Oil and gas

Extraction depths may exceed 3000 m and any equipment failures can result in extremely expensive shutdowns. Accordingly the industry is willing to use the very highest performance materials such as PEK and PEKEKK as well as PEEK. It is worth noting that PAEK find many of the same applications in geothermal energy production which also faces high temperatures and pressures in a superheated water environment. 

There are also a number of patents on even more challenging applications for pipes [12]. For example, ABB claimed a PEEK pipe wrapped in continuous carbon fibre PEEK composite for use as an oilfield riser. Such risers could be several kilometres long and their near neutral buoyancy and excellent environmental resistance would allow recovery of oil from the deep oceans. The specific mechanical properties of composite pipes mean that they may also find uses as drill pipes. 

It seems inevitable that the need for PARK will continue to increase as oil and gas extraction becomes more demanding. 

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Covers all land eastwards to the Urals, southwards to North Africa and up to Syria, Iraq and Iran. Scale - 1 5,500,000, 4-colour artwork. Features main roads, railways, oil and gas pipelines, plus extra information including national flags, currencies and populations. 

The objective of this book is to provide a comprehensive introduction to the upstream industry useful for industry professionals who wish to be better informed about the basic methods, concepts and technology used. It is also Intended for readers not directly working in oil and gas companies but who are providing related support services. 

Despite such improvements, exploration remains a high risk activity. Many international oil and gas companies have large portfolios of exploration interests, each with their own geological and fiscal characteristics and with differing probabilities of finding oil or gas. Managing such exploration assets and associated operations in many countries represents a major task. 

Introduction and Commercial Application This section will firstly examine the conditions necessary for the existence of a hydrocarbon accumulation. Secondly, we will see which techniques are employed by the industry to locate oil and gas deposits. 

Hydrocarbons are of a lower density than formation water. Thus, if no mechanism is in place to stop their upward migration they will eventually seep to the surface. On seabed surveys in some offshore areas we can detect crater like features ( pock marks ) which also bear witness to the escape of oil and gas to the surface. It is assumed that throughout the geologic past vast quantities of hydrocarbons have been lost in this manner from sedimentary basins. 

In many oil and gas fields throughout the world hydrocarbons are found in fault bound anticlinal structures. This type of trapping mechanism is called a combination trap. 

Eventually, only the drilling of an exploration well will prove the validity of the concept. A wildcat ls drilled in a region with no prior well control. Wells may either result in discoveries of oil and gas, or they find the objective zone water bearing in which case they are termed dry . 

Introduction and commercial application Safety and the environment have become important elements of all parts of the field life cycle, and involve all of the technical and support functions in an oil company. The Piper Alpha disaster in the North Sea in 1988 has resulted in a major change in the approach to management of safety of world-wide oil and gas exploration and production activities. Companies recognise that good safety and environmental management make economic sense and are essential to guaranteeing long term presence in the industry. 

Management of the environmental impact of projects is of major concern in the oil and gas industry, not only to meet the legislative requirements in host countries, but is also viewed as good business because it is ... 

The following section outlines some of the current environmental concerns in the world s mature oil and gas development areas. 

The oil and gas industry produces much waste material, such as scrap metal, human waste, unspent chemicals, oily sludges and radiation. All of the incoming streams to a facility such as a production platform end up somewhere, and only few of the outgoing streams are useful product. It is one of the responsibilities of the engineer to try to limit the amount of incoming material which will finally become waste material. 

Reservoir fluids are broadly cafegorised using those properties which are easy to measure in the field, namely oil and gas gravity, and the producing gasioil ratio (GOR) which is the volumetric ratio of the gas produced at standard condition of femperature and pressure (STP) fo fhe oil produced at STP. The commonly used units are shown in the following table. 

The oil and gas samples are taken from the appropriate flowlines of the same separator, whose pressure, temperature and flowrate must be carefully recorded to allow the recombination ratios to be calculated. In addition the pressure and temperature of the stock tank must be recorded to be able to later calculate the shrinkage of oil from the point at which it is sampled and the stock tank. The oil and gas samples are sent separately to the laboratory where they are recombined before PVT analysis is performed. A quality check on the sampling technique is that the bubble point of the recombined sample at the temperature of the separator from which the samples were taken should be equal to the separator pressure. 

Typical analysis in the laboratory consists of sample validation, a compositional analysis of the individual and reoombined samples, measurement of oil and gas density and viscosity over a range of temperatures, and determination of the basic PVT parameters Bo, Roand B. ... 

The fluid properties of formation water may be looked up on correlation charts, as may most of the properties of oil and gas so far discussed. Many of these correlations are also available as computer programmes. It is always worth checking the range of applicability of the correlations, which are often based on empirical measurements and are grouped into fluid types (e.g. California light gases). 

Flence it can be seen that from the density of a fluid, the pressure gradient may be caloulated. Furthermore, the densities of water, oil and gas are so significantly different, that they will show quite different gradients on a pressure-depth plot. 

SWS are useful to obtain direct indications of hydrocarbons (under UV light) and to differentiate between oil and gas. The technique is applied extensively to sample microfossils and pollen for stratigraphic analysis (age dating, correlation, depositional environment). Qualitative inspection of porosity is possible, but very often the sampling process results in a severe crushing of the sample thus obscuring the true porosity and permeability. 

A large investment is made by oil and gas companies in acquiring open hole log data. Logging activities can represent between 5% and 15% of total well cost. It is important therefore to ensure that the cost of acquisition can be justified by the value of information generated and that thereafter the information is effectively managed. 

The parametric method is an established statistical technique used for combining variables containing uncertainties, and has been advocated for use within the oil and gas industry as an alternative to Monte Carlo simulation. The main advantages of the method are its simplicity and its ability to identify the sensitivity of the result to the input variables. This allows a ranking of the variables in terms of their impact on the uncertainty of the result, and hence indicates where effort should be directed to better understand or manage the key variables in order to intervene to mitigate downside and/or take advantage of upside in the outcome. 

The main differences between oil and gas field development are associated with ... 

In contrast to an oil production profile, which typically has a plateau period of 2-5 years, a gas field production profile will typically have a much longer plateau period, producing around 2/3 of the reserves on plateau production in order to satisfy the needs of the distribution company to forecast their supplies. The Figure 8.9 compares typical oil and gas field production profiles. 

Figure 8.9 Comparison of typical oil and gas field production profiles...

Horizontal wells were drilled as far back as the 1950s, but have gained great popularity in the last decade, as lower oil prices have forced companies to strive for technologies which reduce the cost of oil and gas recovery. Horizontal wells have potential advantage over vertical or deviated wells for three main reasons ... 

Section 10.1 will consider the physical processes which oil and gas (and unwanted fluids) from the wellhead must go through to reach product specifications. These processes will include gas-liquid separation, liquid-liquid separation, drying of gas. 

Before designing a process scheme it is necessary to know the specification of the raw material input (or feedstock) and the specification of the enc/procfucf desired. Designing a process to convert fluids produced at a wellhead into oil and gas products fit for evacuation and storage is no different. The characteristics of the well stream or streams must be known and specifications for the products agreed. 

Before oil and gas processing are described in detail in the following sections it is useful to consider how oil and gas volumes and compositions are reported. 

A container full of hydrocarbons can be described in a number of ways, from a simple measurement of the dimensions of the container to a detailed compositional analysis. The most appropriate method is usually determined by what you want to do with the hydrocarbons. If for example hydrocarbon products are stored in a warehouse prior to sale the dimensions of the container are very important, and the hydrocarbon quality may be completely irrelevant for the store keeper. However, a process engineer calculating yields of oil and gas from a reservoir oil sample will require a detailed breakdown of hydrocarbon composition, i.e. what components are present and in what quantities. 

When oil and gas are produced simultaneously into a separator a certain amount (mass fraction) of each component (e.g. butane) will be in the vapour phase and the rest in the liquid phase. This can be described using phase diagrams (such as those described in section 4.2) which describe the behaviour of multi-component mixtures at various temperatures and pressures. However to determine how much of each component goes into the gas or liquid phase the equilibrium constants (or equilibrium vapour liquid ratios) K must be known. 

These constants are dependent upon pressure, temperature and also the composition of the hydrocarbon fluid, as the various components within the system will interact with each other. K values can be found in gas engineering data books. The basic separation process is similar for oil and gas production, though the relative amounts of each phase differ. 

Once oil and gas have been processed the products have to be evacuated from the site. Stabilised crude is normally stored in tank farms at a distribution terminal which may involve an extended journey by pipeline. At a distribution terminal, crude is stored prior to further pipeline distribution or loading for shipment by sea (Figure 10.28). 

Crude oil and gas from offshore platforms are evacuated by pipeline or alternatively, in the case of oil, by tanker. Pipeline transport is the most common means of evacuating hydrocarbons, particularly where large volumes are concerned. Although a pipeline may seem a fairly basic piece of equipment, failure to design a line for the appropriate capacity, or to withstand operating conditions over the field life time, can prove very costly in terms of deferred oil production. 

Product quality is not limited to oil and gas quality certain effluent streams will also have to meet a legal specification. For example, in disposal of oil in water, the legislation in many offshore areas demands less than 40 ppm (parts per million) of oil in water for disposal into the sea. In the UK, oil production platforms are allowed to flare gas up to a legal limit. 

Many oil and gas companies do not consider the detailed design and construction of production facilities as part of their core business. This is often the stage at which work is contracted out to engineering firms and the client company will switch manpower resources elsewhere, although some degree of project management is commonly retained. 

Introduction and commercial application Investment opportunities in the exploration and production (E P) sector of oil and gas business are abundant. Despite areas such as the North Sea, Gulf of Mexico and the North Slope in Alaska being mature areas, there are still many new fields under development in those regions, and new areas of business interest are opening up in South America, Africa and South East Asia. Some fields which have a production history of decades are being redeveloped, such as the Pedernales Field in Venezuela. 

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