There is an ever-increasing use of variable speed drives in submersible pump applications. However with all new applications new problems can be encountered. The long cable lengths associated with submersible pump equipment have limited the effectiveness of variable speed drives. Many drives have to use external filters, inductors and conditioners to keep from damaging the cable and motor. The extra costs associated with this equipment, as well as the custom use, limit the overall effectiveness. VSG (Variable Sine-wave Generation) technology has been developed to overcome these limitations, as well as providing the user all the flexibility that initially attracted them to Variable Speed Drives.

Beam pumping systems are the most commonly applied world wide artificial lift method. This paper reviews many of the concerns that operators face when using the sucker rod pumping system. The beam pump concerns are introduced with a review of the advantages/disadvantages of the system.

The Dynapump is a means of artificial lift that has been gaining recognition in West Texas and Eastern New Mexico over the past two years. The Dynapump is a hydraulic, ultra long stroke pumping unit that has heavy lift capabilities. The use of solid-state electronics and computerization lower energy costs while giving new flexibility to the artificial lift process. The pumping cycle is optimized through consistent feedback of surface and down hole conditions. The DynaPump's capability to independently adjust the speed of the up and down strokes and change stroke lengths during changing operating conditions result in well optimization while reducing surface and down hole maintenance. The result of the DynaPump design and pumping concept results in an overall reduction in artificial lift costs.

Plunger lifts are used widely to remove liquids from gas wells. The Pacemaker plunger is a new approach to this traditional method of artificial lift. Traditional plunger lifts require shut-in time for the plunger to fall and to build pressure to drive the plunger to surface. Shut-in time equates to lost production and forces liquids back into the formation. The Pacemaker normally only requires 5-10 seconds of shut-in time per cycle, and little or no pressure build-up time. The plunger operates as two interdependent pieces. Each fall separately and can do so against significant gas rates. Once on bottom, the ball scales off in a cavity in the piston. Gas velocity then drives both to surface. At the surface a rod in the lubricator separates the ball from the piston, and the next cycle begins. The end result is that the well produces continuously and liquids arc not forced hack into the formation

A study of the requirements for gathering, metering, compressing, processing and the marketing of products from liquid hydrocarbon recovery units is presented. Costs of installations and payout periods are discussed.

Since the cost of producing oil is continually increasing, oil operators have found themselves in a position of having to determine more economical production methods in order to make a profit. One of the first steps in this direction was the dual completion which enabled the operator to produce two zones, isolated from each other, through the same well bore, at the same time. Although the dual completion is not necessarily new, vast improvements have been made both in technique and equipment and a present day dual completion, producing through parallel strings of tubing is quite commonplace. The dual completion therefore provided the basic principle of multizone completions and was the forerunner of triple and quadruple completions. Also, since the economic aspect of the dual completion has been proved, it was felt that further development in technique and equipment would enable operators to produce three or four zones, isolated from each other, through the same well bore, at the same time, thus providing additional economic gains. Although triple completions are not an everyday occurrence they are no longer a novelty and several quadruple completions have been made successfully. It is the purpose of this paper to present several methods by which three or four zones, isolated from each other, may be produced through the same well bore.

Each member of the panel will be allowed ten minutes to express his opinions. The next forty minutes will be devoted to the members of the panel questioning each other and we will set a five minute time limit on each question and answer. The remainder of the time will be devoted to question from the floor.

The discussion this afternoon will be on the methods of artificially lifting multiple completed wells. I"m the moderator, Medford McCoy, Continental Oil Company. Mr. Smith, assisted by My Gallian, will discuss the merits of rod pumping; Mr. Morgan, assisted by Mr. Elner, will discuss the merits of gas lift installations for producing multiple completed wells.

When permitted by State and/or Federal law regulations, the pipeline will receive crude oil on the basis of unattended custody transfer measurement so long as it is satisfied as to the accuracy of the measurement and the ability of the facility to sustain this accuracy. Facilities for unattended custody transfer measurement may consist of positive displacement meters, weir tanks or dump tanks.

Paraffin control is a major operating problem with practically all oil producing companies in the Mid-Continent Area. It is generally so in the Permian Basin and particularly so in certain pools or fields in this area. Fields particularly troublesome, from a paraffin control standpoint in this area, are Levelland, Slaughter, Vacuum, Foster, North Cowden, Spraberry Trend and many others.

The accumulation of paraffin in both pumping and flowing wells has been a major problem to the production of crude oil since the very beginning of the petroleum industry. During recent years much progress has been made in methods of removing paraffin from these wells, some of the methods noted are chemical solvents, hot oil treatment, steaming and etc. These methods usually involve wells shut down, lost time, extra labor, special equipment and much expense to the operator. Therefore, the search for a more economical method has been continued and in almost every case plastic coating has been the answer to these problems. In the special cases where plastic will not perform to expectation are pumping wells, due to the abrasive wear from rods, even in these cases plastic will benefit the operator to a certain degree.

Recent technology has contributed many breakthroughs in the use of electromagnetic technology in the industrial, medical, automotive, and commercial marketplace. Among these applications are electromagnetic brakes and clutches, magnetic resonance in the medical field, flow meters, electromagnetic polarization, etc. Ener-Tee was formed in 1977, solely to develop the technology of applied electromagnetic polarization to liquids, gases, and solids (fluid stabilization). The first product, a Linear Kinetic Cell (LKC), was introduced in 1978 as an effective means of scale control in water systems. Over 7,000 systems have been installed throughout the United States as well as in 47 foreign countries. Applications for the product are many and varied. In 1982 the electrostatic control system was introduced to reduce electrostatic charges in dry materials with great success. At approximately this same time Ener-Tee, Inc. was experimenting with the LKC system on oils of various types in an effort to determine if there was an application for the system in the petroleum industry. Tests showed that the LKC system would prevent deposition of paraffin and other minerals by polarizing the molecules within the fluid using electromagnetic fluid stabilization. At this time the Permian Corp. was contacted and they reported the problems that are faced in the oil fields on a regular basis. The worst problem reported was paraffin buildup in oil wells and pipelines. A LKC test unit proved to be very effective in dealing with this problem.

This presentation deals with five aspects of paraffin in oil wells. The text discusses the chemistry of paraffin, the mechanism of paraffin deposition in oil wells, physical means of reducing paraffin deposits, paraffin control with chemical inhibitors, and common paraffin removal practices. Fundamentals are stressed so that preventive or removal methods may be more carefully engineered.

Forty crude oils having 10% or less paraffin content were examined for their potential to deposit paraffin. The deposition was then correlated against several crude oil characteristics. It was found that the paraffin cloud point and the paraffin content were the two most important factors which dictated deposition potential. Viscosity versus temperature plots allow estimation of both paraffin cloud point and paraffin content. Pour point was not a factor in dictating deposition. It is suggested that a cloud point depression test is a better method than a pour point depression test for choosing a paraffin inhibitor. This is true only for low paraffin content crudes. However, there does not appear to be any quick test which allows one to predict the best paraffin inhibitor 100% of the time.

Paraffin problems exist in the majority of petroleum producing areas. The chemistry of paraffin and methods of analysis are discussed. Asphaltenes are also described and differentiated from paraffin. Three types of chemical treatment for paraffin problems are compared: paraffin inhibitors, paraffin dispersants, and paraffin detergents. Each has advantages, and factors are given which would influence the choice of one method over the other. Recent developments and possible pitfalls in paraffin treatment are discussed.

A study was initiated to establish a uniform method of removing paraffin from wells completed in the San Andres formation in Hockley and Cochran Counties, Texas. Several methods of paraffin removal, including hot-oiling, batch treating with chemical, paraffin inhibitor squeezes, and batch treating with paraffin-eating bacteria, were evaluated and the results reported. Each year thousands of dollars are spent removing paraffin from tubing and flow lines in San Andres wells. The best methods for optimizing paraffin removal while minimizing lease expense will be discussed.

The accumulation of paraffin wax in petroleum reservoirs and production equipment remains a continuous problem and expense in the production of oil. These problems have been remedied in the past by scrapers, hot-oil treatments and solvents. However, with the advent of extremely deep production, offshore drilling, and the possibility of ocean floor completion, the application of remedial measures becomes economically prohibitive. As a result, the use of chemical additives as paraffin deposition inhibitors has become necessary. Since no one additive has been proven universally effective, the problem of selecting an efficient additive for a specific application is presented. In order to define a suitable additive, a better understanding of the mechanisms of inhibition is necessary. Previous work showed that high molecular weight fractions from crude oil significantly affected paraffin crystal growth and subsequently retarded or prevented paraffin deposition. Some investigators found that these fractions were preferentially adsorbed to a metal surface and that a reduction in deposition occurred. In addition, it was noted that decreased deposition could be attributed to modifying the paraffin wax crystals or changing the wetting characteristics of the pipe surface. Although there is considerable experimental evidence to support each mechanism, there is no way to predict which mechanism and chemical inhibitor is the most efficient way to prevent wax deposition for any given crude oil system.

Crude oil is a complex mixture of organic materials consisting of saturated and unsaturated linear and branched hydrocarbons, organic acids, amines, hetero atomic and polycyclic molecules combined in various proportions. Paraffins waxes are an important component of the saturated linear and branched hydrocarbon portions of these grand mixtures. They are important for several positive reasons; primary among these is their fuel value as a refinery feedstock. However, they are also important because of their tendency to negatively affect the physical properties and behavior of the crude oils in which they reside. Two important physical properties that are affected by the presence of these paraffin waxes are viscosity and deposition tendency. These properties are of significant importance to ability of oil companies transport these crude oils from the reservoir to the consumer. Paraffin waxes form networks of crystals within crude oils as the temperature drops, producing deposits on cold surfaces like pipe walls. These deposited waxes then act to impede the flow of oil fluids through the transporting conduit. But before deposits are formed the Waxes produce large increases in the viscosity of the crude oil fluids that results in higher energy costs as pumping energy requirements are rapidly escalated. Sometimes accumulations of paraffin waxes can have catastrophic consequences such as line plugging and ruptures that can result in severe environmental damage. Thus control measures that act to mitigate the negative physical properties produced by paraffin waxes are of high priority among oil producing and refining companies. Laboratory distillation methods provide good comparisons to crude oil reservoirs, since gases and fluids are forced kom areas of elevated heat and/or pressure to areas of lesser heat andor pressure within each system. In both cases, gases condense and fluids cool as they migrate kom the flask or reservoir. The condensation products may be gas, liquid, or solid at varying temperatures and pressures. In the case of paraffin waxes, these condensation products comprise a spectrum of variable carbon chain lengths ranging fkom 18 to 100+ carbons. As deeper and hotter reservoirs are put into production higher carbon chain length hydrocarbons become more prevalent, since the lighter gases and fluids have greater mobility through the porous geologic structures above. Thus, with the advent of new technologies enabling greater production depths and increased production in areas of deep water offshore, the crude oils being produced contain increased amounts of paraffin waxes.

Prior to 1971, the Devonian formation of the Three Bar Field, Andrews County, Texas was hydraulically fractured with a variety of conventional techniques. These treatments gave fair after-frac results but sustained increases were small and sand backflow caused severe fill and pump problems. Much of the backflow material appeared to be finely crushed frac sand. Core studies and computerized treatment evaluation indicated 12-20 glass beads placed in a partial monolayer with a high viscosity fluid would yield better production increases, eliminate proppant crushing and minimized backflow problems. Since January, 1971, ten partial monolayer treatments have been performed in the Three Bar Field, which have resulted in more than two times the sustained production increase of conventional jobs and times the sustained production increase of conventional jobs and proppant backflow problems have been eliminated. In addition, no proppant screen-out problems were encountered. The partial monolayer frac technique appears to have particular application in hard rock formations where large fracture flow capacities are needed. Care should be taken in application and design of this technique to assure optimum results.

A general survey of corrosion and control in the petroleum industry illustrated with color slides and field specimens.

This paper discusses a numerical pattern recognition scheme NUPRO*. NUPRO is used to diagnose rod or subsurface pump problems by recognizing downhole dynamometer cards. NUPRO discretizes a dynamometer card into a set of points. Three point picking methods have been developed for NUPRO: constant position increment, constant time increment, and constant arc length increment. These methods vary the accuracy and run time of NUPRO. These methods were tested with a library of 37 known cards (cards l-37) and 100 unknown cards (cards 38-137).

This paper discusses a numerical pattern recognition scheme NUPRO*. NUPRO is used to diagnose rod or subsurface pump problems by recognizing downhole dynamometer cards. NUPRO discretizes a dynamometer card into a set of points. Three point picking methods have been developed for NUPRO: constant position increment, constant time increment, and constant arc length increment. These methods vary the accuracy and run time of NUPRO. These methods were tested with a library of 37 known cards (cards l-37) and 100 unknown cards (cards 38-137).

Yates Petroleum has developed successful drilling and completion practices through experience with 250 wells in the Pecos Slope Abo gas field. Several methods have been used for estimating ultimate reserves from the wells in this low permeability reservoir. The most promising is a drawdown analysis that matches computerized type curves with data on daily flow rates and tubing pressure.

Modern perforating techniques designed to maximize production seem as varied as the wells they are applied to. However they have one trait in common: an instantaneous pressure drawdown (reverse pressure) is applied to surge the perforations clean and create the highest effective shot density possible. The pressure drawdown lends itself to a pressure buildup test immediately thereafter. This paper discusses reverse pressure surging techniques with casing, thru-tubing, and tubing conveyed perforating guns along with a discussion of the capabilities and versatility of the Measurement While Perforating (MWP*) and Measurements After Perforating (MAP*) buildup testing techniques.

Perforating through multiple strings of casing is one of the most difficult design problems in recompletions. The overlap of casing sections may occur in the middle of a series of pay zones as the result of drilling breaks, hole problems or pressure control. Tests in surface targets have provided information that is useful in design for perforating two and three strings of casing as well as addressing problems of perforating in large diameter casing and the thick cement sections of hole wash-outs. In the surface tests, large deep penetrating charges in large diameter guns with minimum gun-casing clearance were found to create the most consistent penetration through multiple strings of casing. Information presented includes evaluation of deep penetrating and big hole charges, charge variances, perforation plugging by debris, and effect of clearance on penetration. Entrance hole information in each string is presented on some targets.