Abstract
An operator recently drilled and completed an onshore well in South Sumatra by intentionally leaving 3-1/2 in. drill pipe in the hole, to be used as the lower completion string. This paper documents the design and execution of this unique drill pipe completion idea, overcoming challenges during drilling due to unanticipated formation collapse, leading to multiple sidetracks. The reservoir contains dry gas with >30% CO2 inside naturally fractured basement rock. Wells in this area are usually drilled with total losses throughout the reservoir section and completed by running a perforated liner.
In the 3rd and final sidetrack, the drill pipe completion idea was successfully executed resulting in a well that is producing ∼40 MMSCFD. The idea was selected after technically evaluating other viable options such as liner drilling using 5-1/2 in. casing or drilling with continuous water injection and then running the liner. The drill pipe completion option provided the highest chance of success to reach total depth (TD) in a single bit run while serving as a mechanical conduit in the wellbore for production and providing a barrier against hole collapse. The detailed planning conducted to finalize the drilling bottom hole assembly (BHA), perforating gun performance, drill pipe cutter, production rate impact, erosional and corrosion impact of using drill pipe as completion will be explained in the paper.
Operationally, after the well was drilled to TD, 1-11/16 in. strip guns were used to perforate the 3-1/2 in. drill pipe and then the pipe was severed using a non-explosive plasma jet cutter and left in hole. A fishing overshot was then run on the bottom of lower completion liner to swallow the cut drill pipe and provide future intervention capability. The upper completion was subsequently run and set prior to rig demobilization.
This unique application of a sacrificial drill pipe completion, also termed as the "crazy drill pipe idea" by the operator, generated a lot of discussion and interest within the oil and gas industry in Indonesia. We are hopeful that the technique and application discussed in this paper will provide valuable insight into this alternative completion design for use in depleted and unstable formations, where opportunities to pursue other viable options are limited.
