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ĐẠI HỌC BÁCH KHOA THÀNH PHỐ HỒ CHÍ MINH KHOA ĐỊA CHẤT-DẦU KHÍ PRODCUTION ENGINEERING GVHD: TS Mai Cao Lân SVTH : Phạm Trần Nhật Duy Nguyễn Ninh Giang Nguyễn Trọng Nhân Lưu Cơng Sơn Nguyễn Anh Phong Đỗ Việt Tồn Mục lục ĐẠI HỌC BÁCH KHOA THÀNH PHỐ HỒ CHÍ MINH I INTRODUCTION II RESEIRVOR- DRIVE MECHANISM: 1 Dissolves gas Free gas cap expansion drive .1 Water drive Combination drive reservoir III Primary production Natural flow Artificial Lift Methods a Beam Pumping (Sucker-rod) b Electrical Sumersible Pumping (ESP): c Progressive Cavity Pump: d Hydraulic Lift: .7 e Plunger Lift: f Gas Lift: IV V VI Secondary recovery .10 Water flooding 10 Gas injection 11 Enhanced oil recovery .13 Thermal : 13 Chemical flood: 13 Miscible gas drive : 14 Refecnces: 15 I INTRODUCTION  The producing life of an oil well can be divided into phases, each defined by the amount of energy or pressure in the reservoir  The life of a gas or oil well is similarly affected by pressure decline II RESEIRVOR- DRIVE MECHANISM: Dissolves gas - Under high pressure, gas dissolve in oil As production proceeds, pressure in reservoir decreases and gas can bubble out of the oil expanding gas bubbles in the pores of the reservoir force the oil through the rock into the well Free gas cap expansion drive - If the reservoir pressure is below the bubble point, there will be a free gas cap - The pressure decreases, the free gas cap will expand, it helps fluid move to well Water drive - Oils are driven by the expansion of water next to or below oil reservoir - The produced oil is replaced in the reservoir pores by water - The recovery of oil in place from a water drive reservoir is relatively high Combination drive reservoir - The most effcient reservoir drive system is a combination of a free gas cap expansion and a water drive III Primary production Natural flow - Natural flow is the simplest, most straightforward, and most profitable stage of a well's producing life - Pressure is the primary motivating force - Source of pressure: dissolved gas expands in fluid and lower’s density - When pressure in the reservoir is above the bubble point, gas dissolves in oil in the reservoir As production proceeds, pressure in the reservoir will decrese and reach the bubble point, allowing gas to evolve in the reservoir.That pressure help fluid move to well Artificial Lift Methods Electrical sumersible pumping Beam pumping Hydraulic lift Articfical lift methods Progessive cavity pump Plunger lift Gas lift a Beam Pumping (Sucker-rod) Modern beam pumps are powered by a prime mover A beam pump typically pumps about 20 times a minute and the amount of oil is directly tied to the size of the pump Some are powered by electricity, but many go off grid because electricity isn't available These are powered by gas from the well, or propane or diesel fuel The prime mover runs a set of pulleys to a transmission, which drives the cranks that have weights on them to help the motor lift heavy sucker rods The sucker rods are driven by the sucker rod pump that resides at the bottom of the well As the beam pump rocks back and forth, the rod string, sucker rod, and sucker rod pump are activated Similar to a piston inside a cylinder, the sucker rod lifts oil from the formation, up through the tubing and into a holding tank on the surface b Electrical Sumersible Pumping (ESP): - Submersible pumps are used in oil production to provide a relatively efficient form of "artificial lift", able to operate across a broad range of flow rates and depths By decreasing the pressure at the bottom of the well (by lowering bottomhole flowing pressure, or increasing drawdown), significantly more oil can be produced from the well when compared with natural production The pumps are typically electrically powered and referred to as Electrical Submersible Pumps (ESP) - New varieties of ESP can include a water/oil separator which permits the water to be reinjected into the reservoir without the need to lift it to the surface There are at least 15 brands of oilfield esps used throughout the world Until recently, ESPs had been highly costly to install due to the requirement of an electric cable downhole This cable had to be wrapped around jointed tubing and connected at each joint New coiled tubing umbilicals allow for both the piping and electric cable to be deployed with a single conventional coiled tubing unit c Progressive Cavity Pump: - The PCP is a closely related technology to the ESP PCPs consist of a helical bore that rotates inside a similar helical cavity The rotation of the bore creates cavities with negative pressure (vacuum) to open and close, forcing fluid up through the pump body The PCP offers proven performance in extracting crude oil at high viscosity However, PCPs are vulnerable to damage from abrasive materials and are limited to well depths of approximately 5000-ft PCPs not perform well in deviated wells d Hydraulic Lift: - A hydraulic lift works by using an incompressible liquid to multiply the effects of the force applied to lift something very large or heavy. A larger surface area requires a smaller amount of force to the same amount of work e Plunger Lift: - This artificial lift method is used primarily in gas wells to remove relatively small volumes of liquid Functionally, a plunger-lift system provides a mechanical interface between the produced liquids and gas Using the well's own energy for lift, liquids are pushed to the surface by the movement of a free-traveling piston (plunger) traveling from the bottom of the well to the surface This mechanical interface eliminates liquid fallback, which boosts the well's lifting efficiency In turn, the reduction of average flowing bottomhole pressure increases inflow f Gas Lift: - Gas-lift systems that inject gas into the crude are sometimes used in conjunction with surface operating reciprocating pumps or horizontal centrifugal pumps However, these systems become far less efficient in deeper, deviated wells Gas-lift systems often increase the degree of component flow constriction caused by scaling and paraffin crystal accumulation Additionally, these techniques require an abundant supply of gas to be stored at the surface Gas that is separated and vented is not easily retained for re-injection, and gas that is re-injected rapidly becomes contaminated with oxygen, carbon monoxide and hydrogen sulphide that can corrode production string components Older gas-lift systems (sometimes prominent in offshore applications) burdened with high water cut are being converted more frequently to ESP systems IV Secondary recovery - Over lifetime of the well, after primary recovery (using natural pressure of the reservoir), the pressure falls so there is insufficient pressure to force the oil to the surface Then the Secondary Recovery methods are applied - In general, Secondary Recovery means the second stage of hydrocarbon production during which an external fluid such as water or gas is injected into the reservoir through injection wells located in rock that has fluid communication with production wells - The purpose of secondary recovery is to maintain reservoir pressure and to displace hydrocarbons toward the wellbore - The most commons method of Secondary Recovery are Water Flooding and Gas Injection Water flooding - Water is pumped down under pressure through a injection well Injection wells can be either drilled or converted from producing wells - A common system of waterflood is “five-spot pattern” 10 a) Key factors that drove waterflooding’s development and increasing use were:  Water is inexpensive  Water generally is readily available in large quantities from nearby streams, rivers, or oceans, or from wells drilled into shallower or deeper subsurface aquifers  Water injection effectively made production wells that were near the water-injection wells flow or be pumped at higher rates because of the increased reservoir pressure b) Limitations of waterflood technology:  Compatibility of the planned injected water with the reservoir’s connate water  Interaction of the injected water with the reservoir rock (clay sensitivities, rock dissolution, or generally weakening the rock framework)  Injection-water treatment to remove oxygen, bacteria, and undesirable chemicals  When evaluating how best to produce a particular oil reservoir, a petroleum engineer should include waterflooding in the options that are analyzed, both technically and economically c) Summary:  Waterflooding is the most commonly used secondary oil recovery method Waterflooding has been used successfully in oil fields of all sizes and all over the world, in offshore and onshore oil fields Gas injection - Gas Injection is a general term for injection processes that introduce miscible gases into the reservoir A miscible displacement process maintains reservoir pressure and improves oil displacement because the interfacial tension between oil and water is reduced - Gases used include CO2, natural gas or nitrogen - If the natural gas is pumped down again, the process called gas reinjection 11 - Profit of using Natural gas and CO2:  Natural Gas: In the past, low levels of natural gas that were produced from oil fields were flared or burned off, now the low levels of natural gas that are produced from prolific oil fields are re-injected into the formation as form of disposal, as well as pressure maintenance Here, produced wet gas from oil fields are stripped of their natural gas liquids, compressed and pumped into an injection well  CO2: Injection or reinjection of carbon dioxide also takes place in order to reduce the emission of CO2 into the atmosphere.This has been proposed as a method to combat climate change   Reinjection of carbon dioxide in the Norwegian Sleipner gas field saves the operators million Norwegian Kroners per day in national carbon taxes 12 V Enhanced oil recovery - After secondary recovery , it can be initiated During EOR , substances that are not naturally found in the reservoir are injected into the reservoir Thermal : a Fire flood: - Pumping oxygen down wells and igniting the oil The heat of combustion would lower the viscosity of the oil, pushing it away from the injection well - The recovery from a fireflood can be 30 to 40% of the oil in place - Disadvantages : The progress of the heat wave through the reservoir could hardly be controlled and the tubulars failed as the heat front approached b Steam flood: - The injection of hot water and steam into heavy-oil reservoirs The heat make lower the viscosity of the oil and increase the amount recovered - The recovery will vary between 25 to 65% of the oil in place c - d - Disavantages: enhanced recovery techniques for shallow (less than 3,000 foot deep) reservoirs containing heavy oil Chemical flood: - Micellar-polymer flood: - Pressure on the polymer water from the injection wells drives - the surfactant and oil microemulsion front ahead through the reservoir rock toward producing wells - It can recover about 40% of the remaining oil 13 - Disavantages: It is an expensive process Miscible gas drive : - CO2,nitrogen or LPG injection : Uses carbon dioxide,nitrogen or LPG that expand in a reservoir They are in contact with oil at high pressures (1,500 to 2,500 psi) forms a miscible mixture, making the oil more fluid That allows more oil to detach itself from the walls of the pores and flow to the producing well - It can often recover about 35% of the remaining oil It is the most common method used in enhanced oil recovery 14 VI Refecnces:      Nontechnical Guide to Petroleum Geology , Exploration, Drilling & Production ( Third Edition ) (Author : Norman J.Hyne, Ph.D Publish in March 31, 2012) Oil and Gas Production in Nontechnical Language (Author : Martin S.Raymond and William L.Leffler Publish in September 30 , 2005) Youtube Petrowiki Wikipedia - production engineering 15