Abstract
To meet and sustain the increasing energy needs of a growing world economy, exploration for oil and gas will be directed to increasingly extended reaches, complex profiles and hostile environments. Progress in harnessing high-pressure high-temperature (HPHT) sour fields (environments containing hydrogen sulphide gas or H2S) and reducing the cost of extracting and refining will be highly leveraged by political and macroeconomic considerations. Motivated to harness the complex tight carbonate reservoirs in offshore Arabian Gulf, a major National Oil Company (NOC) in UAE and its partners embarked on an extensive and ambitious project to produce oil and gas from offshore artificial islands. To capture the full economic benefits of this project, operators are expected to drill farther and farther into one of the world's longest deep-water reservoirs (wells with laterals lengths beyond 40,000 feet). It has also taken them a decade of innovative technology development to be able to successfully harness these challenging deep-water assets. Among the technologies developed, one of the essential tools, a dissolvable plugged nozzle assembly (DPNA) with its ability to withstand higher pressures encountered at larger depths, while maintaining its mechanical integrity for extended times in heavy brines, enabling longer sweeps, thus service deeper wells was needed by operators. Recognizing this grand challenge, we designed and developed a pressure balanced HPHT DPN (PB-HPHT DPN) with erosion resistant Ni alloy jointly developed with a major Japanese steel and Ni alloy producer and anion-insensitive nano-BMGC plug developed by us. The PB-HPHT DPN has the following groundbreaking properties: (i) It can sustain pressures of up to 5,500 psi differential pressure (ΔP) for 48 hours when pressurized from inner diameter (ID) to outer diameter (OD), and can subsequently breakthrough on 500 psi DP pressure reversal (OD to ID) within 14 days from the start of the operations; (ii) It can be deployed in environments encompassing up-to 43% Bromide or up-to 21% Chloride brines and reaching temperatures as high as 250° F. Additionally, verification and validation (V&V) is supported by flow testing combined with Computational Fluid Dynamics (CFD). The design of the PB HPHT-DPN allows a fluid flow of up-to 0.6 bpm across the nozzle without experiencing a differential pressure increase of >2400 psi in a 4 mm DPN. In summary, the PB-HPHT DPN is a revolutionary device that will allow operators to efficiently produce oil and gas in extremely hostile environments.
