pressure recorded at the first packer setting over the roof of the first production interval in the direction of the HW drilling, then on the basis of recorded flow rate of the working fluid it is necessary to calculate quantity of the fluid absorbed by each production interval per time unit.

EFFECT: receipt of accurate data to issue a quantitative injectivity profile for hot horizontal wells.

2 cl, 1 ex, 3 dwg

Downhole modulator // 2515624

FIELD: oil and gas industry.

SUBSTANCE: group of inventions relates to a downhole modulator intended for use in a well. The device intended for the well contains an elongated body of the tool, expansible drill rods and a flexible valve membrane. The expansible drill rods are installed on the body so that they can be opened or closed. The membrane is fixed to the expansible drill rods; it is made so that it can slide in between folded and unfolded positions. The valve membrane contains the first convergent section with the first end of the first diameter and the second end of the second diameter. The first diameter is bigger than the second diameter and the inner well diameter. The first convergent section is connected to the expansible drill rods so that a part of the valve membrane is born against the well walls between the first and second diameters. The valve membrane is a tube and the diameter of its one end exceeds the biggest diameter to be sealed. The diameter of the second membrane end is less of the least diameter to be sealed. The above device intended for use in the well can be included into a modulator which beyond this device contains a valve for fluid pressure modulation in the filled well.

EFFECT: eliminating need of modulator being built-in into the well structure as well as elimination of need in a pump or a nozzle.

7 cl, 13 dwg

FIELD: mining industry.

SUBSTANCE: invention can be used in case of gas-lift operation of wells equipped by free piston-type installations. Invention envisages stopping well, connecting tube space and annular space in wellhead, recording bottom zone and wellhead pressures in tube and annular spaces, and computing well operation parameters using inflow curve plotted according to differences of bottom zone and wellhead pressures. Volume of produced fluid is found from potential output of formation and from condition of output of free piston. When comparing these volumes, parameters of well are computed in the base of minimum volume value.

EFFECT: optimized well operation.

2 dwg

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