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Home My WebLink AboutCOM 0133.001 2014-2016COUNTY CLE COUNT"-.' ' :1 A l n 2M5 MAR -3 PH IZ 42 MEMORANDUM March 3, 2015 TO: Dru Mamo Kanuha, Council Chair And Members of the Hawaii County Council FROM: aura Murashige, Executive Assistant to Council Chair Office of the County Clerk/Council Division SUBJECT: Resolution No. 89-15 (Communication No. 133) The attached letter is a copy that was submitted to the 2010-2012 Hawaii County Council term as testimony. Copies were dropped off at the Hilo Council Chambers by Mr. Thomas Yeh of Yeh & Moore LLLC Law Offices; in which Mr. Yeh is Counsel for PGV and provided verbal testimony. Copies were distributed at the Agriculture, Water and Energy Sustainability Committee meeting on March 3, 2015. DMK/lm Att. Carirn. No. Ref. To: Ref. Date MAR 0 3 2015 NEEL GOVERNOR GOVERNOR OF HAWAII t6 ..0 F,~4� loss) WILLIAM I. AILA, JR BOARD OF LAND CHAIRPERSON NATURAL RESOURCE'. .(' R i COMMISSION ON WATER RESOURCE MANAGEMENT 777 1 ESTHER KIA'AINA O( and �� ,¢� FOIST DEPUTY WILLIAMM.TAM DEPUTY DDLECTOR - WATER AQUATIC RESOURCES [� i fX . .0� BOATING AND OCEAN RECREATION BUREAU OF CONVEYANCES COMMISSION ON WATER RESOURCE MANAGEMENT STATE OF HAWAII CONSERVATION AND COASTAL LANDS CONSERVATION AND RESOURCES FNFORCEMINT ENG04EEMG s teof 2 DEPARTMENT OF LAND AND NATURAL RESOURCES HISTORIC �RIYPRES PRESERVATION I(AHOOIAWE 6IAND NISFRVE COMMISON POST OFFICE BOX 621 STA PTE`ANAPAS HONOLULU, HAWAII 96809 NOV 8 2012 c .. :Z Hawaii County Council =� c/o Office of the County Clerk C-) 25 Aupuni Street >►m Hilo, Hawaii 96720PIK Dear Chair Yagong and Council Members: County of Hawaii Bill No. 292 — Relating to Geothermal Drilling The Department of Land and Natural Resources (DLNR) is tasked with the management of geothermal resources and its development to ensure its continued viability for future generations. Geothermal resources development in the State of Hawaii is a priority and has contributed to energy diversification. Bill No. 292 proposes to limit the drilling of geothermal wells that occur within a mile of a residence to between the hours of 7 a.m, and 7 p.m. DLNR opposes Bill No. 292 as restrictions on night time drilling could increase the risk for groundwater contamination and blow -outs. Repeated interruption of drilling operations for extended periods of time is unprecedented in the industry and could contribute to unintended consequences that could impact the public safety and our geothermal and water resources. We wish to share with you information prepared by GeothermEx, DLNR's independent geothermal consultant. The first memo identifies potential public safety impacts that may occur if geothermal well drilling was restricted from the industry standard 24/7 operations. The second memo addresses time and cost impacts that drilling restrictions could also incite. We recognize that noise may be construed as a public nuisance and one of the main reasons for the Hawaii County Council to consider this measure. If noise is the primary concern, we recommend that additional mitigative measures be implemented in lieu of restricting drilling operations at night. We believe this would be a reasonable balance that addresses the concerns of those living in close proximity, while not increasing the risk to public safety or our resources. Thank you for the opportunity to comment. Sincerely, WILLIAM J. HILA, JR. Chairperson Attachments c: DBEDT GeothermEx A Schlumberger Company To: Carty Chang Chief Engineer cc: From., Subject: Introduction MEMORANDUM Date: Department of Land and Natural Resources State of Hawaii carty.s.chang@hawaii.gov Cameron Black 3260 GLUME DRIVE, SUITE 220 AOND. CALIFORNIA 94806 USA PHONE: (510) 527-9876 PAX: (510) 527-8164 www.geothermex.com 31 October 2012 Hawaii State Energy Office Department of Business, Economic Development & Tourism State of Hawaii Cameron.B.Black@dbedt.hawaii.gov James Lovekin and Eduardo Granados Safety Aspects of Restrictions on Night -Time Drilling of Geothermal Wells GeothermEx has prepared this memo to summarize the ways in which restrictions on night- time geothermal drilling could affect the safety of drilling operations. Fundamentally, shutting down drilling operations at night would cause repeated interruptions in the circulation of drilling fluids, and it would extend the period of time in which the wellbore is exposed to drilling fluids without having casing installed. There are three consequences of this that could create adverse conditions for safety: (1) thermal cycling of the well casing; (2) a build-up of gas pressures in the wellhead; and (3) loss of integrity of the wellbore wall. These three topics will be discussed in greater detail below. Thermal Cycling As a geothermal well is drilled, a sequence of pipes (casing strings) are cemented at successively greater depths to help keep the shallow underground aquifers from being contaminated, seal up the upper parts of the well and protect the formation from pressures that could lead to fracturing. By the time a well is completed, there are several concentric strings of casing at the surface, with cement in between each string and in the annulus between the outer casing and the formation. Each casing string is susceptible to thermal expansion when it gets hot, and thermal contraction as it cools. The cement around the pipes helps control this expansion and contraction by binding the concentric casing strings to each other and to the surrounding formation. The cement also prevents the unwanted migration of fluids from the geothermal Page 1 of 3 GeothermEx 3260 BLAME DRIVE, SUITE 220 RICHMOND, CALIFORNIA 94806 USA A Schlumberger Company PHONE: (510) 527-9676 FAX: (510) 527-8164 www.geothermax.com reservoir to shallower formations through annular spaces outside the casing strings. In the normal operation of a geothermal well, casings are exposed to periodic cycles of heating and cooling (for example, when a production well is put on line and when it is shut in). These cycles are relatively infrequent, and well -cemented casing strings are designed to accommodate this. However, repeated thermal cycling of a well during drilling can lead to cracking of the cement sheaths around the casing strings. This renders the cement less effective in controlling expansion and contraction. It can also make the cement sheaths prone to leakage of geothermal fluids to zones nearer the surface. Once pathways for fluid flow through the broken cement sheath outside the casing strings are established, they can become progressively worse over time. This can lead to contamination of shallow groundwater aquifers, and in extreme cases, can lead to discharges of geothermal fluids to the atmosphere around the wellhead and from areas at some distance from the well. The odds of this happening are difficult to predict, and the incidence of such leakages is low - in large part because geothermal drilling operations put a premium on keeping circulation going (even when the bits are not penetrating new formation), in order to keep thermal cycling to a minimum. However, an enforced regimen of shutting down drilling operations at night would increase the frequency of thermal cycling and correspondingly increase the safety risk of groundwater contamination and blow -outs. Build-up of Gas Pressures In normal drilling operations, gases that are present in the formation (either in solution or as gas pockets) will typically enter the wellbore in small amounts and be continuously circulated out of the hole by the drilling fluids. Once circulation stops for a period of several hours, these gases can migrate to the top of the wellbore and accumulate in the wellhead. Because they originate in high-pressure zones at depth, these gases actually remain at high pressures as they rise in the well, resulting in an increase in pressure at the wellhead. The higher wellhead pressure, in combination with the hydrostatic pressure of drilling fluids and natural liquid -phase fluids in the well, can exert pressures at the bottom -most casing string that are much higher than just the weight of the liquid -phase column alone. This can lead to fracturing of the formation and flow of drilling fluids or geothermal fluids into unintended zones. Depending on natural zones of weakness, these fluids can break through to shallower intervals, and again there is some risk of a breach to the surface, even at some distance from the wellbore. This is a separate phenomenon from leakages induced by thermal cycling, but the safety consequences of groundwater contamination and well blowout are much the same. Loss of Integrity of Wellbore Wall Drilling fluids (often referred to as drilling mud) are designed to coat the wall of freshly drilled hole with a "mud -cake" that seals off small fractures and pore spaces to prevent seepage of drilling fluids into the formation. The formation typically contains certain amounts of clay Page 2 of 3 GeothermEx 3BLUMEORSUITE 20 RICHMOND, CALIFORNIA 94806 USA A Schlumberger Company PHONE: (510) 527-9878 FAX: (510) 527-8184 www.geothermex.com minerals (all the more common in rocks that have been altered by high-temperature geothermal fluids), that can swell on exposure to waters of different chemistry than natural formation fluids. It is commonly recognized that the longer the formation is exposed to drilling fluids (even in conditions where circulation is maintained), the more susceptible the formation is to sloughing. To the extent that night-time drilling restrictions increase the overall duration of drilling, this loss of formation integrity can lead to a higher incidence of getting drilling tubulars stuck in the hole. This not only increases the duration and cost of the drilling operation, it also increases the likelihood that some form of uncontrolled flow to the surface will occur, due to the intense use of pressure containment equipment such as blow-out preventers ("BOPs") at the wellhead. The loss of wellbore integrity at depth also contributes in some degree to the possibility that geothermal fluids will channel and break through to shallower horizons, thereby compounding the risks of groundwater contamination and blowouts from thermal cycling and gas -pressure build-up. Page 3 of 3