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Collaborating Authors
Cameron, Gareth
Development and Successful Field Trial of Retrievable, Instrumented & Tandem Downhole Isolation Valve RIT-DIV System
Amangeldiyeva, Diana (Weatherford) | Aliyeva, Aida Askarovna (Weatherford) | Amanbayev, Yerlan (Weatherford) | Toralde, Julmar Shaun Sadicon (Weatherford) | Higginson, Timothy Peter (Weatherford) | Tilekkabyl, Akzharkyn Assetkyzy (Weatherford) | Nurseiitov, Dinmukhamed Jangaliuly (Weatherford) | Fan, Yong (Tengizchevroil) | Cameron, Gareth (Tengizchevroil)
Abstract This paper describes the development and field deployment of a new downhole isolation valve system called the Retrievable, Instrumented & Tandem Downhole Deployment Valve (RIT-DDV). The purpose of this technology is to provide a temporary mechanical barrier to isolate and monitor the well during drilling operations in an environment where a full column of single-phase fluid cannot be maintained. The RIT-DDV is based on predominantly used downhole isolation valve (DIV) design and technology, which is a hydraulic flapper-type isolation device installed in the casing that seals the open hole during pipe tripping operations. The key features of the new RIT-DDV systems are dual flapper valves with three downhole pressure and temperature gauges to take measurements above, between, and below the flappers. The advantage of this configuration is that it enhances safety by enabling double-block-and-bleed system functionality, providing valve redundancy, and moreover allowing for continuous real-time monitoring of downhole well conditions. In addition, the RIT-DDV is designed to be reusable and can be tested upon installation and replaced if necessary. The RIT-DDV system enabled the operator to isolate and monitor the well while drilling through a depleted formation that prevented drilling with a full column of single-phase drilling fluid. The RIT-DDV was successfully trialed in western Kazakhstan and demonstrated the potential of this technology to enhance the safety of drilling heavily fractured carbonate formations with reservoir fluids containing hydrogen sulfide (H2S) / carbon dioxide (CO2) that are prone to total loss of circulation. The downhole pressure / temperature monitoring capabilities that the system provides within the casing string helped drill through the depleted fractured carbonate reservoir section without incurring non-productive time (NPT).
- Europe (1.00)
- Asia > Kazakhstan (0.49)
- North America > United States > Texas (0.28)
- Asia > Kazakhstan > Mangystau Oblast > Precaspian Basin > Tengiz Field > Tengiz Formation (0.99)
- Asia > Kazakhstan > Mangystau Oblast > Precaspian Basin > Tengiz Field > Korolev Formation (0.99)
- Information Technology > Architecture > Real Time Systems (0.54)
- Information Technology > Communications > Networks (0.46)
Abstract Nitrogen Cap Drilling (NCD) is a technique developed by Tengizchevroil (TCO) that enables drilling a highly fractured reservoir under conditions where more conventional pressurized mud cap drilling techniques are not viable. NCD is an extension of the closed hole circulating drilling (CHCD) technique (Ref SPE Paper # 79850) previously developed and used extensively by TCO for drilling a highly fractured carbonate reservoir where severe loss circulation is encountered and incurable. CHCD is a pressurized mud cap drilling technique that relies on the ability to fill the well with a fluid density lighter than the reservoir pressure gradient in order to maintain communication with the reservoir pressure. Once the reservoir pressure gradient drops below the density of the lightest fluid available, the well will no longer support a full column of fluid to surface and an alternate drilling method must be employed. TCO has developed NCD as a response to this operating reality in the Tengiz field. The NCD technique involves filling the annulus with a heavier than reservoir pressure gradient fluid once severe lost returns are encountered. The annulus fluid level does not reach the surface, and the resulting air gap is pressurized with nitrogen gas. This nitrogen "cap" is contained under the Rotating Control Device (RCD) which allows for maintaining pressure communication with the formation. Well status is continuously monitored by tracking the wellhead pressure and measuring the annulus fluid level. The bottom hole pressure is balanced by manipulating the composition of the annular fluid column and controlling the wellhead pressure. In 2017, TCO conducted successful field trials and demonstrated that NCD is a viable technique to enable the continuation of the low reservoir pressure drilling program in Tengiz. TCO has since adopted NCD as the standard technique in wells where CHCD is not technically viable or operationally preferable. This paper will describe NCD technique development, equipment, procedures, operational implementation, and key learnings to date.
- Asia > Kazakhstan > Mangystau Oblast > Precaspian Basin > Tengiz Field > Tengiz Formation (0.98)
- Asia > Kazakhstan > Mangystau Oblast > Precaspian Basin > Tengiz Field > Korolev Formation (0.98)
- Asia > Kazakhstan > Mangystau Oblast > Precaspian Basin > Korolev Field (0.98)