RU2231630C1 - Method for restoring productiveness and starting operation of standing oil and gas wells - Google Patents

Abstract

FIELD: oil and gas extracting industry.

SUBSTANCE: method includes performing maintenance and isolation operations, reopening of productive layer in starting range with depth, surpassing limits of polluted well-adjacent area by radius. Then, sparing perforation of operation column is performed, for example, by drilling perforators or hydraulic sand-blast perforation, in range of watered portion of productive bed below water-oil and water-gas contact for 1-2 meters. Newly formed perforation apertures are used to pump water-repellent compound through them, which forms water-repellent screen forcing water into depths of bed along radius. Then, sparing perforation of operation column is performed below starting range and above water-oil and gas-oil contact for 1-2 meters. Into behind-column space through newly formed apertures, above water-oil and gas-oil contact water-repellent compound is force-pumped, for example, compound on basis if polyvinyl alcohol. For prevention of behind-column flows of water and gas, cement bridge is placed in the column, which bridge covers newly formed perforation apertures. Productive bed is reopened by means of sparing perforation of operation column in first range of perforation with depth of perforation apertures surpassing limits of polluted area by radius. Flow is produced, well treatment is performed, well operation is started.

EFFECT: reliable restoration of wells productiveness, prevented flow of bed water to pit-face as well as appearance of behind-column flows of water and gas along cemented ring with minimal monetary costs.

5 dwg

Description

The invention relates to the oil and gas industry, namely, to restore the productivity of idle oil and gas wells with difficult to build reservoirs, with low filtration and capacitive properties (FES) and closely spaced water-oil (BHC) or gas-water (GWK) contacts.

When developing an oil and gas field in Western Siberia by the method of advanced drilling, wells are drilled without waiting for the development of the field and the supply of pipelines to the wells, diverting the production of the well to the producing field, i.e. the well is drilled, the production string is perforated, inflow from the reservoir is called, after which the well is shut off with a clay or saline solution of the appropriate density and preserved for a period of waiting for commissioning (up to several years, as, for example, at the Yamburgskoye field). A long stay of the well in anticipation of being connected to the pipeline and the producing field under the influence of clay or salt solutions negatively affects the reservoir properties of the reservoir rocks and the productive characteristics of the well. It is impossible to develop a well using standard methods, for example, by reducing back pressure on a formation. In such cases, it is usually practiced to re-open the reservoir by drilling the second shafts, by hydraulic fracturing, or by reperforating the initial perforation interval.

There is a method of restoring productivity and putting into operation idle oil and gas wells, including the production of repair and insulation works, opening the reservoir in the casing and putting the well into operation [Kustyshev A.V. et al. Restoring the productivity of idle oil and gas wells / Oil and gas: problems of subsoil use, production and transportation: Materials of the scientific and technical conference dedicated to the 90th birthday of V.I. Muravlenko. - Tyumen: Tsogu, 2002. - P.112].

The disadvantage of this method when restoring the productivity of idle wells with complex reservoirs and with low reservoir properties by perforating a production string with high power perforators is a violation of the tightness of the cement ring behind the column (its complete or partial destruction), which leads to the occurrence of annular flows of water and gas.

Known (the closest solution taken as a prototype is) a method of restoring productivity and putting into operation idle oil and gas wells, including the production of repair and insulation works, opening a productive formation in the casing string and putting the well into operation [Application 98116654/33 of the Russian Federation, E 21 B 47/00, claimed 04.09.98, published 20.06.00. Bull. No. 17].

The disadvantage of this method when restoring the productivity of idle wells with complex reservoirs and low reservoir properties by drilling a second wellbore when re-opening the reservoir beyond the contamination of the near-wellbore zone of the formation (FZP) is the high cost of drilling a new wellbore and its low probability of falling into the productive zone, especially in reservoirs with lenses and interlayers of rocks having fairly good FES.

The challenge facing the development of the invention is to develop a reliable method for restoring productivity and putting into operation idle oil and gas wells with low reservoir properties of reservoir rocks and closely located VNK or GVK.

The achieved technical result, which is obtained as a result of the invention, is to ensure reliable restoration of well productivity, to prevent the influx of formation water to the bottom and the occurrence of annular flows of water and gas along the cement ring with minimal capital costs.

The task and technical result are achieved by the fact that in the known method of restoring productivity and putting into operation idle oil and gas wells, including the production of repair and insulation works, re-opening the reservoir in the initial interval with a depth that extends radially outside the contaminated borehole zone, in contrast to the prototype produce “gentle” perforation of the production casing, for example, drilling perforators or sandblasting perforation (GPP) , in the interval of the flooded part of the reservoir below the BHC or GWC by 1-2 meters, a water-insulating composition is pumped through the newly formed perforations, forming a water-proof screen, pushing the water into the depth of the reservoir along the radius, produce a “gentle” perforation of the production string below the initial perforation interval and 1-2 meters higher than VNK or GVK, a sealing composition, for example, a composition based on polyvinyls, is pumped into the annulus through newly formed holes above the VNK or GVK of alcohol [Kleschenko II. and others. Insulation work in the completion and operation of oil wells. - M .: Nedra, 1998. - 267 pp.], To prevent behind-the-casing flow of water and gas, a cement bridge is installed inside the production string, blocking the newly formed perforations, re-opening the reservoir by “sparing” perforation of the production string in the initial perforation interval with the depth of the perforations extending radially outside the contaminated zone, they call the inflow, development and commissioning of the well.

Figure 1 shows the design of the well before restoring productivity and putting into operation, figure 2 - the same, in the process of displacing produced water from the bottom and installing a water insulating screen, figure 3 - the same, in the process of "gentle" perforation production columns below the initial perforation interval and above the OWC or GWC and injection of the sealing composition to prevent annular flow of water and gas, Fig. 4 is the same, during the installation of the cement bridge, Fig. 5 is the same, after restoration of productivity and commissioning exploited atation.

The method is implemented in a well idle for a long time, filled with a killing fluid (clay or saline) 1, the filtrate of which through the initial perforation interval 2 in the production casing 3 penetrated into the bottomhole formation zone and degraded the reservoir properties of the reservoir rocks to the depth of the contamination zone (contaminated bottom hole zone) 4. During the same time, due to the development of the main part of the deposit, the initial VNK or GWK rose from a depth of 5 to a depth of 6. At the same time, during the initial perforation of production casing 3, a partial th destruction cement ring 7, which can lead to casing flow of water and gas.

Initially, a “gentle” perforation of production casing 3 is performed in the well in the interval below the current oil-and-gas complex or GWC 6 by 1-2 meters. “Gentle” perforation can be produced by firing perforators, GPP or in any other way that does not destroy the cement ring 7 behind the production string 3. After that, the water-insulating composition 10, forming a water-proof screen 11, is pumped into the flooded part 8 of the productive formation through the lower, newly formed holes 9 pushes water into the depths of the reservoir along the radius. The water-insulating composition 10 is injected through drill or tubing 12, while the annulus 13 of the well to cut off the initial perforation interval 2 from the newly formed lower interval 9 is blocked by a packer 14, for example an inflatable one. The water-insulating composition 10 is put into the formation using a squeezing solution 15. Then, “gentle” perforation of the production casing 3 is made below the initial perforation interval 2, but 1-2 meters higher than the current VNK or GVK 6, in the gas-bearing part of the productive layer 16. Through the upper , the newly formed perforations 17 pump the sealing composition 18, for example, a composition based on polyvinyl alcohol. The sealing composition 18 also fills the channels previously formed during primary perforation in the cement ring 7. After that, a cement bridge 19 is installed inside the production casing 3, overlapping the newly formed upper 17 and lower 9 perforations to a depth of 1-2 meters. Produce a “gentle” repeated perforation of the production string 3 in the initial perforation interval 2 with the depth of the perforations 20 extending radially outside the contaminated zone 4. Then the inflow is called and the well is developed.

The proposed method for restoring productivity and putting idle oil and gas wells into operation is more reliable than opening a productive formation by drilling a new wellbore, since it requires less work costs and increases the likelihood of restoration of well productivity.

Claims (1)

A method of restoring productivity and putting into operation idle oil and gas wells, including repair and insulation work, re-opening the reservoir in the initial interval with a depth that extends along the radius of the contaminated borehole zone, characterized in that they produce “sparing” perforation of the production string , for example, with drilling perforators or sandblasting perforations, in the interval of the flooded part of the reservoir below the oil-water or gas water contact at 1-2 m, a water-insulating composition is pumped through the newly formed perforations, forming a water-proof screen, pushing the water deeper into the formation along the radius, produce a “gentle” perforation of the production string below the initial perforation interval and 1-2 m above the oil-water or gas-water contact , pumped into the annulus through the newly formed holes above the oil-water or gas-water contact sealant composition, for example, a composition based on polyvinyl to prevent annular flow of water and gas, a cement bridge is installed inside the production casing, blocking the newly formed perforations, the productive formation is re-opened by “gentle” perforation of the production casing in the initial perforation interval with the perforation depth extending radially outside the contaminated zones, make an inflow call, development and commissioning of the well.

Images