NOVELTY - The structure has a conical surface (93) provided at a terminus of a pin end of a first tubular element, where the conical surface comprises an angled primary seal surface (85) relative to a longitudinal bore of the first element. A lip (86) is provided at a terminus of a pin end of a second tubular element and designed to engagingly mate with the conical surface of the first element when the first and second elements are connected by a tubular coupling (73). An angle of the lip is slightly greater than an angle of the primary seal surface relative to a longitudinal bore of the second element.    USE - Threaded connection structure for releasably coupling and sealing tubular elements e.g. oil country tubular goods (OCTG) such as casings, tubing, pup joints and couplings, associated with drilling, producing or servicing subsurface wellbore such as oil wells, natural gas wells and geothermal wells, in an oil and gas drilling industry.    ADVANTAGE - The structure provides improved performance over tensile and compressive load carrying capabilities of connections, provides an external pressure seal to prevent influx of well bore fluids and pressure to a thread region, and maintains greater contact load on the internal seal and shoulder geometry during tension loading. The structure is designed to optimize sealing capabilities, so that the coupling and the pin ends are designed to work together to generate interference needed to create an internal metal-to-metal leak-tight contact pressure seal when separate tubular elements are joined by the coupling and fully made up.    DETAILED DESCRIPTION - The pin end of the first tubular element is a field pin end (74). The pin end of the second tubular element is a mill pin end (75).    DESCRIPTION OF DRAWING(S) - The drawing shows a sectional view of a threaded connection structure including a first threaded tubular element whose a field end releasably engages a mill end of a second threaded tubular element by a coupling.    Tubular coupling (73)    Field pin end of tubular element (74)    Mill pin end of tubular element (75)    Angled primary seal surface (85)    Lip (86)    Conical surface (93)