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The use of continuous coiled tubing to perform various types of remedial treatments or workovers has been well documented.1~2*3~4 Numerous successful treatments have been obtained with this device in oil, gas, injection and geothermal wells. However, the occurrence of and, more importantly, the causes of failures in operations involving coiled tubing have not been addressed by the industry. An examination of causes of failure should lead to a higher success ratio.

Having reliable and readily accessible relative permeability information is a problem for many reservoir engineers, particularly for waterflooding and other reservoir simulation calculations; currently, no central repository exists and data within a company is often not centrally organized. A large effort was required to collect data from public and private sources and modify it to fit a common format. The central database thus constructed maintains relative permeability data in a format that is easily retrieved and processed.

Fracturing has become a viable and important option for completing horizontal wells. This is especially true in case of tight gas formations. There are many fracturing processes and methods to consider for placement of these fractures. The optimization of the completion process including the number and size of fractures is still a challenging consideration. Fracturing of a horizontal well has unique aspects that require very special attention to obtain successful treatment.

This paper demonstrates lessons learned on a 5-year effort to improve and enhance field-wide influences on the Central Mallett and Slaughter CO2 WAG Units. The developments on data analysis, reservoir and production engineering, and solutions in these mature units have provided the opportunity to make major impacts on recovery and production rates, operation enhancements, and cost reductions.

In straight or continuous gas lift, the flow is continuous, that is, not interrupted by intermitting nor aided by any artificial pumping method for obtaining submergence. This type of gas lift resembles a flowing well more than does any other type of artificial method in producing a well. Gas is injected at the top of the well through the tubing or casing, as the case may be, and the flow of the oil and gas takes place through the other pipe rather than the pipe through which the gas is admitted.

Commonly known as sour gas, hydrogen sulfide (H2S) is a highly toxic chemical agent found in petroleum drilling, production and refining operations. As secondary and tertiary recovery efforts are undertaken on older reservoirs, H2S is being found where previously it was not recorded. The gas is present in many crudes and is produced in common refinery processes such as cracking and desulfurization. Hydrogen sulfide is formed primarily by decomposition of organic matter containing sulfur.

Most gas wells produce liquids that are often not removed from the well because of low gas velocity. Failure to produce these liquids severely restricts gas production. This paper discusses the continuous removal of these fluids from gas wells by gas lift. It will also discuss compressor installation and operation.

The objective of this presentation is to outline an approach to complete systems automation of a major oil and gas production facility with emphasis on telemetry and the fundamentals of digital coding as they apply to telemetry.

Recent changes in the federal and state clean air laws and regulations will affect the operation of glycol dehydration units used by the oil and gas industry to remove water vapor from natural gas. These laws and regulations will limit the amount of aromatic hydrocarbons such as benzene, toluene, ethyl benzene, and xylene (BTEX) and volatile organic compounds (VOC's) that may be emitted into the air from the glycol regenerator still vent.

To control lifting costs, we first must understand what they are. What parts are subject to our control. How much difference doe it make to our company if we can reduce the costs that we do control.

The theory of corrosion and inhibition is discussed. The types of chemicals used as inhibitors and generalized treating methods are outlined. Results of inhibitor treatment of various crude oil producing systems are given. A discussion of requirements for field testing and economics relating to the use of inhibitors is included.

When paraffin is deposited from crude oil on downhole and surface equipment, it can reduce oil production and increase maintenance costs. Paraffin may deposit in tubular goods as a hard coating that gradually decreases flow capacity of lines and producing capability of wells. Paraffin crystallized from solution may be trapped at restrictions (beans, valves, controllers) and cause complete or temporary plugging of the system. Pressure surges caused by intermittent plugging and extrusion of the paraffin can overload pumps, flood the separators, and may result in equipment failure.

As deeper and deeper well are put on the pump, sucker rod strings are being subjected to higher and higher loads. As a consequence, joint failures are becoming more prevalent. This phenomenon is invariably due to corrosion fatigue. An understanding of the stresses and environment under which this occurs will suggest the means of control. Proper tightening procedures, corrosion inhibition, thread form and correct heat treating procedures are discussed.

The work described in this paper was performed in conjunction with a contract from the U.S, Bureau of Land Management, Pecos District to estimate oil and gas development in southeastern New Mexico for the next 20 years. This district covers the bulk of the Permian Basin in New Mexico, and contains numerous oil and gas reservoirs. Producing oil and gas fields of the region were divided into 27 plays, based upon similarities such as depositional environment, lithology, tectonic history, and trapping mechanisms.

Secondary recovery projects continue to place greater demand on existing sucker rod pumping systems. Increased water injection, water breakthrough, and water encroachment have placed greater requirements on individual sucker rod pumping systems than was anticipated originally. This paper presents the conventional beam pumping production charts as a guide for reviewing the existing sucker rod pumping systems. The analysis will discuss gear reducer torque, rod stress, critical speed, and polished rod stroke length in conjunction with fluid production by pump diameter versus strokes per minute.

Core data can play a vital role in development drilling programs and recovery planning operations. Well-conceived field coring programs and subsequent laboratory testing procedures can strengthen log interpretation criteria, aid in completion/stimulation operations; provide a sound basis for reserves estimates and reservoir modeling, and supply much-needed guidance in secondary and tertiary recovery programs. This paper presents the need for pre-planning during the development phase of the reservoir so that necessary parameters are properly evaluated.

To achieve maximum recovery from an oil field, especially when using supplemental recovery methods, the nature of the reservoir must be known in the greatest detail possible. In the past, several large reservoirs have been subjected to waterflooding under the assumption that they were "blanket" accumulations. When later detailed geologic analyses have been forced by a multitude of operational problems, the reservoirs were found to possess significant lateral discontinuity and/or marked permeability variations, requiring radical changes in the injection patterns.

A computational technique has been developed whereby formation evaluation of wells penetrating a long transition zone can be accomplished. This paper discusses how answers to pertinent questions relative to interstitial water and oil saturation quantity and distribution, water-oil level, optimum zones of completion, and zonal water-cut behavior can be obtained with a high degree of reliability.

The elements of a successfully planned and executed foam stimulation treatment have characteristically included surface and bottom-hole foam quality calculations, foam rheology, foam structure, surfactant and polymer requirements, pressure volume and temperature considerations, proppant transport, and fluid and nitrogen rates. Often taken for granted is the importance and advantages of foam flowback after the treatment to obtain maximum load recoveries with minimum or no proppant flowback into the wellbore or to the surface.

Due to out-of-zone injection problems in a water flood unit, investigations and a designed remediation to the problems was developed using diagnostics and new technologies with super absorbent crystallized co-polymer systems.Current profiles with their rates and pressure transients were analyzed through multi-rate injectivity profile analysis. Criterion were then established on the physical and chemical attributes needed by a solution to address the problems.

When a string of sucker rods fail conversely, the comment most frequently heard is that "they must have been rolled from a bad heat of steel;" this in face of the fact that sucker rod steel is rolled under far more restrictive requirements than ordinary structural steel. Following is a typical specification clause taken from an order, placed on a mill for sucker rod steel.

This paper describes a program to define the effects of free gas on the performance of electric submersible centrifugal pumps. The effects of the free gas show up as a deterioration of the head-capacity curve, such as areas of unstable head production, and effects similar to cavitation at higher flow rates. Depending on the amount of free gas through the pump, these effects may vary from slight interference to gas locking. Gas interference is indicated on the surface amp chart by rapid variation of the motor loading.

The useful life of oil field equipment is often measurably reduced by corrosion. There is a corresponding increase in both capital and operating costs which ultimately will shorten the economic life of the producing property. In the last 15 to 20 years there have been continuing advances in corrosion control technology. Such advances have resulted from a better understanding of the causes and occurrences of corrosion and steady improvements in mitigation materials and techniques.

For the purposes of this paper, deep, hot gas wells will be considered to be those that fall within the following ranges of conditions: Deeper than 10,000 feet; hotter than 2000F bottomhole temperature (BHT); and bottomhole pressure (BHP) higher than 5,000 psi. Corrosive wells also contain an aggressive acid gas (H2S or C02) in amounts of 0.1% or greater. In addition, water production considerably aggravates corrosion especially if it is a heavy brine.

Equipment handling water containing relatively large quantities of carbon dioxide and hydrogen sulfide is susceptible to excessive corrosion which may attain conditions not economically controllable using corrosion inhibitors. One such extreme condition developed in the Wickett Waterflood in Ward County, Texas where selective injection into multiple zones through common wellbores necessitated annular injection which eliminated the feasibility of using downhole protective coatings.