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Abstract Perforating is crucial for connecting reservoirs to wellbore in cased-hole completions. High-pressure, high-temperature (HPHT) and sour gas reservoirs present challenges in achieving deep penetration as high-temperature (HT) shaped charges have lower performance than lower temperature rated shaped charges. This paper examines modelling and testing of HT shaped charge penetration by three service companies. It highlights the lack of research on perforating in HPHT gas-filled carbonate formations, emphasizing the need for further investigation in this area. Three major perforation service companies provided shaped charge performance for an HPHT carbonate field for 2 7/8- and 3 1/2-in. guns. The field has five reservoir layers with different properties. There was a wide range in predicted depth of penetration between the models used by each company for their HT shaped charges. This prompted the design of performance tests following API RP19B guidelines to validate model predictions. Two outcrop carbonate rocks were selected, matching the range of reservoir properties. All companies carried out shots into these rocks using their 2 7/8-in. shaped charge under simulated downhole conditions. Three shots were fired in each rock type by each company giving 18 data points. Operators generally use perforation model results from service companies without validating the accuracy of predictions. However, test results came up with some notable surprises - both in penetration results, and in API RP19B procedure. Firstly, there were challenges in finding suitable strength rocks as the measured strength of cores cut from the same source rock varied widely between the three companies as well as from the rock supplier data. One company also had a booster failure at elevated temperature of 190° C. After these were fixed, results from perforation tests were compared with model results. The outcome varied from slightly better performance for one company to about 50% lower performance for another. Only one company managed to match their model predictions. There were significant variations observed in perforation tunnel in the rock. For all companies, the casing hole diameter was found to be about 70% of the model prediction. In conclusion, penetration models need to be challenged by conducting tests into rocks under simulated downhole conditions especially as most penetration models are based on performance in concrete rather than rock, and, even for companies with a rock-based model, little work has been done with gas-filled rocks and gas-filled carbonate rocks. This was a unique project due to the combination of HPHT, gas-filled, carbonate rock, with multiple service companies supplying predictive data. The tests emphasized the importance of challenging perforating models in critical developments as results can be misleading. Therefore, there is a requirement to standardize the procedure for measuring rock strength, as the three companies had substantially different readings from the same piece of rock using similar equipment. This was later attributed to the different companies following different test procedures.