RU2515641C1 - Surveying method of horizontal well - Google Patents

Abstract

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

Description

The invention relates to geophysical exploration of deep wells, in particular to geophysical exploration of horizontal and shallow wells.

In hydrodynamic studies of horizontal wells, an important task is to determine the working intervals of the wellbore. This problem is especially relevant for the analysis of the development of low-permeable, anisotropic reservoirs, since it is impossible to evaluate the reservoir area covered by the production or absorption of the injected working agent without joint knowledge of the actual inflow or absorption interval and their quantitative parameters when developing productive intervals together, especially when studying steam injection horizontal wells with high thermodynamic state parameters, providing an increase in the rate formation temperatures up to 250-300 ° C.

A known method of researching an injection well, including the descent of tubing into the wells, pumping a working agent, for example water, into the well with a measurement of flow rate and injection pressure at the wellhead. The method involves changing operating modes by changing the amount of injected water. When researching production wells, the flow rate of the well is changed several times, and also each time the mode is changed, flow rate and pressure are measured. The data obtained make it possible to construct indicator curves, on the basis of which the injectivity coefficient of injection wells or the productivity coefficient of production wells are determined (See the book “Technology and Technique for Oil and Gas Production”, authors: Muravyev IM, Bazlov MN, Zhukov A . I. and Chernov BS, Publishing House "Nedra", M., 1971. - p. 135).

However, the known method does not allow to obtain the filtration parameters of heterogeneous production intervals along the length of the horizontal wellbore, that is, with zonal heterogeneity of the reservoir.

Also known is a method of researching a horizontal well, adopted by the authors as a prototype, which includes lowering a tubing string, injecting a working agent into pipes with measuring flow rate and discharge pressure (See RF patent No. 2269000 from 06/24/2003, IPC: E21B 47/00) . The method involves the descent to the bottom of the horizontal trunk on tubing made in the form of long flexible pipes, a flow meter. Then create a circular circulation of the working agent through the annulus and lengthy flexible pipes, which are simultaneously raised to move the flow meter along the entire length of the horizontal barrel, while the flowmeter fixes the flow rate of the working agent through the annulus.

However, the known method cannot be used to study steam injection wells used to inject coolant (steam, hot water) with high thermodynamic state parameters that increase the temperature of the formation to 250-300 ° C, as, for example, when developing a perm-carbon deposit in the Usinsky field high viscosity oil. High temperatures lead to the failure of electrical circuits of flowmeters, pressure sensors and other devices that store recorded information. As a result, the received information is distorted or not recorded at all. Devices executed in a heat-resistant state or located in special heat-resistant containers can be in the well without failure for no more than six hours, and the process of studying a horizontal well with a barrel length of about 300 meters is carried out for more than a day. In addition, when using this method in the so-called "hot" wells, the water returned during circulation can have a temperature of 150-200 ° C, which boils at atmospheric pressure and poses a great danger to personnel performing research of steam injection wells.

The objective of the invention is to obtain reliable information for constructing a quantitative injectivity profile of productive intervals of "hot" horizontal wells.

This object is achieved by the fact that in the claimed method, the tubing string is lowered into the well and the working agent is pumped into the pipes with a measurement of its flow rate and discharge pressure at the wellhead.

The salient features of the claimed method are:

- assemble the tubing before lowering with a multi-action packer and a liner;

- install during the descent of the tubing the packer above the roof of the first productive interval in the direction of drilling the horizontal wellbore;

- fix at the mouth the discharge pressure after its stabilization;

- carry out the breakdown of the packer and the subsequent descent of the tubing with the subsequent installation of the packer over the roof of the next productive interval along the horizontal drilling;

- again carry out the injection of the working agent, and after stabilization of the wellhead pressure of the injection support it equal to the injection pressure of the working agent in the previous study and also record the flow of the working agent;

- disruption of the packer, descent of the tubing and installation of the packer over the roofs of the productive intervals is carried out repeatedly depending on the number of productive intervals covered by the horizontal wellbore;

- the pressure of the injection of the working agent during each study is maintained at the wellhead constant, equal to the pressure of the injection of the working agent when the packer is installed above the roof of the first production interval along the horizontal well;

- based on the recorded costs of the working agent, determine the amount of working agent absorbed by each productive interval per unit time;

- maintaining during the study at the wellhead the pressure of the injection of the working agent at productive intervals is constant, if it exceeds the value from the initial pressure of the injection, it is carried out by pouring the excess of the working agent into the measured tank.

The specified set of essential features allows the study of "hot" wells used to inject working agents with high thermodynamic state parameters, providing an increase in the temperature of the formation to 250-300 ° C without fear of failure of the measuring instruments and does not pose a threat to the personnel conducting the study, since it is discharged into a measured tank at the wellhead, the working agent is cold. In accordance with the inventive method, the conditions of constant injection pressure, temperature and composition of the working agent are provided, that is, during the entire full cycle of studies, the conditions for the identity of the work of productive intervals in the process of absorption of the working agent are fulfilled, which allows simultaneous measurements of the receiving ability of each of the joint working under the same conditions to compare productive intervals and on this basis to build injectivity profiles.

Thus, simultaneous sequential determinations of the costs of the working agent absorbed by individual working productive intervals, subject to the identical conditions of their work, become identical to the conditions for simultaneous measurements and ensure the purity of the studies, that is, obtaining reliable information to build a quantitative profile of the injectivity of productive intervals of any “hot” horizontal wells .

The claimed combination of essential features is not known to us from the prior art, therefore, the claimed invention is new. The claimed features of the invention are not obvious to the average person skilled in the art. In this regard, we believe that the claimed invention has an inventive level. The invention is industrially applicable, since the available equipment and technology developed by us, allow us to implement the method in full.

Figure 1 shows the scheme of research in a well with a horizontal wellbore in the presence of three productive intervals with the installation of the packer at the beginning of the study above the first productive interval in the direction of drilling the horizontal wellbore. Figure 2 and 3 shows the scheme of research in a well with a horizontal wellbore at various positions of the installation of the packer relative to the productive intervals in the research process.

The method is implemented as follows.

To conduct research into a well 1 with a horizontal wellbore 2 at productive intervals 3, 4, 5, tubing 6 is assembled with a multiple-action packer 7 and a liner 8. In studies, a packer, for example, of the anchor type, is used. If necessary, a packer with support on the face can be used. Near the well, a measuring tank 9 is installed, in which a drain pipe with shutoff valves is mounted, connected to the tubing string (Fig. 1). At the first stage of research, the packer 8 is installed over the roof of the first productive interval 3 in the direction of drilling the horizontal wellbore, and a working agent, such as water, is pumped into the tubing. Low viscosity oil and other mobile liquids can also be used as a working agent. In the future, when describing the method, the term "water" will be used instead of the term "working agent". After stabilization of the discharge pressure, its value and water flow rate are fixed at the mouth. The recorded water flow rate corresponds to the total water flow rate absorbed by all productive intervals, and it is determined by formula 1, regardless of which of the flow rates is zero.

$$Q_{\mathrm{about}bu}^0=q_{\mathrm{one}}+{\mathrm{<figure-callout\; id="2"\; label="q"\; filenames="00000007.png,00000008.png"\; state="\{\{state\}\}">q</figure-callout>}}_2+{\mathrm{<figure-callout\; id="3"\; label="q"\; filenames="00000008.png,00000009.png"\; state="\{\{state\}\}">q</figure-callout>}}_3+q_{\mathrm{from}l\mathrm{and}\mathrm{at}.},\left(\mathrm{one}\right)$$

where q ₁ is the flow rate of water absorbed by the first production interval 3 in the direction of drilling a horizontal well,

q ₂ - the flow rate of water absorbed by the second production interval 4 in the direction of drilling a horizontal well,

q ₃ - the flow rate of water absorbed by the third production interval 5 in the direction of drilling a horizontal well,

q _drain. - the flow rate of water entering the measuring tank at the wellhead.

Then, the packer 8 is disengaged and the tubing is lowered until the packer is installed above the roof of the next productive interval 4 along the horizontal wellbore and the water is pumped again into the tubing, while after stabilization of the water injection pressure at the wellhead it is kept constant at the water injection pressure during the first examination when installing the packer above the production interval 3. If the discharge pressure exceeds the discharge pressure of water in the first position of the packer above the production interval 3, then to maintain of the required constant pressure, water is discharged into the measuring tank 9. The total water flow rate and the volume of water entering the measuring tank are also recorded. The recorded water flow rate corresponds to the flow rate of water absorbed in productive intervals 4 and 5 minus the volume entering the measuring tank 9 and it is determined by formula 2, also regardless of which of the flow rates is zero.

$$Q_{\mathrm{about}bu}^{\mathrm{one}}={\mathrm{<figure-callout\; id="2"\; label="q"\; filenames="00000007.png,00000008.png"\; state="\{\{state\}\}">q</figure-callout>}}_2+{\mathrm{<figure-callout\; id="3"\; label="q"\; filenames="00000008.png,00000009.png"\; state="\{\{state\}\}">q</figure-callout>}}_3+q_{\mathrm{from}l\mathrm{and}\mathrm{at}.},\left(2\right)$$

where q ₂ is the flow rate of water absorbed by the second production interval 4 in the direction of drilling a horizontal well,

q ₃ - the flow rate of water absorbed by the third production interval 5 in the direction of drilling a horizontal well,

q _drain. - the flow rate of water entering the measuring tank at the wellhead.

Then, the packer is again disengaged and the tubing string is lowered until the packer is installed over the production interval 5 and, as described earlier, water is pumped into the tubing while maintaining a constant discharge pressure equal to the injection pressure of the working agent in the first position of the packer installation over the production interval 3. The total water consumption and the volume of water entering the measuring tank. If the discharge of water into the measuring tank is equal to the previous flow rate, then in this case the productive interval 5 does not accept water, that is, the volume of absorbed water is zero.

The fixed water flow rate is determined by the formula 3, also regardless of which of the flow rates is zero.

$$Q_{\mathrm{about}\mathrm{<figure-callout\; id="2"\; label="b\; u"\; filenames="00000007.png,00000008.png"\; state="\{\{state\}\}">b\; </figure-callout>}u}^2={\mathrm{<figure-callout\; id="3"\; label="q"\; filenames="00000008.png,00000009.png"\; state="\{\{state\}\}">q</figure-callout>}}_3+q_{\mathrm{from}l\mathrm{and}\mathrm{at}.},\left(3\right)$$

where q ₃ is the flow rate of water absorbed by the third production interval 5 in the direction of drilling a horizontal well,

q _drain. - the flow rate of water entering the measuring tank at the wellhead.

The installation of the packer over the roofs of the productive intervals is carried out repeatedly depending on the number of productive intervals covered by the horizontal wellbore, and the injection pressure of the working agent at the wellhead in each production interval is kept constant equal to the injection pressure of the working agent during the first study when installing the packer over the roof of the last slaughter of the productive interval of the horizontal trunk. When conducting research, they also provide conditions for the constancy of temperature and composition of water.

Thus, taking into account the constancy of the injection pressure, temperature and water composition during the entire full cycle of studies, the conditions for the identity of the operation of productive intervals in the absorption process are fulfilled, which allows us to compare the simultaneous measurements of the receiving ability of each of the productive intervals working in the same conditions.

Then, based on the recorded water consumption, the amount of water absorbed by each productive interval per unit time is determined by mathematical dependencies converted from formulas 1, 2, 3.

$${\mathrm{<figure-callout\; id="3"\; label="q"\; filenames="00000008.png,00000009.png"\; state="\{\{state\}\}">q</figure-callout>}}_3=Q_{\mathrm{about}bu}^2-q_{\mathrm{from}l\mathrm{and}\mathrm{at}.}\left(\mathrm{four}\right)$$

$${\mathrm{<figure-callout\; id="2"\; label="q"\; filenames="00000007.png,00000008.png"\; state="\{\{state\}\}">q</figure-callout>}}_2=Q_{\mathrm{about}bu}^{\mathrm{one}}-q_3-q_{\mathrm{from}l\mathrm{and}\mathrm{at}.}\left(5\right)$$

$$q_{\mathrm{one}}=Q_{\mathrm{about}bu}^0-q_2-q_3-q_{\mathrm{from}l\mathrm{and}\mathrm{at}.}\left(6\right)$$

Thus, in general terms, the mathematical dependence for the "n" quantity will be presented in the following form:

Q _total = q ₁ + q ₂ + q ₃ + ... Q _n + q _drain. ,

where q ₁ is the flow rate absorbed by all productive intervals before the bottom of the horizontal trunk;

q ₂ is the flow rate absorbed by the productive intervals before the bottom of the horizontal trunk, except for the last interval from the bottom;

q ₃ is the flow rate absorbed by the productive intervals before the bottom of the horizontal trunk, except for two long productive intervals farthest from the bottom;

q _n is the flow rate absorbed by the productive intervals before the bottom of the horizontal wellbore, except for the previously passed productive intervals in the course of drilling the horizontal wellbore;

q _drain. - the flow rate of water entering the measuring tank at the wellhead.

To clarify the results of the studies, pressure losses at the end of the column are calculated for each position of the packer using pipe hydraulics formulas (Darcy-Weisbach) and, depending on the values of the losses, they are either neglected or the discharge pressure is adjusted by the outlet to achieve the condition: (Ru- Mercury) previous equals (Ru-Mercury) subsequent.

An updated hydrodynamic characteristic of the permeable zones in the horizontal wellbore can be obtained if the studies are carried out repeatedly with different injection pressures of the working agent.

The inventive method can be used to study horizontal wells drilled in productive formations of the Permian-Carboniferous deposits of the Usinsky field with pronounced zonal heterogeneity, containing highly viscous oil (oil viscosity in reservoir conditions, 710 MPa · s), the development of which is carried out using heat exposure to layer. In injection wells with a horizontal well length of 400 m, steam is injected at a pressure of 12.0 MPa and with a temperature of 320 ° C. The method can also be used at the Yaregskoye oil field of highly viscous oil, developed both by the thermal mine method and from the surface (Lya-El Square). The productive formation lies at a depth of about 200 m and contains oil with a viscosity of about 15 thousand µPa · s. To develop the field, steam is injected with a pressure of up to 1.6 MPa, but not lower than 0.5 MPa. The saturated steam pressure above 1.6 MPa cannot be raised for the conditions of thermal mine development of the Yarega field, since it corresponds to a steam temperature of 200 ° C, and sublimation of oil begins after 200 ° C, which is unacceptable for the conditions of mine development. When steam is injected, steam with a temperature of 250-300 ° C is pumped into surface injection wells.

Thus, the inventive method provides reliable information for constructing a quantitative injectivity profile of productive intervals of "hot" horizontal wells, the studies of which were practically not carried out.

Claims (2)

1. A method of researching a horizontal well, including lowering the tubing string into the well and injecting the working agent into the pipes with measuring its flow rate and pumping pressure at the wellhead, characterized in that the tubing is assembled with a multi-action packer with a liner before lowering, and when lowering the tubing, the packer is installed above the roof of the first productive interval in the direction of drilling the horizontal shaft, the injection pressure of the working agent is fixed on the mouth after it about stabilization, then the packer is disengaged and the tubing pipes are further lowered, followed by the packer installed over the roof of the next productive interval in the direction of drilling the horizontal wellbore and the working agent is injected again, and after stabilization of the wellhead injection pressure, it is maintained equal to the working agent injection pressure at the previous the study and also record the flow rate of the working agent, with the breakdown of the packer, the descent of the tubing and the installation of the packer over the roofs, etc. of productive intervals is carried out repeatedly depending on the number of productive intervals covered by the horizontal wellbore, and the injection pressure of the working agent in each study is kept constant at the wellhead equal to the injection pressure of the working agent when the packer is installed above the roof of the first production interval along the horizontal well, then on the basis of the recorded costs of the working agent, determine the amount of working agent absorbed by each productive interval per unit time. 2. The method according to claim 1, characterized in that during the study, maintaining at the wellhead the pressure of the injection of the working agent at productive intervals is constant, when it exceeds its value from the initial pressure of the injection, it is carried out by pouring the excess of the working agent into the measured capacity.

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