Method for determining behind-casing flows

IPC classes for russian patent Method for determining behind-casing flows (RU 2510457):

E21B47/10 - Locating fluid leaks, intrusions or movements

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FIELD: oil and gas industry.

SUBSTANCE: as per the proposed method a well is equipped with a pipe string with a swab. The string bottom is arranged below perforated interval of a productive formation. The well is equipped with a bottomhole thermometer on a cable in annular space. The swab is lifted via the pipe string and at the same time, the bottomhole thermometer in a recording mode is lifted via the annular space on the cable. During the swab lifting there is the change of liquid flow direction in the well from direction from the productive formation in an upward direction of the well at oil production, for direction from the productive formation in a downward direction to the pipe string column. Operations are repeated; thermograms are recorded at the changed direction of well fluid flow; thermograms are analysed and compared to the thermogram of the killed well. On thermograms at the changed direction of well fluid flow there indicated is rise of temperature at the investigated interval. It is assumed that behind-the-casing flows are available in a downward direction from overlying to underlying formations. A conclusion is made on flow of the fluid from the overlying formation in the direction of behind-the-casing flows to the perforated interval.

EFFECT: determination of the behind-the-casing flows at downward flow of fluid behind the well.

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The invention relates to the oil industry and can be used when defining a cross-flows well.

There is a method of research wells, according to which the well will be equipped with a column tubing (tubing) with a funnel at the lower end. The Shoe of the casing is placed above the top of the perforated interval 10-30 meters Before conducting the research, conduct the operation of wells with pumping the working agent used in the development of oil deposits on the tubing string within 3 days and more. Stop the well. Conduct technology exposure for 1-2 days. Spend thermometry and gamma logging (CC) bore through the tubing string with the recording of background values of natural radioactivity of the rocks and the background temperature distribution in the wellbore. Download the first disturbing amount of water in the reservoir through the tubing or annulus. When pumping disturbing amount of water repeatedly move the devices from the borehole bottom to the interval set at 40-60 m above the casing Shoe, at different speeds and record the readings of the flow meter. Download stop and re thermometry well from the bottom to the mouth to record the current temperature distribution in the wellbore. After re-thermometry resume downloading the odes and in the process raise water injection devices to the wellhead with the registration of the readings of thermometer and flow meter. Download the second disturbing amount and write thermograms injection around the wellbore after 5-10 minutes after stopping. After injection of the second disturbing amount of water and thermometry down the devices in the interval of the reservoir, pumped the third disturbing amount of water with simultaneous carrying out at least one measurement of temperature in the interval of the productive formation and after stopping the injection of the third disturbing amount spend thermometry with the removal of at least two images in the productive interval of the formation from the bottom and 50 m above the productive formation to determine annulus circulation. Analyze the data. After analysis of the received information to perform the drill-temperature measurements on the section of the wellbore with the detected temperature anomalies. In the detected intervals are conducting additional studies to confirm or refute the presence of temperature anomalies, to Refine the intervals of temperature anomalies. To determine the intervals of the wellbore in which there is a horizontal movement of groundwater is additionally pumped disturbing amount of water, stop the injection and produce thermometry in the range from wellhead to the interval that overlaps the zone of active groundwater movement through 5-10 min, Ceres min, after 60 min and 3 hours after the cessation of injection. In the case of temperature anomalies research done. In the absence of temperature anomalies continue to hold the temperature until the water temperature in the wellbore, equal to the temperature of the surrounding materials (Patent RF №2384698, publ. 20.03.2010).

The closest to the proposed invention the technical essence is a method of examination of the technical condition of the well, including the connection of the measuring device logging cable, the descent of the measuring device into the borehole, the transmission of measurement data logging cable in surface equipment, data output in the form of a thermogram obtained by measuring the magnitude of the heat flux of the inner surface of the borehole wall in a continuous non-contact mode by using the device for the study of heat flow, identifying deviations thermograms from the standard geoterma and determining the location of the annular flow. Simultaneously with the measurement of heat flow, get a video image of the internal surface of the well, pass this image on a geophysical cable in ground equipment, produce a thermogram overlay on the video map display with video and rejecting thermograms from the mill is artego geoterma analyze the video image of the internal surface of the well to identify factors that can affect the readings of the radiometer, then according to the results of the total generalizations give a conclusion about the presence of annular flow (RF Patent No. 2389873, publ. 20.05.2010 - prototype).

Known methods can reliably determine the intervals cross-flows well when the fluid flow well from the bottom up, however, the methods do not allow sufficient reliability to determine the behind-the-casing flows in the liquid flow well from top to bottom.

In the proposed invention solves the problem of determining the cross-flows in the liquid flow well from top to bottom.

The task is solved in that in the method of determination of cross-flows, including registration thermograms in the well and its analysis according to the invention, the well will be equipped with casing pipe with a swab and place the bottom of the column below the perforated interval of the reservoir, the well equipped in-depth thermometer on the cable in the annular space, raise the swab on the string of pipe and at the same time raise in the annular space on the cable depth thermometer in the registration mode, the rise of Swabi organize the change of direction of fluid flow in the borehole from the direction from the reservoir up through the borehole during oil extraction, in the direction from the productive formation down to the bottom of the column TRU the, the operation is repeated, recorded thermograms for the modified flow direction of the fluids in the borehole, analyze the captured image and compare with thermogram stopped well marked on thermograms for the modified flow direction of the fluids in the borehole, the temperature increase in the studied interval, make the assumption about the presence of cross-flows from the top down, from above, lying in the underlying layers, make a conclusion about the admission of fluid from above the underlying layer along the path behind-the-casing flows into the perforated interval.

The invention

Traditional geophysical studies in the annular space of wells equipped with sucker rod pumps methods: thermometry, alagomeji, resistivimetry methods, manometry, well thermoconductive debitoren (default), the civil code and the locator allow you to determine the profile of the flow of fluid, the presence or absence of cross-flows from the bottom, the integrity of the sump well. Suspension pump is located above the perforated interval. Such studies, as a rule, the presence of cross-flows of the overlying layers is not defined due to the fact that the sensor of thermometer is in the upward flow of the liquid delivered from the perforated interval. To register heat flux occurring due to grosslingova fluid, circulating to the annulus of the above lying unperforated perforated seam it is necessary to direct the flow of fluid from the perforated interval down to prevent the flow sensor of thermometer at a temperature in the range, located above the filter well. For this purpose, the well will be equipped with casing pipe with a swab and place the bottom of the column below the perforated interval of the reservoir, and the geophysical survey device on the cable is placed in the annular space. The inflow into the well excite by using a swab. Recording thermometer carried out simultaneously with the rise of Swabi.

An example of a specific implementation.

In well No. 1 Novo-elkhovskoye deposits perforated tournaisian reservoir of oil in the interval 1040,8-1044,8 m (see figure 1). Well equipped with oil pump and put in the work year, with oil output of 4.0 tonnes/day. Over time the flow rate was steadily increasing and reached 32 t/sutulin production rate of this well does not correspond to the flow rates of the surrounding oil wells, comprising approximately 4 tonnes. An assumption was made about the flow of oil in the perforation interval to the annulus with the overlying oil-bearing terrigenous reservoir bobrikovsky age, located in the interval 1032,0-1039,6 m To identify the being is by increasing the flow rate of the geophysical study No. 1 through the annular space in the borehole methods: thermometry, STD, CC, locator, resistivimetry methods, manometry, alagomeji. According to a study issued by the conclusions of the perforated layer. Explanations for the increased flow rate is not obtained. The presence of annular flow from the overlying terrigenous formation in this study were not identified.

To solve your tasks conducted study No. 2. Well equipped column tubing with a swab. The bottom of the tower is placed below the perforated interval of the productive formation. Well equipped in-depth thermometer on the cable in the annular space. Spent the rise of the swab on the tubing string and at the same time fulfilled the rise in the annular space on the cable depth of thermometer in the registration mode. The operation was repeated several times with registration thermograms for the modified flow direction of the fluids in the borehole (curves 1-4). Analyzed thermal image and compared with thermogram stopped well. Noted on thermograms for the modified flow direction of the fluids in the borehole, the temperature increase in the studied interval. In the interval 1032-1043 m detected temperature anomaly, i.e. the temperature increase by 0.2-0.5°C, which indicates a casing string flow from above, namely from a depth of 1032 m to the top of the perforated interval, that is, to the depth of 1040,8 m

Thus managed to solve the backside of the Chu determination of cross-flows in the liquid flow well from top to bottom.

The application of the proposed method will reveal behind-the-casing flows wells coming from the upper layers at the bottom.

The method of determination of cross-flows, including registration thermograms in the well and its analysis, characterized in that the well will be equipped with casing pipe with a swab and place the bottom of the column below the perforated interval of the reservoir, the well equipped in-depth thermometer on the cable in the annular space, raise the swab on the string of pipe and at the same time raise in the annular space on the cable depth thermometer in the registration mode, with the rise of Swabi organize the change of direction of fluid flow in the borehole from the direction from the reservoir up through the borehole during oil extraction, in the direction from the productive formation down to the bottom of the pipe string, the operation is repeated, register thermograms for the modified flow direction of the fluids in the borehole, analyze the captured image and compare with thermogram stopped well marked on thermograms for the modified flow direction of the fluids in the borehole, the temperature increase in the studied interval, make the assumption about the presence of cross-flows downward from the upstream to the underlying layers, make a conclusion about the admission of fluid from the upper reservoir on the way annulus re the fetters in the perforated interval.