SU791954A1 - Device for measuring piezoconductivity factor - Google Patents

Description

(54) METHOD FOR DETERMINING THE POWER CONDUCTIVITY COEFFICIENT

one

The invention relates to the field of geological exploration and can be used to determine the intensity of water withdrawal and well placement in the production of construction dewatering and drying mine workings.

A known method for determining the coefficient of piezoconductivity, based on an analysis of the reaction rate of a water pump formation, measured in an observation well when pumping from the central 1.

This method can be applied by TcyjbKO in the case of one central and at least one monitoring well.

A known method for determining the piezoconductance coefficient includes pumping a fluid from a well with a constant flow rate, periodically measuring the level and determining the change in the decrease in the level of the pumping duration with a correction in terms of the hydrodynamic imperfection of the well 2.

The essence of the known method is that the results of the nabitions are represented as a diagram in coordinates x 9, where 5 is the lowering of the level, -fc is the time from the beginning of the rollouts. The decrease and time with a constant pumping rate are interconnected by a known equation

and 2Soit

TO

o.1gs

c), and)

3 g to. Well

 whereC

constant well flow rate;

km water conductivity of rocks; coefficient of piezoconductivity;

and the well radius;

g figure hydrodynamic

15th well imperfection, depending on the quality of the opening of the aquifer.

From formula (1), it follows that the diagram in the above coordinates represents a straight line with a slope to the abscissa axis equal to

1-5 (1),

25

cut on the y-axis (axis of lowering) segment

L-1 (c

2D5A

(one

thirty

Measured on diagram i and A, determine the piezoconductivity and water conductivity.

The formula (3) includes two unknown quantities a and c. Effective methods for determining the hydrodynamic imperfection indicator of wells (C) are currently absent, but it is known that at a distance greater than the reservoir power from the C 0 excitation well. Since a decrease in the level (pressure) at this point is described by the same form | Muloy (1), the determination of the coefficient of piezoconductivity, provided that the change in the decrease in the level (formation pressure) in it is known, is not labor. To measure the level (pressure) a special observation well is drilled. The pumping duration is 10-30 days. depending on the distance between the center and observation wells.

The disadvantage of the method is that its implementation requires the drilling of at least one observation well.

The aim of the invention is to simplify the method of investigation by eliminating drilling of observation wells, which leads to a significant reduction in exploration costs without loss of reliability and representativeness of its results.

This goal is achieved by additionally performing a series of short-term pumpings from wells with different constant flow rates, determining a decrease in levels, values of the coefficient of conductivity and their product for each pumping, after which they find dependencies between the specified products and flow rates, compare it with the target and by the comparison result determines the hydrodynamic imperfection index of the well.

The essence of the method is:. next.

The drawing shows the relationship between the indicator of the intensity of the well, water conductivity and flow rate.

the magnitude of the hydraulic losses due to the imperfection of the well depends on the flow rate of the well - it increases with increasing flow rate and increases with its decrease, with a flow rate equal to zero, vanishes.

Conducting a series of short term pumpings allows us to establish a relationship between a decrease in the level (pressure) in the well, reflecting hydrodynamic imperfection and flow rate. It is not excluded, however, that with a change in flow rate, the actual capacity and, consequently, the water conductivity of the reservoir, which also affects

the observed decrease in the level (pressure).

To study this phenomenon, an additional operation is introduced - determination of the well activity intensity indicator (product of lowering the S level for a given production rate for the conduction value determined for the same production rate). The lowering of the level is chosen for the same period of time from the beginning of each of the short term pumpings. The amount of conduction is determined by the formula (2).

A relationship is established between the product of the decrease in the level of conduction and the flow rate of the well 5 (curve 1, the relationship / distance is determined by the value of conduction and the flow rate (curve 2), tangent 3 to curve 1 is drawn, which is the ideal relationship (at C O) by comparing the flow rate with a decrease in the level and the flow rate. A comparison of the flow rate of the well’s imperfect imperfection according to the formula is determined when the flow rate is long from pumping (5 km) f c (Skm)

. (| X

oh 1st

G - the rate of continuous pumping;

(Skm) and (Skm) M product. conduction to a decrease in the level, respectively, the actual and specified (ideal).

According to the results of long from pitching using formulas (3) and (4)

determine the coefficient of piezoconductivity.

The economic effect of the implementation of the proposed method is to save money on the determination of the piezoconductivity coefficient due to the abandonment of drilling of observation wells.

Claims (1)

1. Underground hydrodynamics. Works NINHiGP them. I.M. Gubkina, vol. 53, 1963, p. 249-252. . 2.6orevsky B.V. et al. Methods for determining parameters of aquifers based on pumping data. M., Nedra, 1971, (prototype). ct