Method of treating bottom zone of injecting wells

FIELD: oil and gas production.

SUBSTANCE: groups of high intake- and low intake-capacity injecting wells are chosen in a single hydrodynamic system and, for each well, oil reservoir properties and permissible degree of pollution of fluid received by high intake-capacity wells are determined. When fluid from low-permeable oil reservoir flows off through high intake-capacity wells, this fluid is cleaned to permissible degree of pollution.

EFFECT: reduced losses in intake capacity of formations and increased time between treatments of wells.

1 dwg

 

The invention relates to the oil industry, and in particular to methods of cleaning the bottom zone of the oil reservoir in the injection wells during the operation of low-permeability layers or impaired their performance due to contamination of the near-wellbore zone.

Known methods for cleaning bottomhole injection wells using physico-chemical effects, in addition to special chemical reagents used various additional downhole tools and equipment (Reseration, Udhar “the Opening of productive horizons and development wells.- Lions: High school, 1982, 152 S. and RF Patent №2140531, E 21 In 43/22. Publ. 27.10.99, BI No. 30).

The disadvantage of these methods is that it requires a large additional costs associated with engagement teams and underground repair of wells and installation of additional downhole equipment and surface equipment.

The closest in technical essence and the achieved results to the present invention is a method of cleaning the bottom zone injection wells, including injection of water into injection wells, uncapped different permeability, cleaning the bottom zone viscoplastic wells through a spout of water in the conduit and the well is s with higher permeability (RF Patent No. 2165012, E 21 In 43/25. Publ. 10.04.2000, BI No. 10).

This method allows for the restoration of the pick-up layers without and underground repair of wells through spout fluid from contaminating particles from viscoplastic wells in vysokopiaristye when operating the pump at the pumping station.

The disadvantage of this method is the fact that brought water from low-permeability reservoirs through iskopaemye well clogging Pravovoe space of the reservoir particles are directed through vysokopiaristye wells in reservoirs with high permeability. Accumulating over time, clogging material displaced from reservoirs with low permeability in high-permeability reservoirs, reduces the permeability of the latter, which, in turn, leads to a decrease in the rate of flooding of oil fields and entails the drilling of new injection wells, reduction of current oil production and oil recovery factor. The negative effect is particularly evident when the spout of water pollution from low-permeability wells in low-permeability, but with less pressured. In addition, contaminated and the conduit, part of the dirt (wax substances, waxes, solid particles) accumulate on the walls of pipes, conduits, increasing hydraulic losses and causing the re-contamination of the reservoir.

The technical objective of the proposed method is to reduce the loss of injectivity of the reservoir, increasing the time between each execution of the bottomhole zone injection wells and, as a result, savings in material costs to maintain reservoir pressure and the drilling of new injection wells.

The technical problem is solved by the described method of cleaning the bottom zone injection wells, including the selection of groups viscoplastic injection wells with low bottom-hole zone of the reservoir and viscoplastic injection wells with highly permeable bottom area of the reservoir in a single hydrodynamic system, the outflow of fluid from low-permeability reservoirs in high-permeability reservoirs through vysokopiaristye well.

What's new is that after the separation of groups into a single hydrodynamic system determine reservoir characteristics of each of the wells, determine the permissible degree of contamination of fluid taken vysokopiaristye injection wells, additionally produce reflux liquid from low-permeability reservoirs in low-permeability, but with a smaller reservoir pressure, the reservoir through vysokopiaristye well, and in the process of outflow of fluid from low-permeability reservoirs in high-permeability and low-permeability is, but with a smaller reservoir pressure, the reservoir through vysokopiaristye wells produce clean the liquid from each discpriest well to the permissible degree of contamination, accept vysokopiaristye injection wells.

From available sources, the patent and scientific literature authors unknown to the stated set of distinctive features. Therefore, the proposed method meets the criterion of “significant differences”.

The drawing shows a diagram of the proposed method.

The method of cleaning the bottom zone of injection wells is carried out in the following sequence.

Release group viscoplastic injection wells 1 with low bottom-hole zone of the reservoir and viscoplastic injection wells 2 with highly permeable bottom area of the reservoir in a single hydrodynamic system 3. After the separation of groups into a single hydrodynamic system determine reservoir characteristics of each of the wells, determine the permissible degree of contamination of fluid taken vysokopiaristye injection wells. Then with closed valves 4 viscoplastic wells are pumping water in iskopaemye wells 1 for a certain period of time, the pump pumping station (SPS) . Next make the opening of the valve 4 on viscoplastic wells 2, resulting in outflow of fluid from low-permeability reservoirs in high-permeability and low-permeability, but with a smaller reservoir pressure, the reservoir through vysokopiaristye well 2. At the same time in the process of outflow of fluid from low-permeability reservoirs in high-permeability and low-permeability, but with a smaller reservoir pressure, the reservoir through vysokopiaristye wells produce clean the fluid filter device 6 of each discpriest well to the permissible degree of contamination, accept vysokopiaristye magnetically wells, by automatically adjusting the direction of flow through the system non-return valves 7 and 8. The flows presented in the diagram: I - water in low-permeability layer, II - water from low-to high-permeability layer (spout). III - pollution.

An example of a specific implementation.

Release group viscoplastic injection well 1 pumping station, with acceleration from 50 to 200 cubic meters per day with wellhead pressure Pmouth=10-15 MPa, and the group viscoplastic injection wells 2 pickup 500-1000 cubic meters per day with wellhead pressure Pmouth=5 MPa in a single hydrodynamic system. After separation of groups within a single guy the dynamic system define the permissible degree of uid contamination, accept vysokopiaristye injection wells - concentration oil 60 mg/l, the suspended sediment concentration 50 mg/l, the size of the contaminant particles 12 microns.

The CND pump 5, for example CNS 180×1422, are pumping the water through the conduit 3 in iskopaemye injection well 1 with a flow rate of Qsupplies=3000 cubic meters per day and the pressure on uicide pump (Poff), is equal to the pressure on the block-comb (PBG) Poff=PBG=15-16 MPa. When this valve 4 to wells with high pickup 2 at this time closed. The injection of water into iskopaemye well 1 (thread I) is produced directly through the check valve 7 (the non-return valve 8 is closed). Taking CND 5 in a given mode within one to three days, make the flow adjustment valve CND, creating a slight differential pressure Poff-RBG=1 MPa and locking the operating parameters of the unit RoffPBG, Qpacxand non viscoplastic wells NSLE. Then open the valve 4 on selected wells with high pickup 2, thereby creating a depression of up to 10 MPa in a single hydrodynamic system. Wellhead pressure on viscoplastic injection wells 1 drops to 5 MPa, and from low-permeability reservoirs is low tide liquid (stream II) in the high-permeability and low-permeability, but with less is m plastove pressure, collectors through vysokopiaristye well 2. When liquid flows from viscoplastic injection wells in the conduit, an automatic closing of the check valve 7 and the opening of the check valve 8. Water pollution made from the bottom-hole zone of low permeability reservoir, clean the filter device 6 on each discpriest well. Water with permissible degree of contamination enters vysokopiaristye well 2, and pollution trapped on the filter device is removed for disposal (stream III).

To use the described principle can repeatedly.

To verify the effectiveness of cleaning the bottom zone of low permeability reservoirs viscoplastic wells need to return to the original preset mode and fix RoffPBG, QpacxNSLE. The change in PoffPBG, Qpacxit is concluded that the degree of effectiveness of a purification of the bottomhole zone.

Use this offer allows you to restore the pickup of low-permeable layers without and underground repair of wells with adjustable spout fluid and simultaneous purification of viscoplastic wells in vysokopiaristye when operating the pump at the pumping station.

Pic is b cleaning bottomhole injection wells, including the selection of groups viscoplastic injection wells with low bottom-hole zone of the reservoir and viscoplastic injection wells with highly permeable bottom area of the reservoir in a single hydrodynamic system, the outflow of fluid from low-permeability reservoirs in high-permeability reservoirs through vysokopiaristye wells, characterized in that after the separation of groups into a single hydrodynamic system determine reservoir characteristics of each of the wells, determine the permissible degree of contamination of fluid taken vysokopiaristye injection wells, additionally produce reflux liquid from low-permeability reservoirs in high-permeability and low-permeability, but with a smaller reservoir pressure, the reservoir through vysokopiaristye well, and in the process of outflow of fluid from low-permeability reservoirs in highly permeable and low permeability, but with a smaller reservoir pressure, the reservoir through vysokopiaristye wells produce clean the liquid from each discpriest well to the permissible degree of contamination, accept vysokopiaristye injection wells.



 

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