Disposal procedure for permanent plugging of abandoned well in oil and gas field
1 Scope
This document establishes the disposal procedure for permanent plugging of abandoned wells in oil and gas fields, including general requirements, plugging design, common sealing process, production layer sealing, sealing of special well sections, disposal of annular casing pressure, wellhead disposal, quality control and inspection, operation data recording and archiving as well as health, safety and environmental protection control.
This document is applicable to the permanent plugging and disposal of abandoned oil, gas and water wells in onshore oil and gas fields.
2 Normative references
The following documents contain provisions which, through reference in this text, constitute provisions of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T10238 Oil well cement
GB/T 19139 Testing of well cements
GB/T 20970 Petroleum and natural gas industries - Downhole equipment - Packers and bridge plugs
GB/T 20972.1 Petroleum and natural gas industries - Material for use in H2S-containing environments in oil and gas production - Part 1: General principles for selection of cracking resistant materials
GB/T 20972.2 Petroleum and natural gas industries - Materials for use in H2S-containing environments in oil and gas production - Part 2: Cracking-resistant carbon and low alloy steels and the use of cast irons
GB/T 20972.3 Petroleum and natural gas industries - Material for use in H2S-containing environments in oil and gas production - Part 3: Cracking-resistant CRAs (corrosion-resistant alloys) and other alloys
SY/T 6277 Code for personal protection in hydrogen sulfide environment
SY/T 6610 Specification for workplace safety of hydrogen sulfide environment
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
abandoned well
oil, gas and water well that cannot continue to be used or have no use value, which are permanently abandoned due to other mandatory reasons, and that have gone through the scrapping approval procedures or approved write-off according to the procedures
3.2
sealing plug
solid plug with certain thickness and strength that can block the flow of fluid, which is formed after sealing materials such as oil well cement or other sealing agents solidify in the wellbore or to-be-plugged annulus
3.3
well barrier
not less than one component or combination of components manually arranged to prevent formation fluid from entering the wellbore, escaping into other formations or flowing out of the surface
Note: The component or combination of components usually include casing, cementing ring, sealing plug, bridge plug, etc.
3.4
the shallowest layer with oil and gas
the shallowest buried layer with oil and gas suggested by the geology that there are many sets of oil and gas layers in the longitudinal direction of the oil and gas well
4 General requirements
4.1 The well barrier for plugging shall prevent formation fluid from migrating from the wellbore, the casing annulus of each layer and the cement annulus outside the casing to the freshwater layer or the surface
4.2 The well barrier for plugging shall prevent surface water from entering the wellbore and escaping into the freshwater layer.
4.3 Well plugging measures shall meet the requirements of technological feasibility and construction safety.
4.4 Sealing tools, sealing materials, etc. shall meet the needs of permanent sealing.
Contents
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 General requirements
5 Plugging design
6 Common sealing process
7 Production layer sealing
8 Sealing of special well sections
9 Disposal of annular casing pressure
10 Wellhead disposal
11 Quality control and inspection
12 Operation data recording and archiving
13 Health, safety and environmental protection control
Annex A (Informative) Example of setting the typical sealing well barrier
