Successful Application of Concentric Casing Nitrogen Injection to Overcome Drilling Challenges and Deliver a Record Horizontal Well in the Tecominoacan Field

Abstract

Abstract The Jujo-Tecominoacan field belongs to the Bellota Integral Active in the Pemex South Region. It is located in the state of Tabasco, northwest of the city of Villahermosa. This field is geologically located in the Chiapas-Tabasco Mesozoic Basin and is developed to maximize production of fractured carbonate formations from the lower Cretaceous to the Kimmeridgian Jurassic. Several drilling challenges are presented including horizontal drilling in dolomites with a high compressive strength, low pressure and high temperature reservoir requiring the use of a biphasic drilling fluid with nitrogen injection through concentric casing annular space, crossing through Cenozoic members of abnormally high pressure that require managed pressure drilling, drilling through inverse geologic faults, and proximity to a salt dome. An interdisciplinary team was formed between the service company and operator to meet the challenges of constructing the deepest and longest concentric N2 injection horizontal well in the world with a total depth of 6611 m in a Low Pressure-High Temperature ambient. A horizontal production section was drilled to a length of 862 m and with an average inclination of 84°. The main objective was to maximize production in fractured carbonate formations from the lower Cretaceous to the Kimmeridgian Jurassic formation. Managed pressure drilling was implemented in the 6 ½" hole section while drilling through the upper Jurassic production zone, allowing establishment of commercial production and incorporation of the oil reserves in these zones. With 260 days of operation, the Tecominoacan 705 well, is the pioneer example of a combined effort of the operator and service company with the objective accomplished, setting a worldwide standard of unprecedented execution.