In this post, two recent cleantech patents in different areas of resource extraction – hydraulic fracturing or “fracing” and commercial fish trawling – are discussed.
The patent cognoscenti often use the word “teach”, to explain what an inventor's invention is. Our definition of "teach" is:
“An inventor is granted an exclusive right to their invention in exchange for teaching others skilled in the art how to make their invention by way of the information in the patent. With respect to prior art, teach is defined as informing and instructing by way of the documents making up the prior art. The prior art references teach the technology disclosed in them or revealed by them.” (For more patent-speak, see the Way Better Patents Glossary.)The first patent below provides excellent teaching regarding the fracing process.
Improving Hydraulic Fracturing EfficiencyHydraulic fracturing (“fracing” or “fracking”) is a technique used to stimulate the production of gases and fluids from underground geologic formations. It is based on the high pressure injection of fluids into a gas or oil wellbore for the purpose of fracturing the geologic formation to increase its permeability, thus stimulating the flow of the desired products into the wellbore. Included in the injected fluid is a “proppant”, typically sand, that holds the fracture open and permeable after the fluid has dispersed. The increased formation permeability, and therefore product flow, will be a function of the total length of the propped fractures. Previous Inkling posts on fracing are here and here.
Patent US 8,127,850, “Method of treating subterranean formations using sequential proppant stages” seeks to increase the effective propped lengths by using ultra lightweight (ULW) proppants. The patent was issued to Harold Dean Brannon (Magnolia, TX) and six co-inventors on March 6, 2012, and was assigned to Baker Hughes Incorporated (Houston, TX).
In Brannon et al.’s invention the ULW proppants are provided in two stages, the first being either more dense or of a different particle size than the second-stage proppant. The two-stage pumping of proppants into the formation fractures increases the effective propped length of the fractures, and thus increases the overall permeability (and yield) of the formation over a one-stage proppant fracing operation.
Brannon et al. teach the hydraulic fracturing process:
During hydraulic fracturing, a viscosified fracturing fluid is pumped at high pressures and at high rates into a wellbore to initiate and propagate a hydraulic fracture. Once the natural reservoir pressures are exceeded, the fluid induces a fracture in the formation and transports the proppant into the fracture. The fluid used to initiate and propagate the fracture is commonly known as the “pad”. The pad may contain a heavy density fine particulate, such as fine mesh sand, for fluid loss control, or larger grain sand to abrade perforations or near-wellbore tortuosity. Once the fracture is initiated, subsequent stages of viscosified fracturing fluid containing chemical agents such as breakers, and containing proppants are pumped into the created fracture. The fracture generally continues to grow during pumping and the proppant remains in the fracture in the form of a permeable “pack” that serves to “prop” the fracture open. Once the treatment is completed, the fracture closes onto the proppants which maintain the fracture open, providing a highly conductive pathway for hydrocarbons and/or other formation fluids to flow into the wellbore. The fracturing fluid ultimately “leaks off” into the surrounding formation. The treatment design generally requires the fracturing fluid to reach maximum viscosity as it enters the fracture which affects the fracture length and width.
Fracturing fluids, including those containing breakers, typically exhibit poor transport properties. High pumping rates are required in order to impart a sufficient velocity for placement of the proppant in the fracture. In such treatments, the proppant tends to settle, forming a ‘proppant bank’, as the linear slurry velocity falls as a function of the distance from the wellbore. This effect is further believed to result in reduced stimulation efficiency as the effective propped length is relatively short. In addition, much of the settled proppant is often below the productive interval.
The recovery of the fracturing fluid is accomplished by reducing the viscosity of the fluid to a low value such that it flows naturally from the formation under the influence of formation fluids and pressure. This viscosity reduction or conversion is referred to as “breaking”. Historically, the application of breaking fluids as fracturing fluids at elevated temperatures, i.e., above about 120–130 °F., has been a compromise between maintaining proppant transport and achieving the desired fracture conductivity, measured in terms of effective propped fracture length. Conventional oxidative breakers react rapidly at elevated temperatures, potentially leading to catastrophic loss of proppant transport. Encapsulated oxidative breakers have experienced limited utility at elevated temperatures due to a tendency to release prematurely or to have been rendered ineffective through payload self-degradation prior to release.By increasing the permeability and yield of individual wells through the use of this newly-patented technology, more natural gas and oil will be available, more profits will be obtained by the producers, more jobs and employee benefits by those produces can be sustained, more money will flow into ancillary purchases in the surrounding communities, and the closer to energy independence the US will be (assuming, of course, that the increased production is not negated by onerous government regulations).
These are good outcomes from using different types of sand.
Release the Young Fishes!We turn from resource extraction below ground to resource harvesting from the seas.
Ireland, not commonly thought of as a commercial fishing nation, nonetheless derives a significant fisheries harvest from its surrounding seas and oceans. These activities are described in the 2009 “Atlas of the Commercial Fisheries Around Ireland”, published by the Marine Institute. The top five most economically valuable fisheries species landed by Irish vessels in 2008 were: mackeral, Nephrops (aka Norway lobster or Dublin Bay prawn, a slim, orange-pink lobster), horse mackeral, monkfish, and edible crab, totalling €101 billion (approximately equivalent to $76.3 billion in 2012 dollars).
Irish inventor Danny Gallagher and three co-inventors have developed a new “Netting arrangement” for pelagic (i.e., water column) and bottom commercial trawling, memorialized in US 8,191,305. The patent was granted on June 5, 2012, and is currently considered by the USPTO to be a trawl fishing net. We’ll see in January 2013 how that consideration changes with the introduction of the upcoming Cooperative Patent Classification System (CPC), based on the European Classification Office’s (EPO) ECLA system.
The ‘305 patent’s first claim is:
A trawl netting arrangement including a main netting component and at least one grid portion formed from a plurality of loops, each loop having four sides, two sides of each loop being formed from longitudinally arranged substantially parallel rigid members and the other two sides being flexible, the flexible sides interconnecting the substantially rigid sides from one another such that each loop of the grid is collapsible, a collapse of the loop effecting a bringing together of the substantially rigid sides.What makes this invention cleantech?
We’ll let the inventor tell it, in keeping with the “teaching” of technological innovations in patents as described earlier in this post.
Gallagher, et al.:
The invention relates to fishing and in particular to trawling. The invention more particularly relates to netting arrangements for use in trawling such as pelagic or bottom trawling and used for selective discrimination in the catch so as to provide for improved selectivity in the size of the captured species. In one embodiment this may be used to reduce the possibility of capture of juvenile species, while in another it may be used to selectively disregard larger fish.
Pelagic trawling is the use of a cone-shaped net behind a boat to catch large schools of fish. It differs from benthic trawling–sometimes referred to as bottom trawling–in that as opposed to towing trawl nets along the sea floor, pelagic trawling provides for a towing higher up in the water column. In both trawling techniques, a flow of water passes through the net as the net is towed behind the fishing vessel.
A fishing trawl may be considered as having two main portions: the trawl-net portion which is the extended area of netting that serves to capture a large volume and which tapers inwardly towards a collecting bag or cod-end, where the captured fish are retained until the trawl is recovered on board the fishing vessel where they are then released and processed. The body of the trawl-net is funnel-like, wide at its mouth and narrowing towards the cod-end. It is long enough to assure adequate flow of water and prevent fish from escaping the net after subsequent capture. It is made of different grades of netting, the size of the mesh of the netting decreasing from the front of the net towards the cod-end. The cod end is where fish are finally caught. The size of mesh in the cod end is a determinant of the size of fish which the net catches.
Such grading of species is important in modern fish management where there are strict controls on the volumes of fish caught and also on the minimum size of the catch. The use of larger mesh sizes in the collecting bag (cod end) was among the first technical measures imposed by fisheries managers to prevent the capture of juveniles. Such arrangements require the fish to reach the side netting to achieve their escape.
While the above described arrangements provide for a certain degree in selection in the size of the captured fish, there is a further need to provide a netting arrangement that provides for discriminative capture of the fish size. It is believed that whilst all of the above described arrangements improve the prospect of escape by juvenile species, there is still a need for an improved netting arrangement.By incorporating improved size selection into the trawl net, the inventors do their part to harvest a renewable resource (fish), yet help protect the juvenile fishes by allowing them to escape.