Wells are classified as HTHP when formation pressures exceed a 15 ppg (1.8sg) equivalent and when static bottom hole temperatures are greater than 350°F. Corresponding downhole pressures may require mud weight as high as 20 ppg (2.4sg) to maintain well control.
In traditionally overpressured and hot hole areas, such as Kuqa's piedmont in Tarim, HuaTugou Block in Qinghai, Western South China Sea. The vertical depth of the wells in above blocks are over 8000m (26000ft), and geothermal gradient are greater than 4°C/100m. The maximum BHT is almost 500°F (260°C) and highest mud weight is up to 21.7 ppg (2.6sg).
In addition to HPHT, other technical challenges include large segments of complex salt formation (pure salt, salt gypsum layer and intersalt high-pressure brine), narrow mud window, serious mud loss, and high-density completion fluid with good thermal stability required by completion process.
HYPERDRIL® oil-based drilling fluid system is designed with unique rheology & suspension properties for the HPHT drilling applications to meet above challenges. Stable at pressures exceeding 40,000 psi (276 MPa) and temperatures greater than 450°F, the High Temperature Oil-Based system avoids the sagging, gelation, and density differentiations commonly observed in extreme conditions.
To ensure that the fluid formulation truly meets your required specifications, SHARK's expert will work with you to pilot test the fluid before fully deploying it as part of your drilling program.
¬ The amount of each above product added into the formulation is g or ml to mix 350 ml (1bbl) volume sample.
¬ Either diesel oil or mineral oil is used as the base fluid for HYPERDRIL® oil-based mud systems.
¬ Combination of LIQUITROL® HT and CARB 5 are recommended to add into the formulation to enhance better thermal stability of the system and less filtration control.
¬ Pilot testing should be performed to determine the exact amount of each product used in a particular formulation under elevated temperatures.
¬ 1ppb = 2.857kg/m3, 1ppb = 1g/350ml
¬ 1.0sg = 8.345ppg
¬ Hot rolled at 375°F (190°C), 16hrs & 72hrs
¬ Rheology properties are tested at 150°F (65°C)
¬ HTHP Filtration loss is tested at 356°F (180°C)
¬ Static Aged @ 375°F (190°C)
¬ Rheology properties are tested at 150°F (65°C)
¬ HTHP Filtration loss is tested at 356°F (180°C)
