New Openhole Technology Unlocks Unconventional Oil and Gas Reserves Worldwide

摘要

Open hole, multi-stage (OHMS) fracturing systems were introduced in 2001. Since then, this technology has been credited with unlocking oil and gas reserves around the world that were previously dismissed as unavailable or uneconomic, enabling companies to maximize production in tight rock formations and mature oil fields. OHMS systems have been run in every type of formation from the much heralded shale gas plays in North America to the massive carbonate formations in Saudi Arabia and have also been used in offshore wells in the North Sea, Black Sea and West Africa. This paper focuses on the open hole packer used in OHMS systems to generate the annular compartmentalization necessary for effective multi-stage stimulation and production. This packer is a dual element, hydraulic-set, mechanical (DHM) packer and provides reliable open hole isolation with various benefits compared to swellable, inflatable and other mechanical packers including: 1) Reduced torque and drag due to their short length (average 5 ft) with only two short sections of rubber with a minimum running outside diameter, 2) Creation of two independent sealing points via dual elements, which together act like a single, 3 ft long seal with redundant sealing, 3) No need to formulate them for specific downhole fluids or wait for them to swell, 4) No thermal contraction such that the seal is not lost during stimulation, and 5) The rubber element does not reduce its durometer rating when set. Laboratory testing and field applications of the DHM packer are presented including HPHT, multi-laterals, proppant fracturing and acid stimulation with on and offshore case histories incorporating stand alone screens, acid jets, fracture ports and combinations thereof.