Method for defining well characteristics, formation bottom-hole zone

FIELD: oil and gas production.

SUBSTANCE: method for defining well characteristics, formation bottom-hole zone includes reagent pumping via tubing with closed tubular annulus, measurement of reagent flow rate at the well mouth and pumping pressure in bottom-hole zone. Measurement data is calculated for bottom-hole conditions. Accumulated flow rate and labour input per reagent flow unit in well bottom-hole zone is determined. These indices are used for definition of current formation conductivity change. Before reagent pumping fresh water is pumped into formation via tubing till well-head pressure reaches Phead=10 MPa with measurement of this pressure change in time and volume of pumped water. Their analysis is used to define initial conductivity of formation bottom-hole zone. After that there performed is an operation of bottom-hole treatment by reagent that is gassy fluid with water solution surfactant ML-81B or water solution of hydrochloric acid HCl. After that fresh water is pumped into formation similarly to the initial operation and final conductivity of formation bottom-hole zone is determined. After comparison of initial and final conductivity of bottom-hole zone there defined is a change of formation bottom-hole zone conductivities. If bottom-hole zone conductivity decreased or its increase is less than 10%, then additional treatment of bottom-hole zone is carried out by this or other reagent.

EFFECT: increase of efficiency of selection of the most effective process operation on improving formation bottom-hole zone conductivity depending upon the type of collector comprising it and simplification of defining well characteristics, formation bottom-hole zone process.

1 dwg, 3 tbl

 

The invention relates to the oil industry and can find application in the determination of the hydrodynamic condition of the bottomhole zone injection wells after the technological impact on the bottom zone.

There is a method of determining parameters in the study of marginal neperliva wells (RF patent No. 2289021, IPC EV 47/10, EV 49/00, publ. 10.12.2006,, bull. No. 34) by the method of successive shifts the stationary States by measuring and recording the pressure build and the actual processing of the inflow curve with the standard technology research, after standard processing of the actual curve of inflow on the basis of the build schedule time tracking pressure and at a known value of the reservoir pressure on the chart hold a straight line connecting the point known reservoir pressure inflection point, which corresponds to the time of occurrence of filtration resistance during filtration of a liquid, this direct counting time, meaning theoretically optimal period of the study, reservoir inflow, then the actual inflow curve inflection point identified on schedule tracking pressure, combined with the point of intersection of the optimal time studies of reservoir inflow and reservoir pressure and get the ISU is Tethyan curve of inflow, which is treated according to the method of unsteady filtration hydrodynamic characterization of the reservoir: productivity, hydroconductivity, permeability and skin factor.

The disadvantages of this method are:

firstly, the complexity of the application of this method;

- secondly, the need for additional equipment for lowering into the borehole;

- thirdly, the long duration of studies over time.

Also there is a method of determining reservoir parameters neftegazonosnyh layers (patent RF №2320869, IPC EV 47/10, publ. 27.03.2008,, bull. No. 9), including the operation of injection and production wells, conducting petrographic studies of core samples and geophysical and hydrodynamic research, construction of correlation dependences of the corresponding parameters on the results of these studies, interference test, determination of optimum modes of operation of wells and participating in the filtering process neftegazonosnyh (working) thickness.

The disadvantages of this method are:

firstly, the complexity of the application of this method;

- secondly, the long duration of studies over time.

The closest to the essence and the achieved result is a method of determining the nature of the stick bore, bottom-hole formation zone (RF patent No. 2189443, IPC 7 EV 47/00, publ. 20.09.2002 year), including non-stationary injection of reagent into the reservoir, the metering pressure injection and chemical consumption at the wellhead, the conversion data is measured downhole conditions, the determination of the accumulated flow and work spent on non-stationary flow in a well bore zone unit of the consumption of the reagent. For these indicators based on the current conductivity of the reservoir expect the coefficient of skin effect, the current conduction use the value defined by the results of non-stationary test this well at the injectivity of the reservoir fluid.

Change the mode of injection of the reagent upon reaching the desired filtration properties of bottom-hole zone of the well defined by the skin-effect is calculated on accumulated flow and work flow unit flow rate of the reagent in a well bore zone based on the current conductivity of the formation. Directly in front of unsteady injection of the reactant annulus between the production column and the column tubing fill homogeneous single-phase stable liquid with a known density. Unsteady injection of reagent into the reservoir lead through the column tubing with a closed annulus. Measuring pressure lead in Zack is atom annulus at the wellhead with the simultaneous measurement of liquid level in a closed annular space. To determine the hydroconductivity, piezoconductivity, the radius of the bottom zone and the coefficient of skin effect for each measurement in conditions of unsteady injection of fluid during each injection regime determines the function of repression, characterizing the non-stationary flow in a well bore zone during this mode of injection fluid, for each mode, build a dependency graph of the function of repression against the logarithm of time uploading to this mode, each of the obtained graphs allocate initial inclined straight section, a mathematical method to find the parameters of a selected linear sections, which determine the water permeability and bezopastnosti contaminated bottom zone, as well as its radius and coefficient of skin effect.

To determine hydroconductivity productive formation determine the accumulated consumption and derived functions repression that characterizes the work spent on non-stationary flow in the reservoir unit flow of the reservoir fluid, build a dependency graph of the derivative function of reprisals from the accumulated consumption for a range of values hydroconductivity, obviously including the desired water permeability, among the set of obtained curves derived choose the line that is closest satisfying the condition of continuity of the derivative, according to the respective searched hydroconductivity layer.

The disadvantages of this method are:

firstly, the complexity and duration of its implementation, associated with the need to determine the current hydraprovokec formation and function of repression;

- secondly, the high cost of implementation due to the need to use expensive reagents;

- thirdly, it is not possible to perform a processing operation to improve the conductivity of the bottom-hole formation zone depending on the type of collector its components.

An object of the invention is to simplify the process of determining the characteristics of well bottom zone and reservoir, as well as reduced time and reduced cost of implementation of the method without loss of efficiency with the possibility of selecting the most effective manufacturing operations to improve the conductivity of the bottom-hole formation zone depending on the type of collector its components.

The problem is solved by a method for determining characteristics of well bottom zone and the reservoir, including the descent into the well of the column tubing (tubing) with an overlapped annular space, measured at the wellhead chemical consumption and pressure injection into the critical zone, the conversion data is measured downhole conditions, the determination of the accumulated consumption and work, spent natezenie in bottom hole unit flow rate of the reagent, these indicators measure the change in current conductivity of the formation.

What's new is that before the injection of the reagent have pumped into the formation through the tubing string of fresh water before reaching the wellhead pressure Pmouth=10 MPa by measuring changes in the pressure over time and volume of injected water from their analysis determines the initial conductivity of the reservoir, after which produce a processing operation for processing bottom-hole formation zone of the reagent, which is used carbonated liquid with the aqueous surfactant solution ML-81B or an aqueous solution of hydrochloric acid Hcl, and then produce the injection of freshwater similarly, initial operation, and determine the final conductivity of the bottom-hole formation zone, after comparing the initial and final conductivity layer zones determine the change in the conductivity of the bottom-hole formation zone, if the conductivity of the bottom-hole formation zone decreased or increased less 10%, then perform additional processing bottom-hole formation zone or other reagent.

The proposed method is as follows and in the following order, considered on the example of the well 2556 "Aznakaevskneft" JSC "Tatneft".

To determine the characteristics of the well bottom-hole formation zone, i.e. the initial carry the STI layer zones make the descent into the well column pump-compressortech pipes (tubing) with the packer. Place the packer 5-10 meters above the roof of the reservoir and produce the fit, i.e. produce sealing the annular space of the well. At the wellhead tie the discharge line of the pump, equipped with a pressure gauge (any known construction with a maximum scale of the measured pressure 40 MPa), for example a pump unit CA-320 with the column tubing. Have pumped into the borehole fluid, such as fresh water (p=1000 kg/m3with simultaneous measurement of the pressure readings of the pressure gauge and flow in the discharge line at a time.

Measurements made in the process of injection of fresh water before reaching the wellhead pressure values Pmouth=10 MPa several times, for example 3 times within 60 seconds after a certain period of time, and measurement results of reduce in table 1 and figure 1.

Table 1
OptionsT1T2T3
Pressure pi, MPa05,010,0
The accumulated volume of injected fluid, Qim30 0,050,1
Time tiwith03060
Change time ∆ Ti=ti-ti-1with03030
The sum of the pressure at the time of registration of the measurement change time0150450

Next, produce a technological operation, such as the washing of bottom-hole formation zone using gas compressor installation. To do this, at the wellhead tie the compressor installation with a capacity filled with prepared in advance technological definite volume of liquid, for example 15 m3.

The process liquid is prepared in aqueous solution with surfactant ML-81B (concentration MLB 0.1%) volumetric capacity at the mortar site. Then using a pump and compressor by the compressor installation, hairout process liquid, bring to the cleaning mode the compressor installation. Then into the tubing string lowered, for example, a flexible tube (GT) and pumped the gas-liquid mixture according to GT with Zap is the implementation of the internal space of the casing and pumped the gas-liquid mixture in the above-mentioned volume of 15 m 3under pressure, for example, 10 MPa through a column of GT 3 through the annular space between the tubing and GT in the gutter capacity placed at the wellhead, while the first is the displacement of the downhole fluid in the internal space of the casing and the annular space between the tubing and GT, gutter capacity and its replacement by gas-liquid mixture of surfactants. In the process of pumping gas-liquid mixture is reduced depression on the formation and cleans the bottom-hole formation zone (gutter capacity washed contamination of bottom-hole formation zone).

After washing the bottom-hole formation zone disassemble the compressor install and remove the flexible tube from the casing. Then repeat the characterization of the well bottom-hole formation zone, i.e. determine the final conductivity of the bottom-hole formation zone after carrying out manufacturing operations. To do this, at the wellhead tie the discharge line of the pump, equipped with a pressure gauge (any known construction with a maximum scale of the measured pressure 40 MPa), for example a pump unit CA-320 with the column tubing. Have pumped into the borehole fluid, such as fresh water ρ=1000 kg/m3with simultaneous measurement of the pressure readings of the pressure gauge and flow in the discharge line at a time.

The measurements produced the lead in the process of injection of fresh water before reaching the wellhead pressure values P mouth=10 MPa, several times, for example 6 times, with values of Pmouth=10 MPa reach for 360 seconds, and the measurement is made in a certain period of time and measurement results of reduce in table 2 and figure 1.

Table 2
OptionsT1T2T3T4T5T6
Pressure pi, MPa02,04,06,08,010.0
The accumulated volume of injected fluid, Qim300,0250,050,0750,10,12
Time tiwith03060120180200
ISM is out of time Δt=t i-ti-1with03030606020
The sum of the pressure at the time of registration of the measurement change time
06018054010201220

As can be seen from graph 1, the conductivity of the layer is decreased, because the curve reflecting the pumping fluid after washing the wells, the gas-liquid mixture gas compressor unit, has gone up relative to the initial curve. Therefore, the washing had a negative impact on the state of the bottomhole zone. Therefore designate additional layer processing another reagent, such as aqueous hydrochloric acid solution model HC1. At the wellhead tie discharge line acid unit with the column tubing and have pumped the calculated amount of acid sufficient to process this layer, for example 4 m3. The concentration and composition of hydrochloric acid is taken in any known proportions used in the processing of bottom-hole formation zone. For example, using hydrochloric acid Inga is new on THE 2122-205-00203312-2000. (Russian Federation, Republic of Bashkortostan, Sterlitamak). Then resist process the pause needed to maximize the effectiveness of acid treatment, and removing the products of reaction of the acid with rock bottom-hole formation zone. For example, swabbing the tubing string with the help of Swanage Assembly to the PCB 5.

Then repeat the characterization of the well bottom-hole formation zone, i.e. determine the final conductivity of the bottom-hole formation zone after carrying out manufacturing operations. To do this, at the wellhead tie the discharge line of the pump, equipped with a pressure gauge (any known construction with a maximum scale of the measured pressure 40 MPa), for example a pump unit CA-320 with the column tubing. Have pumped into the borehole fluid, such as fresh water ρ=1000 kg/m3with simultaneous measurement of the pressure readings of the pressure gauge and flow in the discharge line at a time.

Measurements made in the process of injection of fresh water before reaching the wellhead pressure values Pmouth=10 MPa, several times, for example 6 times, with values of Pmouth=10 MPa reach for 180 seconds, and the measurement is made in a certain period of time and measurement results of reduce in table 3 and figure 1.

Table 3
OptionsT1T2T3T4T5T6
Pressure pi, MPa02,04,06,08,010,0
The accumulated volume of injected fluid, Qim300,050,10,150,20,25
Time tiwith06090120150180
Change time ∆ Ti=ti-ti-1with06030303030
The sum of the pressure at the time of registration to the measurement change time 0120240420660960

According to table 1, 2, 3 build a picture of the accumulated amount of the works of the pressure at the wellhead and change the time p×Δt in Cartesian coordinates as a function of total injected water volume Qi.

Well 2556 "Aznakaevskneft" JSC "Tatneft".

Conducted three stages of measurement of parameters of a well.

1. Stage - injection of fresh water (determination of the initial conductivity of the reservoir) water Injection in a volume of 0.1 m3, rise of the wellhead pressure to a value of Pmouth=10 MPa for 60 S.

2. Stage - wash booster. Water injection in a volume of 0.12 m3, rise of the wellhead pressure to a value of Pmouth=10 MPa at 360 C.

3. The stage is the injection of an aqueous solution of hydrochloric acid Hcl (15% concentration). Water injection in a volume of 0.25 m3, rise of the wellhead pressure to a value of Pmouth=10 MPa at 180 C.

The figure shows that at the initial stage, all three curves are approximately parallel to the values of the pumped volume of 0.03 m3. Then the curve reflecting the pumping fluid after washing the gas-liquid mixture of bottom-hole formation zone using gas compressor installation has gone up relative to the initial curve. Sledovat is Ino, flushing the gas-liquid mixture had a negative impact on the state of the bottomhole zone. And only the third stage, involving the injection of acid, allowed to increase the injection capacity of the well (the slope of the curve decreased).

Diagnostic parameter is the slope of the curve, which is determined by the following formula:

where π=3,14159...;

kw- the permeability of the reservoir;

h is the thickness of the reservoir;

Bw- the volume ratio of water;

µw- viscosity of water;

reand rwthe radii of the power line and the well, respectively;

S is the skin factor of the well.

Therefore, the slope of the graph is the inverse value of the coefficient pickup:

Tilt allows you to visually monitor the change of the coefficient of capacity of the well. Since the slope of the line (see figure) is inversely proportional to thermal capacity of the well To aCRwith increase of the coefficient of the injectivity of the reservoir decreases, the slope, and Vice versa, with a reduction factor injectivity of the reservoir increases, the slope (see figure).

The proposed method allows to effectively perform a selection of the most efficient manufacturing operations to improve conductivity is bisabolol zone of the reservoir depending on the type of its collector comprising, and has a simple process of determining the characteristics of well bottom zone and the reservoir, and allows the plot to determine the change in the ratio of the capacity of the well after carrying out one or another technological operations and thereby reduce the cost of implementation of the method without loss of efficiency.

The method of determining the characteristics of the well bottom-hole formation zone, which includes the injection of the reagent through the column tubing (tubing) with an overlapped annular space, measured at the wellhead chemical consumption and pressure injection into the critical zone, the conversion data is measured downhole conditions, the determination of the accumulated flow and work spent on the course in a well bore zone unit of reagent consumption, these indicators measure the change in current conduction layer, characterized in that before the injection of the reagent have pumped into the formation through the tubing string of fresh water before reaching the wellhead pressure Pmouth=10 MPa by measuring changes in the pressure over time and volume of injected water from their analysis determines the initial conductivity of the bottom-hole formation zone, and then produce technological operation processing bottom-hole formation zone of the reagent, which is used as carbonated liquid with water is a surfactant solution ML-81B or an aqueous solution of hydrochloric acid Hcl, then have pumped into the reservoir of freshwater similarly, initial operation, and determine the final conductivity of the bottom-hole formation zone, after comparing the initial and final conductivity layer zones determine the change in the conductivity of the bottom-hole formation zone, if the conductivity of the bottom-hole formation zone decreased or increased less than 10%, then perform additional processing bottom-hole formation zone or other reagent.



 

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17 cl, 2 tbl, 1 ex, 1 dwg

FIELD: oil producing industry.

SUBSTANCE: invention belongs to the oil producing industry and may be used for acid treatment of an oil exploitation well bottom-hole area characterized by the uncapped productive formation with carbonate reservoir rock. Acid treatment of an oil exploitation well bottom-hole area technique involves running-in of a flexible flush-joint coiled tubing unit along the annular space with the subsequent injection into the well, advance of the flexible flush-joint coiled tubing up to the well bottom, oil injection up to the full change of killing fluid to the oil, removal of flexible flush-joint coiled pipes of a coiled tubing unit up to the roof of the productive accumulation, shutting-in a well, injection of soldering acid solution to the bottom-hole area through the flexible flush-joint coiled pipes of a coiled tubing, pulling of the bottom part of flexible flush-joint coiled pipes of a coiled tubing unit to 0.8-1.2 m and injection of soldering acid solution up to the reach of productive formation bottom, running of the bottom part of flexible flush-joint coiled pipes of a coiled tubing unit to the centre of the well and curing within the period of 2-3 hours., gradual pulling of the bottom part of flexible flush-joint coiled pipes of a coiled tubing unit to the well bottom and simultaneous oil injection with the borehole fluid drainage through the annular space, flushing-out of well with oil, removal of the bottom part of flexible flush-joint coiled pipes of a coiled tubing unit and closing of the annular space, carrying out of advancing and closing operations and launching of a well. The aforementioned adaptation requires a well with the uncapping productive formation with the permeability not less than 0.01 mcm², formation pressure not less than or equal to 7 MPa, productivity index not exceeding 0.1 m³/day*atm. Immediately prior to processing, the well production rate within the bottom-hole pressure conditions should be not less than or equal to 1.5 MPa, while the formation dispersion should be not less than or equal to5.5 MPa. Within the processing the acid volume should be not less than 0.5-1 m³ for 1 m of the perforated load. Productive formation interval is perforated no sooner than in a year prior to such processing with perforation of the productive formation interval amounting to more than 10m.

EFFECT: efficiency enhancement of acid treatment of an oil exploitation well bottom-hole area.

2 ex

FIELD: oil and gas industry.

SUBSTANCE: in processing method of bottom-hole formation zone, which involves pumping to the formation of magnesium granules with further pumping of acid compound, first, hydraulic fracturing of the formation is performed with further pumping of mixture of magnesium granules and propane with fluids on hydrocarbon or water basis. Then, to the processed zone of the formation there pumped is combustible oxidation composition (COC) which contains oxidiser, catalyst decreasing the value of the temperature required for the beginning of oxidation reaction, surface-active substance required for removal of hydrocarbon film from magnesium, and water. After oxidation reaction is completed and additional cracks are formed, acid compound increasing the size of the formed cracks is pumped.

EFFECT: increasing processing efficiency of the bottom-hole formation zone at increasing safety of the work execution process.

2 ex

FIELD: oil and gas production.

SUBSTANCE: procedure for stimulation and stabilisation of region of underground bed consists in: delivery of acidulous liquid into region of underground bed and allowing acid, at least partially, to dissolve part of region of underground bed, in pumping cementing liquid containing agent increasing stickiness and including water stickiness increasing agent, in delivery of liquid for successive flushing into region of underground bed and in pumping replacing liquid into underground bed directly upon stage of delivery of acidulous liquid into region of underground bed.

EFFECT: increase and maintaining well output.

55 cl

FIELD: oil and gas production.

SUBSTANCE: method of treating underground formation through which goes the bore can be put into practice by forming treatment fluid from hydrated polymer water solution that is mixed with water-soluble, non-symmetric, heretolytically cleaved, nonorganic peroxide diluting agent and the fluid if injected into formation.

EFFECT: increasing the treatment efficiency.

14 cl, 5 ex, 4 dwg

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