Boring or penetrating the earth – Processes – Boring with specific fluid
Reexamination Certificate
1998-04-03
2001-04-17
Neuder, William (Department: 3672)
Boring or penetrating the earth
Processes
Boring with specific fluid
C175S038000, C175S217000
Reexamination Certificate
active
06216801
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to the introduction of additives to drilling fluids.
BACKGROUND
Drilling through the earth is a complex endeavor, requiring sophisticated drilling equipment and drilling fluids, commonly referenced as drilling mud, in order to drill substantial distances through the various types of rock and soil commonly encountered during the drilling of vertical and horizontal bores.
Drilling mud is generally pumped from a reservoir of the drilling mud to the bottom of the bore through a central channel in the drill string. Drilling muds must be capable of performing a number of different functions, including specifically, but not exclusively, (i) cooling and lubricating the drill bit, (ii) delivering hydraulic power to the drill bit, (iii) carry cuttings upward during circulation, (iv) suspending cuttings and preventing appreciable settling when circulation is stopped, (v) preventing blowout, (vi) prevent wash out, and (vii) preventing excessive permeation of water from the bore into the surrounding formations.
A number of different drilling muds have been used over the years. Simple, unadulterated water can be used for some limited applications, but is not generally used due to its limited functionality as a drilling mud. One of the most elementary drilling muds is water mixed with drilled solids, commonly referenced as native drilling mud. Native drilling muds are generally effective for cooling and lubricating the drill bit, delivering hydraulic power to the drill bit, and preventing blowout at shallow depths. However, native drilling mud possesses a limited ability to carry cuttings upward during circulation, suspend cuttings when circulation is stopped, or reduce permeation of water into surrounding formations and washout. Over time, a number of different additives have been developed for native drilling muds in an effort to overcome these limitations.
The standard base drilling mud used today in both vertical and horizontal drilling is an aqueous slurry of bentonite clay (hereinafter “bentonite mud”). The bentonite clay may be modified with any of a number of different organic and inorganic drilling fluid additives such as sodium hydroxide, barium sulfate, lignite, polyacrylamide, and/or carboxymethylhydroxyethyl cellulose in an effort to enhance performance of the drilling mud.
U.S. Pat. No. 4,867,256, issued to Snead, discloses a method and apparatus for introducing polymer additives, such as a polyacrylamide, into drilling muds by periodically pumping liquid polymer into the conduit used to convey drilling mud from a mud pit to the kelley of a conventional drilling rig. Snead specifically discloses that a convenient method for adding the polymer into the drilling mud is to inject a defined quantity of the polymer each time an additional length of pipe is added to the drill string. While this method of introducing additives into a drilling mud comprises a substantial advance over prior procedures, the method has limited potential for commercial application due to the potential variability in the concentration of polymer within the drilling mud, and the relatively high cost of most additives compared to the cost of standard bentonite mud. In other words, the performance benefits provided by addition of a drilling fluid additive by this method are generally considered insufficient to justify the significant increase in cost.
In order to provide drilling fluids having the appropriate concentration of bentonite and/or additives, drilling fluids are routinely prepared by a batch process wherein the bentonite and/or additives are mixed into a known volume of water and then pumped into the bore. Such a procedure is highly labor intensive and requires either multiple mixing tanks or periodic pauses in drilling to permit another batch of drilling fluid to be mixed.
Accordingly, a substantial need exists for a cost effective method of introducing drilling fluid additives into drilling mud.
SUMMARY OF THE INVENTION
The invention is directed to a cost effective method and apparatus capable of proportionally injecting a drilling fluid additive into a drilling fluid.
The method involves injection of a drilling fluid additive into a drilling fluid, as the drilling fluid is being pumped into a bore hole, in direct proportion to the amount of drilling fluid being pumped. Injection of the additive in direct proprtion to the drilling fluid is important as the concentration of additive in the drilling fluid can significantly impact performance of the drilling fluid, with deteriorating performance observed when insufficient or excessive additive is injected into the drilling fluid. This is particularly true for horizontal directional drilling.
The apparatus is a standard drilling rig equipped with a means for injecting a drilling fluid additive into the drilling fluid, as the drilling fluid is being pumped by the rig into the bore hole, in direct proportion to the amount of drilling fluid being pumped.
A specific system capable of providing the desired directly proportional injection of drilling fluid additive into a drilling fluid, comprises (i) a primary pump for pumping the drilling fluid, (ii) a secondary pump for injecting the drilling fluid additive into the drilling fluid, and (iii) a control system in communication with both the primary and secondary pumps for operating the secondary pump at a flow rate directly proportional to the flow rate of the primary pump.
REFERENCES:
patent: Re. 29716 (1978-08-01), Clampitt et al.
patent: 1816324 (1931-07-01), Hansen
patent: 3231030 (1966-01-01), Blom
patent: 3502543 (1970-03-01), Sewell
patent: 3559739 (1971-02-01), Hutchinson
patent: 3637031 (1972-01-01), Hull et al.
patent: 3852200 (1974-12-01), Meyer
patent: 3909421 (1975-09-01), Gaddis
patent: 3988246 (1976-10-01), Hartfiel
patent: 4012329 (1977-03-01), Hayes et al.
patent: 4120369 (1978-10-01), Fischer et al.
patent: 4128528 (1978-12-01), Frisque et al.
patent: 4187911 (1980-02-01), Hutchinson et al.
patent: 4321968 (1982-03-01), Clear
patent: 4445576 (1984-05-01), Drake et al.
patent: 4633950 (1987-01-01), Delhommer et al.
patent: 4664816 (1987-05-01), Walker
patent: 4704213 (1987-11-01), Delhommer et al.
patent: 4867256 (1989-09-01), Snead
patent: 5010966 (1991-04-01), Stokley et al.
patent: 5076373 (1991-12-01), Hale et al.
patent: 5333698 (1994-08-01), Van Slyke
patent: 5586608 (1996-12-01), Clark et al.
patent: 5715896 (1998-02-01), Naraghi
patent: 6035952 (2000-03-01), Bradfield et al.
patent: 6039128 (2000-03-01), Brunato
Griffin, “Trends in HDD Drilling Fluid Products,”Underground Construction, pp. 45-48, Mar. 1998.
American Polywater Corporation
Neuder William
Sherrill Michael S.
Walker Zakiya
LandOfFree
Method and apparatus for providing proportional injection of... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and apparatus for providing proportional injection of..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and apparatus for providing proportional injection of... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2554242