Enhanced oil recovery may be defined as any combination of methods and materials which recovers oil more effectively than either plain waterflooding or gas injection. The three basic mechanisms which can be used (individually or in combination) to achieve increased recovery are to: (1) lower interfacial tension between oil and water; (2) use a solvent to extract oil; and (3) reduce viscosity contrast between the oil and displacing fluid by thinning the oil or thickening the displacing fluids. Many methods and materials have had- extensive laboratory and field testing, and many combinations have been proved to be effective for displacing oil. However, economic and technical constraints limit current choices to 10 methods which use a total of only 8 individual compounds or general groups of chemical substances which include: light hydrocarbons, nitrogen, carbon dioxide, surfactant formulations (including co-solvents and salts), water-solublenpolflers, alkaline materials, air, and water. Technical screening criteria forn selecting the methods appropriate for Permian Basin reservoirs are described. Economic limitations are also discussed. The technical and economic logic behind the big push for CO2 flooding in the Permian Basin are emphasized.

Recent advances in the design of sonic logging tools and in the development of computer software have provided methods for the detection of hydrocarbons in porous formations. The detection of hydrocarbons is based on changes in the acoustical proper-ties of the formation, such as compressive wave travel time, Tc, shear wave travel time, Ts, attenuation of the acoustic energy, and changes in the frequency of the acoustic signal. The compressive and shear wave travel time to the compressive wave travel time is termed the velocity ratio. Extensive prior research has demonstrated that each rock type has a fairly specific velocity ratio. However, when compressible fluids occupy a portion of the pore space in the rock, the compressive wave travel time increases, which results in a lower than expected velocity ratio for a given lithology. One of the limitations of using the velocity ratio as a method for detection of compressible hydrocarbons is that the lithology must be known. Interpretation methods have been developed which combine the velocity ratio and Photoelectric absorption index, Pe. This technique enables the velocity ratio to be used for the detection of hydrocarbons in formations where there may be changes in the lithology. The velocity ratio has been compared to a synthetic velocity ratio which is calculated from the volumetric fractions of the various lithologies present in the formation. This method has been used successfully in formations composed of a mixture of many lithologies. Several log examples will be presented that show these techniques have been successful for the detection of hydrocarbons.

The main purpose of staged fracture treatments is to selectively treat all the zones of interest in place of a collective treatment. Historically, cast iron bridge plugs were used for isolation of previously treated zones. After all desired intervals were stimulated, the plugs were drilled and the well brought on to production. However, cast iron bridge plugs do not allow the lower zones to be flowed back until the plugs are drilled out of the well bore. In the Sonora Area Field in West Texas (Sutton County), an operator was encountering a lower percentage of fracturing fluids recovered and decreased initial production rates. A new method of zonal isolation, which included immediate flow-back, was successfully tried and adopted to solve this problem. This method using composite bridge plugs achieved an improved flow-back of fracturing fluids and enhanced the wells productivity. This paper will detail how this problem was successfully addressed.

When does a string of tubing look like? When a 10,000ft string of tubing is run into a well, all that is left to see is a few inches of tubing innocently sticking out of the wellhead, graphically portrayed in Figure 1. But, just what does the rest of the tubing look like?

In I977 the on-.site operations began on the Edna Delcambre No. I to evaluate the geothermal potential of high-pressure, high-temperature salt-water-bearing sands which are common to the Gulf Coast region. This projects, which was funded by the Energy Research and Development Administration (ERDA), tested two sands of the Planulian sand series. A discussion of the problems encountered, tests conducted, and equipment used. along with a summary of the results is presented in this paper.

Rule 36 of the Texas Railroad Commission is rapidly being recognized as one of the most, perhaps the most significant safety regulation of the post-OSHA era. Until the initial publication of Rule 36 in 1975 the many hazards of HIS were only vaguely understood and no regulation for positive control of the gas existed. It covers drilling operations as well as production and provides that every operator have written operating and training plans to protect both employees and the general public from uncontrolled gas leakage. It provides a workable mathematical formula for computing gas dispersion. Since its final issue in 1976, Rule 36 has become a model for similar state oil and gas regulations in numerous states and was one of the principal sources of data for the proposed safety standard recommended by NIOSH. Its scope and thoroughness make it a landmark.

The use of a long slow stroke in rod-pumped oil wells has been the goal of prudent operators for many years. They have recognized that a major cost of operation was the repair and replacement of sucker rods, tubing, and bottom-hole pumps. Since most of these failures were the result of fatigue, corrosion fatigue, or wear, a reduction in the number and magnitude of fatigue-producing strokes would dramatically reduce their operating costs.

In the search for an improvement in rate of penetration in deep wells, the mechanics of rock failure during drilling has been reevaluated in order to understand functional relationships between the cutting process and the drilling parameters. Also, the relationship between wellbore pressure conditions and calculated mechanical specific energy is presented based on the laboratory results of rock cutting with polycrystalline compact diamond cutter under both the atmospheric and different magnitudes of differential pressure conditions. The analyses of experimental data, as well as the data presented in the literature lead to the development of an improved PDC model that accounts for the cutting removal process during PDC bit drilling. This process is highly related to both rock properties and downhole pressure conditions.

The purpose of this presentation is to share the internal efforts and measurably successful crusade put forth by an oilfield rental tool company embarking on a quality initiative. The establishment of a viable alternative to the way the company had been operated during the previous seventeen years was paramount to this effort launched in 1989. At that time, the demands set forth by the oil companies of the industry established mandates for tighter and higher standards in the quahty and performance of rental tools. The rental tool company's desire to participate in the deeper drilling projects was to be realized, great strides in quality processes would be essentiaL This quality initiative involved a sound commitment on the parts of the owner and management of the company to converge around a central theme: A commitment to quality through perseverance and teamwork resulting in unparalleled and superior service. This charge and charter for change would require a complete overhaul of the infrastructure of the company thereby accommodating the new edicts set forth by this initiative.

The principles of cathodic protection, when applied to oil field vessels and well casings, have been more or less generally accepted within the last few years, and the application of cathodic protection to these structures has been the solution of many of the corrosion problems in the West Texas area. It is the purpose of this discussion to outline the procedures for determining the need as well as the application of the equipment to vessels and casings in the West Texas area. A typical vessel will be discussed along with an outline of the procedures followed in the protection program in a field where corrosion of well casings has become a problem.

The design of successful well stimulation treatments requires a thorough knowledge of the geologic characteristics of the formations involved. A discussion of the current methods of analysis is presented. In particular, the application of X-ray diffraction, scanning electron microscopy and energy-dispersive X-ray fluorescence analysis is demonstrated. The relative strengths and limitations of all the methods of analysis currently in use are compared. Examples of actual analyses are given to illustrate the value of formation analysis to the design of stimulation treatments.

This paper will demonstrate a different and proven approach to internal corrosion control in steel tubing, line pipe and casing. Polyvinyl chloride (PVC) plastic and fiberglass-epoxy (FRP) insert linings can be installed in either new or used tubulars to prevent corrosion. These rigid linings afford a smooth uniform nominal inside diameter and are not affected by the rough pitted inner surfaces usually encountered in used pipe. Protecting the connections is a large part of the battle in corrosion control. For this purpose, the lining system uses the more practical reinforced oil-resistant rubber corrosion barrier ring. This rubber corrosion barrier ring is compressed when the connection is made up in the field. The design of this system will be explained in detail as we discuss the installation, handling and running procedures that make this system corrosion resistant.

The purpose of this paper is to illustrate the application of pressure and temperature surveys to gas lift installations, not to discuss the mechanics of bottom hole pressure and temperature instruments. The advantages of pressure surveys prior to the installation of gas lift equipment are discussed. The procedure for running surveys in intermitting gas lift wells is offered. The determination of the operating valve or valves, using both the temperature and pressure survey in the same well, is presented. Examples of surveys in a gas lift well with a tubing leak and a well with leaky valves are given. Bottom hole pressure surveys for chamber installations are noted which show the minimum flowing bottom hole pressures obtained with low pressure versus high pressure operating gas lift valves. The paper concludes by illustrating the use of a pressure survey for estimating per cent fallback in an intermitting gas lift installation.

The Queen Sand of southeastern New Mexico is characterized as a sequence of laminated sandstones and shale, bounded by anhydrite seals. Good permeability is evident but still the Queen requires fracture stimulation to be successful. The case presented in this study is an injection well from Chaves County in southeastern New Mexico. For this stimulation study, surface treating pressure data from a fracture treatment was history-matched with a pseudo 3D fracture simulator. Fracture characteristics such as height and fluid distributions from the pressure match were compared with that from the radioactive and temperature tracers to analyze the fracture treatment in this formation. An additional complication is the existence of a compressible, friable sand bed, resulting in difficulties in hydraulic fracture effectiveness. Two fracture designs are compared: a vertical fracture with high proppant concentration in a restricted interval, and a horizontal fracture due to the shallow depth and high frac gradient.

Safety must be paramount to both the service provider as well as the service recipient as our industry is mandated to provide a safe work environment for all personal involved in the well service and maintenance industry. It is incumbent on our industry to develop, implement, and accept safety systems that as managers we insure all that can be done is being done to meet that safety mandate.This paper deals with recent technological developments dealing with rig systems that will enhance both the safe operation of a rig and protect the wellbore environment against catastrophic failures and or mistakes that lead to costly workovers and occasionally the loss of a wellbore. Discussion topics, actual field data, and technology introduction will be centered around: - Decreasing the likelihood of a crown or floor out incident - Preventing over pulling and stretching of rods and tubular - Alarming the rig operator when the rig is being operated out of the safe envelope of weight and speed relationships - Measuring and alarming when uneven derrick loading or tilt has occurred.

When crude oil is brought to the surface, various amounts of water, gas and other elements are mixed with the oil into a homogeneous mixture referred to as an "emulsion. " Before the oil is refined, the water, gas and other elements must he removed from the oil. This removal, or separation process, is referred to as "treating. " A combination of heat, settling and chemical treatment is used to affect "treating." A recent development adds the use of electrostatic grids to improve "treating. "

There are six basic API Loads critical to beam pumping. These loads interact during a complete pumping cycle. Fortunately these loads can be measured and compared against their respective counterparts. A building block approach which combines these basic loads aids in diagnosing operating and design problems. Standing and traveling valve actions tend to follow a fairly definite pattern during a normal pumping cycle. When abnormal pumping conditions occur, these valves may not conform to their respective normal patterns of opening and closing. A dynamometer is a useful instrument which can be used to record specific loads generated during the pumping cycle. Certain pumping equipment malfunction can be diagnosed by interpreting dynamometer cards. Normal and abnormal valve action can also be detected using the principles associated with dynamometer card interpretation. There are many basic components which must be considered when designing or operating beam pumping equipment. These must be in harmony with each other to have a relatively trouble free pumping operation. When one of these components malfunctions or is changed, it may be necessary to change other parts of the system to maintain the desired relationship. Certain operating parameters can be established to promote optimum operating conditions. The use of dimensionless speeds, dimensionless loads and acceleration factors aids in determining the most trouble free portion of the beam pumping "operating window". It is equally important to operate the equipment with the proper counterbalance. Over-pumping a well can aggravate an otherwise properly counterbalanced operation. In these situations it is necessary to bring the well outflow into a satisfactory relationship with the well inflow. Redesigning the producing equipment is one way to accomplish that objective. When changing the producing equipment might not be the practical thing to do, intermitting the pumping cycle is another often used and satisfactory method.

There are six basic API Loads critical to beam pumping. These loads interact during a complete pumping cycle. Fortunately these loads can be measured and compared against their respective counterparts. A building block approach which combines these basic loads aids in diagnosing operating and design problems. Standing and traveling valve actions tend to follow a fairly definite pattern during a normal pumping cycle. When abnormal pumping conditions occur, these valves may not conform to their respective normal patterns of opening and closing. A dynamometer is a useful instrument which can be used to record specific loads generated during the pumping cycle. Certain pumping equipment malfunctions can be diagnosed by interpreting dynamometer cards. Normal and abnormal valve action can also be detected using the principles associated with dynamometer card interpretation. There are many basic components which must be considered when designing or operating beam pumping equipment. These must be in harmony with each other to have a relatively trouble free pumping operation. When one of these components malfunctions or is changed, it may be necessary to change other parts of the system to maintain the desired relationship. Certain operating parameters can be established to promote optimum operating conditions. The use of dimensionless speeds, dimensionless loads and acceleration factors aids in determining the most trouble free portion of the beam pumping "operating window." It is equally important to operate the equipment with proper counterbalance. Over-pumping a well can aggravate an otherwise properly counterbalanced operation. In these situations it is necessary to bring the well outflow into a satisfactory relationship with the well inflow. Redesigning the producing equipment is one way to accomplish that objective. When changing the producing equipment might not be the practical thing to do, intermitting the pumping cycle is another often used and satisfactory method.

Care in handling either new or used tubing will result in fewer operational difficulties and less maintenance.

The care and maintenance of rod pumps may be considered under two categories; first, proper care, maintenance, and handling of the pump during its assembly, its delivery from the pump shop to the well and its installation in the well; and second, a careful analysis of the conditions of the well being pumped and operating the surface equipment to suit those conditions. We will discuss this subject of how we can prolong the life of pumps before the pump is installed and after it is run in the well.

The three phase squirrel cage induction electric motor built today is the most efficient electric motor that the industry has ever produced. It is the product of over one hundred years of evolution in materials and design of rotating electrical apparatus. Technology has allowed the manufacturer to reduce the physical size of the electric motor while increasing its efficiency. Concurrent with this reduction in frame size per horse power, we have experienced a product that is more sensitive to aberrant line, load and operating conditions than the more massively built product of previous generations. This paper will explore the conditions that compromise the electrical and mechanical life expectancy of the modern state-of-the-art electric motor. To illustrate the changes in NEMA frame sizes of electric motors, let us evaluate the evolution of a 5 HP 1800 RPM squirrel cage open drip motor over the last four decades. In 1950, this motor was in a 254 original NEMA frame and weighed approximately 195 lbs. With the NEMA redesign of 1952, this same 5 HP motor was condensed into a NEMA 215 frame and weighed 127 lbs. With the NEMA redesign of 1965, the 5 HP motor was further condensed to the smaller and current 184 frame weighing 88 lbs. The same 254 frame that was able to accommodate a 5 HP 4 pole motor in 1950, today accommodates a 15 HP 4 pole electric motor. The larger mass of the older apparatus represented a considerable heat sink for all the conditions that cause motor thermal failures. Consequently, the original NEMA and 1952 rerated motors were more forgiving of all the detrimental conditions that result in motor failures and particularly premature failure. The apparatus we use today is quite a different piece of equipment from that of yesteryear and a higher level of concern for its application and aberrant operational conditions must be considered if we are to maximize the design life and our return on capital investment. In order to preserve our investment in our rotating apparatus, it is incumbent that we understand the conditions that impact the electrical and mechanical life expectancy of the current vintage state-of-the-art electric motor. We will focus on five critical areas: 1.Electrical 2.Mechanical 3.Thermal 4.Environmental 5.Application

Although there are many different ways of artificially lifting oil from a well, the old beam type pumping unit is still by far the most popular means and probably the most reliable under all conditions. Most of these units are actuated by a gear reducer which is powered by some kind of prime mover. For years, the internal combustion engine was practically the only source of power. Recently, however, the electric motor is replacing engines to a large degree.

This paper discusses the common causes and effects of measurement error in LACT unit custody transfers. The discussion covers the major components of a LACT unit, and their effects on measurement accuracy. It also pinpoints how the neglect of each of these components causes the loss of millions of dollars to the oil industry through inaccurate measurement. Also discussed is how the failure to strictly observe API procedures, during the testing of the crude oil sample, can result in measurement error. Although these errors may be small percentage wise; when multiplied by monthly or yearly sales, the results can amount to a substantial dollar amount.

Schlumberger's Cement-Scan * log was offered to west Texas clients in June 1985. Since then, the product has greatly enhanced interpretation of cement conditions where standard cement evaluation techniques left unanswered questions. Specifically, the Cement-Scan log has provided superior answers in light (or foam) cements and in cements degraded by gas intrusion. The Cement-Scan log is a single presentation that combines information from both the CET* cement evaluation log and the CBL cement bond log. Through the use of a statistical gas logic system, Cement-Scan measurements can be used to discriminate between water channels and gas-cut cement behind the casing. Also, a new light-weight cement compressive strength algorithm is available for use when a known light or foam cement has been used in cementing operations. A cement map (from CET data) with shadings corresponding to acceptable cement, water channels, gas-cut cement, and free gas is presented. Additionally, a radial profile presents the four materials in terms of percent circumferential coverage of each. The above information is further enhanced by presenting a bond index curve and a Variable Density display from the CBL. The utility of the Cement-Scan log is illustrated by citing several examples from actual west Texas wells. Interpretation techniques, as well as gas logic verification, are described.

The oil and gas estate is the dominant estate, and the oil and gas lessee has the right to use so much of the leased premises and in such manner as reasonably necessary to comply with the terms of the lease and to produce the oil and gas. A landowner who seeks to recover money damages from the lease operator for damages to the surface or injury to animals has the burden of proving either specific acts of negligence or that more of the land was used than was reasonably necessary. It is not ordinarily contemplated, however, that the utility of the surface for agricultural purposes will be destroyed or substantially impaired. Further, there will be an accommodation of the conflicting interests of the surface owner and the mineral owner in deciding what limitations will be imposed upon the use of the surface by the operator. These conflicting statements of the law determining the rights of user of the surface have been recently made by the Supreme Court of Texas in the appeal of one case. They are well calculated to confound and confuse the lease operators and their supervisory landmen, production foremen, geologists and engineers. They illustrate the changes lately being made in this field of oil and gas law so important to the economy and well-being of the oil and gas industry.