A Simplified and Effective Method of Landing the Production Tubing in Subsea / Deep Water Wells: A Case in Southeast Asia

Abstract

Difficulties due to well and water depths, deviations, and rig heave while spacing out production tubing and landing the tubing hanger on subsea completions can significantly challenge space-out operations. Another challenge occurs when attempting to enter the casing at the subsea tree in deep water. During actual completions, subsea currents can produce a bending motion on the riser, causing the bottom of the completion to enter the casing at an angle. If the angle is too great, set-down weight or compression must be added to push the completion through, making shearable-activated travel joints risky. Premature stroking of a standard travel joint from friction in deviated wells is also possible. These problems and the fact that deepwater rig rates are significant, make it imperative that the production tubing string be landed efficiently. Therefore, a successful completion design must manage friction while having sufficient rigidity to land seals into production packers at high angles with limited slack-off weight. This paper discusses a recent deepwater project in Malaysia where these potential problems and others due to the high deviations were possible during the completions. To address these issues, a service/engineering company had developed a long space-out travel joint (LSOTJ) designed to telescope downward in response to a timed application of a compressive load instead of a shearing event as in standard designs. The LSOTJ then slowly scopes downward during lowering of the production tubing until the hanger is landed. The Malaysian operator decided to use the LSOTJ in their development because of its success in the Gulf of Mexico. Eleven of the non-continuous sealing (NCS-LSOTJ) version and three of the continuous sealing version (CS-LSOTJ) were used. This was the first usage of the NCS-LSOTJ in Malaysia, and the first usage world-wide of the CS-LSOTJ. The case history will discuss the completion success. Introduction This field in Malaysia would be the first deepwater development for this operator as well as the first wholly deepwater subsea development in Malaysia. The offshore Malaysia field lies in water depths up to 1,220 meters. The field was to be developed initially using 14 subsea wells with oil exported via a pipeline to a new oil and gas terminal that would be built in Kimanis, Sabah. The production system was to have a capacity of 135,000 B/D. When on production, this would represent 25% of Malaysian oil production. Sweep efficiency was a critical factor in the development of the field, and for that reason, intelligent well configurations were chosen for some of the injector wells. Any natural gas produced along with the oil was to be re-injected into the reservoir to help improve oil recovery. Treated seawater would also be injected into the reservoir to help with pressure maintenance. The 14 subsea wells from 4 drilling centers (A, B, C and E) would consist of 2 single-zone conventional water injector wells, 1 single-zone conventional gas injector well, 1 dual-zone gas intelligent injector well, 2 dual-zone water injector wells and 8 single-zone producer wells.