Pecos River Water Treatment For Water Injection
Authors: Meyers Brent D. , Daggett Lydia P. 
Published: December 2007

This paper presents a review of water quality controls utilized in preparing Pecos River water for fluid injection in the Ford Geraldine (Delaware Sand) Unit, Culberson and Reeves Counties, Texas. The nature of Pecos River water has necessitated the Pecos River water has necessitated the combined use of chemical and mechanical water treatments in order to minimize corrosion and the plugging tendency of this water, resulting in a successful waterflood. River water is used in the Ford Geraldine Unit as supplemental water to produced water, and is the only available water source at the required 25,000 BPD rate.

Extensive laboratory and field testing has been conducted to analyze and develop an efficient, economical and operational system of water treatment that utilizes sulfur dioxide to scavenge dissolved oxygen, chlorine to kill bacteria, and upflow filters to remove suspended solids from the raw river water. This paper discusses laboratory data, field data, and total system operational data.

Introduction

The Ford Geraldine (Delaware Sand) Unit is located in far West Texas with limited surface or ground water availability. Continental Oil Company is operator of the subject unit located in extreme northern Reeves and northeastern Culberson Counties, Texas. Field development began in mid 1956 with unitization and fluid injection commencing during 1968. Refer to SPE Paper 6383 for a case history of the Ford Geraldine (Delaware Sand) Unit. Producing interval is the Delaware Sand at an average depth of 2680 feet.

An initial waterflood pilot was installed using produced water to evaluate the potential of expanded waterflood operations potential of expanded waterflood operations and to allow time to develop a supplemental water source for full scale water injection. A system using Pecos River water was developed in 1972 with a design capacity of 25,000 BWPD. Due to possible incompatability between produced water and Pecos River water, two separate injection systems were installed and maintained.

Several operational problems were immediately encountered in using Pecos River water for injection. First, the river water was saturated with dissolved oxygen necessitating oxygen removal. Secondly, river water is a very good median for bacterial growth with the subsequent corrosion effects associated with bacteria. Finally, river water contains a variety of suspended solids that affects treating chemicals through secondary reactions and the good possibility of formation plugging due to fines. plugging due to fines.

WATER SOURCE

Pecos River water was selected to use for fluid injection due to its abundant supply and for the lack of another reliable water source in the nearby area. In fact, the Pecos River is located approximately eight miles to the north of the Ford Geraldine Unit and flows into the Red Bluff Reservoir which is a flood control project. Red Bluff Reservoir also serves as a holding pool for irrigation purposes downstream during the dry growing season. Red Bluff Power Control District has constructed a river water pump station to supply pressured water to Continental Oil Company.

A few miles upstream of the river water pump station is a natural super-saturated pump station is a natural super-saturated salt water spring that flows into the Pecos River.