Downhole flow-back control for oil and gas wells by controlling fluid entry

Abstract

A method and apparatus for use in hydrocarbon exploration. The method and apparatus improve downhole flow back control in oil and / or gas wells by controlling fluid entry into the well bore. Either a single limited entry opening or a small cluster of limited entry openings is provided in a well liner or casing and cement sheath allowing fluid communication between a region of a well bore and a subterranean reservoir. The method also uses the limited entry opening or the cluster during an injection treatment of the subterranean reservoir to control fluid entry. The method also provides a proppant flow back treatment following the injection treatment of the subterranean reservoir.

Description

FIELD OF THE INVENTION [0001] The present invention relates generally to a method and apparatus utilized in hydrocarbon exploration. More specifically, the present invention relates to a method and apparatus for improving downhole flow-back control in oil and / or gas wells by controlling fluid exiting the wellbore during injection of a treatment fluid and entering the wellbore during treating fluid clean-up or production of reservoir fluids. BACKGROUND OF THE INVENTION [0002] For many oil and / or gas wells, there are problems related to the inflow of various solids into the wellbore from the formation. In some cases, formation particles are being transported into the wellbore by the inflow of the reservoir fluid and / or fluids and / or gases. The transportation of formation particles into the wellbore is particularly likely if the formation rock particles are not well cemented together and / or if the pressure differential between the wellbore pressure and the reservoir pressure becomes re...

AI Technical Summary

Benefits of technology

[0012] The present invention relates generally to a method and apparatus utilized in hydrocarbon exploration. More specifically, the present invention relates to a method and apparatus for improving downhole flow-back control in oil and / or gas wells by effectively controlling fluid exit or entry into the wellbore.

[0016] The method also comprises controlling fluid entry using a single limited entry opening or a small cluster of limited entry openings during sequential injection treatments of the subterranean reservoir at multiple locations along the wellbore at separate stages of the completion process. The method also comprises providing one or more treatments that enhance formation consolidation and / or a proppant flow-back treatment following each of the sequential injection treatments of the subterranean reservoir. In some applications, there may be a single treatment method that would serve to provide both benefits of enhancing formation consolidation and reducing proppant flow-back during treatment clean-up, formation fluid production, or both flow periods.

Problems solved by technology

For many oil and / or gas wells, there are problems related to the inflow of various solids into the wellbore from the formation.

Other problem cases involve the flow-back of granular solids that have been pumped into the formation by some treatment process, such as proppant placed during a hydraulic fracturing treatment.

Flow-back of these grains during production can also be a problem.

In some of these cases, as well as in many other reservoirs, there can be both downhole and surface facility problems resulting from the flow-back of either formation solids or solids that were placed downhole during a pumping operation, such as during a hydraulic fracturing process, a frac-pack operation, a gravel pack completion, and the like.

One of the recurring problems with conventional technologies is that an operator cannot afford the cost of many of the most effective available treatment methods.

In many conventional well completions, particularly those using shape-charge perforating techniques and / or open-hole hydraulic fracturing methods, the operator does not have substantially complete control over where a pumped fluid is entering the reservoir (i.e., exiting the wellbore) at substantially all times during an injection operation.

Additionally, there is seldom a cost-effective method for controlled injection of such a treatment and / or chemical subsequent to injection of the solids but before fluid is produced back through these solids that could undesirably carry the solid back into the wellbore.

However, only if this conventional “limited entry” technique is applied in a very extreme and very expensive manner will there be any assurance that substantially all such holes will be accepting injected fluid throughout substantially the entire injection period.

Furthermore, even if such a conventional “limited entry” technique is applied in this very extreme and very expensive manner, it is proven that not all such entry points are adequately accepting fluid at the final stages of the injection period.

Moreover, there is seldom any effective post-treatment method to increase through-casing communication with hydraulic fractures, such as the multiple substantially parallel hydraulic fractures 450, 460, and 470, created by such a conventional “limited entry” technique applied in this very extreme and very expensive manner, so that produced fluid entry to the wellbore will also be limited to the same small number of small perforations.

These problems severely limit the usefulness of such an extreme “limited entry” technique completion method.

However, this gravel-pack technique is usually cost-prohibitive for low permeability reservoirs and also for many moderate permeability wells.

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