February 4, 2023


For computer aficionados

An Enhanced Geothermal System Uses Oil And Gas Technology To Mine Low-Carbon Energy. Part 2.


The US Section of Vitality (DOE) has funded a venture named FORGE in which hot granite rock will be drilled and fracked using the ideal oil and gas technological innovation. An general purpose is to see if water pumped down 1 very well can be circulated as a result of the granite and heated prior to pumped up a 2nd very well to generate turbines that crank out electrical power.

John McLennan, Department of Chemical Engineering, University of Utah, is the co-principal investigator for this DOE job. A webinar presentation on this matter was sponsored by NSI on April 6, 2022: Frontier Observatory for Analysis in Geothermal Vitality (FORGE): An Update and Lookahead

Section 1 tackled these issues to John McLennan:

Q1. Can you offer a brief background of geothermal power?

Q2. What are increased geothermal programs, and wherever is fracking used?

Q3. Explain to us about the web page of the FORGE project in Utah and why it was selected.

This writeup is Aspect 2, which addresses a few supplemental concerns beneath:

Q4. What is the basic layout of the injection and manufacturing wells?

6 wells have been drilled to date. Five of these wells are vertically drilled checking wells, which is constant with the tactic of getting a industry laboratory. Fiber optic cables and geophones in the monitoring wells can map the chronologic expansion of hydraulic fractures interconnecting an injection nicely, which has been drilled, and an impending production perfectly.

The injection effectively was drilled to a measured depth of 10,987 ft (a correct vertical depth of 8520 ft± under floor degree). This entailed drilling vertically and then developing a curved portion at 5°/100 ft drilled, and last but not least preserving a lateral at 65° to the vertical, for about 4,300 toes in an azimuth just south of east (N105E). This direction favors subsequent hydraulic fractures remaining orthogonal to the properly.

Immediately after drilling, all but the bottommost 200 ft of the very well was cased (much larger diameter 7-inch casing was utilised to transfer important portions of h2o with minimal friction and parasitic pumping losses) and cemented to the area (to hydraulically isolate the annular room).

Q5. Could you summarize the 3 frac treatment options in the injection perfectly and their final results?

In April 2022, three hydraulic fractures had been pumped in the vicinity of the reduce extremities (the toe) of the injection very well. Geophones in 3 wells, surface instrumentation, and downhole fiber optic sensors give a view of the evolving fracture geometries during pumping. Based mostly on the interpretation of these fracture geometries, the generation properly will subsequent be drilled to intersect these clouds of microseismicity.

3 fracture stages ended up consecutively pumped. The 1st targeted the overall openhole duration of the properly (the reduce 200 toes that experienced not been cased). That cure was slickwater (friction-minimized water). 4,261 bbl (~179,000 gal) were pumped at fees up to 50 bpm (2100 gpm). Just after shutting in briefly, the very well was flowed back again at temperatures of about 220°F.

The subsequent stage involved pumping slickwater at charges up to 35 bpm through a 20-ft extensive part of casing that experienced been perforated with 120 formed prices to give access to the formation by way of the casing and the cement sheath. 2,777 bbl of slickwater were pumped and then the nicely was flowed back.

The last stage entailed 3,016 bbl of crosslinked (viscosified) fluid pumped by perforated casing at prices up to 35 bpm. Microproppant was pumped. In the foreseeable future, evaluations will be designed to assess the requirement and viability of propping fractures to be certain conductivity of the produced fractures.

Preliminary processing of the 3rd phase implies pseudo-radial fracture progress, around the well at the heart. This favors a separation involving the present injector and the future producer on the get of 300 ft. A professional situation may perhaps have to have higher offset than this having said that, this experimental program desires to 1st establish the skill to interconnect two adjacent wells with hydraulic fracturing.

Q6. What is the probable for industrial software?

In a commercial setting, a multiplicity of hydraulic fractures would be developed to interconnect wells. At the FORGE industry laboratory, the size of the lateral will be devoted to tests out new technologies. These contain approaches for figuring out reservoir qualities, hydraulic fracturing and perforating methods, conformance – nominally equal flow as a result of each and every hydraulic fracture, and the traits of circulating via these fracture networks and the charge at which thermal depletion is skilled. Study contracts are allow to other events (universities, national laboratories, industrial entities) to develop these technologies and exam them out at FORGE.

In a professional EGS location, chilly drinking water would be injected and pass by means of the array of hydraulically-designed fractures, buying heat in the process. The sizzling h2o would be manufactured to floor through the generation effectively. At the floor, typical geothermal engineering would be applied for electrical energy era (an organic and natural Rankine cycle (ORC) plant, applying a secondary natural performing fluid that is flashed to vapor to push a turbine/generator or, direct flashing to steam). The created water, after warmth has been taken out, is recirculated.

The FORGE web page will not be a electric power producer. It is intended to be employed to check and develop technologies that will boost the commercialization of this kind of geothermal electrical power. Accomplishment centers all-around engineering advancement. Previously, considerable developments have been created by promoting the software of polycrystalline diamond compact bits (PDC) that permit remarkable improves in the fees of penetration. Evaluation protocols of subsurface measurements and schooling of all rig web page personnel have enhanced the drilling economics of this geothermal undertaking.

It appears that hydraulic fracturing can be proficiently carried out – but the genuine check lies in circulation effectiveness and warmth restoration soon after the generation properly is drilled.

EGS results listed here could be utilized somewhere else. Take into consideration working with hydraulic fracturing for hybrid EGS applications the place conventional purposes have encountered the geothermal equal of a dry gap – purely natural fractures were being not encountered throughout drilling but could be intersected by fracturing.

Achievements at FORGE usually means screening technologies that would not in any other case be regarded as, passing feasible systems to personal sector, and encouraging geothermal development overall.


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