Traditionally Wireline logging tools are rated for continuous operation to 350°F and 20,000 psi downhole conditions. With many reservoirs exceeding these limits, the need for specialized, High-Pressure and/or High-Temperature Wireline tools has been an issue for some time. Sensors were accordingly developed to ratings of 500°F and 25,000 psi. Recently, Ultra-Deep drilling has pushed the boundary to above 25,000 psi, resulting in the development of 30,000 psi and 500°F rated wireline tools. Currently, basic Petrophysical evaluation Quad-combo strings are available and wells in excess of 480°F, 26,000 psi have been successfully evaluated. Significant work is underway to upgrade specialized wireline services such as pressure testing, fluid sampling, dipmeter imaging, sidewall coring, Dipole Sonic, Magnetic resonance, natural and spectral Gamma ray measurements.
Like most other oilfield services, Wireline HPHT technology development pauses serious challenges. When the extreme is temperature or pressure only, the solution is relatively simple. Significant complications arise when both extreme conditions occur simultaneously, requiring at times timely and costly redesign of sensors and related electronics. The paper follows Wireline HPHT evaluation development to date, outlines technological challenges and barriers to continuously expand current tool rating limits while increasing the range of services. Recent case histories from North America are presented. Finally future development and well evaluation technology trends are discussed.
HPHT Logging Across the US and Gulf of Mexico is becoming an increasingly larger part of the oil & gas industries focus. As the shallower, easy markets continue to dry up, focus will fall on deeper, Hi-pressure, Hi-temperature or " Hostile" reservoirs known to have difficulties in drilling and evaluation.