PETE 456 Lecture 2_Upper Completions PDF

Kwame Nkrumah University of Science & Technology, Kumasi, Ghana LECTURE 2 INTRODUCTION TO WELL COMPLETION & STIMULATION Samuel Erzuah...

Kwame Nkrumah University of Science & Technology, Kumasi, Ghana LECTURE 2 INTRODUCTION TO WELL COMPLETION & STIMULATION Samuel Erzuah PB 318  OUTLINE o Completion  Lower Completion (PRODUCTION CONTROL)  Upper Completion (WELL CONTROL) o Causes of Completion Failure  Material Selection o Stimulation www.knust.edu.gh COMPLETION CONCEPTS www.knust.edu.gh COMPLETION EQUIPMENT www.knust.edu.gh LOWER (RESERVOIR) COMPLETION METHODS www.knust.edu.gh  UPPER COMPLETION It responsible for well control  Expansion mechanism Christmas tree (XMT) (PBR)  Packer  Circulation  Packer fluid valves/sliding sleeves  Production tubing  Gas lift mandrels  DHSV  ASV www.knust.edu.gh  XMT  Provide the primary method of closing in a The required pressure well rating of the tree is a critical completion  Isolate the well from adjacent wells decision connect a flowline It should be rated above  Provide vertical access for well the maximum interventions (slickline, electricline, coiled anticipated pressure for the life of the well tubing, etc.) whilst the well is live  Interface with the tubing hanger www.knust.edu.gh  CHRISTMAS TREE (XMT) XMT is placed at the top of the wellhead before the onset of production Its main function is flow control www.knust.edu.gh 8  VERTICAL VS HORIZONTAL XMT The difference between the vertical and horizontal tree is in the position of the valves www.knust.edu.gh 9  Horizontal X-mas tree: The tubing hanger and the tubing are suspended in the X- Conventional (dual bore / vertical) X-mas tree: The tubing hanger and tubing is mas tree. suspended in the wellhead. www.knust.edu.gh VERTICAL VS HORIZONTAL contd www.knust.edu.gh FMC - SUBSEA XMT www.knust.edu.gh XMT VS EXPLODED www.knust.edu.gh DRILLING TO COMPLETION SEQUENCE : VERTICAL XMT www.knust.edu.gh DRILLING TO COMPLETION SEQUENCE : HORIZONTAL XMT www.knust.edu.gh SEQUENCE OF INSTALLING XMT (VERTICAL VS HORIZONTAL www.knust.edu.gh  XMAS TREE (XMT) The difference between the vertical and horizontal tree is in the position of the valves. In a vertical tree, the master valves are in the vertical position and inline with the tubing In a horizontal tree, they are horizontal and away from the production/casing bore www.knust.edu.gh 17  XMAS TREE (XMT) One difference between subsea and platform/land wells is the requirement for ‘A’ annulus access through the tree  This is required for pressure monitoring  bleed down of ‘A’ annulus fluids  gas lift For a conventional (vertical) subsea tree, the tubing hanger and tree are dual bore www.knust.edu.gh WELLHEAD SCHEMATIC www.knust.edu.gh WELLHEAD SCHEMATIC Tubing hanger Upper Casing hanger Lower Casing hanger www.knust.edu.gh 20 WELLHEAD SCHEMATIC All casings are locked inside the Wellhead www.knust.edu.gh 21  TUBING HANGER & RUNNING TOOL Note the four control lines protruding through the tubing hanger Three of these control lines (currently capped) are for operating sliding sleeves The fourth (with temporary test line) connects to the downhole safety valve Photograph courtesy of D. Thomas www.knust.edu.gh 22  SCHEMATIC OF THE TUBING HANGER From FMC Technologies Tubing hanger is used to lock the tubing in place. NB. Tubing can be retrieved and replaced when damaged unlike casing www.knust.edu.gh 23 SCHEMATIC OF THE CASING HEAD www.knust.edu.gh  SUBSURFACE SAFETY VALVE Subsurface safety valves are fail-safe valves that are designed to prevent an uncontrolled release of hydrocarbons from the well if something catastrophic occurs at surface Events that could lead to the required closure of a downhole safety valve include: A major platform incident such as  an explosion or hurricane that could cripple a Christmas tree  An impact with the tree, for example, a heavy truck colliding with a land well, a dropped BOP or a submarine colliding with a subsea tree  Loss of integrity of the tree through structural failure, corrosion, fatigue, improper use, incorrect design or installation or poor maintenance  Stealing of the Christmas tree for scrap or ransom www.knust.edu.gh  DOWNHOLE SAFETY VALVE (DHSV) Downhole safety valves should provide minimum impediment to production when open and fail closed under all conditions They are normally hydraulically controlled, although electric versions exist (Gresham and Turcich, 1985). Because they are a backup system to the tree and designed to fail close, they should not be tied into the facility shut-down system In the unlikely event that the tree does not close in the well, the safety valve can be closed manually,  by loss of power or  by rupture of the control line www.knust.edu.gh  DOWNHOLE SAFETY VALVE TWO (2) TYPES  Held open by WL retrievable hydraulic  Run/retrived on wireline pressure  Installed in a nipple profile in the tubing – failsafe  Possible to replace without pulling production tubing  Closes in case of Tubing Retrivable emergency  Integrated in the production tubing  Installed  Same inside diameter as the production tubing (no inside tubing restrictions)  Need to pull the whole tubing if it shall be replaced www.knust.edu.gh 27  DOWNHOLE SAFETY VALVE WL retrievable Tubing Retrivable www.knust.edu.gh  TUBING VS WIRELINE RETRIEVABLE DHSV Most modern completions use tubing retrievable safety valves, except where conditions and rates are benign These valves are more reliable than wireline retrievable versions, provide fewer restrictions and do not need to be pulled for every well intervention www.knust.edu.gh CONTROL LINE CONNECTION TO DHSV The hydraulic pressure in the control line must overcome the spring force to maintain the valve open. Hydraulic pressure comes from a combination of applied surface pressure and hydrostatic pressure of the control line (or annulus) fluid. If the valve is positioned too deep, the hydrostatic pressure can maintain the valve open even when all surface pressure has been bled off. www.knust.edu.gh  SINGLE ROD PISTON WITH THE CYLINDER Hydraulic pressure from the control line acts on a piston. This piston is then connected to the flow tube Many safety valves use a single rod piston although two rod pistons are also common. www.knust.edu.gh  ROD PISTON VS CONCENTRIC PISTON Rod pistons are simpler (easier sealing geometry) than concentric piston designs. The concentric piston design has the advantage of requiring less hydraulic pressure to open the valve because of its greater piston area, but correspondingly requires more control fluid and will therefore be slower acting. www.knust.edu.gh 32  DHSV SETTING DEPTH where Dmax is the maximum fail close setting depth (ft) pvc the recorded valve closing pressure (psia) pmc the closing safety margin (usually provided by the manufacturer) (psi) 𝜌𝑓 the control line or annulus fluid density (whichever is greater) www.knust.edu.gh 33  DHSV SETTING DEPTH contd This ensures that the valve remains fail close if the control line leaks or parts Note that no allowance is made for the pressure applied by the tubing contents, as the worst case is to assume that the well is open to atmosphere and venting gas. www.knust.edu.gh 34  DHSV SETTING FOR ULTRA DEPTH WELLS The fail close setting depth can be increased by using a stronger spring The spring force can be augmented or replaced with a nitrogen charge for deep-set applications (e.g. deep water). The nitrogen pressure acts on the opposite side of the piston from the control line pressure These valves are therefore insensitive to tubing pressure but are sensitive to changing temperature. Dual control lines with a balanced piston design remove the hydrostatic forces of the control line fluid from the setting depth calculation www.knust.edu.gh 35  ANNULAR SAFETY VALVE (ASV) SYSTEM  Used in gas lift wells  Introduced/ required after the Piper Alpha accident  A barrier element www.knust.edu.gh  GAS LIFT Used for increased oil recovery when ”reservoir pressures” are too low for natural flow. The effective flowing well pressure is reduced Gas is injected down the annulus Need communication with the tubing Side pocket mandrels www.knust.edu.gh 37 PRODUCTION WELL BARRIER (WITHOUT GAS LIFT) www.knust.edu.gh 38 PRODUCTION WELL BARRIER (WITH GAS LIFT) www.knust.edu.gh 39  ANNULAR SAFETY VALVE (ASV) SYSTEM In many applications, particularly involving gas lift, a safety valve is required on the annulus side as well as the tubing side They are mainly used for platform wells with large inventories of gas in the annulus Their operation is similar to tubing retrievable safety valves in that they are control line operated, fail closed and pump through. They incorporate a packer with annulus bypass. The packer should be designed for setting in uncemented (i.e. unsupported) casing. ASVs are typically set hydraulically (control line, tubing or annulus pressure) and are positioned below the tubing retrievable safety valve. www.knust.edu.gh 40  PRODUCTION PACKER Packers provide a structural purpose (anchor the tubing to casing) and a sealing purpose. They are used in a variety of applications:  Isolate the annulus to provide sufficient barriers or casing corrosion prevention (production packer)  Isolate different production zones for zonal isolation (e.g. downhole flow control wells)  Isolate gravel and sand (gravel pack packer)  Provide an annular seal in conjunction with an ASV  Provide a repair or isolation capability (e.g. straddle packers). www.knust.edu.gh 41  PACKER A packer without a seal is an anchor www.knust.edu.gh 42  PACKER SETTING Packers can be set mechanically (weight or rotation). However, in completions, they are often hydraulically set The setting of a hydraulic set packer requires that the tailpipe is sealed. This is achieved with a plug, standing valve, drop ball and seat or a smart plug (e.g. pressure cycle to open or expend). The applied tubing pressure creates a pressure differential on the setting piston At a predetermined pressure (typically around 2000 psi), a shear pin connected to the piston breaks, and the piston is free to compress the slips and element or allow the packer element to move down relative to the slips. www.knust.edu.gh 43  PACKER SETTING contd A ratchet mechanism ensures that once the packer sets, it does not release. Some packers incorporate features designed to prevent premature setting (i.e. caused by the packer hanging up whilst running into the well) A hydraulic set packer sets with a differential between the tubing and the annulus. The port to the annulus can be replaced with an atmospheric chamber, and the packer is now hydrostatic (or absolute pressure) set. Such a packer does not need tailpipe isolation but does need a sealed wellbore (e.g. non-perforated liner) www.knust.edu.gh 44 PACKER SETTING SCHEMATIC www.knust.edu.gh 45  PRODUCTION PACKER Two types HOW TO REMOVE PACKER – Permanent – Retrievable  Cut production tubing above packer – Permanent  Mill packer  Fixed with slips  Remove packer debris and tailpipe  Clean well – Retrievable  Install new completion  Run as part of the tubing  Easy to lock and unlock  Normally used in production wells www.knust.edu.gh 46  POLISHED BORE RECEPTACLE (PBR) The packer locks the tubing However, temperature changes and other effect may increase/decrease the length of the tubing which induces “large” forces. We need “a moving seal” to take up these movements ie. Length compensation Hence, PBR www.knust.edu.gh 47 PBR contd www.knust.edu.gh  LANDING NIPPLES Profiles in the tubing where we can install tools, equipment, plugs etc. Common places – Where the DHSV is to be installed – Above the production packer – Below the production packer – In the tail pipe It is less common to use (no go) nipple profiles/lock mandrels since it reduces the inner diameter www.knust.edu.gh 49  LANDING NIPPLES, LOCKS & SLEEVES A number of proprietary systems are available for the locking and sealing of wireline (occasionally coiled tubing) deployed tools into the completion. The applications include:  Plugs for pressure testing, isolation and well suspension (e.g. removal of the BOP).  Check valves (standing valves) for pressure testing  Deployment of memory (or wireless telemetry) gauges for pressure build-up (PBU) analysis  Being able to move sliding sleeves [sliding side doors (SSDs)]  Deployment of downhole chokes www.knust.edu.gh 50  NIPPLE PROFILE & LOCK There are two methods of landing such devices:  Running a lock into a nipple profile pre- installed in the completion. Attached to the lock will be a blanking plug, standing valve, gauge, etc.  Using a wireline (slickline or electric line) deployed packer ( bridge plug ) that can be set anywhere in the tubing. Attached to the packer is a plug, standing valve, gauge, etc. www.knust.edu.gh 51 NIPPLE PROFILE & LOCK www.knust.edu.gh 52  SLIDING SLEEVE SCHAMATIC Connection between the annulus and the tubing  Inject kill fluid into the well  Gas lift  Control production from several zones www.knust.edu.gh 53  SLIDING SLEEVE SCHAMATIC Sliding sleeves – sometimes called sliding side doors (SSDs) – are also manipulated by wireline locks and use nipple profiles. This sleeve uses a collet to ‘hold’ the sleeve in one of three positions  Open  Equalizing  Closed Sliding sleeves have earned a poor reputation – they either fail to open or fail to close. These problems are caused by scale, asphaltene, solid debris or erosion www.knust.edu.gh 54 SLIDING SLEEVE SCHAMATIC www.knust.edu.gh  SIDE POCKET MANDREL A mandrel is a permanent attachment to the side of the completion. The side pocket mandrel for gas lift It provide the interface for installing  Dummy valve  Gauges (temp, pressure)  Gas lift valves www.knust.edu.gh 56  PERMANENT DOWNHOLE GAUGE Mandrels can be used for downhole gauges. Because of the complexity of an electronic or fibre optic wet-connect, the gauge is permanently connected to the mandrel. It is typically externally mounted and bolted in place. A port allows pressure communication to the inside of the completion. Such gauges typically measure internal pressure and temperature, although they can easily be configured for additional external pressure and temperature measurement for multi-zone completions with sleeves. www.knust.edu.gh 57 THANK YOU !!! www.knust.edu.gh