Submersible Pumping Operations in the Long Beach Unit
Authors: Yancey I.R. , Khamis A.G. 
Published: December 2007

The principal method of producing some 150,000 barrels of oil a day from theLong Beach unit is the electrical submersible pump. This equipment is liftingcrude from seven separate formations of varying subsea depths, at a wide rangeof rates, gravities, and GOR'S. More than 400 units have been installed, andthe system can be considered highly successful.

Introduction

Development of the East Wilmington oil field began on July 16, 1965, underthe planning and supervision of the THUMS Long Beach Co. On April 1, 1965, thisfield was unitized as the Long Beach unit, with the City of Long Beach as unitoperator. THUMS, as the agent for the successful bidder, is the fieldcontractor responsible to the unit operator. Since July, 1965, four 10-acreislands have been constructed; 586 wells have been drilled (as of Sept. 1,1969); a daily oil rate exceeding 150,000 bbl, and a daily water injection rateexceeding 400,000 bbl have been achieved; and one-tenth of the estimated oilreserves bas been produced. Because of the anticipated individual-well highgross rates, the viscous nature of the crude, and the rapid rate of equipmentinstallation, the primary lift method selected to artificially produce thislarge oil reserve was the electrical submersible pump. Currently over 436 wellsof the 485 producers are being pumped by this method. This includes wells thatare pumped by this method. This includes wells that are temporarily idleawaiting remedial work as well as those curtailed because of excessive GOR'S. All in-zone injection wells have been produced with submersible equipment forwellbore cleanup prior to conversion. We shall relate here the designing andoperating experiences that THUMS has had with this lift method over the past 4years.

Reservoirs

The Long Beach unit is located in the Wilmington oil field and encompassessome 6,400 acres. About 93 percent of this area lies within State of Californiaocean waters off the City of Long Beach. The reservoir bas seven producinghorizons at subsea depths from 2,000 to 7,700 ft. The field was placed underwaterflooding at the time of initial production to increase recovery andmaintain formation pressures. The Wilmington oil field is a highly faulted areawith a history of surface subsidence. The fact that formation pressures can bemaintained has demonstrated that subsidence can be controlled. The type ofcrude being produced varies in gravity from 12 degrees to 35 degrees API. TheGOR varies from 200 to 2,000, with approximate tubing ratios of 50 to 300. Producing water cuts range from 0.5 to as high as 95 percent. The upperformations are unconsolidated sands containing producible particles of silty, finegrained materials; permeabilities range from 50 to 5,000 md. The lowerthree formations are consolidated sands and fractured shales; permeabilitiesrange from 25 to 1,700 md.

Well Completions

Because of the available drill sites dictated by a City of Long Beachordinance, and because the reserves are located under the ocean, virtually allwells have been directionally drilled. A typical well-casing program (Fig. 1)in most of the wells includes 60 ft of program (Fig. 1) in most of the wellsincludes 60 ft of 20-in. conductor, 1,000 ft of 13 3/8-in. surface string,4,000 ft of 8 5/8-in. production string and 500 ft of 6 5/8-in. liner. Thegravel-flow packed liners have two sets of external, inflatable formationpackers that are used for subzonal segregation within a given producing zone. Cement placed between each packer set insures lasting segregation.

JPT

P. 1480