PETROLEUM DEVELOPMENT GEOLOGY DRILLING

© Schlumberger 1999 DRILLING ☯ Making a hole or well to make access into reservoir and to produce hydrocarbon (oil & gas) from subsurface ☯ To collect the subsurface geological and reservoir data/information for further hydrocarbon exploration as well as development Christmas Tree Pipeline to Flow Process and Storage Surface Casing Cement Intermediate Casing Cement Production Casing Tubing Completion Fluid Packer Cement Oil or Gas Zone Well Fluids Perforations OIL EXTRACTING HISTORY In the earliest day of oil production, oil was collected from surface seepages Mine shafts were dug to make a well (like water well in Java) to produce shallow oil In the early 19th century peoples developed cable tool drilling DRILLING TYPE OF DRILLING : • Cable Tool Drilling • Rotary Rig Drilling TYPE OF RIG : • Onshore drilling rigs • Semi-submersible rigs • Jack-up units TYPE OF WELL DRILLING : • Conventional Drilling • Directional Drilling • Slant Drilling CABLE TOOL DERRICK JACK UP UNIT A jack-up unit is a barge with legs that can be lowered or raised The barge is towed to the drilling location with its legs in the raised position Once in position, the legs are lowered When they reach the sea-bed, the barge's body is hoisted above the water, creating a stable drilling platform The length of the legs determines the depth of water in which a jackup barge can be used They can generally be used in up to 100 meters of water Jack-up barges are widely employed in the relatively shallow waters of the North Sea's Southern basin SEMI-SUBMERSIBLE RIG A semi-submersible drilling rig is normally a selfpropelled working platform supported by vertical columns on submerged pontoons By varying the amount of ballast water in the pontoons, the unit can be raised or lowered in the water A semi-submersible vessel is normally held in position by up to eight very large anchors, or by dynamic positioning: computer controlled directional propellers to keep the vessel stationary relative to the sea-bed, compensating for wind, wave or current Semi-submersibles can drill in water depths to 300 meters or more all year round SETTING UP THE RIG • • • Depending upon the remoteness of the drill site and its access, equipment may be transported to the site by truck, helicopter or barge Some rigs are built on ships or barges for work on inland water where there is no foundation to support a rig (as in marshes or lakes) Once the equipment is at the site, the rig is set up Here are the major systems of a land oil rig: – Power System – Mechanical System – Rotating Equipment – Casing – Circulation System – Derrick – Blowout Preventer • Mechanical system - driven by electric motors – hoisting system - used for lifting heavy loads; consists of a mechanical winch (drawworks) with a large steel cable spool, a block-andtackle pulley and a receiving storage reel for the cable – turntable - part of the drilling apparatus • Power System – large diesel engines - burn diesel-fuel oil to provide the main source of power – electrical generators powered by the diesel engines to provide electrical power • There's more to drilling than simply rotating the bit • Fluid is circulated while the drilling proceeds • Powerful pumps move the fluid down the pipe, through the bit and back to the surface, carrying the cuttings and other debris with it • Thus, on a rotary rig (unlike the cable tool), drilling can be continuous as stopping to bail the cuttings is no longer required • The drilling mud also stabilizes the walls of the hole • Circulation system - pumps drilling mud under pressure through the kelly, rotary table, drill pipes and drill collars – pump - sucks mud from the mud pits and pumps it to the drilling apparatus – pipes and hoses - connects pump to drilling apparatus – mud-return line - returns mud from hole – shale shaker - shaker/sieve that separates rock cuttings from the mud – shale slide - conveys cuttings to the reserve pit – reserve pit - collects rock cuttings separated from the mud – mud pits - where drilling mud is mixed and recycled – mud-mixing hopper - where new mud is mixed and then sent to the mud pits CONTROLLING THE WEIGHT ON THE BIT The weight is held partly by the hook etc If not, the drill bit wouldn’t turn! Collars are added to the drill string to add more weight Hence the driller can control the weight on the bit by adding/ removing collars or by raising/lowering the swivel tackle Which bit? •Largest bit is used first, decreasing with depth •For each formation & depth have a particular set of jet sizes, gallons per minte, pump strokes per minte, minimum annular velocity (speed mud returns at to keep the hole clean), bit hydraulic horsepower •Hence the hydraulic and bit programs work in tandem to most efficiently drill the well giving best cost per foot, drilling time, minimum down time • Drilling continues in stages: – Drill – run and cement new casings, then drill again • When the rock cuttings from the mud reveal the oil sand from the reservoir rock, the final depth may have been reached • At this point, the drilling apparatus is removed from the hole and perform several tests to confirm this finding: – Well logging - lowering electrical and gas sensors into the hole to take measurements of the rock formations – Drill-stem testing - lowering a device into the hole to measure the pressures, which will reveal whether reservoir rock has been reached – Core samples - taking samples of rock to look for characteristics of reservoir rock WELL COMPLETION TYPE PRODUCING SAND Openhole Completion PRODUCTION STRING Openhole completion merupakan penyelesaian sumur dimana casing dipasang hanya sampai di atas zona produktif (interest zone) Jadi sumur diproduksi dengan kondisi terbuka di sepanjang zona produksi CASING CEMENT PACKER PRODUCING LAYER CASING SHOE Liner Completion Ada dua model penyelesaian sumur menggunakan Liner Completion : Perforated Liner Completion Metode penyelesaian sumur dengan melakukan pemasangan liner dan disemen pada zona produktif yang kemudian dilaksanakan pelobangan (perforated) pada zona-zona yang paling produktif CASING CEMENT PACKER PRODUCING LAYER Screen Liner Completion Casing diset sampai di atas zona produksi yang kemudian digabungkan dengan kombinasi liner dan screen yang tidak disemen di seluruh permukaan zona produksi PRODUCTI ON STRING LINER HANGER CASING SHOE OIL SAND SLOTTED LINER LINER SHOE Perforated Casing Completion CASING CEMENT PACKER PRODUCING LAYER Perforated casing completion adalah penyelesaian sumur dengan menutup semua zona produktif dengan menggunakan casing dan disemen kemudian dilakukan perforasi (pelubangan) pada daerah-daerah produksi di lubang sumur PRODUCTION STRING OIL SAND PERFORATION CASING SHOE PRODUCING WELL COMPLETION THE MAST (CHRITMAST-TREE) Setelah pemboran dinyatakan berhasil dan mendapatkan minyak atau gas, maka di kepala sumur dipasang chritmas tree yang didefinisikan sebagai rangkaian dari valve dan fitting yang digunakan untuk control produksi dan disambungkan dengan bagian atas tubing head Pertama kali christmas tree digunakan untuk tekanan aliran rendah dan menengah dari suatu sumur, dimana rangkaian dari tees, elbows, nipples, valve yang dibeli secara terpisah dan dirangkaikan jadi satu di lokasi [...]... the cable tool), drilling can be continuous as stopping to bail the cuttings is no longer required • The drilling mud also stabilizes the walls of the hole • Circulation system - pumps drilling mud under pressure through the kelly, rotary table, drill pipes and drill collars – pump - sucks mud from the mud pits and pumps it to the drilling apparatus – pipes and hoses - connects pump to drilling apparatus... materials (tungsten carbide steel, diamond) that are specialized for various drilling tasks and rock formations Casing - large-diameter concrete pipe that lines the drill hole, prevents the hole from collapsing, and allows drilling mud to circulate • There's more to drilling than simply rotating the bit • Fluid is circulated while the drilling proceeds • Powerful pumps move the fluid down the pipe, through...• • Derrick - support structure: holds the drilling apparatus – tall enough to allow new sections of drill pipe to be added to the drilling apparatus as drilling progresses Blowout preventers and Rams high-pressure valves (located below the rotary table or on the sea floor) – seal the high-pressure... tandem to most efficiently drill the well giving best cost per foot, drilling time, minimum down time • Drilling continues in stages: – Drill – run and cement new casings, then drill again • When the rock cuttings from the mud reveal the oil sand from the reservoir rock, the final depth may have been reached • At this point, the drilling apparatus is removed from the hole and perform several tests... shale shaker - shaker/sieve that separates rock cuttings from the mud – shale slide - conveys cuttings to the reserve pit – reserve pit - collects rock cuttings separated from the mud – mud pits - where drilling mud is mixed and recycled – mud-mixing hopper - where new mud is mixed and then sent to the mud pits CONTROLLING THE WEIGHT ON THE BIT The weight is held partly by the hook etc If not, the drill... (uncontrolled gush of gas or oil to the surface, often associated with fire) – Can shut off either the annular space (between pipe and well) or the complete hole • Rotating equipment - used for rotary drilling – swivel - large handle that holds the weight of the drill string; allows the string to rotate and makes a pressure-tight seal on the hole – kelly - four- or six-sided pipe that transfers rotary ... cable tool drilling DRILLING TYPE OF DRILLING : • Cable Tool Drilling • Rotary Rig Drilling TYPE OF RIG : • Onshore drilling rigs • Semi-submersible rigs • Jack-up units TYPE OF WELL DRILLING :... Conventional Drilling • Directional Drilling • Slant Drilling CABLE TOOL DERRICK JACK UP UNIT A jack-up unit is a barge with legs that can be lowered or raised The barge is towed to the drilling. .. • Derrick - support structure: holds the drilling apparatus – tall enough to allow new sections of drill pipe to be added to the drilling apparatus as drilling progresses Blowout preventers and