Hydraulic Systems-A Tool for the Prevention of Formation Damage
Authors: Silberman R.J. , Wetzel Rod 
Published: December 2007

This paper was prepared for the Society of Petroleum Engineers of AIME Symposium on Formation Damage Control, to be held in New Orleans, La., Feb. 7–8, 1974. Permission to copy is restricted to an abstract of not more than 300 words. Illustrations may not be copied. The abstract should contain conspicuous acknowledgment of where and by whom the paper is presented. Publication elsewhere after publication in the JOURNAL paper is presented. Publication elsewhere after publication in the JOURNAL OF PETROLEUM TECHNOLOGY or the SOCIETY OF PETROLEUM ENGINEERS JOURNAL is usually granted upon requested to the Editor of the appropriate journal, provided agreement to give proper credit is made. provided agreement to give proper credit is made. Discussion of this paper is invited. Three copies of any discussion should be sent to the Society of Petroleum Engineers office. Such discussion may be presented at the above meeting and, with the paper, may be considered for publication in one of the two SPE magazines.

Abstract
The pertinent features of hydraulic systems which are used for workover operations are described so that the reservoir engineer may become familiar with their use in the prevention of formation damage. The use of the prevention of formation damage. The use of the several systems to prevent specific types of damage is generally evaluated and several of the equipment limitations are detailed. The conclusion is that several arrangements of hydraulic equipment are valuable tools for use in the prevention of formation damage.

Introduction
Several arrangements of hydraulic systems are utilized in the oilfields to drill and service wells. One of the primary reasons for the use of these systems is that they may be utilized to prevent formation damage. Formation damage is often experienced if "conventional" equipment is used in the conventional manner; that is, "killing" a well with weighted fluids.
The purpose of this paper is to describe the physical and operational characteristics of these hydraulic systems which in fact enable the operator to protect the formation. Some references to results and some selected data secured in representative wells will be included. Equipment utilized to accomplish these results will be correlated with the results.
The effect of recent crude and gas shortages is stepped up drilling and workover activity to produce and to continue to produce wells. The experienced capability of produce wells. The experienced capability of hydraulic equipment in the performance of these jobs leads to the conclusions presented at the end of the paper. presented at the end of the paper.

GENERAL CAUSES AND REMEDIES FOR FORMATION DAMAGE
It is not the objective to describe all the means by which formation damage can occur. Several general statements as to how formation damage can occur will provide the necessary insight to what conditions exist which cause damage and how the use of certain types of hydraulic equipment (the subject of this paper) alters these conditions. Table I lists paper) alters these conditions. Table I lists some categories of formation damage and contains a brief statement of the condition which exists at the formation. A basic remedy accompanies the condition. Categories 1 and 2 type damage (solids loss and perforating trash) both are concerned with solids matter or material. In an overbalanced hole condition this matter or material will move into the formation and reduce the flow of the well either temporarily or permanently.