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The considerations and standards guiding pipeline design insures stability and integrity in the industry. The fluid flow equations and formulas presented thus far enable the engineer to initiate the design of a piping or pipeline system, where the pressure drop available governs the selection of pipe size. This is discussed below in the section on velocity considerations for pipelines. Once the inner diameter (ID) of the piping segment has been determined, the pipe wall thickness must be calculated. If there are no codes or standards that specifically apply to the oil and gas production facilities, the design engineer may select one of the industry codes or standards as the basis of design. The design and operation of gathering, transmission, and distribution pipeline systems are usually governed by codes, standards, and regulations. The design engineer must verify whether the particular country in which the project is located has regulations, codes, and standards that apply to facilities and/or pipelines. In the U.S, piping on offshore facilities is mandated by regulation to be done in accordance with ANSI/ASME Standard B31.3. Most onshore facilities are designed in accordance with ANSI/ASME Standard B31.4 or B31.8, depending on whether it is an oil or gas facility. Some companies use the more stringent ANSI/ASME Standard B31.3 for onshore facilities.
Ordinary carbon steel is by far the most important alloy in the oil and gas industry because it accounts for more than 98% of the construction materials used in produced-water systems. As a general rule, every attempt should be made to use steel, such as modifying the process with corrosion inhibitors in the fluid or coating the steel. Proper material selection is critical for long operation life and minimal maintenance. A small increase in capital expenditure for an optimum material selection can greatly reduce the mean time to maintenance or failure, thus greatly saving on operating expenses. Ordinary carbon steel is by far the most important alloy in the oil and gas industry because it accounts for more than 98% of the construction materials used in produced-water systems.
Chemicals play an important role in the oil producing operation. They assist oil/water/gas separation, aid in fluid transport, protect treating equipment, and improve the quality of the gas, oil, and water. A wide range of chemicals is available for water treating. A chemical-injection package enables various types of chemicals to be dosed into the water stream to optimize the treatment process. Storage-tank capacity is designed to allow the plant to run for several days between refills. General dosing rates and injection points for the main chemical classes are listed in Table 1. These rates provide guidelines for sizing injection pumps and chemical-storage tanks.
Natural gas is a mixture of many compounds, with methane (CH4) being the main hydrocarbon constituent. When natural gas is produced from an underground reservoir, it is saturated with water vapor and might contain heavy hydrocarbon compounds as well as nonhydrocarbon impurities. In the raw state, natural gas cannot be marketed and therefore must be processed to meet certain specifications for sales gas. Additionally, it might be economical to extract liquefiable hydrocarbon components, which would have a higher market value on extraction as compared with their heating value if left in the gas. Gas treating facilities, therefore, must be designed to convert a particular raw gas mixture into a sales gas that meets the sales-gas specifications, and such facilities must operate without interruption.
Corrosion of metal in the presence of water is a common problem across many industries. The fact that most oil and gas production includes co-produced water makes corrosion a pervasive issue across the industry. Age and presence of corrosive materials such as carbon dioxide (CO2) and hydrogen sulfide (H2S) exacerbate the problem. Corrosion control in oil and gas production is reviewed in depth in Treseder and Tuttle, Brondel, et al., and NACE, from which some of the following material is abstracted. Iron is inherently (thermodynamically) sufficiently active to react spontaneously with water (corrosion), generating soluble iron ions and hydrogen gas. The utility of iron alloys depends on minimizing the corrosion rate. Corrosion of steel is an "electrochemical process," involving the transfer of electrons from iron atoms in the metal to hydrogen ions or oxygen in water. This separation of the overall corrosion process into two reactions is not an electrochemical nuance; these processes generally do take place at separate locations on the same piece of metal. This separation requires the presence of a medium to complete the electrical circuit between anode (site of iron dissolution) and cathode (site for corrodant reduction). Electrons travel in the metal phase, but the ions involved in the corrosion process cannot. Ions require the presence of water; hence, corrosion requires the presence of water.
Oil and gas wells produce a mixture of hydrocarbon gas, condensate or oil; water with dissolved minerals, usually including a large amount of salt; other gases, including nitrogen, carbon dioxide (CO2), and possibly hydrogen sulfide (H2S); and solids, including sand from the reservoir, dirt, scale, and corrosion products from the tubing. The purpose of oil and gas processing is to separate, remove, or transform these various components to make the hydrocarbons ready for sale. The goal is to produce oil that meets the purchaser's specifications that define the maximum allowable amounts of the following: Similarly, the gas must be processed to meet purchaser's water vapor and hydrocarbon dewpoint specifications to limit condensation during transportation. The equipment between the wells and the pipeline, or other transportation system, is called an oilfield facility. An oilfield facility is different from a refinery or chemical plant in a number of ways.
Oil or gas wells produce a mixture of hydrocarbon gas, condensate, or oil; water with dissolved minerals, usually including a large amount of salt; other gases, including nitrogen, carbon dioxide (CO2), and possibly hydrogen sulfide (H2S); and solids, including sand from the reservoir, dirt, scale, and corrosion products from the tubing. For the hydrocarbons (gas or liquid) to be sold, they must be separated from the water and solids, measured, sold, and transported by pipeline, truck, rail, or ocean tanker to the user. Gas is usually restricted to pipeline transportation but can also be shipped in pressure vessels on ships, trucks, or railroad cars as compressed natural gas or converted to a liquid and sent as a liquefied natural gas (LNG). This chapter discusses the field processing required before oil and gas can be sold. The goal is to produce oil that meets the purchaser's specifications that define the maximum allowable water, salt, or other impurities. Similarly, the gas must be processed to meet purchaser's water vapor and hydrocarbon dewpoint specifications to limit condensation during transportation. The produced water must meet regulatory requirements for disposal in the ocean if the wells are offshore, reservoir requirements for injection into an underground reservoir to avoid plugging the reservoir, and technical requirements for other uses, such as feed to steam boilers in thermal-flood operations, or in special cases, for irrigation. The equipment between the wells and the pipeline, or other transportation system, is called an oilfield facility. An oilfield facility is different from a refinery or chemical plant in a number of ways.
Chemical treatment with demulsifiers is used to counteract the natural surfactants present, and wetting agents or other chemicals sometimes are used to carry the suspended solids into the water layer. The presence of a band of emulsion in centrifuged samples indicates that further chemical treatment might be needed.
Abstract This work presents a matrix acidizing formulation which comprises a salt of monochloroacetic acid giving a delayed acidification and a chelating agent to prevent precipitation of a calcium salt. Results of dissolution capacity, core flood test and corrosion inhibition are presented and are compared to performance of 15 wt% emulsified HCl. Dissolution capacity tests were performed in a stirred reactor at atmospheric pressure using equimolar amounts of the crushed limestone and dolomites. Four different chelating agents were added to test the calcium ion sequestering power. Corrosion tests were executed using an autoclave reactor under nitrogen atmosphere at 10 barg. Core flood tests were performed to simulate carbonate matrix stimulation using limestone cores. It was found that the half-life time of the hydrolysis reaction is 77 min at a temperature of 100 °C. Sodium gluconate and the sodium salt of D-glucoheptonic acid were identified to successfully prevent the precipitation of the reaction product calcium glycolate at a temperature of 40 °C. Computed Tomography (CT) scans of the treated cores at optimum injection rate showed a single wormhole formed. At 150 °C an optimum injection rate of 1 ml/min was found which corresponds to a minimum PVBT of 6. In addition, no face dissolution was observed after coreflooding. Furthermore, the corrosion rates of different metallurgies (L80 and J55) were measured which are significantly less than data reported in literature for 15wt% emulsified HCl. The novelty of this formulation is that it slowly releases an organic acid in the well allowing deeper penetration in the formation and sodium gluconate prevents precipitation of the reaction product. The corrosivity of this formulation is relatively low saving maintenance costs to installations and pipe work. The active ingredient in the formulation is a solid, allowing onsite preparation of the acidizing fluid.
Romer, Michael Christopher (ExxonMobil Upstream Research Company) | Spiecker, Matt (ExxonMobil Upstream Research Company) | Hall, Tim James (ExxonMobil Upstream Research Company) | Dieudonne, Raphaël (Hydro Leduc) | Porel, François (Hydro Leduc) | Jerzak, Laurent (Hydro Leduc) | Ortiz, Santos Daniel (KSWC Engineering & Machining) | King, George Randall (KSWC Engineering & Machining) | Gohil, Kartikkumar Jaysingbhai (KSWC Engineering & Machining) | Tapie, William (Deteq Services) | Peters, Michael (MTI) | Curkan, Brandon Alexander (C-FER Technologies)
Summary What do you do after plunger lifting? What if lift gas is not readily available or your liquid level is around a bend? What can you do with a well that has low reservoir pressure, liquid-loading trouble, and fragile economics? Do you give up on the remaining reserves and advance to plugging and abandonment? These questions were considered, and the answers were found to be unsatisfactory. This paper will describe the development and testing of a novel wireline-deployed positive-displacement pump (WLPDP) that was invented to address these challenges. Artificial-lift (AL) pumps have historically been developed with high-producing oil wells in mind. Pumps for late-life wells have mostly been repurposed from these applications and optimized for reduced liquids production. The WLPDP development began with the constraints of late-life wells with the goal of addressing reserves that conventional AL methods would struggle to produce profitably. Internal and industry-wide data were first reviewed to determine what WLPDP specifications would address the majority of late-life wells. The primary target was gas wells, although “stripper” oil wells were also considered. The resulting goal was a pump that could deliver 30 BFPD from 10,000-ft true vertical depth (TVD). The pumping system must be cost-effective to be a viable solution, which led to several design boundaries. Pumps fail and replacement costs can drive economics, so the system must be deployable/retrievable through tubing. The majority of new onshore wells have tortuous geometries, so the system must be able to function at the desired depth despite them—without damaging associated downhole components. The system should use as many off-the-shelf components and known technologies as possible to reduce development costs and encourage integration. Finally, the pump should be able to handle a variety of wellbore liquids, produced gases, and limited solids. The WLPDP was designed to meet the established specifications and boundary conditions. The 2.25-in.-outer-diameter (OD) pump is deployed through tubing. and powered with a standard wireline (WL) logging cable. The cable powers a direct-current (DC) motor that drives an axial piston pump. The piston pump circulates a dielectric oil between two bladders by means of a switching valve. When each bladder expands, it pressurizes inlet-wellbore liquids, pushing them out of the well. Produced gas flows in the annulus between the tubing and production casing. The intake/discharge check valves and bladders are the only internal pump components that contact the wellbore fluids. The WLPDP system was able to meet the design-volume/pressure specifications in all orientations, as confirmed through laboratory and integration testing. Targeted studies were conducted to verify/improve check-valve reliability, gas handling, elastomer suitability, and cable-corrosion resistance. The results of these and related studies will be discussed in the paper.