Modeling Dynamic Shock Loads for High-Pressure/Deep-Water Tubing-Conveyed Perforating Operations in the Gulf of Mexico

Abstract

Good perforating design is essential in maximizing the value that can be pulled from the reservoir. Poorly-planned and/or executed perforating strategies in high-pressure, deep-water wells can easily increase operational costs and reduce production and revenue streams. With the increased demand for oil and gas over the last decade, operators have been forced to explore deeper to find the most prolific reservoirs to meet this growing need. In the U.S. Gulf of Mexico, these deep-water opportunities have required constant improvements to equipment and services to increase their technical capabilities for performing in more critical environments while minimizing non-productive time (NPT). Higher shot densities, propellants, larger perforating guns, electronic firing heads, shrouded assemblies, and dynamic shock modeling have been used to meet these new challenges. A major problem with these deep wells is the increased cost it takes to develop them. The use of more powerful perforating systems to increase flow area is required to maximize well productivity and recoup this cost. With the use of such systems comes the additional explosive load and the difficulty in predicting dynamic wellbore behaviors that could cause tubulars to burst, collapse, bend, buckle, and shear, as well as tubing to move excessively, packer seals to fail, and packers to unset as perforating guns are detonated. Understanding and mitigation of dynamic events at gun detonation, in addition to solid loading imparted to the tubulars, packers, and other completion hardware in the perforating assembly, were needed if the industry was to continue exploring new frontiers with complex challenges. A high-confidence level was needed to use these larger gun assemblies to go forward with these well completions without incurring NPT. This paper discusses a successful execution of a high-pressure, deep-water shoot-and-pull job with a custom-designed bottomhole assembly to address casing integrity challenges and the dynamic shock-modeling software program that evaluates the mechanical integrity of all well components.

Numerical Investigation of Downhole Perforation Pressure for a Deepwater Well

“…The perforating peak pressure can be alleviated by installing the longitudinal spring shock absorber. It is proposed that the shock absorbers installed in the middle of the string can achieve the best shock absorption effect [5].…”

“…The exploitation of deepwater oil and gas resources has increased gradually, and the safety of downhole perforation is an important technical problem [3]. The shaped charge jet perforation has been widely used in deepwater completion operations, the purpose of which is to form a channel between reservoir and wellbore that can effectively transport oil and gas [4,5]. On the one hand, the energy released by the explosion of perforating charge is converted into the effective energy to penetrate casing.…”