RU2593606C1 - Method for monitoring process parameters in stratum tube test - Google Patents

Abstract

FIELD: oil industry.

SUBSTANCE: invention relates to investigations of oil wells during pipe testing of productive formations, in particular, to control intensity of formation. Method for monitoring process parameters in stratum tube test involves using weight sensor, flushing fluid flow rate transducers, and gas-air mixture flow sensor, located on drilling site, for process control of stratum test procedure. In this testing method, before starting stratum test procedure, weight sensor is placed in area between chain bloc (or elevator) and upper pipe of testing layout, directly at drilling hook or swivel, and rotor rotation speed sensor is installed on upper pipe of testing layout. According to changes in readings of weight sensor, flushing fluid flow rate transducers, and sensor of gas-air mixture, flow rate of formation fluid supplied to pipe is accounted, control of well shaft tightness is performed, and time of open formation test period is corrected.

EFFECT: technical result is increased information value of investigations during stratum pipe testing, higher labour efficiency of formation testers, ensuring rapid control over test mode, and higher data accuracy concerning hydrodynamic properties of formation.

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Description

The invention relates to the field of research of oil and gas wells during the testing of reservoirs on pipes, in particular to control the intensity of manifestations of the reservoir. From the history of the issue.

Tests of formations in pipes (hereinafter - IPT) are carried out, as a rule, by service companies during the construction of exploratory and exploratory wells. The process of IPT itself is quite formalized, there is a sufficient amount of regulatory documentation that governs the details of the entire cycle of preparation and testing [1, 2]. However, information on the success of the operation obtained in the process of IPT by known methods is insufficient. First of all, this is due to the lack of an information communication channel between the bottomhole pressure gauges and the wellhead - all information is only available after lifting the test assembly from the well on the drill pipes and then decrypting the records of the autonomous manometers. The indirect information obtained in this way is subjective, not reliable. Moreover, as you know. - one of the signs of opening the inlet valve of the formation tester is an intensive air outlet from the drill pipe, accompanied by an influx of fluid. Depending on the intensity of the air outlet, the time of the open / closed formation testing period is adjusted. Monitoring of this process is carried out from one of the riser branches, which is not always convenient and unsafe for operating personnel, and the degree of manifestation of the inflow by personnel is determined intuitively, based on practical experience, which is in principle unacceptable!

It is known to use the diagram of changes in the readings of the weight sensor on the hook to estimate the amount of fluid entering the well during the test, as well as its density [3]. A weight sensor is available on all rigs and is usually duplicated. The essence of the measurement method is to control the degree of tension of the fixed end of the hoist rope, depending on the volume and density of the fluid entering the well according to the readings of the flushing fluid flow sensor and the gas-air flow sensor. However, the accuracy of such measurements is insufficient, since the weight sensor is fixed in the "dead zone" of the hoist rope, which leads to significant errors introduced by the friction force of the hoist system. In this case, the approximate production rate of the well is estimated only after completion of the test and lifting the test assembly by counting running meters of pipes filled with formation fluid:

$$Q=\frac{H\ast \pi \ast r^2}{T}$$

where Q is the flow rate, N is the increase in fluid in the pipes for the entire test period,

r is the radius of the drill pipe, T is the time of the open test period.

The value of H is determined visually from the boundary of the liquid level in the pipes, and when a large amount of gas is contained in the liquid, it is subject to a significant error. Thus, the flow rate of the well during the test process is practically not quantifiable, and therefore, the adjustment of the inflow time is delayed in time or does not occur at all in the absence of indirect signs of inflow, for example, such as an intensive exit of air from the pipes.

In addition, the time of the open formation testing period is set by the subsoil user on the basis of known methods for controlling the estimation of the amount of fluid entering the well during the test, based on the average statistical data of previous tests on other wells in the region and is not always optimal for the qualitative determination of the characteristics of an individual formation under study. In addition, during long-term operations of formation testing, there is a risk of environmental pollution of the environment by products poured out of the well during the ongoing work.

The objective of the present invention is to increase the information content of studies when testing a formation on pipes, increase the efficiency of monitoring the work of a formation tester, provide operational control of the test mode and increase the accuracy of data on the hydrodynamic properties of the formation.

The problem is solved as follows.

In accordance with the method of monitoring technological parameters during the testing of formations on pipes, including the use of a weight sensor, flow rate sensors for flushing fluid and an air-gas mixture flow sensor for technological control of the formation testing process, according to the invention, before starting the formation testing process, the weight sensor is placed in the area between the tackle block (or elevator) and the upper tube of the test assembly - directly on the drill hook or swivel, and the rotor speed sensor installed vayut directly on top of the test tube arrangement, by total weight sensor readings change, the flushing fluid flow sensors and sensor-gas mixture is carried out keeping flow rate entering the tube formation fluid, control the tightness of the wellbore and adjusting the open seam test period.

The proposed method for monitoring technological parameters in the process of testing formations on pipes has the following advantages:

- placing the weight sensor in the area between the tackle block (or elevator) and the top pipe of the formation tester, namely, directly on the drill hook or swivel, excludes the influence of friction forces introduced by the tackle system on its readings.

- installation of the rotor speed sensor directly on the upper pipe of the test assembly provides the convenience of personnel monitoring the number of pipe turns when changing the open-to-closed positions of the intake valve, while the sensor itself is not exposed to external dynamic influences, (for example, during accidental impacts the assembly pipe on the rotor table during the descent of the test assembly to a depth);

- the readings of the weight sensor in conjunction with the data of the flow sensors available at the drilling site provide the necessary information about the flow rate of the fluid coming from the formation into the pipes during the inflow period; which, together with the data of the air-gas mixture flow sensor, allows you to quickly adjust the time of the open formation test period, and together with the readings of the fluid flow sensor at the outlet pipe, provides information about the tightness of the test column and packer.

In practice, to implement the proposed method for monitoring technological parameters in the process of pipe formation testing (IPT), a weight sensor, liquid flow sensors and a gas-air mixture flow sensor (GVS), as well as a rotor revolution sensor, are mounted before the start of testing according to the proposed invention. Namely, the weight sensor is mounted directly on the drill hook or swivel, and the rotation sensor is mounted directly on the top pipe of the test assembly. Depending on the task of the formation tests, the flushing fluid flow sensor is installed on the manifold or in the injection line of the mud pump to control the amount of pumped fluid, or on the exhaust pipe at the outlet of the well to control the absorption of flushing fluid. At the same time, the DHW flow sensor is installed on the lead pipe outlet - when testing the formation with the wellhead piping through the lead pipe, or on the production line from the well to the tank - when testing with the wellhead.

To test the formation, the indicated sensors already available at the drilling site can be used if their layout corresponds to the locations of the equipment for conducting the formation testing as claimed in the invention.

Then, on a string of drill pipes or tubing (tubing), a set of test equipment is lowered into the well, which usually includes one (or two) packer, IPT, shut-off valve, sampler, jar, circulation valve. The interval of the well with a possibly productive formation is isolated with a packer, the weight sensor readings are recorded until the product arrives from the formation in the pipe string and the formation tester inlet valve and / or shut-off valve are opened. The shut-off valve is opened by rotating the drill pipe (or tubing) from the wellhead by rotating the rotor of the drilling rig. The rotation sensor available on the upper pipe allows you to record the number of pipe revolutions and thereby accurately determine when the shut-off valve is set to the “open” position (commercially available shut-off valves (type ZPKM 2-146M) used to test formations on pipes are switched sequentially from the “open” to “closed” position by rotating the pipes 10 turns to the right).

Data from the weight sensor, liquid flow sensors, dhw flow sensor and rotor speed sensor via electrical conductors is sent to the driller’s console (or any other system for collecting and processing sensor signals with a personal computer or remote display). After the well is opened for inflow, the weight sensor readings are incremented, by which the filling of the internal volume of the pipes with the product coming from the formation is monitored and, together with the readings of the DHW flow sensor, the time allotted for the open formation testing period is corrected, if necessary.

Further, in the process of working on the totality of the parameters of all these sensors, the driller’s console monitors the process of the formation test mode. In this case, directly during the IPT, the flow rate of the additional fluid coming from the formation is calculated, which is determined by the formula:

$$Q=\frac{\Delta P}{\rho \ast \Delta T}$$

where Q is the flow rate, is the weight gain at the sensor over the time ΔТ, ρ is the fluid density previously calculated from other geophysical studies.

This shows that the accuracy of determining the flow rate of the liquid entering the pipes during the IPT process depends only on the resolution of the used weight sensor (in this connection, more sensitive weight sensors should be installed for objects with low flow rates).

Thus, by changing the parameter of the weight sensor located in the area between the tackle block and the upper pipe of the test assembly, in conjunction with the readings of the fluid flow sensors, one can judge the intensity of reservoir manifestations and make timely adjustments to the time allotted for the open test period - reduce the time of the open period tests with large flow rates of the well, or increase the time of the open test period with small flow rates of the well.

In this case, in the absence of changes in the readings of the weight sensor, i.e., by Q = 0, it can be judged on the presence of low-permeability reservoirs in the reservoir study interval, indirectly confirmed by the absence or very weak air exit from the pipes, recorded by the air-gas mixture flow sensor. And by comparing the readings of the flow rate indicator of the washing liquid before and after the opening of the shut-off valve in the absence of their changes, one can judge the tightness of the layout of the test equipment and the packer.

Creating successive periods for the influx of reservoir fluid and the restoration of pressure in the pipes by means of a shut-off-rotary valve, the program for conducting reservoir research is carried out.

Claims (1)

A method for monitoring technological parameters during the testing of reservoir formations, including the use of a weight sensor, flow rate sensors for flushing fluid and an air-gas mixture flow sensor located at the drilling site for technological control of the formation testing process, characterized in that a weight sensor is placed before the formation testing process in the area between the tackle block (or elevator) and the upper pipe of the test assembly - directly on the drill hook or swivel, and the rotation speed sensor ora is mounted on top of the test tube arrangement, by total weight sensor readings change, the flushing fluid flow sensors and sensor-gas mixture is carried out keeping flow rate entering the tube formation fluid, control the wellbore integrity and correcting the open seam test period.