Method of increasing the well rate of exploitation and recharge wells

Abstract

The invention includes a method of increasing of the well rate of exploitation and recharge wells, comprising a means of decreasing the stress state in the well area by constructing of slot-like discharge key seats, wherein the slot-like key seats have a screw-like shape, wherein preliminary internal rock friction angles ρ are determined for a rock composing a productive strata, and a pitch of the slot key seat screw is selected such that the tangent of the angle of deviation of the slot surface from the φ vertical will be between tg(45−ρ / 2)≧tg(φ)≧1 / √3, where ρ—is the internal rock friction angle where the key slot is being made.

Description

FIELD OF THE INVENTION [0001] The present invention relates to the oil and gas extracting and hydrogeology industry and is designed to increase the well rate of exploitation and / or recharge wells by means of decreasing the stress state of the well area at the productive strata. BACKGROUND OF THE INVENTION [0002] There are known methods of increasing well rates that are applied in cases if the rate is much lower than the estimated rate. Vertical and horizontal relief slots are cut into borehole walls, the effective drainage area is fractured, and the bottom-hole area is processed by strata treating reagents like liquids and powders, for example. [0003] The most effective of above-mentioned methods is the discharge of the well area by the cutting of slots and that means the formation of orientable slot-like cavities. Such a method can increase the well rate by several times and maintain it for a long time period. Methods of fracturing and strata treatment provide less effect, which us...

AI Technical Summary

Benefits of technology

"The present invention provides a method to increase the efficiency of a well by improving the slot discharge of a well zone with less difficulty and labor intensity. This is achieved by constructing slot key seats with a screw shape in low productive intervals of the productive strata. The screw-shaped slot key seats are designed to eliminate the need for orientation and a pair of additional slots perpendicular to the main ones. The orientation of the slot key seats is determined by the internal friction coefficients of the rocks forming the productive strata, and a screw pitch is selected to ensure that the slot key seats are perpendicular to the force vectors of the main massive stresses. The method includes constructing separate vertical jogs in stages from the downside up, and a second pair of vertical jogs with a right angle to the first pair. The orientation of the second pair of jogs is determined based on the formula ½<(sin α=d / L)<√ 2 / 2. The third and following pair of jogs is made of the same length and is oriented relative to the previous jogs. The technical effect of this invention is to increase the well rate by improving the efficiency of slot discharge."

Problems solved by technology

Besides that, when the strata is treated by chemical reagents considerable difficulties arise when the strata treating solution is being delivered to the strata—huge amounts are lost when the liquid is injected into the borehole.

This process changes the compound and can badly impact injecting devices, constructive elements and the borehole.

When the border of the discharge zone initiates a fracture crack during fracturing, such a crack is always formed outside the wall packing zone.

This method is hindered by the necessity to orientate discharge slots and to determine the direction of the main compounding stresses in the massive.

Difficulty and sometimes impossibility in determining the force vectors of main stresses, across which the slots should be formed;

Difficulty and sometimes impossibility to orient the created slot in the well zone to a given direction;

High labor intensity in creation of discharge cavities without optimal guarantees and guarantees to increase the well rate.

Mentioned shortcomings do not allow increasing well rates up to their potential possible index and / or up to their estimated amount.

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