Systems of injecting phenolic resin activator during subsurface fracture stimulation for enhanced oil recovery
OwnerGeorge L. Scott, IIIinventor
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Abstract
In connection with downhole placement of proppant materials for the purpose of enhancing oil recovery through a subsurface fracture-stimulation treatment, phenolic resin activator is injected after resin-coated proppant is pumped. The results are a reduced probability of problems attendant to premature screenout, savings in the quantity of activator needed, more concentrated placement of the activator close to the wellbore, and the ability to continue the fracturing treatment longer. Injection of activator is accomplished through tubing extending at least as deep as the perforations, while injection of proppant is done through the tubing-casing annulus.
Claims29
A method of fracturing a subsurface formation adjacent to a cased well containing tubing comprising:
- (a) pumping a mixture containing fluid and non-activated resin-coated proppant downhole between casing and tubing, thereby causing the mixture to pass under pressure through perforations in the casing;
- and
- (b) after pumping of the proppant is substantially complete, breaching a tubing-conveyed container holding a quantity of activator fluid, thereby causing the activator fluid to pass from the tubing through perforations in the casing.
A method of producing oil by fracturing a subsurface formation adjacent to a cased well containing tubing comprising:
- (a) pumping a mixture containing fluid and non-activated resin-coated proppant downhole between casing and tubing, thereby causing the mixture to pass under pressure through perforations in the casing;
- (b) while pumping the mixture, monitoring the surface injection annulus pressure in the well;
- (c) ceasing the pumping of proppant when the pressure exceeds a predetermined level;
- (d) after pumping of the proppant is substantially complete, causing an activator fluid to pass from the tubing through perforations in the casing;
- (e) thereafter pumping cleaning fluid down the tubing and up the annulus between the casing and the tubing;
- and
- (f) thereafter extracting oil flowing into the casing from the well.
An apparatus for fracturing with resin-coated proppant a subsurface formation adjacent to a cased well containing tubing comprising:
- (a) a tubing-conveyed container holding a quantity of resin activator and situated in a wellbore adjacent to perforations in casing lining the wellbore;
- (b) a surface-controlled breaching device coupled to said container;
- (c) a surface pump having an outlet positioned to pump fluid under pressure between casing and tubing;
- and
- (d) a surface pressure monitor positioned to measure pressure in the casing-tubing annulus.
A method of fracturing a subsurface formation adjacent to a cased well containing tubing comprising:
- (a) pumping a mixture containing fluid and non-activated resin-coated proppant downhole between casing and tubing, thereby causing the mixture to pass under pressure through perforations in the casing;
- (b) monitoring the pressure in the well;
- (c) while pumping the mixture, causing radioactivated tracer to enter the formation with the mixture;
- (d) measuring the level of radioactivity at a predetermined vertical distance from the casing perforations;
- (e) ceasing the pumping of proppant at the earlier of (i) when the pressure exceeds a first predetermined level, and (ii) when the measured level of radioactivity exceeds a second predetermined level;
- and
- (f) after pumping of the proppant is substantially complete, causing an activator fluid to pass from the tubing through perforations in the casing.
A method of fracturing a subsurface formation adjacent to a cased well containing tubing comprising:
- (a) pumping a mixture containing fluid and non-activated resin-coated proppant downhole between casing and tubing, thereby causing the mixture to pass under pressure through perforations in the casing;
- and
- (b) after pumping of the proppant is substantially complete, causing an activator fluid tagged with a radioactive tracer to pass from the tubing through perforations in the casing.
Dependencies are inferred from the claim text.