Drillstem/well testing

Well 01 and Well 02 are part of the phase 1-6 project that involved the development of six wells with the potential to deliver an additional 70% production increase to the LNG export market. The sand face for both wells was drilled with 0.72psi/ft pseudo oil-based mud (POBM). After the initial well clean-up, both wells produced sub-optimally (~20% of estimated potential) with relatively high drawdown (ranging from 500psi – 1000psi). This low production was suspected to be because of downhole (screen and formation) impairment or partial opening of the formation isolation valves (FIV).

A restoration team was set up with a responsibility to proffer a robust well intervention execution plan and select the most potent barite dissolver. Nine stimulation chemicals were tested and based on the team criteria, CHEM-001 and CHEM-002 were selected as main-treatment and pre-flush chemicals, respectively.

The downhole and surface conditions that exist in deep high-pressure wells pose many challenges to the coiled tubing industry as it strives to provide safe and reliable access to the wells. This paper highlights a case history of successfully snubbing coiled tubing (CT) into two deep (about 14,000ft+) live wells (Well 01 and Well 02) with a high surface pressure (7000psi+) and temperature (80 – 100°C) to stimulate both wells. The success criteria post stimulation was targeted at 75% of the potential production value. However, post treatment results show that cumulative gas production increased by 375% (with about 200psi) with a potential to increase up to 400%.

This paper details the entire operations during the CT well intervention, the planning, design, and technical analysis which led to the selection of a CT with 130,000psi yield strength on a 125K CT injector system, force simulations, and laboratory tests on CT with stimulation chemicals which led to a successful stimulation campaign. The paper also covers the initial planned versus actual operations and the lessons learned leading to on-the-spot optimization plans that resulted in a highly successful intervention operation.

Content of PetroWiki is intended for personal use only and to supplement, not replace, engineering judgment. SPE disclaims any and all liability for your use of such content.

Content of PetroWiki is intended for personal use only and to supplement, not replace, engineering judgment. SPE disclaims any and all liability for your use of such content.

Content of PetroWiki is intended for personal use only and to supplement, not replace, engineering judgment. SPE disclaims any and all liability for your use of such content. A well that can flow to the surface unassisted.

Content of PetroWiki is intended for personal use only and to supplement, not replace, engineering judgment. SPE disclaims any and all liability for your use of such content. The depth in a well where the standing or percolating level is located.

Content of PetroWiki is intended for personal use only and to supplement, not replace, engineering judgment. SPE disclaims any and all liability for your use of such content. Usually done to control water or gas entry or to assist in ball sealer action in selective treatments.

Content of PetroWiki is intended for personal use only and to supplement, not replace, engineering judgment. SPE disclaims any and all liability for your use of such content. A smaller separator than the main production separator, used for regular production tests to measure oil, gas and water rates on a well.

Content of PetroWiki is intended for personal use only and to supplement, not replace, engineering judgment. SPE disclaims any and all liability for your use of such content. A method using decision trees to place a value on the acquisition of some form of predicting information, such as a well test, a pilot study, or a 3D seismic interpretation.

Thin oil columns overlain by free gas and underlain by water pose difficult problems in well spacing and completion method, production policy, and reserves estimation. In this context, "thin" is a relative term. Whether an oil column is considered thin depends on costs to drill and produce the accumulation. For example, in the Bream field (Australia Bass Strait, 230 ft water depth), 44 ft was considered thin,[1] whereas in the Troll field (offshore Norway, 980 ft water depth), 79 ft was considered thin.[2] Onshore U.S.A., 20 ft is considered thin. Irrgang[3] takes a pragmatic approach, defining thin oil columns as those that "will cone both water and gas when produced at commercial rates."

Content of PetroWiki is intended for personal use only and to supplement, not replace, engineering judgment. SPE disclaims any and all liability for your use of such content. The pore pressure in the reservoir, usually at current value unless otherwise specified.