Successful Primary Cementing Can Be a Reality

Abstract

Distinguished Author Series articles are general, descriptive representations that summarize the state of the art in an area of technology by describing recent developments for readers who are not specialists in the topics discussed. Written by individuals recognized as experts in the area, these articles provide key references to more definitive work and present specific details only to illustrate the technology. Purpose: to informthe general readership of recent advances in various areas of petroleum engineering. Introduction The most important operation performed on a well is the primary cementing job at the time of completion. It must primary cementing job at the time of completion. It must achieve complete zonal isolation in the wellbore; that is, obtain a hydraulic seal of cement to casing and cement to formation while atthe same time eliminating mud or gas channels within the cement sheath. Fig. Idepicts the objective. If the cementing operation is not performed correctlyand successfully, the well most likely will never be the total well it couldhave been. A successful primary cementing job requires a positive attitude. commitment, dedication, proper alignment of priorities, and application of proven technology. This paper presents an overview of primary cementing and the interaction of the various factors necessary to achieve a successful job. Several references are included that furnish detailed instruction. Discussion Consider the overall primary cementing operation as a chain with three links:cementing philosophy,knowledge, andquality control. Although these are separate and distinct links, they are interdependent. Eachis discussed in this paper. Cementing Philosophy Through many years of association with cementing operations, I have arrived at one major conclusion: Primary cementing field practices must go through a major revolution to achieve increased cementing success. This revolution mainly involves a rededication to application of technology and materials already available, and requires a change in attitude, commitment, dedication, and setting proper priorities. As summarized in Fig. 2, these factors form the foundation for successful cementing. The adage "mix it, pump it, and bump it" is archaic. The negative attitude ("It's impossible to get a good primary job, so why try?") is a self-fulfilling prophecy. The positive attitude must contain a real commitment to a successful job and will involve dedication of people, time, and money. The usual response to the foregoing statement is "time and people are not available for such acommitment." Yet time and people always are allocated to repair a poor primarycementing job that can cost from a few thousand primary cementing job that can cost from a few thousand to several hundred thousand dollars. So time, people, and money are available to do the job correctly the first time. What is lackingis the setting of proper priorities. What is the first priority? A successful cementing job the first time! Usually, the added cost to perform a successful primary job is much less than the cost of remedial work primary job is muchless than the cost of remedial work to repair a failure (not to mention the potential delay or loss of production). In fact. substantial savings arepossible with a successful primary job. possible with a successful primary job. If this cementing philosophy is to work, a team effort is essential. This will involve the service company, the operator, and the rig contractor communicating and cooperating together. From the operator's standpoint, the team effort required to handle the varied quality control measures will involve not onlythe drilling foreman, but also the dedication of one or two drilling orcompletion engineers. All personnel must apply the total engineered conceptwhich starts with planning, continues through design, blending, and mixing, andculminates in displacement. The drilling engineer usually is involved intenselyin drilling the well safely and as fast and economically as possible. His interest is directed toward minimizing the possible. His interest is directedtoward minimizing the number of days to reach the target depth. However, hisultimate objective still must be to provide a wellbore suitable forcementing. JPT p. 1851