Publications

The Handbook of Ground Water Development is a comprehensive text covering subjects related to this industry. Written by distinguished experts, this book was edited by Roscoe Moss Company and published by John Wiley and Associates. Used by professionals as a reference, it also serves as a graduate level textbook in many major colleges and universities.

A direct benefit of efficient wells is reduced pumping costs. Well efficiency is controlled by several factors, including aquifer, drilling damage, and turbulent-flow losses at or near the well screen. Screen entrance velocity is not a critical design factor if values are less than 2-4 fps (0.6-1.2m/s). For most wells, the required open area of a screen need only be 3-5%. A new method of designing minimum length of well screen based on laminar flow-turbulent flow considerations is presented, along with a simple field test to calculate the efficiency of an existing well or to provide a criterion for termination of development of a newly constructed well.

This paper details specific design considerations that should be taken into account when designing a water production well.

To further the understanding of ground water development and design of efficient wells, Roscoe Moss Company designed and built the world’s largest and most sophisticated well aquifer model. Research focused on understanding the aquifer relationship with the gravel pack and well screen, and corresponding effects on well efficiency, production, and sand control.

Five basic techniques of well development have been studied and are the subject of this report. The purpose of the investigation was to provide a quantitative basis for evaluating the relative efficiency of respective development methods in gravel envelope wells. The techniques evaluated were:

• jetting
• line swabbing
• rocker beam swabbing
• single swab mounted on drill pipe with simultaneous injection below the swab
• double swabs mounted on drill pipe with injection between the swabs

The analyses assumed a completed well with a filter pack between the screen and aquifer. The primary goal of studies performed was determination of the direction and magnitude of the flow velocity field at the pack/formation interface. Evaluation of this flow velocity distribution gave clear indication of the ability of the development technique to clean drilling debris and wall cake from the formation.

Results of the study indicated that both swabbing and jetting can be effective development methods for gravel envelope wells. Swabbing methods involving pumping appeared to offer even further benefits. The efficiency of jetting techniques was found to be conditional on use of a filter pack size distribution that would enable filter particle circulation to develop. In the absence of this circulation, jetting would likely be of limited use.

This booklet discusses casing and screen materials in common use in the world today. It also sets forth the factors to be considered in their choice. These factors include methods of well construction and their relationship to well design. While a complete answer to every planning requirement cannot be provided here, the information presented in this document can be used as a general guide by those concerned with ground water development.

This paper examines concepts related to water well corrosion and incrustation.

A comprehensive corrosion study undertaken by Geoscience Support Services Inc. was conducted to identify the corrosion rate of five types of steel: mild steel, copper bearing, high-strength low-alloy (HSLA) steel and stainless steel types 304 and 316L. Three sets of five types of metal coupons were placed down hole in Well No. 7 on March 11, 1998 in Fountain Valley, California.

This report compares the production capabilities of a group of high capacity water wells of varying design drilled in the Pleasant Valley Basin near the city of Camarillo, California. Thirty-four wells were chosen for the study and represent different screen types in addition to development and completion methods. The type of screens in the wells range from low open area milled and punched slotted casing to higher open area, continuous slot screen and shutter screen. The total depth and length of screen vary considerably between wells as does the type of aquifer penetrated.

Because of the variety of screen types and development methods, the Pleasant Valley area affords an excellent opportunity to study the relationship between well yields and screen design.

The scope of the investigation included plotting of a typical geologic cross section through the Pleasant Valley aquifers and a computer analysis and comparison of specific capacities per foot of screen for each of the wells.

Roscoe Moss Company sponsored research conducted at the University of Southern California Geohydrology laboratory in Claremont, California. The purpose of this program was to study the relationship between formation and gravel pack graduations and screen slot size. The goal was to set design perimeters required to minimize sand production and maximize well efficiency.