Recommended Practice for Produced-water Reinjection in Gas Field
1 Scope
This standard specifies the evaluation requirements for produced-water reinjection well and reinjection layer in natural gas field, recommended water quality indexes, detection analysis method for up-to-standard reinjection water quality and recommended water quality treatment process & method.
This standard is applicable to sewage discharge and reinjection of produced-water in sandstone and carbonate natural gas field.
2 Normative References
The following normative documents contain provisions which, through reference in this text, constitute provisions of this standard. For dated references, subsequent amendments (excluding corrections), or revisions, of any of these publications do not apply to this standard. However parties to agreements based on this standard are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition of the normative document referred to applies.
GB/T 6920 Water Quality - Determination of pH Value - Glass Electrode Method
GB/T 11901 Water Quality - Determination of Suspended Substance - Gravimetric Method
GB/T 16488 Water Quality - Determination of Petroleum Oil, Animal and Vegetable Oils - Infrared Photometric Method
SY/T 5329 Water Quality Standard and Practice for Analysis of Oilfield Injecting Waters in Clastic Reservoirs
3 Terms and Definitions
For the purposes of this standard, the following terms and definitions apply.
3.1
suspended solid
the substance indissoluble to oil and water residual in microporous membrane after its crude oil is washed away with gasoline or petroleum ether solvent in filtering process with fiber resin microporous membrane with average pore diameter of 0.45μm
3.2
mid-value of suspended particles' diameter
the particulate diameter in case that the cumulative volume of particles in water occupies 50% of the total volume of particles
3.3
oil content
petroleum substances which may be extracted with gasoline or petroleum ether in water under acidic conditions
4 Evaluation Requirements for Produced-water Reinjection Layer and Reinjection Well in Gas Field
4.1 Evaluation requirements for reinjection layer
4.1.1 Depleted formation or discarded layer is preferred.
4.1.2 The fresh water aquifer shall not be affected after reinjection according to local hydrogeological information.
4.1.3 Sufficient reservoir space shall be provided to meet long-term reinjection requirements.
4.1.4 Upper and lower isolation layers shall not leak, the horizontal connectivity of injection layer shall be in good condition, and there shall be no fault, surface occurrence or exposure point within the affected range of total injection rate.
4.1.5 Sufficient adsorption and seepage capacity shall be provided, pump injection back pressure shall not be high, reverse injection and escape of reinjection water shall not occur.
4.1.6 The lithology of reinjection water and reinjection layer as well as compatibility of stratum water shall be in good condition and secondary sedimentation shall not be formed to block the stratum.
Foreword i
1 Scope
2 Normative References
3 Terms and Definitions
4 Evaluation Requirements for Produced-water Reinjection Layer and Reinjection Well in Gas Field
5 Recommended Water Quality Indexes of Produced-water Reinjection in Gas Field
6 Detection Analysis Method for Up-to-standard Reinjection Water Quality and Recommended Water Quality Treatment Process Flow
Bibliography
