Upload
vuhanh
View
218
Download
2
Embed Size (px)
Citation preview
The Office of Oil and Gas; Oil and Gas Wells West Virginia Department of Environmental Protection
9/04/2013
Presentation Coverage
• Why Casing / Cementing?
• Engineering Considerations.
• Requirements for Casing / Cementing.
• Standards for Casing / Cementing.
• Unanticipated Issues: What do we do now?
9/04/2013
General Well-Bore Construction
• Conductor Casing— Unconsolidated Ground Protection – Cement Circulated throughout casing annulus.
• Surface Casing— Ground Water-Aquifer Protection – Cement Circulated throughout casing annulus.
• Coal Protection Casing— Mineral Protection – Cement Circulated throughout casing annulus.
• Intermediate Casing— Critical Well Control @ Drilling – Deep Wells and Abnormal/High Pressure Expectations.
• Production Casing— Critical Fracturing (Completion)
and Production Isolation.
9/04/2013
Wellbore Engineering General Considerations and Constraints
• Pre-Planning is key.
• Drilling and Completion Techniques, Economics, Policy and Governmental Compliance.
• Location and placement of well stake.
• Knowledge of the area and geological issues; fresh water aquifers, open mine and voids, sensitive formations, etc.
• Local data / well records / experience.
• Hole conditions, mud and filter cake, and formation characteristics and strengths, and invasive fluids/gasses.
• Cement Designs; compressive strengths, density, properties of rheology/viscosity, thickening time and yields, annular and coupling spacing, prevent introduced fluid invasion - thieving and damages; quality control and assurance.
• Casing Designs; burst, collapse, tensile strengths, corrosive resistance, coupling and torque, centralizers, baskets and float equipment; quality control and assurance.
• API and ASTM Standards and Specifications.
9/04/2013
Coal bed methane
Marcellus shale
Trenton-Black River
Stratigraphic Column
Strata of interest
Oil and Gas Producers
Utica shale
DEEP WELL Any Wellbore Depth
past 100’ at Top Onondaga Ls
9/04/2013
Why Casing/Cementing?
§22-6A-24(a) Horizontal Well Control Act . . .
the operator shall construct the well and conduct casing and cementing activities for all horizontal wells in a manner that will –
• provide for control of the well at all times,
• prevent migration of gas and other fluids into fresh groundwater and coal seams, and
• prevent pollution of or diminution of fresh groundwater.
9/04/2013
Why Casing/Cementing?
• §35-4-11.1 All Wellbore Programs . . .
there shall be in each well such material and equipment and there shall be employed such additional procedures as are necessary for the purpose of –
• Separating high pressure zones from low pressure zones,
• Separating the producing horizons,
• Separating the water bearing strata, and,
• Protecting mineable coal zones for life of the well. 9/04/2013
Requirements Casing / Cementing Programs
• §35CSR4-11 All Wellbore Programs
– 11.2 Coal protection casing to be installed through the workable coal seam(s) shall be in addition to the production casing - §22-6-18 through §22-6-20,
– 11.3 Fresh water casing required shall have cement circulated in the annular space outside the casing §22-6-18.
9/04/2013
Requirements Casing / Cementing Programs
• §35CSR4-11 All Wellbore Programs
Cement placed in the annular space around the casing shall be allowed to set to a minimum –
1. Compressive strength of 500 pounds per square inch, 2. Waiting time for cement shall be 8 hours or more.
Cement used to fill the annular space around the casing required in subsections 11.2 and 11.3 shall be –
1. American Petroleum Institute Class A Portland 2. No greater than 3% calcium chloride and 3. No other additives.
9/04/2013
Requirements Casing / Cementing Programs
• §35CSR4-16.5.b All Wellbore Programs
When rotary drilling penetrates a formation known to contain substantial amounts of salt water - 1. Drilling will continue to the next casing point by
drilling with mud, foaming, or other satisfactory methods for the purpose of isolating the salt water in the formation or preventing the discharge of salt water into a fresh water horizon, or above the surface of the ground.
2. In the case of foaming, it is recognized that a certain amount of salt water, mixed with the cuttings, will be discharged above the surface of the ground which will be contained in sump pits no larger than necessary for this purpose. 9/04/2013
Requirements Casing / Cementing Programs
§22-6A-24(d) Horizontal Well Control Act . . .
Permit Applications - The operator shall prepare a casing program demonstrating how the horizontal well is to be drilled, cased, and cemented -
– Anticipated depth and thickness of any producing formation, expected pressures, fresh groundwater zones, method or info by which depths were determined.
– Diameter of borehole.
– Casing type, new or used, depth, diameter, wall thickness, burst pressure rating.
– Cement type, yield, additives, estimated amount to be used
– Estimated location of centralizers.
– Proposed borehole conditioning procedures.
9/04/2013
Casing Standards §22-6A-24(f) Horizontal Well Control Act
(f) Minimum Casing Standards
– All casing installed, new or used, shall have a pressure rating that exceeds the anticipated max pressure to which it will be exposed and meet appropriate nationally recognized standards,
– Be of sufficient quality and condition to withstand the effects
of tension and maintain structural integrity during entire life, – Centralizers shall be used, – Shall not be disturbed for a period of at least eight hours after
completion of cementing operations, – No gas or oil production or pressure may exist on the surface
casing or the annulus or the coal protection casing annulus. 9/04/2013
Where do you Case?
§22-6A-24(f) Casing Types Horizontal Wells
Conductor - – set where necessary to stabilize unconsolidated
sediments and should be installed in a manner that prevents infiltration of surface fluids,
– May be driven into place, unless it will penetrate fresh groundwater zones; if drilled the casing annulus shall be cemented,
– If drilled, shall be drilled using only air, freshwater, or freshwater-based drilling fluid.
9/04/2013
Where do you Case? §22-6A-24(f) Casing Types – Horizontal Wells
Freshwater Casing –
– Shall extend at least 50 feet and no more than 150 feet below the deepest freshwater horizon and cement shall be circulated in the annular space outside of the casing - • For conventional wells the casing is required to extend at least 30 feet below the
deepest fresh water horizon (§35CSR11.3) • May extend below 150’ to cover coal seams as long as all other conditions are met,
– Minimum of 300 feet of casing should be installed unless it is to avoid any penetration of salt water or oil and gas bearing zones,
– Casing shall be installed and cemented prior to drilling into any strata known or likely to contain oil, gas or saltwater,
– Should be drilled using only air, freshwater or freshwater-based drilling fluid,
– If not CTS then inspector shall be notified; if top cannot be determined then an electric log or similar technology shall be used,
– For conventional wells if the coal protection casing is cemented to surface it may also be considered a fresh water protective casing.
9/04/2013
Where do you Case?
§22-6A-24(f) Casing Types – Horizontal Wells
Coal Protection Casing -
– No oil or gas production or pressure shall exist on the annulus,
– If no CTS, the inspector shall be notified,
– Sound engineering practices approved by the Chief shall be used to fill the annular space back to the surface,
– Either freshwater or intermediate casing may serve as the coal protection casing.
9/04/2013
Where do you Case?
§22-6A-24(f) Casing Types – Horizontal Wells
Intermediate Casing -
– Shall be installed to a depth that provides for
well control, down-hole stability, safety, and
separation of zones,
– Shall be CTS (circulated to surface),
– A formation integrity test (shoe test) may be
required before drilling ahead.
9/04/2013
Where do you Case? §22-6A-24(f) Casing Types – Horizontal Wells
Production Casing -
– Shall be installed subsequent to drilling and logging operations,
– May be cemented in place or set without cement to allow for packer completion -
• If cemented, shall be placed by displacement method from bottom of hole to a point at least 500’ above the shallowest producing zone,
• If no intermediate casing is installed, should be cemented to a point at least 500’ above shallowest fluid bearing zone.
9/04/2013
Well-Bore Construction Horizontal Well Development
• Conductor Casing— Unconsolidated Ground Protection – Cement Circulated throughout casing annulus.
• Surface Casing— Ground Water-Aquifer Protection – Cement Circulated throughout casing annulus.
• Coal Protection Casing— Mineral Protection – Cement Circulated throughout casing annulus.
• Intermediate Casing— Critical Well Control @ Drilling – Deep Wells and Abnormal/High Pressure Expectations.
• Production Casing— Critical Fracturing (Completion)
and Production Isolation.
9/04/2013
What Goes Down Must Come Up - To the Surface
“The key to well integrity is a good cement job,” Stephanie Meadows, a senior policy adviser at the American Petroleum Institute MIDWEST ENERGY NEWS 10/2/2012
Witness Cement Jobs
Routine Priority with Inspectors
9/04/2013
555 605 563 703 301 177 103 112 104
401 287 328 316
329 399 348 329 271
0 0 11
383
480 430 542 625 425
1716 2263 2391
1889
893
508 277 154
97
0
500
1000
1500
2000
2500
3000
3500
2005 2006 2007 2008 2009 2010 2011 2012 2013 Aug 19th
NEW WELLS
HORIZONTAL
PLUGGING
OTHERS
Approximately 250 Marcellus Wells Drilled/Completed YEARLY
PERMITS ISSUED
PERMIT TREND
Drilling Rigs Statewide Currently
45 Total Reported (30) Marcellus Operations
Horizontal 22-6A Permits - 20 Operators
(416) Permits apply to H6A Requirements
9/04/2013
Horizontal Wells
Development - Marcellus
Drilling Rigs Active
30 Total Current Reports
(10) Top Hole Rigs
9/04/2013
Unanticipated Issues • If the operator encounters an unanticipated void, or
an anticipated void at an unanticipated depth, the operator shall notify the inspector within 24 hours,
• Modifications to the casing program may be necessary to comply with W. VA. Code § 22-6A-5a (12) or W. Va. Code § 22-6-20, which requires drilling to a minimum depth of 30’ below bottom of the void, and installing a minimum of 20’ of casing,
• Under no circumstances should the operator drill more than 50’ below the bottom of the void or install less than 20’ of casing below the bottom of the void,
• During casing and cementing process, in the event that cement does not return to surface, the inspector shall be notified within 24 hours. 9/04/2013
General Expectations Cementing • Terms of the permit required.
• Density consistency and volume of cement calculated using approved engineering methods to assure the return of the cement to the surface.
• Cement does not return to the surface, the district inspector shall be notified.
• Sound engineering practices approved to determine quality of cement placements and cement tops by use of electric logs or similar technology.
• Sound engineering practices approved to fill the annular space and back to the surface.
• Supporting documents necessary; electric logs, job summary, strip charts, etc.
9/04/2013
Summary and Comments • Proper planning and engineering expected by the
Operator/Permittee.
• Wellbore designs and proposals are reviewed and approved during the application process.
• Any casing/cementing activity including remedial actions of oil and gas wellbores considered a permit requirement.
• Supporting documents on site inspections.
• Primary cementing activities are critical.
• Investigations - First look at existing wellbore integrity if local issues arise.
9/04/2013
David J. Belcher Office of Oil and Gas
Department of Environmental Protection 601 57th Street, SE
Charleston, WV 25304 304-926-0450
[email protected] www.dep.wv.gov
9/04/2013