Methods For Preventing Proppant Carryover From Fractures, And Gravel-Packed Filters

Abstract

This invention relates to the oil and gas industry, in particular, to methods affecting the formation productivity at the oil and gas production stage.A method for fracture propping in a subsurface layer, which ensures a reliable protection of wells from the proppant carryover from the fracture, has been proposed. According to the proposed method, a fracturing fluid is mixed with a propping agent and particulate binding material wherein the particles have an average length-to-width ratio of less than or equal to about 10; thereafter, a formation fracturing process is implemented. Then, the particulate binding material hardens and forms a homogenous firm mass with the propping agent, which impedes the closing of the fracture and precludes proppant carryover from the fracture. Or, a fracturing fluid composition obtained by mixing a propping agent with a binding compound in the form of a powder whose size varies from about 1 to about 500 μm. A gravel-packed filter is then constructed; the said filter is based on the application of the working fluid comprising a propping filler and particulate binder with a length-to-width ratio of less than or equal to 10, or comprising a propping filler and a binding compound in the form of a powder with a size varying from about 1 to about 500 micrometers.

Description

[0001]This application claims foreign priority benefits to Russian Patent Application No. 2006146962, filed on Dec. 28, 2006.FIELD OF THE INVENTION[0002]This invention relates to the oil and gas industry, in particular, to methods affecting the formation productivity at the oil and gas production stage.BACKGROUND OF THE INVENTION[0003]The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.[0004]A carryover of proppant from a fracture to the well at the post-fracturing period either during the initial cleaning or even after completion of the well construction is a crucial issue for the oil production sector. Up to 20% of proppant can be conveyed into the well, which, can lead to negative consequences. In marginal wells, proppant settles in a casing; thus, regular washings are required and the cost of well repair operations grows. Premature wear and failure of electrical submersible pumps is another conse...

AI Technical Summary

Benefits of technology

[0015]Specifically, the invention provides methods for fracture propping in an subterranean formation which provides reliable protection of the well from excess proppant conveyance from the fracture.

[0018]The invention further provides fracturing fluid compositions obtained by mixing a propping filler and a particulate binding composition in the form of a powder, whose size varies from about 1 μm to about 500 μm. In this case, powder-like particles of the binder get into contact with the propping filler and are then solidified, increasing the propping filler pack strength.

Problems solved by technology

A carryover of proppant from a fracture to the well at the post-fracturing period either during the initial cleaning or even after completion of the well construction is a crucial issue for the oil production sector.

Up to 20% of proppant can be conveyed into the well, which, can lead to negative consequences.

In marginal wells, proppant settles in a casing; thus, regular washings are required and the cost of well repair operations grows.

Premature wear and failure of electrical submersible pumps is another consequence of the carryover of unbound proppant or other solid particles of rocks.

Also, oil or gas production decreases occur due to a significant loss of the near wellbore conductivity caused as a result of a reduced fracture thickness or overlapping of a production zone.

However, the use of this type of proppant produces undesired chemical reactions of the resin coating with the fracturing fluid.

This interaction causes partial degradation and disintegration of the coating, thus reducing the contact strength among proppant particles and, therefore, decreasing the proppant pack strength.

Further, the interaction between the resin coating components and fracturing fluid components causes uncontrolled changes in the rheological properties of the fluid, which also diminishes the fracturing process efficiency.