With the increase in shale oil and gas activity and complexity, companies deploy new solutions to safely and efficiently drill, complete, and produce wells in unconventional plays. These include Oil Country Tubular Goods (OCTG) connections, which must withstand installation, stimulation, and production loads specific to this application. Industry available standards provide manufacturers and operators a framework for quality founded on best practices and testing.

In some instances, existing testing protocols may not be adequate (e.g. insufficient or overconservative) to assess connections’ performance for this application. For this reason, the American Petroleum Institute established an expert working group to develop Technical Report 5SF (TR 5SF) intended to evaluate casing connections performance in multi-fractured horizontal wells.

The objective of this paper is to present a set of verified testing protocols applicable to casing connections used in the most common shale plays, complementing the existing body of knowledge.

We discuss testing elements and parameters tailored to the conditions of various shale plays. Based on the operations planned for the life of a well, the testing procedure is adjusted to resemble the expected conditions and loads in the correct order. This includes make-up, high-cycle fatigue associated with the casing string installation, thread compound degradation under temperature and time, and mechanical load cycles generated by stimulation. Specimen sealability is confirmed under production loads, after which failure testing is performed. Some of the inputs to build the testing protocol are: maximum internal pressure, axial load, dogleg severity, number of cycles, temperature, and fluid type.

Since connections play a crucial role in the integrity of a well, a testing procedure to ensure their performance is shown. Testing protocols for Multi-fractured Horizontal Wells (MFHW) applied to two connection types are presented, highlighting how tailored testing protocols and robust engineering improve product reliability and well integrity assurance.

We compile a set of testing inputs for the most relevant shale plays worldwide, together with the testing elements, sequence, and acceptance criteria. This should help end users validate and benchmark products’ performance while improving industry knowledge of connections capabilities.

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