Manufacturers of down-hole sucker rod pumps have developed materials, coatings and treatments for barrels and plungers. Some of these have become standards in the industry while others have been tested and either did not meet expectations or were not economically viable. This paper will review historical, current and new materials, coatings and treatments for down-hole sucker rod pump barrels and plungers.

Completions for thermal recovery installations are closely related to the many new and sophisticated approaches to well design which have come of age during the last decade. This writer likes to compare them with completions in the 15,000 - 20,000 ft range, to high pressure gas completions in corrosive environments. perhaps to wells on platforms in deep water or completed by TFI methods. This comparison is made not because the magnitude of engineering difficulty in each instance is equal, but because the total probIem content of each of these completion techniques represents a distinct engineering challenge and required unique solutions. Finding these solutions in turn required the use of classical methods and theories mixed with original thinking. Let us then examine why thermal recovery wells qualify for a position amongst difficuIt and sophisticated technological accomplishments

In 1972 a carbon dioxide/water injection project began in the SACROC Unit, Kelly-Snyder Field in Scurry County, Texas. The injection of CO2 and the highly corrosive produced water has created some very unique problems with downhole equipment. New materials of construction, new design parameters, and new treatment methods have been developed to deal with these problems. The paper describes the corrosion problems encountered with submersible pumps, sucker-rod pumps, tubing, sucker-rods, and other downhole equipment, and it describes the solutions found for these problems. Chemical treatments, coatings, and monitoring programs are discussed. Finally,, the effect CO2 injection on downhole corrosion is evaluated.

The Downhole Diverter Gas Separator increases the liquid capacity and gas separation capacity over conventional poor boy or Improved Collar Sized downhole gas separators. The increased separation capacity of the diverter gas separator is provided by using the larger tubing-casing annulus for both gas separation and liquid separation. A simple movable rubber seal is used to divert the flow of liquids and gas vertically from below the rubber seal through a central tube approximately 5 feet in length. When the fluids exhaust into the tubing-casing annulus above the seal, the large annulus flow area reduces the annular gas velocity which allows the liquid to fall back through the large area tubing-casing annulus into the pump intake. Larger tubing-casing annular area below the diverter exhaust port provides high liquid capacity. Large tubing-casing annular area above the diverter exhaust port reduces the gas velocity, reduces liquid holdup and provides high gas separation capacity.

The Downhole Dynamometer is a tool designed primarily for the acquisition of sucker-rod load and position data at any point in the rod string. The tool is completely sealed, battery-operated, and microprocessor-controlled to sample the various parameters at specific times and sampling rates and to store the data digitally in a nonvolatile memory for later retrieval. Other parameters sampled are temperature and pressure and, with the present design, bending data is also collected. Axial position is derived from acceleration. At the time of this presentation two-dimensional lateral accelerations may also be available. While used predominantly for code validation the tool could be an effective well-diagnostic device as well.

The Downhole Dynamometer is a tool designed for making dynagraph measurements at any point in the rod string. The tool is completely sealed, battery-operated, and microprocessor-controlled to sample axial load, position, lateral acceleration, fluid pressure, and temperature at preprogrammed times and sampling rates and to store the data digitally in a non-volatile memory (Figure 1). Load is measured at three points spaced radially equidistant around the body of the tool enabling the derivation of bending and buckling loads. Rod velocity and acceleration are also measured. The tool is used in the industry as a diagnostic device and to validate predictive and diagnostic codes. Any number of tools can be used simultaneously at different points in the string. 1994 was a maturing year for the tool. This presentation one year ago was devoted to the evolution of the downhole device. The focus this year is on the present state of the tool, calibration, accuracy and how to use it.

Downhole Oil Water Separation (DOWS) is becoming one of the key technologies of the oil industry and to reap the benefits promised by this concept, a new system has been developed to separate oil and water in the wellbore. The first test of the system - the Triple Action Pumping System (TAPS) - will be described in this article. The new system has accomplished a number of industry firsts in oil/water separation. The potential of DOWS to improve revenues, reduce expenses and investments, and protect the environment when the right conditions exist has been described in previous article. By virtue of its capability to inject at high pressure, TAPS opens the door for DOWS to provide a whole new (less costly) method of waterflooding. The successes of this test are primarily attributable to two conscious efforts: 1) commitment at all levels - from the field to management and 2) true team effort involving an operator, vendors, and government agencies. As the DOWS acronym suggests, the TAPS is capable of economically separating and injecting water downhole while producing only a fraction of the water to surface with the hydrocarbons. TAPS has extended the applicability of DOWS to "hard rock country" where high injection pressures are common. The TAPS is believed to have accomplished a number of industry firsts: -It showed that oil and water segregation occurs even when the pump is placed below the well's producing perforations. This is significant when it is important to minimize backpressure on a well. -It employed produced water recycling to achieve environmentally friendly "zero discharge". That is, any water produced to surface was dumped back down the annulus and injected so that no water hauling was necessary. This process is a closed system that reduces discharge opportunities and facilitates chemical treating. -A pseudo-permeability log4 (created using neural networks) was used to select the optimum injection interval for a DOWS application. -A water-soluble, oil-dispersible chemical was used to protect both the producing and injection zones. This treating method appears to be far more successful than previous approaches.

A novel image acquisition system has been developed that will enhance our knowledge of downhole pumps. This system, comprised of a video camera, digital frame grabber and image processing routines, has been integrated to the downhole pump test fixture at the University of Texas at Austin where in the past pressure at various point of interest around both the standing and travelling valves have been recorded. As the images and pressure information have been recorded at the same exact time, one can now look at the picture of the pump to see the actual valve movement for each interesting

With today's economic condition, competitive market, and customers world wide clamoring for lower prices, the need to maximize the economic operation of an oilfield has never been greater. This paper is directed toward abrasive wear and increasing pump barrel life. The first step in increasing the life of a pump barrel is to understand why it wears out. After we grasp the cause of wear we can design or select a product that wears slower. Wear cannot be stopped but only slowed. The user must examine worn out parts, keep records, and have a working knowledge of available materials in order to select a barrel most economic for the task. The cost you notice most is when you have to pay for another barrel, but the more significant costs are those of pulling, repairing and reinstalling the pumps, and the lost revenue when the oil stops flowing. Those costs tend to get lost in the general aggravation of being in business in the first place.

The Drill Stem Test (DST) is a temporary well completion, which is made in the early production life of a potential reservoir to determine both the quality and quantity of produced reservoir fluids. This can be done prior to completing the well. The drill stem is used to lower the packer(s), downhole valve assemblies and other auxiliary tools to the bottom of the hole. The packer is a device which expands and effects a seal with the wall of the hole and isolates the zone to be tested from the drilling fluid in the annulus. The surface-operated downhole valve assemblies are devices used to relieve the hydrostatic drilling fluid pressure from the face of the formation to be tested, allowing the produced fluids to enter the drill pipe and be trapped so that they may be recovered and measured at the surface. An upper tool valve allows the formation to produce into the drill pipe for a specified time. The tool can then be closed and the formation buildup pressure can be recorded again for a specified time. The opening and closing of the downhole valve can be repeated for two or more flow times and closed-in times. Other tools and accessories are also used in modern drill stem tests. Accurate pressure data are very necessary for the interpretation of the test and analysis of the tool behavior. During DST"s, two or more subsurface pressure recorders should be used. These provide the means for obtaining accurate reservoir pressure records. One recorder should be located below the packer, in a blanked-off position. Since no fluid should flow past this recorder during the test, it will record the pressures directly from the annulus. The other recorder is in the flow stream above the packer but below the tools and bottomhole choke. This arrangement of recorders is necessary to help insure the detection of any anchor, tool and/or choke which could cause plugging, and for obtaining accurate pressure data. Most downhole pressure recordings are under dynamic rather than static conditions.

Damaged pipe, especially in horizontal applications, is costly. The large number of planned horizontal drilling projects
coupled with the expense of pipe replacement and fishing operations made it imperative that Mobil E&P gain a better understanding of drillpipe life. Previous internal studies of failure flurries have shown that excessive doglegs, high H2S environments, and improper specifications or makeup on tubing connections can accelerate fatigue leading to failure. The effect of high bending stresses on drill pipe connections is also a concern. Inspections, typically used to determine pipe condition, prove only obvious defects and not fatigue. The goal is to evaluate DPLIFE2's ability to predict failures by comparing the program result with actual failures. Another objective is to evaluate the overall consumed life of the tubing and determine a "best practice" for replacing pipe before failures occur.

Prior to the 1973-74 Infill Program, the Shell operated Denver Unit, Wasson San Andres Field, Gaines and Yoakum Counties, Texas (Fig. 1) included over 900 producing or injecting wells. Upon project completion in October 1974, the 1973- 74 Denver Unit Infill Program added 120 wells (14 injectors, 3 replacement wells, and 103 new producers) to this total. The 1973-74 program was sufficiently different from previous Denver Unit programs to require some changes in techniques and equipment. The most significant differences were cementing production casing to surface and drilling "intown" and/or directional wells. These changes and the large number of wells necessitated the review of all drilling program facets to optimize performance and reduce costs. This paper presents the more significant points of this review and was prepared to document the cost reduction methods and the experience gained for use in future programs. The items discussed individually represent small cost reductions but collectively resulted in reducing 1973-74 Denver Unit Infill Program expenditures by $250,000.

With the use of invert emulsion fluids, environmental responsibility has increased the cost and liability associated with the disposal of contaminated drill cuttings. In environmentally sensitive areas it is unlikely that any discharges of contaminated cuttings will be permitted and responsible treatment methods must be found to minimize future liability. Development of an invert emulsion drilling fluid designed for both the high performance drilling and optimized treatment of contaminated cuttings has been a key in minimizing environmental impact. Developing efficient treatment techniques for the local environment has been equally as important. True environmental responsibility has been achieved by combining chemistry and treatments to produce an end product which can be beneficially re-used in the local environment. The Authors will discuss the drilling fluid chemistry and treatment techniques, will show the field performance of these fluids, and will review the potential for beneficial Reuse of contaminated cuttings in this context and show results of field trials.

Drilling is required for the exploration and production of almost all forms of energy and mineral resources found in the earth. Current drilling activity in this country is large and working near the industrial capacity. For example, the petroleum industry alone drilled approximately 145 million feet of hole in 1974 at an average cost of $24 per foot. The uranium industry drilled an additional 22 million feet to bring the total drilling cost to almost $4 billion in 1974. This figure was exceeded in 1975 and projections for 1976 are higher still. Using today's rotary technology, the cost of drilling for petroleum increases exponentially with hole depth as shown in Fig. I. The future development of geothermal resources will pose even more severe problems to the drilling industry. The more competent basement rocks at elevated temperatures are more difficult to drill, and footage costs are factors of two to four higher than for comparable depth sedimentary drilling. If improved drilling technology is not developed, this expense, coupled with the shortage of rigs and trained crews, could severely limit the timely development of this resource. Drilling technology could become a limiting factor in future energy development if ways are not found to increase the footage drilled and reduce the costs per foot. Significantly increasing the active rig count does not seem to be a viable option due to the very long lead time associated with new rig deliveries and the severe shortage of trained personnel.

Before 1950, drilling strings contained few drill collars, and the hole depth was shallow enough so that grade-E drill pipe easily satisfied most requirements for drilling and drill-stem testing. In 1957, when Great Western Drilling Company drilled the Phillips Petroleum Company Montgomery A-l to 23,400 feet, engineered drilling strings became necessary. Between 1957 and the time the API published RP7G, drilling-string design was a daily necessity for drilling engineers to avoid operational problems and to satisfy contractural requirements. Each engineer designed his drilling strings based on his knowledge and training, and the procedures were based on techniques previously used in the design of casing. In the vacuum created by operational necessity and the lack of API recommended practice we developed a philosophy and two report forms for our use which have worked well. Examples of the use of these report forms and a comparison between our philosophy and the API RP7G recommended approach are presented in this paper.

This paper presents a case history of the methods used by Exxon co., U.S.A. to drill the St. Lawrence Field in Glasscock County, Texas. Lightweight oil base mud was used to combat salt and lost circulation, while brine water weighted with hematite was used to drill an abnormally pressured section. Two-stage and tack-and-squeeze cementing were used to place cement across lost circulation zones. The lightweight oil base mud was technically successful, yet proved uneconomical. In contrast, the hematite was cost effective as a weighting material. The tack-and-squeeze method proved to be the most successful method of cementing.

In 1982 the Employment and Productivity Sub-Committee of the U.S. Senate Committee on Labor and Human Resources held a series of four hearings on United State's productivity performance. Testimony was heard from witnesses representing education, science, industry, high technology, labor and government. During those hearings, information surfaced that was serious enough to warrant holding a fifth hearing. Seventy bit lion dollars down the drain. Think about it. According to the Sub-Committee's findings, seventy billion dollars is how much money American business loses annually because of alcohol and drug abuse by employees. Not possible? Consider---A business climate with decreased productivity, unmet quotas, absenteeism, tardiness, and couple that with an increase in security problems, accidents on the job, and destruction and theft of company property. Get the picture? It doesn"t take a computer analyst. from California, or a financial expert on Wall Street to spell it out for you. Pot., pills, powders and booze...sapping the strength and drive of America's work force. These impaired workers function at slightly more than half their normal capacity. With three million alcoholics in the United States and up to fifty-three million people using drugs occasionally, we are looking at almost sixty million workers performing at significantly less than their normal capacity daily.

DTS sensing is an emerging technology in which a local operator used on 16 wells to determine the effectiveness of acid treatments. The technology uses a fiber optic cable to read temperature realtime downhole per foot along the wellbore. This allows the service company to validate fluid placement. The effectiveness of the acid treatment can now be determined. Effectiveness can also be determined by how much improvement in production takes place after the job. In the case studies observed, effectiveness was determined during the pumping of the job with DTS sensing rigged up to the well. It is this configuration that an operator can decide if a change to the design should be made, real time-during pumping. The effectiveness of an acid job is dictated by effective fluid placement. One wants to know where the acid was placed in the well. Does all the acid go where it is supposed to go, in each zone? Or, does a high percentage of the acid go into the first least resistive zone and subsequent zones go untreated. If the latter takes place, a portion of investment capital used on gallons of acid will be wasted. Acid treatments can include a wide variation of stimulation methods or processes to improve the effectiveness of the treatment. These processes include stimulating the formation using fracturing or matrix rates, varying the acid percentage, varying the type of acid, using linear, gelled or crosslinked acid, varying the rate at which acid is pumped, and using particulate and chemical diverters. Previously on acid jobs, surface readings for pressure and rate were the only indicators to judge the effectiveness of the treatment. The legitimacy of this type of interpretation can be questioned because friction pressure encountered can mask what is actually taking place downhole. As the operator attempted all the above acid treatments and also monitored treatment with DTS, it was revealed that what we see at the surface can be misleading.

The term "dual completion" refers to a method of producing two zones through the same well bore without co-mingling of fluids. A dual completion is one that promises greater economy. During recent years the percentage of such completions has been greatly accelerated, due to mounting development costs. Because of the success of dual completions, and the favorable economic aspect, there is no reason to predict a downward trend. Equipment manufacturers are constantly redesigning and improving their equipment to meet the demands of equipment applications. The purpose of this paper is to discuss various types of dual completion installations, beginning with the very basic type and progressing to the later types, which are becoming more commonly used.

The need to produce large volumes of fluids from secondary recovery wells, and to produce normal levels of fluid from deeper wells, made possible an innovative artificial lift option using a Dual Displacement Pump.(Fig. 1) Reciprocated with a standard beam pumping unit using coiled tubing, this production system (patent pending) consist in reciprocating a plunger of a down hole pump, were both motions of the pumping unit are utilized to convey fluid to surface. While in the down stroke production reaches surface through the annular space between CT and production tubing, in the up stroke fluids reach the surface through the annular space between CT and production tubing, The pump design incorporates two independent sets of traveling valves and two sets of standing valves with only one Plunger/barrel configuration.

In 1994 Texaco personnel viewed chemicals as the primary means to reduce water handling costs. They recognized from downhole videos that oil and water remain separated in the tubing-casing annulus. Capitalizing on this revelation of "gravity segregation," they conceptualized a dual-ported, dual plunger rod pump to produce oil and water from the annulus on the upstroke while injecting water on the downstroke. Texaco and Dresser jointly developed this pump and named it the Dual Action Pumping System (DAPS). In January 1995, the first generation prototype was installed. It verified the technical and economic feasibility of this new technology. It substantially increased production while simultaneously reducing power requirements. A second generation prototype was developed to improve the valve design. It has continued to function without problems since its installation in October 1995. Tests in a Rocky Mountain Oilfield Testing Center well and several Talisman wells have further demonstrated that this will be a unique, new tool for the oil industry. These papers will both explain how DAPS works and describe some of the early testing results. Work is continuing to improve the performance predictions. Tests have shown it to be an inexpensive technology that can reduce lifting costs and thereby increase and/or accelerate reserves recovery when the right conditions exist. While many potential applications or benefits of DAPS have been identified, these can generally be classified in three categories: _ Increase oil production _ Reduce water handling costs Reduce potential investment costs

This paper reviews our experience, dating from 1953, with dually completed wells equipped with tandem pumps (two pumps actuated by one rod string). In this span of time newer designs in dual-zone equipment and packer-tubing combinations have antiquated the initial installation. Subsurface schematic drawings depict seven deviations in equipment installed in various wells, which encompass most of the major techniques and assemblies. Commentaries on each method, which include installation and operational problems and production results from specific wells, give an insight into the applications and limitations of each assembly.

This technology utilizes a thixotropic, in-situ polymerized, gelation system. It is designed to prevent gravity slumping to form a chemical packer in horizontal and deviated wells. This system has relatively low viscosities at surface temperature but develops its thixotropic properties in a time frame of 20 to 30 minute as temperature increases while being pumped down hole. This thixotropic blend can be used in wells with bottomhole injection temperatures ranging from 100oF (38oC) to 180oF (82oC). The system utilizes synthetic clays which impart the thixotropic properties to maintain a temporary chemical seal until the second vinyl polymerization occurs to form the final packing seal. The vinyl polymerization system is a low viscosity monomer solution which uses temperature-activated initiators to induce a phase change from liquid to a ringing gel at predictable times.

The dynamic properties of nitrified cements are dependent on the temperature and pressure state of the downhole system as well as the physical properties of the base fluid. The density, viscosity, volume, and rate of a nitrified fluid change as the downhole temperature and pressure circumstances change. Mathematical formulas based on gas density, molecular weight, specific gravity, and Ideal Gas Law provide the means of calculating the fluid properties at anypoint in its pumping history.

Many of us today are being confronted with a new and different problem, that of obtaining maximum production from a given well. This problem can arise from a number of different sources. Perhaps we are starting a waterflood program and we need to utilize our present equipment as far as possible in the life of the flood or perhaps we are finding that out wells are making as increasing volume of water and that we must handle increasing amounts of fluid to obtain maximum production. In addition, there is the everyday problem of those of us who are responsible for equipment selection. We need to know the maximum capabilities of our equipment design and the best methods to utilize these capabilities; we can then select adequate equipment for the full lift of the well at minimum installation cost. This means that at some time in the well life, we must expect this equipment to deliver its maximum production capabilities. Most of users today look at only three or, at the most, four possibilities in our search for maximum production. Many times we do not even attempt to evaluate these various methods to find out which one will give as the best utilization of the equipment at the least cost.