A 2015-16 SPE Distinguished Lecturer Joint Meeting presented by the Completions & Production Study Group and the Permian Basin Study Group.
The term "Well Design and Integrity" has taken on added meaning as a result of intense media scrutiny and public interest regarding hydraulic fracturing and the tragic Macondo well blowout in the Gulf of Mexico. The complexities and costs of well design have increased significantly to meet the challenges of ultra-deep wells exceeding 30,000 ft., ultra-HPHT wells (500F and 30,000 psi), and ultra-deepwaterdrilling (exceeding 10,000 ft.). As a consequence, the risk to companies designing wells for these applications has increased. As we know from recent events, the consequences of failures can be enormous, and minimizing the risk of such catastrophic failures is imperative. It is not simply coincidental that the engineering tools for well design have become ever more complex. Tools such as nonlinear finite element analysis (FEA), computational fluid dynamics (CFD), and multi-physics software are now commonly used. What are these tools and the input data required for output of dependable and accurate results? This presentation will summarize applications of these tools, exhibiting their input requirements, and output interpretation and quality. Applications will include threaded connection pressure integrity, cement and rock strength and deformation, formation-cement-casing interactions, all of which involve complex nonlinear material and interface behavior. I will discuss computational modeling of the temperature dependent, viscoplasticresponse of salt and "soft" porous rocks, and compactivebehavior of high-porosity formations. Downhole tools may include stainless steels, elastomer and polymer components. Seal rings and inflatable packers are highly temperature dependent and exhibit significant creep behavior. Calibration of material model parameters is vitally important, but for non-metals can require a significant number of samples, which are difficult and expensive to acquire and test. The correct selection of a validated material model can be the key to success or failure in minimizing risk.