ANSI API RP 10B-6:2010 (2020) pdf download.Recommended Practice on Determining the Static Gel Strength of Cement Formulations.
This part of ISO 10426 specifies requirements and provides test methods for the determination of static gel strength (SGS) of cement slurries and related materials under simulated well conditions.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced standard (including any amendments) applies.
API 1OB-2/lSO 10426-2:2003, Petroleum and natural gas industries — Cements and materials for well cementing
— Part 2: Testing of well cements
3 Terms and definitions
For the purposes of this part of ISO 10426, the following terms and definitions apply.
3.1
bottom-hole pressure
Hydrostatic pressure at the bottom of the well calculated from the true vertical depth and the fluid densities in the wellbore.
3.2
bottom-hole circulating temperature
Maximum temperature encountered in a wellbore during cement slurry placement.
3.3
critical static gel strength
CSGS
Specific static gel strength of a cement in which hydrostatic-pressure equilibrium is reached between the decayed hydrostatic pressure transmission of the cement column (and other fluids in the annulus) and the pore pressure of the formation.
See Annex A.
NOTE The critical static gel strength is measured in pascals or newtons per square metre (pounds force per 100 square feet).
3.4
critical static gel-strength period
CSGSP
Time interval required for the cement to progress from the critical static gel strength value to a static gel strength of 250 Pa
static gel strength
SGS
Shear strength (stress) measurement derived from force required to initiate flow of a fluid.
NOTE The static gel strength is measured in pascals or newtons per square metre (pounds force per 100 square feet).
4 Sampling
4.1 General
Samples of the dry cement or cement blend, solid and liquid additives and mixing water are required to test a slurry in accordance with this part of ISO 10426. Accordingly, the best available sampling technology should be employed to ensure the laboratory test conditions and materials match as closely as possible those found at the well site.
4.2 Method
Applicable sampling techniques for the dry cement or cement blend, solid and liquid additives and mixing water used in typical cementing operations can be found in ISO 10426-2:2003, Clause 4. If required, the temperature of the mix water, cement or cement blends, and liquid additives may be measured with a thermocouple or thermometer capable of measuring temperature with an accuracy of ± 2 °C (±4 °F). These temperatures should be recorded. Temperature-measuring devices shall be calibrated (in the case of a thermocouple) no less frequently than every three months or checked (in the case of a thermometer) annually.
NOTE Descriptions of commonly used sampling devices can be found in ISO 10426-2:2003, Figure 1.
5 Preparation
Prepare the test samples in accordance with ISO 10426-2:2003, Clause 5.
If larger slurry volumes are needed, an alternative method for slurry preparation is found in ISO 10426-2:2003, Clause A.1.
NOTE The density of the cement slurry can be verified by methods found in ISO 10426-2:2003, Clause 6.ANSI API RP 10B-6 pdf download.