Well control(new)

WELL CONTROL Trình bày: ĐỖ QUANG KHÁNH Bộ mơn Khoan – Khai thác Dầu khí Khoa Kỹ thuật Địa chất Dầu khí Đại học Bách Khoa TP HCM Email: dqkhanh@hcmut.edu.vn CONTENT INTRODUCTION WELL CONTROL PRINCIPLES WARNING SIGNS OF KICKS SECONDARY CONTROL GEOPET Well Control  CONTENT WELL KILLING PROCEDURES BOP EQUIPMENT BOP STACK ARRANGEMENTS EXERCISES GEOPET Well Control  INTRODUCTION GEOPET Well Control  GEOPET Well Control  INTRODUCTION Ensure that fluid (oil, gas or water) does not flow in an uncontrolled way from the formations being drilled, into the borehole and eventually to surface  This flow will occur if the pressure in the pore space of the formations being drilled (pf) >= the hydrostatic pressure exerted by the column of mud in the wellbore (pbh)  It is essential that pf, due to the column of fluid, exceeds the formation pressure at all times during drilling GEOPET Well Control  GEOPET Well Control  INTRODUCTION  If, for some reason, pf >= pbh an influx of fluid into the borehole (known as a kick) will occur  If no action is taken to stop the influx of fluid once it begins, then all of the drilling mud will be pushed out of the borehole and the formation fluids will be flowing in an uncontrolled manner at surface This would be known as a Blowout  This flow of the formation fluid to surface is prevented by the secondary control system  Secondary control is achieved by closing off the well at surface with valves, known as Blowout Preventers – BOPs GEOPET Well Control  GEOPET Well Control  GEOPET Well Control  10 BOP STACK ARANGEMENTS GEOPET  General considerations  API Recommended Configurations • Low Pressure (2000 psi WP) • Normal Pressure (3000 or 5000 psi WP) • Abnormally High Pressure (10000 or 15000 psi WP) Well Control  127 BOP STACK ARANGEMENTS  The individual annular and ram type blowout preventers are stacked up, one on top of the other, to form a BOP stack  The configuration of these components and the associated choke and kill lines depends on  the operational conditions and  the operational flexibility that is required GEOPET Well Control  128 7.1 General Considerations The placement of the elements of a BOP stack (both rams and circulation lines) involves a degree of judgement, and eventually compromise  However, the placement of rams and the choke and kill line config should be carefully considered if opt flexibility is to be maintained  Although no single opt stack config., consider the config of the rams and choke and kill lines in the BOP stack as GEOPET Well Control  129 Normal kill operation  There is a choke and kill line below each pipe ram to allow well killing with either ram  Either set of pipe rams can be used to kill the well in a normal kill operation GEOPET Well Control  130 Killing through kill line If there is a failure in the surface pumping equipment at the drillfloor the string can be off the lower pipe rams, the blind rams closed and a kill operation can be conducted through the kill line GEOPET Well Control  131 Ram to ram stripping operation  If Hydril fails the pipe can be stripped into the well using pipe rams  In this operation the pipe is run in hole through pipe rams With the pressure on the pipe rams being sufficient to contain the pressure in the well  When a tooljoint reaches the upper pipe ram it is opened and the tooljoint allowed to pass  Upper pipe ram is then closed and the lower opened to allow tooljoint to pass  This operation is known as ram to ram stripping GEOPET Well Control  132 General Observations  The following general observations can be made about the above arrangement detailed: No drilling spools are used => minimises the number of connections and chances of flange leaks The double ram is placed on top of a single ram unit => will probably provide sufficient room so that the pipe may be sheared and the tool joint still be held in the lower pipe ram Check valves are located in each of the kill wing valve assemblies => will stop flow if the kill line ruptures under high pressure killing operations GEOPET Well Control  133 General Observations Inboard valves adjacent to BOP stack on all flowlines are manually operated ‘master’ valves to be used only for emergency  Outboard valves should be used for normal killing operations  Hydraulic operators are generally installed on the primary (lines and 2) choke and kill flowline outboard valves => allows remote control during killing operations No choke or kill flowlines are connected to the casing-head outlets, but valves and unions are installed for emergency use only  It is not good practise to flow into or out of a casing head outlet If this connection is ruptured or cutout, there is no control  Primary and secondary flowlines should all be connected to heavy duty BOP outlets or spools GEOPET Well Control  134 7.2 API Recommended Configurations  The stack composition depends on the pressures which the BOPs will be expected to cope with (i.e the working pressures) The API publishes a set of recommended stack configurations but leaves the selection of the most appropriate configuration to the operator  An example of the API code (API RP 53) for describing the stack arrangement is: 5M - 13 5/8" - RSRdAG where,  5M refers to the working pressure = 5000 psi  13 5/8" is the diameter of the vertical bore  RSRdAG is the order of components from the bottom up GEOPET Well Control  135 7.2 API Recommended Configurations  and where,  G = rotating BOP for gas/air drilling  A = annular preventer  Rd = double ram-type preventer  S = drilling spool  R = single ram-type preventer  BOP stacks are generally classified in terms of their pressure rating The following BOP stack arrangements are examples of those commonly used and given in API RP 53: GEOPET Well Control  136 7.2.1 Low Pressure (2000 psi WP)  This stack generally consists of one annular preventer a double ramtype preventer (one set of pipe rams plus one set of blind rams) or some combination of both Such an assembly would only be used for surface hole and is not recommended for testing, completion or workover operations GEOPET Well Control  137 7.2.2 Normal Pressure (3000 or 5000 psi WP) This stack generally consists of one annular preventer and two sets of rams (pipe rams plus blind rams) As shown a double ram preventer could replace the two single rams GEOPET Well Control  138 7.2.3 Abnormally High Pressure (10000 or 15000 psi WP) This stack generally consists of three ram type preventers (2 sets of pipe rams plus blind/shear rams) An annular preventer should also be included GEOPET Well Control  139 7.2 API Recommended Configurations  In all these arrangements the associated flanges and valves must have a pressure rating equal to that of the BOPs themselves  The control lines should be of seamless steel with chicksan joints or high press hoses may be used  These hoses must be rated at 3000 psi (i.e acc press.) GEOPET Well Control  140 THANK YOU VERY MUCH FOR YOUR ATTENTION! GEOPET Well Control  141