Al Khalij Research Articles

Successful Application of Intelligent Completions in Al Khalij Field

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 172027, “Successful Application of Intelligent Completions in Al Khalij Field,” by X. Briz-Quintero, M. Sofyan, P. Pouget, J. Le-Roch, J. Authier, and Y. Deffous, Total; S.F. Gurses, E. Gulamov, and N. Mukashev, Schlumberger; and M.R. Jaafar, I. Abul-Hamd, and A.R. Al-Naimi, Qatar Petroleum, prepared for the 2014 Abu Dhabi International Petroleum Exhibition and Conference, Abu Dhabi, 10–13.November. The paper has not been peer reviewed. Al Khalij field offshore Qatar is formed of a highly heterogeneous carbonate reservoir with significant remaining dynamic uncertainties. Moreover, given the current high field water cut, any operation to decrease it can have a large effect on field oil potential. This paper details the design, planning, and execution of the intelligent-completion technology in the field and covers the value generated for field development. Field Location The field, discovered in 1991, is located offshore Qatar (60-m water depth) and is adjacent to the Iranian border (please see the complete paper for a reservoir and geological description). The field was put into production in 1997 and has been developed through three successive phases. In 2013, 42 electrical-submersible-pump (ESP) -activated wells were producing 223,000 B/D of liquid, with an average water cut slightly below 90%. Eight injectors are available for a total injection capacity of 205,000 BWPD. A water- treatment platform, PP1 (adjacent to the DP2 platform), allows an injection rate of 190,000 BWPD on the DP3 and WP3 platforms. On the DP4 and DP1 platforms, injected water is produced from a regional shallow aquifer, Umm Er Radhuma (600. m). The production is exported to Halul Island facilities through two pipes (Fig. 1). Well Architecture The well architecture in Al Khalij field is characterized by a 1500- to 2000-mlong 9.-in. production casing set in the Mishrif formation, an (on average) 1500-m-long 7-in. cemented-andperforated production liner, and an (on average) 1500-m-long 6-in. openhole extension. Both the 7-in. liner and the open hole are acid stimulated before well production. Other well architectures are also present in the field. The oil-producing wells are ESPactivated. They are completed with two ESP strings in order to avoid production shortfalls while waiting on the workover rig should the primary ESP fail. Downhole monitoring is provided by the pressure/temperature (P/T) gauges located at the bottom of each ESP. Fig. 2.presents a schematic of a standard dual-ESP completion with zone selectivity. Smart-Well Strategy Intelligent-Completion Components. The subsurface components consist of a subsurface-controlled subsurface safety valve, production packer, temporary tubing-plugging device (to set the production packer), ESPs (including P/T gauges), isolation packers, and surface hydraulic-controlled flow-control valves (FCVs). No valve-positioning modules or additional gauges are incorporated in the string; therefore, a robust valve-tracking system is available in order to track the valve position. The FCV actuation is achieved with portable hydraulic pumps and can be actuated manually by the service- provider specialists whenever needed.

Delayed-Release Acid System for Cleanup of Al Khalij Horizontal Openhole Completions

This article, written by Assistant Technology Editor Karen Bybee, contains highlights of paper SPE 98164, "Delayed-Release Acid System for Cleanup of Al Khalij Horizontal Openhole Drains," by P. Leschi, SPE, and G. Demarthon, Total E&P, and E. Davidson, SPE, and D. Clinch, Halliburton, prepared for the 2006 SPE International Symposium and Exhibition on Formation Damage Control, Lafayette, Louisiana, 15-17 February. The full-length paper describes a new approach that uses a slow-acting stimulation treatment for damage removal and stimulation. The stimulation treatment comprises a starch enzyme to degrade the most troublesome polymer and an organic compound that reacts with the carrier brine to release organic acid in situ over a period of several hours. The system has been used recently in the Al Khalij field in Qatar with openhole lengths ranging from 162 to 576 ft and treatment volumes ranging from 125 to 725 bbl. Introduction The oil-bearing Mishrif reservoir is a stratigraphic trap in the Upper Cenomanian limestone. Laid down with several repeating phases of deposition and erosion, the reservoir typically consists of 20- to 30-ft sequences, each alternating between poor-permeability matrix intervals and highly productive diagenetically weathered layers. Permeability estimated from test data ranges from 100 md to a few darcies in drain layers and 1 to 50 md in matrix intervals. The oil-bearing strata are at approximately 366 ft true vertical depth, and the Mishrif formation can be as much as 46 ft thick. The formation is normally pressured, and bottomhole temperature (BHT) is 127°F. During initial development, it was thought that vertical or slightly deviated wells with electrical submersible pumps (ESPs) would be used because the naturally high permeability could be expected to provide good productivity. However, there was a change in plan when permeability was found to be very irregular. This prompted the decision to develop the field with horizontal wells with long horizontal sections. Subsequent development work on this field concentrated on optimizing the drilling process and improving acidizing treatments for cased-hole wells. Great success was achieved by the combined use of retarded and emulsified hydrochloric acid (HCl) and ball sealers for mechanical diversion. Cased or Openhole Completions In general, fractured reservoirs offer the best prospects for openhole completions, but only if there is no need for selectivity and if wellbore damage can be cleaned up satisfactorily. Openhole completions offer several benefits including cost effectiveness and ease of execution. In limestone completions, some openhole-wellbore stimulation usually is necessary to remove drilling damage. However, in some formations, deep acid penetration is required. In such cases, acid must be forced to penetrate several feet into the rock, either by creating large wormholes or by fracturing. Such operations require a cased-hole completion and use of mechanical and chemical diversion techniques. The major disadvantage of these completions is that the extra materials and time required for the casing, cementing, and perforating operations result in significantly higher costs.

Resources and Development in the al Khalij Region of Libya

During 1979 and the early part of 1980 the Government of Libya was engaged in a review of the state of social and economic development of the country with a view to preparing a long-range strategy to the year 2000. The exercise involved assessment of the position in 1979 and examination of alternative courses of economic change for the country as a whole and for its constituent regions. While this was far from being a first essay in economic and social planning, it represented a new time horizon (twenty rather than five years) and a rather different approach from previous proposals. In particular, it had become apparent from 1980 that Libyan oil reserves, when set against probable production to reserves ratios for the 1980-2000 period, would be fast depleting by the turn of the century. The last two decades of the twentieth century could be the last years in which Libya could lay the basis for economic survival while still comparatively wealthy from the proceeds of bulk oil exports.This short article will set out to discuss the resource base of the al Khalij area which was the source of the largest part of Libyan crude oil and natural gas supply and which might be expected to be the region on which Libyan prosperity might be founded in the post-oil era.