This paper discusses the results of high volume submersible lift equipment (HVL) installed in a West Texas carbonate reservoir. Field-wide installation of HVL was made in a primary field in 1978 during the last stages of depletion. With a high capacity reservoir and a strong water drive, a significant increase in oil production was obtained. A reserve growth by HVL installation is documented with field results. Included is a historical overview of field installations with a post installation economic analysis and a summary of required facility revisions.

This paper presents basic data concerning the peripheral water flooding of three Haxbar sand reservoirs in the old Oscar field, Jefferson County, Oklahoma. The significance of reservoir data, its importance in interpretation of field conditions, operating procedures and resulting performance of the three reservoirs are discussed.

Fluid cleanup effects have hampered stimulation success in many tight, naturally fractured sandstone reservoirs. In some cases, cleanup problems affect not only short-term but long-term reservoir deliverability. The Wolfcamp intervals in Val Verde Basin, West Texas are tight, naturally fractured reservoirs and exhibit better responses to CO2 energized fluids than non-energized fluids. We will present data from a case study of several wells in the Wolfcamp intervals where 100% COz treatments have increased productivity in both initial and remedial applications. We will discuss how production was increased by 100% CO2 treatments in wells where non-energized and energized fluids were previously pumped. Then we will discuss treatments where 100% CO2 was effectively to propagate a fracture and transport proppant. An economic evaluation will be presented on the 100% CO2 remedial treatments in the Wolfcamp intervals. Finally operational concerns and the equipment set up for 100% CO1 and CO2 proppant treatments will be discussed.

This paper presents a field case history of a highly successful waterflood program in the Seven Rivers Sand (named Soma locally) at 1,000-1,700 ft. in Crockett County, Texas. The program has been completed and the project abandoned; consequently recover figures and performance are factual. They show that secondary oil recovery equaled almost three (3) times primary oil recovery.

The 600 acre Forest A. B. Gordon lease has produced 5,500,OOO bbl (9,167 B/A) of waterflood oil to March 1, 1966. This oil has been produced from the Yates formation and principally from, the Penn Bennett member. The primary recovery from this lease was 2,474,OOO bbl or 4,123 B/A, or a waterflood to primary ratio of 2.2 to 1. The A. B. Gordon waterflood is but one of many successful floods in the South Ward Field of southeastern Ward County, Texas, several of which have been reported on previously. It is the intent of this paper to review some of the information available at the start of waterflooding to see how reliable the various types of initial information would be in predicting waterflood response. Before going into these comparisons we will briefly look at the general character of the reservoir involved.

The ASR Hydro-Impact

Twenty-two sands in the Hewitt Field have been simultaneously flooded by the Exxon operated Hewitt Unit and a case history of the operations is detailed in this paper. A multiple sand waterflood project requires special optimization methods to improve oil recovery. Highlighted are the injection and production surveillance proTrams and optimization methods used at the Hewitt Unit. These include injection wellbore design, injection distribution, production stimulation, polymer augmented injection, and infill drilling. Successful application of these techniques has increased the ultimate recovery from this waterflood operation.

Water flooding is utilized extensively for oil recovery in the Permian Basin. Finding compatible and accessible make-up water can be problematic in some areas. In these situations, proper selection and application of scale inhibitors can enable the mixing of otherwise incompatible waters. This case study discusses the various methods used for product selection and application, including a testing methodology which can be used for direct measurement of scale inhibitor effectiveness and treatment optimization.

An analysis and economic evaluation of over 150 plunger installations in the San Juan Basin (SJB) has been made. The case study reviews performance and results of all installations, and clearly shows that plunger lift has significantly increased volumes and reserves. Best practices, screening criteria and design considerations are presented. Individual well results are presented in tabular form showing before and after rates. Economic analysis indicates plunger lift on these SJB wells is extremely attractive with average payout of installations in two months.

Virtually all west Texas wells possess, to varying degrees, conditions of internal and/or external casing corrosion. The majority of the corrosion problems begin when produced (or injected) fluids come in contact with the casing inner wall, or when formation fluids come in contact with the outer wall of the casing in areas not protected by adequate annular cement. Both internal and external casing corrosion problems can become more severe with time, and can, if not addressed, lead to premature demise of the well. In order to ascertain the severity of corrosion problems in any specific well, many wireline logging devices have been developed over the past several years. Basically mechanical/magnetic in makeup, quantitative interpretation from the classic tools depends largely upon assumption of unknowns that, in most cases, are very hard, if not impossible, to accurately identify. A new corrosion evaluation procedure developed by Schlumberger uses a uniquely different approach to the challenge of quantitative casing inspection. The technique uses full ultrasonic casing resonance information recorded with a modified cement evaluation tool. Using the CET* tool, all necessary casing inspection data can be recorded simultaneously with cement evaluation information. The waveforms recorded at each of the eight (8) radially spaced CET ultrasonic transducers can be analyzed to obtain the following information regarding the condition of the casing: - The specific internal geometry of the casing - An internal casing roughness profile. - A casing metal thickness profile. A derivation of the measurements obtained at each CET transducer will be presented followed by discussion of the currently available display presentations and casing imaging techniques. The specific utilities of the ultrasonic casing inspection technique will be highlighted by citing several examples from west Texas wells.

Casing inspection logs have proven to be an effective tool to help design and implement remedial operations during- waterflood redevelopment. A series of magnetic logging tools was run in a Tubb- Drinkard water flood located in SE New Mexico. The casing inspection logs qualitatively evaluated overall casing condition and indicated packer set points prior to conversion to water injection. In extreme cases, the logs discovered terminal casing damage requiring well abandonment. Many Permian Basin waterflood units have been infill drilled to reduce the pattern spacing. Older wells, some dating to the 30"s, are often converted to water injection to complete injection patterns. From the time a well is first completed, the casing wall thickness decreases. Corrosion, wear and physical damage combine to reduce the mechanical integrity of the casing, eventually destroying it. The casing inspection logging program has proven its value by substantially reducing workover costs and improving the success rate of injection well conversions.

When the drilling operation of an oil well is finished, an oil string of casing is left in the hole. In the early days, if the well would flow, it was allowed to flow through the casing. When it quit flowing, tubing was installed inside the casing. Oil was then pumped through the tubing with a working barrel and valves. The valves used leather cups with a ball check in the traveling and the standing valves. When this type pump needed repairs, it was necessary to pull both the rods and tubing to effect repairs on the pump. Then the rod pump came into use. This pumped was seated in the tubing and only the pump and rods were pulled for repairs to the pump.

Presentation of factors affecting casing pumps selection and application of casing pumps to high volume wells. Examples of successful applications are given.

A casing pump is a large rod pump that is run in the well casing instead of in the tubing. It is composed of four principal parts. The packer assembly, the anchor assembly, the rod assembly and the pump assembly.

Kobe Hydraulic Casing Type pumps are confined to two basic types at the present time. There is the Conventional Insert and Free Type. Both have common features in that they use the casing for the production tubing and require only one string of tubing for power oil transmission.

Corrosion can be separated into four parts, 1) an anodic site, 2) a cathodic site, 3) an electrolyte and, 2) a metallic path. Corrosion can be minimized by eliminating or controlling any one of these four components. Cathodic protection (CP) works by controlling the anodic and cathodic sites in a corrosion cell. This is accomplished by creating an anode separate from the equipment being protected. The anode can be either a more active metal or a material induced with an outside source of direct current. Cathodic protection has been used successfully to protect buried piping, storage tanks, production separators, well casings, offshore platforms, etc. This paper is an overview of cathodic protection in the oilfield and presents basic information on the design and maintenance of CP systems.

Cathodic protection as a tool for controlling corrosion of oil field lease equipment is discussed in some detail. Special emphasis is given to cathodic protection of well casing on which effectiveness, limitations, and economics are discussed. Cathodic protection of flow lines, gas gathering lines and vessels such as tanks, heater treaters, and filters is also described and discussed.

Corrosion of steel, in contact with the earth, or brine, results from the creation of anodic and cathodic areas caused by differences in the electrolyte, and/or differences in the surface of the metal occurring in manufacture or fabrication. In the anodic areas current leaves the surface of the structure and enters the electrolyte, causing loss of metal or pitting action. In the cathodic areas, current flows from the electrolyte onto the surface of the structure and no corrosion occurs.

Corrosion of steel in contact with the earth or brine results from the creation of anodic and cathodic areas by reason of differences in the electrolyte and/or differences in the surface of the metal caused in manufacture or fabrication.

External casing corrosion with resultant leaks is a problem of major economic significance in the oil and gas producing industry. Cathodic protection systems, where practically and economically feasible, provide a means of arresting external casing corrosion. Sound engineering of these systems includes assessment of the problem, determination of the feasibility of cathodic protection, and an economic study. If the decision is made to install cathodic protection, elements of design include determination of protective current requirements, ground bed requirements, rectifier specifications, and choice of auxiliary equipment. After installation, proper maintenance is a must to realize the maximum benefit from the investment. Several commercial services such as casing inspection tools and voltage profile logs are available to aid in both the assessment of the problem and the design of the system.

One of the largest investments in petroleum equipment today is the steel casing of the many oil, gas and water wells located throughout the country. The cost per pound of the steel in place in these casings is certainly very high. The annual cost of failures of casings due to external corrosion reaches into astronomical figures when the cost of the casing, lost production and damage to producing sands are all considered. It is the purpose of this paper to review the present state of the art in the application of cathodic protection to oil well casings for control of corrosion on the external surfaces.

Cathodic protection of steel is possible through use of sacrificial anode, and thermoelectric generator methods. This paper outlines the application of these methods to the protection of oil lease vessels and well casing installation. System design, anode selection, current requirements, and well casing survey consideration and reviewed.

The author reviews the fundamentals of corrosion and the causes of external casing corrosion. Methods of determining occurrence of casing corrosion and the value of protective current required for protection are outlined. Case histories and examples of interference are given. A model depicting external casing corrosion will be used to visually illustrate the paper.

Cathodic protection has been used to control corrosion for many years; however, its use in crude oil production is relatively new. It is being used to protect well casings, pipelines, emulsion treaters, gun barrels, tanks, and other water handling equipment. Many time it is used in conjunction with other corrosion control measures. Good design, proper installation, and continued maintenance are all necessary if a system is to be effective.

A water injection program was commenced in the San Andres reservoir of the Cedar Lake Southeast Field of Dawson County, Texas in May 1962. The Cedar Lake Southeast Field was unitized with the unit including virtually all of the San Andres reservoir that could reasonably be expected to be productive of oil or gas. The Cedar Lake Southeast San Andres reservoir is small in volume as compared to the many large reservoirs of the same age in the Permian Basin provenance. The size of this reservoir along with principles of its development and operation under water injection offer a good opportunity to observe the hydraulic behavior of fluids of San Andres age when subjected to complete reservoir water flood practices of production. Response to water flood operations in this field have been excellent during the 21 months of its operation. Production from the reservoir during the past 8 months has been retained within the limits prescribed by statewide proration. The history of this reservoir and the operational practices that have aided its realization of an economic performance are presented.