Part 9  Heavy Oil Production Equipment

1. Steam Injection Thermal Recovery Equipment

The steam injection is a major technique for heavy oil recovery at present. The steam is produced by steam injection boiler and flows to the steam injection well through steam injection pipe network, passes the thermal recovery wellhead, insulated tubing, expansion joint and thermal packer in turn, then enters and heats the oil layer.

The Steam Injection Boiler

The steam injection boiler is a special-purpose boiler for the recovery of heavy oil. It is a direct current boiler of forced circulation. This boiler is of sub critical working pressure. The steam quality is 80-85%.

●   Specifications of Steam Injection Boilers

Parameters	Type
	YZG-22.5/17.2-G, D		YZG-22.5/9.5-G, D		YZG-22.5/21-G, D		YZG-9.2/9.5-G, D
Rated evaporation capacity t/h (lb/h)	22.5 (50, 000)		22.5 (50, 000)		22.5 (50, 000)		9.2 (20, 000)
Rated working pressure MPa (psi)	17.2 (2, 500)		9.5 (1, 400)		21 (3, 000)		9.5 (1, 400)
Feed temperature ℃ ( ˚F)	>10 (50)		>10 (50)		>10 (50)		>10 (50)
Steam temperature ℃ ( ˚F)	350 (660)		307 (610)		370 (700)		307 (610)
Steam quality ％	80		80		90		80
Combustion typ	pressure combustion		pressure combustion		pressure combustion		pressure combustion
Thermal efficiency ％	80		80		86		86
Control mode	Screen & PLC		Screen & PLC		Screen & PLC		Screen & PLC
Loading mode	Packaged		Packaged		Packaged		Packaged
Fuel discharge	Gas	Oil	Gas	Oil	Gas	Oil	Gas	Oil
	1, 500 Nm3/h  (53, 000 ft3/h) 1, 400 kg/h (3, 000 lb/h)		1, 500 Nm3/h (53, 000 ft3/h) 1, 400 kg/h (3, 000 lb/h)		1, 500 Nm3/h (53, 000 ft3/h) 1, 400 kg/h (3, 000 lb/h)		680 Nm3/h (23, 900 ft3 /h) 560 kg/h (1, 240 lb/h)
Weigh	95 t (21, 000 lb)		75 t (16, 500 lb)		85 t (18, 750 lb)		35 t (7, 700 lb)

Parameters	Type
	YZG-9.2/17.2-G、D		YZGM-9.2/17.2-G、D		YZGM-9.2/21-G、D		YZGM-11.2/21-G、D
Rated evaporation capacity t/h (lb/h)	9.2 (20, 000)		9.2 (20, 000)		9.2 (20, 000)		11.2 (25, 000)
Rated working pressure   MPa (Psi)	17.2 (2, 500)		17.2 (2, 500)		21 (3, 000)		21 (3, 000)
Feed temperature ℃ ( ˚F)	>10 (50)		>10 (50)		>10 (50)		>10 (50)
Steam temperature   ℃ ( ˚F)	350 (660)		350 (660)		370 (700)		350 (660)
Steam quality ％	80		80		80		80
Combustion type	pressure combustion		pressure combustion		pressure combustion		pressure combustion
Thermal efficiency ％	86		86		86		86
Control mode	Screen & PLC		Screen & PLC		Screen & PLC		Screen & PLC
Loading mode	Packaged		Packaged		Packaged		Packaged
Fuel discharge	Gas	Oil	Gas	Oil	Gas	Oil	Gas	Oi
	680 Nm3/h (23, 900 ft3 /h) 560 kg/h (1, 235 lb/h)		680 Nm3/h (23, 900 ft3 /h) 560 kg/h (1, 235 lb/h)		680 Nm3/h  (23, 900 ft3 /h) 560 kg/h (1, 240 lb/h)		770 Nm3/h (27, 200 ft3 /h) 640 kg/h (14, 010 lb/h)
weight	40t (88, 000 lb)		45t (99, 000 lb)		45t t (99, 000 lb)		50t (11, 000 lb)

Thermal Recovery Wellhead Assemblies

Thermal recovery wellhead assemblies are specialized wellheads suitable for steam huff-puff, steam drive, and SAGD, which have the functions of both production and steam injection. By using them, steam with high temperature and high pressure is controlled during steam injection.

●   KYS14.8-Y Thermal Recovery Wellhead

This wellhead consists of big cross, tubing hanger flange, choke, small cross and gate valve. The gate valve of this wellhead is of a single-plate type, belonging to pressurized self-acting float seal system. The valve plate is pushed to the valve seat at the exit end under the pressure of the medium, making the sealing surfaces between the valve plate and the valve seat at the exit end contact closely to provide a good sealing. The valve plate and the valve seat are made by the special process of composite plating, so the friction mate between the valve plate and the valve seat is self lubricated, which gives the valve an ideal friction property, reliable sealing and a small switch torque.

◆ Specifications

Nominal bore diameter	65 mm (2-9/16”)
Nominal bore diameter of big cross	165 mm (6-1/2”)
Max working pressure	14.8 MPa (2100 psi)
Applicable working temperature	-18 to 345 ℃ (0-650 ˚F)
Applicable medium	Oil, water, saturated steam, workover fluid
Connecting thread of casing flange	7CSG (5-1/2LCSG)
Connecting thread of tubing hanger flange	4-1/2UPTBG
Connecting mode	Clamp-on

●   KR21-370 Thermal Recovery Wellhead

This wellhead consists of big cross, tubing hanger flange, choke, small cross and gate valve. It is an integrated wellhead specially designed for both steam injection and oil production, more suitable for steam drive of heavy oil. Main components of the wellhead are all made of high quality alloy and stainless steel, with the features of temperature and pressure resistance, anti-corrosion and low fluid resistance.

The gate valve is expanded dual-plate type, with single-side semi-forced sealing obtained by hand-operating rising stem. Each gate valve consists of expander, valve seat and two valve plates of certain slope. The valve plate and the valve seat contact each other by plane, and the expander and the plate contact each other by slope. When the gate valve is closed, the valve stem drives the valve plate to move downward, and the expander brings the valve plate a horizontal movement, which guarantees the forcing contact between the valve plate and the valve seat. Pressurized by the medium, the valve plate is tightly against the valve seat on the exit end to keep the gate valve in the sealing condition. The specific contact angle between the valve plate and the expander allows for an easy operation, small switch torque without any self-locking, and compensates the interval change due to linear expansion.

◆Specifications

Nominal bore diameter	65 mm (2-9/16”)
Bore diameter of big cross	165 mm (6-1/2”)
Max working pressure	21 MPa (3, 000 psi)
Suitable temperature	-29 ℃to 370 ℃ ( -20 to 700 ˚F)
Suitable medium	Oil, water, saturated steam, workover fluid
Connecting thread of casing flange	7CSG
Connecting thread of tubing hanger flange	4-1/2UPTBG
Connecting mode	Clamp-on

●   SAGD Wellhead

The SAGD (Steam Assisted Gravity Drainage) wellhead consists of casing flange, big cross, gate valve, thick flange, hanger assembly of coiled tubing and wellhead shut-in equipment. The SAGD wellhead assembly is expected to hang three tubing strings at the same time so as to meet the dynamic adjustment of technology parameters in SAGD production process. The three-tubing strings and the reducing coupling arrangement of SAGD wellhead assembly allows the wellhead assembly to hang production tubing and the guide tubing at the same time, and the guide tubing encloses a testing string for the coiled tubing. Due to high pressure, the downhole gas mixture has great possibility of upwelling during oil production, and causes blowout. It is at the well site, so measures must be taken. A shut-in device is installed at the cross of the wellhead. In case of any emergency, the blow-out can be controlled by turning the hand-wheel on both sides to drive the packing elements to seal the polished rod quickly, thus the high pressure fluid can not flow up to the well.

◆Specifications

Nominal bore diameter	80 mm (3.15”)
Bore diameter of big cross	245 mm (9-5/8”)
Max working pressure	21 MPa (3, 000 psi)
Working temperature	-29 ℃to 370 ℃ ( -20 to 700 ˚F)
Applicable medium	Water, saturated steam, crude oil
Connecting thread of casing flange	9-5/8BSCG
Connecting thread of tubing head reducing joint	4-1/2TBG
Connecting thread of dual testing tubing string	1.9TBG
Connecting mode	Flange

Pre-stressed Insulated Tubing

Insulated tubing is one of the important parts in downhole for thermal recovery of heavy oil. The purposes of employing insulated tubing in steam injection (steam drive or steam puff & huff) are: avoid the damage or distortion of casing and cement sheath under high temperature in the steam injection well; decrease heat loss during steaming process; and inject the heat energy of high temperature and pressure steam to the heavy oil layer maximally.

Insulated tubing consists of an insulated system (formed by inner tube, outer tube and multi-layer insulation material), coupling and insert and insulation sleeve. The method of pre-stressing is applied on the inner tube to compensate the extension differences between the inner and outer pipes to guarantee the working performance of the insulated tubing during production.

The annular between the inner tube and the outer tube is vacuum, and charged with getter material. In addition, there is an insulation sleeve inside of the coupling, which will minimize the heat loss caused by steam condensing on the inner wall of the coupling and that caused by convection. To farther reduce the heat loss, material with low heat conductivity is used to replace that with high heat conductivity for the insulation sleeve.

●   Specifications

Size mm (in)	OD of tube mm (in)	ID of tube mm (in)	OD of collar mm (in)
127×76 (5×3)	127.0 (5)	76 (3)	141.3  (5.56)
127×62 (5×2.44)		62 (2.44)
114×76 (4-1/2×3)	114.3  (4-1/2)	76 (3)	132.0 (5.2)
114×62 (4-1/2×2.44)		62 (2.44)
114×50 (4-1/2×2)		50.6 (2)
88×50 (3-1/2×2)	88.9 (3-1/2)		108.0 (4-1/4)
73×40 (2-7/8×1.61)	73.0 (2-7/8)	40.9 (1.61)	88.9 (3-1/2)

Expansion Joint

The expansion joint, called downhole thermal compensator, is applied to compensate the thermal expansion and compression of the tubing string during steam injection. It features good sealing, high tensile load and high material strength.

●   Specifications

Items	SS50-108Y	KSS62-132Y	KSS76-132Y
Casing OD (in)	5	7	7
Length (ft)	10-30
ID (in)	2	2-1/2	3
OD (in)	4-1/4	5-1/4	5-1/4
Expansion range (ft)	3.28
Temperature ( ˚F)	660
Pressure (psi)	2500
Connection Thread	4-1/2 BCSG×3-1/2 TBG	4-1/2 BCSG×4-1/2 TBG	4-1/2 BCSG×4-1/2 TBG

Thermal Packer Model Y421

This product is mainly used for packing the annulus between the casing and tubing string. It prevents the migration of high temperature/high pressure steam up the well annulus, which helps to avoid the loss of heat and pipe pressure. The product shall be easily set or released by turning or pulling the tubing string. It has double slips to provide reliable anchoring and adopts complex sealing elements, featuring high mechanical strength, high temperature resistant, corrosion proof and good sealing ability. With an internal channel, the cyclic well washing and pressure balancing can be realized after release. The running depth reaches 1860m with a max borehole deviation of 28℃.

●   Specifications

Packer			Casing		Connection thread
Model (in)	OD (in)	ID (in)	Size (in)	Weight (lb/ft)	Upper nut	Lower nut
5	4	1.57	5	18-13	2-7/8TBG	2-7/8TBG
5-1/2	4-1/2	1.97	5-1/2	20-15.5	2-7/8TBG	2-7/8TBG
6-5/8	5-1/2	2.16	6-5/8	28-22	2-7/8UPTBG	2-7/8UPTBG
7	6	2.44	7	29-23	2-7/8UPTBG	3-1/2TBG
9-5/8	8-3/8	2.95	9-5/8	40-32.3	4-1/2TBG	4-1/2TBG

2. Electric Heating Equipment

Electric Heating System for Pumping Unit

The system consists of four major parts, including power supply unit, hollow sucker rod, electric cable and sucker rod pump. Electric cable goes through the hole of hollow sucker rod body and connects to the end of hollow sucker rod. When the alternating current is supplied, the wall of hollow sucker rod is heated based on the principle of skin conductive. The crude oil in the whole tubing string is heated, which can decrease the oil viscosity, improve oil flowability and avoid paraffin trouble.

Power Supply Unit

●   Specifications

Rated Power    50-200 kVA

Input Voltage    380 V 3 Phases  50 Hz

Output Voltage Single Phase 300-900 V  (Commercial Frequency)

Single Phase 500-1, 000 V (Mid-frequency)

Plastic-coated Cable

The cable is composed of four major parts, including protecting layer, insulating layer, cable conductor and steel core. The plastic-coated cable is the core heating component in the equipment.

●   Specifications Heat resistance -30 ℃to +250 ℃ (-22 to +662 ˚F) Insulation resistance ≥300 MΩ.km (20 ℃or 68 ˚F relative humidity 80%) Rated voltage: A.C 2, 000 V Tensile strength: ≥335 MPa (48, 600 psi) Period of usage: ≥2 years Steel-armored Cable Steel-armored cable is composed of three major parts, including metal casing, metal wire and heat-resistant insulation material. The steel-armored cable is the core heating component in the equipment, and it can be put into tubing and make an electric circuit itself to heat crude oil in nature flow wells. ●   Specifications Heat resistance -30 ℃to +350 ℃(-22 ˚F to +662 ˚F) Insulation Resistance ≥300 MΩ.km (20 ℃ or 68 ˚F relative humidity 80%) Rated Voltage: A.C 2, 000 V Tensile Strength: ≥335 MPa (48, 600 psi) Period of Usage: ≥2 years

Due to the metal casing at surface layer, it provides a complete solution to the shortcoming in cable surface layer breakage and thereby substantially reduces short circuit faults.

Heater Under Pump

If the oil is difficult to enter into pump because of high oil viscosity, by using a hollow pump and a heater passed through the hollow pump, the oil under the pump can also be heated at the same time.

●   Specifications

Rated power: 30 kW/unit (41 HP/unit)

Rated Voltage: AC 2, 000 V

Max OD: 16-18 mm (0.63-0.71 in)

Length: 10 m (33 ft)

Electric Heating System for PC Pump Well

The system is mainly composed of the following parts: power supply, hollow sucker rod, steel-armored cable and electric collector. Based on the  skin effect electric-thermal principle, the hollow rod  generates heat energy and thereby  heats the crude oil in the well bore to sustain/increase oil temperature. During the process, crude oil resistance is reduced and pump load is decreased and thereby the possibility of fault occurrences is minimized. Furthermore, it also decreases the crude oil viscosity and increases the pump efficiency and oil productivity.

●   Electric Collector

Electric collector (Electricity Supply Conversion Machine) is the key component for electric-heating power supply switching between the static state and the dynamic state. It is applied to connect ground power supply and downhole electric-heating devices.

●   Specifications

  ●  Rated Speed: 300 rpm

  ●  Power Transfer Limit: 150 kW (204 HP)

  ●  Rated Voltage: 1, 200 V

  ●  Rated Current: 125 A

  ●  Rated Operating Temperature: ≤60 ℃(140 ˚F)

The explosion-proof grade is in accordance with the Classification of Locations for Electrical Installations at Petroleum Facilities, Oil and Gas Industrial Standard of People’s Republic of China (SY0025-95)

Electric Heating System for Natural Flow Well

A steel-armored cable is put in tubing by using steel-armored cable pressurized injection equipment, through a BOP and a hanging sealer installed on the wellhead. The metal casing of steel-armored cable inside tubing is heated under the skin effect and adjacency effect when power is supplied by surface power control system, so as to realize the purposes of heating and paraffin removal of crude oil during production. The heating time, temperature and power shall be determined according to the actual paraffin problem and change of production of the well. The applicable specifications are the same as those of electric heating system for pumping unit.