Worldwide Second Longest Expandable Cased Hole Liner Enables Sustainable Injection across the Reservoir in Long Radius Power Water Injector Well
Authors: Polo Juan Manuel , Buzaid Sami , Al-Hameli Mohammed Moteb , Andrews Stacey Kyle 
Published: May 2016

Severe damaged casing in a long radius, power water injector onshore well in Saudi Arabia compromised the workover objective of incrementing the water injection after reaching the well total depth (TD) and deploying a production liner. A total of pre-expanded 3,040 ft of 5½ x 7 in. solid expandable cased hole liner was run, expanded and tested successfully, covering the damaged section of casing plus an uncemented shallower section of casing, delaying any development of future leaks.

Before solid expandable systems came to the market, scab liners and cement squeeze methods were used to accomplish the repair. Scab liners reduce injection rates, whereas the cement squeeze methodology cannot be used effectively over extended lengths.

This paper explains how expandables were used to repair the casing and extend the life of the well without significantly restricting the internal diameter (ID) while enabling the desired injection rates.

Introduction

When Saudi Aramco initiated a workover strategy to optimize production from wells drilled in the 1990s, solid expandable tubulars provided the necessary technology to retain valuable hole size. The technology driven workover project began in mid-2003 and continues nowadays. Wells that have compromised integrity, production and injectivity, due to leaks formed either by poor to no cement bond behind the casing or by corrosive formation water, have been put back on line while preserving production or injection volume without compromising hole size.

Historically, mitigating these types of leaks consisted of running and cementing scab liners inside the production casing, resulting in reduction of production and injection rates.

Changing Directions

A power water injector well drilled vertically in 1996 in an onshore field was providing good injection rates until the injection declined and falloff test results indicated formation damage. A stimulation job in 2005 increased the injection rates, but not as adequately as expected. Because of the less than desirable injection rates, Saudi Aramco decided to sidetrack the well long radius and recomplete it as a horizontal power water injector, followed with an acid stimulation.

During the workover operations taken place in 2009, the original wellbore was plugged back by running a cement retainer and squeezing cement across the open hole. A leak found across the 9" in., 43.5 lb/ft casing in the interval from 2,378 ft to 2,428 ft was successfully repaired by squeezing 72 bbl of 118 pcf class "G" neat cement. The casing was pressure tested satisfactorily with water to 2,000 psi at 5,991 ft. The 7 in., 26 lb/ft liner was extended from 2,383 ft to the surface to fully isolate the repaired casing leak. A whipstock was run in the hole and a window was cut across the 7 in. casing from 5,970 ft to 5,983 ft. After cutting the window, a 6? in. curved section was drilled 1,900 ft followed by 3,500 ft of horizontal section drilled across the target reservoir to 11,414 ft measured depth (MD) (7,266 ft true vertical depth (TVD)).