PD ISO/TS 12835 provides procedures for the assessment of casing connections for those field applications in which the operating temperatures cyclically vary between minimum values appreciably below 180 °C and maximum values that range from 180 °C to 350 °C or above, and in which the primary axial loading on the casing-connection system is strain-based and driven by constrained thermal expansion and leads to a stress state that exceeds the casing-connection system's yield envelope.
PD ISO/TS 12835 contains an evaluation procedure for a candidate connection comprising of the uniquely defined pin, box and interfacial components. The evaluation procedure includes:
Note: PD ISO/TS 12835 does not address impacts of external pressure, incomplete lateral pipe support, rotational fatigue, formation-induced shear, or environmentally-induced corrosion or cracking.
PD ISO/TS 12835 on the qualification of casing connections for thermal wells is useful for:
PD ISO/TS 12835 is the culmination of a thorough review of factors contributing to the performance of casing connections in thermal well applications.
The evaluation procedure adopted in PD ISO/TS 12835 has been developed using input from operators’ descriptions of field practices, manufacturers’ feedback on connection design and production, available literature, knowledge of past connection qualification programs, and additional analytical and experimental work performed in support of the protocol development.
Thus, PD ISO/TS 12835 facilitates the assessment and qualification of threaded casing connections for service in intermediate or production casing strings in thermal recovery wells and in other wells experiencing significant temperature excursions such as in geothermal applications.
PD ISO/TS 12835:2022 supersedes ISO/PAS 12835:2013, which has been technically revised. The main changes are as follows:
ISO/TS 12835