Optimizing the Deepwater Completion Process Offshore Israel
Authors: Carpenter Chris 
Published: October 2018

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 189637, “Optimizing the Deepwater Completion Process: Case History of the Tamar 8 Completion Design, Execution, and Initial Performance Offshore Israel,” by John Healy, SPE, Steven M. Waggoner, Ian Magin, SPE, Matt Beavers, SPE, Kevin Williams, and Russell Hebert, SPE, Noble Energy, prepared for the 2018 IADC/SPE Drilling Conference and Exhibition, Fort Worth, Texas, USA, 6–8 March. The paper has not been peer reviewed.

This paper describes the successful delivery of one ultrahigh-rate gas well (more than 250 MMscf/D) completed in a significant gas field offshore Israel with 7-in. production tubing and an openhole gravel pack (OHGP). The Tamar 8 well was completed approximately 4 years after the start of initial production from the Tamar development. Several operational innovations and process improvements were implemented that resulted in a significant reduction in rig time.

Introduction

The Tamar field was discovered in 2009 in 5,505 ft of water at a total depth (TD) of 14,967 ft. Tamar is one of several recent gas discoveries made in the deep waters offshore northern Israel and Cyprus in the Levant Basin (Fig.  1). The field consists of three gas-bearing sandstone layers separated by two shaley units. The trap for the reservoir is a large four-way anticline cross-cut by northwest bearing faults. There is an approximately 4,900-ft-thick evaporate sequence in the shallow overburden above the field consisting of mostly halite, with interbedded anhydrite and clastics.

Tamar was designed as a subsea development with five initial wells tied back 150 km to a new shallow-water production-processing platform located near the existing Mari-B platform. As the world’s longest subsea tieback, the Tamar field came online in March 2013 at gas rates ranging from 600 to 950  MMscf/D from a production platform designed for 1,200 MMscf/D. Since 2013, all wells have produced with high reliability and minimal difficulty.

Tamar 8

In early 2016, a decision was made to add an additional well, Tamar 8, to the existing well stock. Accelerated well planning was conducted thereafter to be ready for a completion start date of 1 December 2016. On the basis of front-end engineering studies, several operational statements of requirements (SORs) were specified consistent with the previous Tamar completion campaign. These SORs included the following:

The production (9 7/8-in.) casing was to be set approximately 10 ft inside the reservoir section.

The reservoir interval must be underreamed to 12¼ in.

The reservoir interval must be vertical to a low angle (less than 20°).

Only 115 ft of reservoir interval would be drilled/completed.

Completion Sandface. The Tamar sandface completion is an OHGP that, in simple terms, is a drilled section of the reservoir [using a qualified and fit-for-purpose reservoir drill-in fluid (RDIF)] in which a gravel pack has been placed. A key geometric attribute of the Tamar OHGP is the requirement to enlarge (underream) the drilled reservoir section; this hole enlargement (from 8½ to 12¼  in.) significantly increases the effective wellbore radius from which multiple production benefits are derived.