SU1705549A1 - Well completion method - Google Patents

Abstract

The invention relates to the oil and gas industry. The goal is to increase the efficiency of the method due to the possibility of increasing the degree of unloading the bottom-hole zone and preventing collapses in the open hole (C). After construction C, the presence of clay interlayers (P) is determined from geophysical data. Perforate C within the P above and below the reservoir. The fluid level in C is lowered so that the resulting pressure drop does not destroy the cement ring and casing. In this position, C is left for a time equal to the clay relaxation period. Clay from II is squeezed out through perforation holes in C. Cementing the perforation intervals C within P. Then the perforation is opened by the perforation and the development is started. C. 3 ate

Description

The invention relates to the oil and gas industry, in particular to methods for completing a well.

The purpose of the invention is to increase the efficiency of the method due to the possibility of increasing the degree of unloading of the wellbore zone and preventing collapses in the open hole.

The method is carried out as follows.

According to the project, injection wells and production wells are drilled at the multi-layer oil field. After construction of wells and determination of productive objects for

Open up according to geophysical data (PS, GC records) determine the location of clay interlayers. Then, by sandblasting perforation, the production column is perforated against clay interlayers located above the top of the roof and / or below the bottom of the productive formations. Then, the hydrostatic level of the fluid in the well is reduced so that the difference between the reservoir pressure of the fluid saturating the producing formations and the bottomhole pressure does not exceed the tensile strength of the production string and the maximum pressure drop across the cement ring. In this position, the well

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leave for a time equal to the clay relaxation period. At the same time, the clay from the interlayers is squeezed through the perforations in the column into the wellbore, which is removed by washing the wells. Flush the well until no clay particles are present in the washing fluid. At the same time, the perforation intervals are sealed by injection of, for example, cement mortar. After sealing, the productive formations are opened by perforation and proceed to the development of wells. The relaxation time is found from the formula:

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Then they began to monitor the increase in the well. After 2 days, the level increased by 13 m. After that, the bottom of the well was washed. To do this, the tubing with a feather was lowered onto the top of the reservoir. After washing, the decrease of the hydrostatic level to the same depth was repeated. At the end of the day, the fluid level in the well was raised by 0.25 m. The well was washed again. After 20 days, the clay supply practically ceased. After that, they proceeded to seal the perforation intervals against clays by pumping cement mortar into the perforation interval. Then productive formations were perforated. After the development, the injectivity of the wells amounted to 900 me / day.

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where t is the load time

(deformation time); te is the relaxation time; Е - instantaneous elastic deformation at t О; E - elastic deformation over time

m t;

EOQ-deformation at t °° The deformation of EQQ corresponds to the complete depletion of the material creep Example. Injection well No. drilled to the productive horizon L,

The depth of the squash is 1750 m. The diameter of the production string is 1U6 mm.

Tensile strength of the production string at cm PCjW kg / cm2. The productive layers were opened by drilling: a, 6Hi, b ,,, c, g. Intervals of layers, respectively: 1761, - 1763.6; Г / 65-1766,8; 1768-1 7 & 9, 1775.8-1778.6; 1783.6-1787.6.

The clay interlayers are represented by argillites in the intervals between the productive strata, the seam tire A and the bottom of the seam of the city. The hydraulic sandblasting perforation opened all the clay interlayers to a depth of 1 m. After lifting the sanding apparatus, the compressor lowered the liquid level to a depth of 1750 m, bottomhole pressure reached the value of atmospheric rate:

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Claims (1)

Invention Formula A well completion method including unloading a producing formation from a rock pressure with a decrease in hydrostatic pressure in the well, setting and cementing the casing in the well and opening it with a perforation interval within the producing formation, in order to increase the degree of the unloading of the bottomhole zone and the prevention of collapses in the open hole, the installation and cementing of the casing are performed before unloading the productive The flippers, and the unloading is performed by opening by additional perforation and time-keeping of the clay interbeds JB by the roof covering and the basement part-. tons of productive formation for a period (relaxation of clay, while reducing the hydrostatic pressure in the well is carried out to a value that does not violate the strength of the production casing and cement stone, after which the perforation intervals of the clay interlayers are cemented, and opening the casing perforation within the producing formation is carried out after cementation of intervals of additional perforation of clay interlayers.