An Organic "Clay Substitute" for Nondamaging Water Base Drilling and Completion Fluids
Authors: Fischer P.W. , Gallus J.P. , Krueger R.F. , Pye D.S. , Simmons F.J. , Talley B.E. 
Published: December 2007

This paper was prepared for the 48th Annual Fall Meeting of the Society of Petroleum Engineers of AIME, to be held in Las Vegas, Nev., Sept. 30-Oct. 3, 1973. 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 OF PETROLEUM TECHNOLOGY or the SOCIETY OF PETROLEUM ENGINEERS JOURNAL is usually granted upon request to the Editor of the appropriate journal 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
Development of a process for making micron-sized powders of organic, oil-soluble materials powders of organic, oil-soluble materials provides the basis for a new generation of provides the basis for a new generation of aqueous well drilling and treating fluids that minimize formation damage. When added to aqueous oil field treating fluids, these materials are effective fluid loss agents and form filter cakes that are completely soluble in the produced oil. This paper describes a new drilling, completion, and workover fluid in which one such additive replaces clay or calcium carbonate. To avoid formation damage by inorganic fine solids, the fluid is formulated entirely of oil- or water-soluble materials in potassium chloride brine. Inclusion of inorganic drilled solids is minimized by the nature of the fluid and use of full stream desilting.
Laboratory formation damage tests were conducted under simulated wellbore conditions with field samples of the new fluid and several commercial drilling and workover fluids. The new fluid minimized permeability damage in Berea cores, and return permeabilities were significantly higher than obtained with the conventional fluids. Field tests have indicated improved results in an area where well damage has been severe.

Introduction
The problem of formation damage during drilling, completion and repair of wells has been a matter of concern to the industry for many years. In these times of declining U.S. production and less fruitful exploration efforts, the need to achieve maximum well productivity assumes even greater importance.
Formation damage during drilling and completion is primarily affected by the nature of the fluids used during these operations, and many papers have been published on this subject. papers have been published on this subject. Formation damage may result from the interaction of filtrate with formation rock and fluids or from particle invasion and movement. The most severe problems have been noted with fresh water-base drilling fluids, and oil-base fluids have been substituted successfully to combat formation sensitivity to filtrate. However, in many cases oil-base fluids cannot be used, particularly in offshore areas where a spill is particularly in offshore areas where a spill is unacceptable for environmental reasons.
In recent years, various brine base fluids have been introduced to minimize filtrate damage, but the invasion of inorganic solids during drilling or workover has continued to be a serious problem. problem.