From the outer casing shoe to total depth td, the external pressure profile is the pore. Conductor and surface casing depth requirements for deep. The large spread in leakoff pressures of the field is further investigated. To determine the yield strength of a given material, a specimen is machined and put into. The best way of avoiding scp because of casing shoe setting depth is to make a thorough investigation of the. Casing design for high pressurehigh temperature wells. Cdex a better and simple way to casing design youtube.
The district manager may require a formation integrity test at the conductor casing shoe if warranted by local geologic conditions or the planned casing setting depth. The casing is run to the required setting depth so that the highpressure wellhead housing hpwhh is landed, latched, and locked andor loaded rigidized into the conductor lowpressure wellhead housing lpwhh. It is imperative to plan for proper selection of casing strings and their setting depths to realise an optimal and safe well at minimal costs. Determination of casing setting depth using kick tolerance. Using the following data, determine the minimum setting depth of the conductor casing below the seabed data. Pressure at the casing seat is combined with the well depth, well diameter, and kick volume to define the casing setting depth as a function of fracture gradient.
On the other hand, an incorrect casing setting depth decision can result in serious consequences. Sufficient cement shall be used to fill the annular space outside the casing from the shoe to the ground surface or to the bottom of the cellar. Surface casing affidavit ohio department of natural. Minimum conductor casing setting depth formulas and. Alliquander investigated various methods, all based on well control, of determining surface casing setting depth. Surface or conductor casings strings these are the largest casings which are set. The importance of the formation and fracture pressures for the selection of the depths for casing setting in slovakia research pdf available june 2015 with 422 reads how we measure reads. Selection is made such that the casing chosen has strength. It is the most important decision made in the preplanning of a well. Surface casing string an overview sciencedirect topics.
Evaluation of casing exit setting depth criteria for. Casing setting depth selection free download as pdf file. Rathole lengths shall be discussed and agreed dependent on wellbore conditions, e. Production casing collapse loads assumes zero pressure on the inside of the pipe and a final mud weight gradient on the outside of the casing. This integrated approach allows operators to gain efficiency and reduce operating costs. A graph of pressure against depth is first constructed at zero depth zero pressure to max. Set surface casing 50 feet below depth of treatable water to be protected and cement from casing shoe to ground surface or as allowed by. The procedure is repeated for other casing strings, usually until a specified surface casing depth is reached. Conductor and surface casing setting depth requirements have evolved from the industrys efforts to provide adequate well control, to protect freshwater zones and to drill at minimum cost. L20120 submittal of the uic intermediate casing setting depth recommendation attachments.
Some pressures of the field is further investigated. The load required to set the casing patch will depend on the size of the casing patch. The selection of casing setting depth is one of the most important tasks in preparing the well plan. Design casings are set in a drilled hole for one or more of the following reasons. An operator must set and cement sufficient surface casing to protect all usablequality water strata, as defined by the groundwater advisory unit in austin. Strength values of available grades in collapse and burst are then plotted as plotted lines. Drilling engineering ii pete 304 casing profile and setting depth by dr. To eliminate scp a good conversion between top of cement toc and setting depth of the previous casing shoe is required. Casing setting depth selection drilling engineering. The depth of intersection is the tentative intermediate casing setting depth, or 8,600 ft in this example. Drilled wells, typically 8 to 10 inches in diameter, require casing to reduce the contamination from the grounds. C the cementing of different casing strings on a well by one cementing company may be consolidated on one form.
As an example, for the case with 7 casing setting depth of 3000 meters and effective average rate of penetration in 8. Setting depths of the surface casing vary from a few hundred feet to as nmch as 5,000 ft. This setting load will vary from 10,000 pounds to in excess of 100,000 pounds. Well planning and construction haynesville shale east texas. The drilling engineer must consider geological conditions such as formation pressures and fracture gradients, hole problems, internal company policies, and, in many cases, a variety of government regulations. To account for the kick tolerance in the casing shoe setting depth selection, there important data are required. Pdf casing setting depth and design of production well. A formation integrity test must be conducted below the surface casing or liner and all intermediate casings or liners. Casing setting depths and depth design concepts will also be covered in detail.
In onshore areas, the primary role of the surface casing string is to protect freshwater zones and that of the conductor is to raise the mud returns to the. Influence of casing shoe depth on sustained casing pressure. The results were generalized for different design scenarios and a simple design method is presented in a. The drilling fluid will be circulated and conditioned to ensure correct fluid properties for the casing installation and cementing. Drilling and well completion cost analysis for geothermal. Shallow dug wells typically extend no farther than 30 feet. Chapter 5 casing setting depth selection the first design task in preparing the well plan is selecting depths the casing will be run and cemented. Casing setting depth design casing borehole oil well. Casing design for high pressurehigh temperature wells p.
Chapter 5 casing setting depth selection chapter 5. Severe lost irculation zones are often encountered in the. Lower the 1214 drilling assembly in the well to the total depth. Casing setting depth and design of production well in. Many aspects, such as lithology, overpressured formations, shallow gases, lost circulation and troublesome zones, directional well profiles and regulations should be considered in this selection. Step 1 determine formation fracture pressure psi 450 x 0. Changing the casing shoe setting depth to a more suited depth or formation cannot alone eliminate scp. Table 2 shows the three scenarios of casing setting depth based on. In these cases, the operations engineerhead of drilling operations shall be contacted and a decision can then be taken considering the following possibilities.
Background what is a whipstock a whipstock is a wedgeshaped steel casting with a tapered concave groove down one side to guide the bit into the wall of the hole to. The results of the program will allow the well to be drilled safely without the necessity of building a steel monument of casing strings. Cdex, pvis casing design software, implements an industryaccepted physics model to perform accurate and practical casing designs for complicated drilling circumstances. From the outer casing shoe to total depth td, the external pressure profile is the pore pressure profile. Search nearly 14 million words and phrases in more than 470 language pairs. It is possible to use thinnerwall casing at significant depths as long as steps are taken to control collapsing pressures and heat. Maximum mud weight to be used while drilling this interval 9. Unfortunately, many well plans give significant considerations to the actual pipe design yet give only cursory attention to the setting depth of the pipe. The setting depth and design load case identification of the actual casing were recalculated in this study using the philippines method. Check the tentative depth to determine if differential pipe sticking will be a problem when running the casing to 8,600 ft. An appropriate setting load table may be found on page 6 of this. Halliburton offers engineered casing solutions to help operators run and land casing to depth and achieve longterm zonal isolation. Result of casing setting depth and design load case identification. Drilling to the licensed total depth of the well must be completed within one year of the issued date of the licence.
In chapter 2, the authors discuss the more serious issues regarding casing design and deal with the various loads encountered by the casing, especially tension, burst and collapse pressures. It is always set across and below the producing zone to provide sufficient rathole space between the packer and the bottom of the casing for perforating and other production logging and producing operations. L20120 without enclosures signed 08182011 uic intermediate casing setting depth recommendation. Cementing company and operator shall comply with the applicable portions of oac 165. Surface casing depth requirements january 2018 3 alberta energy regulator 2. It includes indepth discussions on simpler topics such as the effects of buoyancy, deviated holes, shock loads, drag and piston forces to more. The importance of the formation and fracture pressures for. A significant part of the course will involve exercises and selfpaced homework activities which may be completed outside the classroom schedule. Casing setting depth is a crucial part of a well planning procedure. The setting depth of the production casing is always deeper than the tubing. Participants should have a personal calculator and access to a computer with a spreadsheet software program.
Halliburton is the only oilfield services provider to offer both cementing services and casing equipment globally. Most pipe ratings are based on the yield strength of the pipe. Background what is a whipstock a whipstock is a wedgeshaped steel casting with a tapered concave groove down one side to guide the bit into the wall of the hole to start a deflection. Maikobi department of petroleum engineering, abubakar tafawa balewa university, p. Casing points selection initial selection of casing setting depths is based on the pore pressure and fracture pressure gradients for the well. Pump depth well depth pumping level draw down static water level pump vertical rise friction.
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