CRUDE OIL HEATING & POWER GENERATION UNIT

(b) Description

Current Practice

Heavy crude oil flow assurance from subsurface of oil producing wells to the processing facilities is considered as a big challenge which is facing operating companies. As to enhance the flow assurance issue big electrical heaters have been used which are expensive and high power consuming.

There are many reasons for interrupting the power supply to the pumps of oil producing wells such as lightening which results in pumps failures (because of back pressure of oil from top to bottom against the normal rotation of pump rod) and that leads to frequent production losses.

The associated gases to crude oil are making complications in oil flow which can stop the flow. In many oil fields which producing huge amount of associated gases, there are different projects of gas utilization, however there are unutilized gases that can't be released in air due to its environmental impact which burned without utilizing its high energy potential.

Generally water is associating oil in different amounts which leads to technical and economical load in pumping and treating.

Oil production measurement for each well separately is considered as missing advantages in many wells which support the management of partners' shares.

There are many off grid wells that its connection to electricity grid is considered economically infeasible and the usage of power generators is not practical as it consumes diesel fuel. 2. Unit Advantages

• Heating heavy crude oil to 80 C which enables the crude oil to flow easily in the pipelines. Using this unit will save the cost of electrical heaters and its consumption.

• Power generation of the sufficient for the production pump which will supply the electricity automatically in case of power interruption.

• Prolonging the pump service life time as it is effected by the back spin which happening in case of any interruption by the crude oil back pressure force and that leads to parting the pump sucker rod. This unit avoiding the oil back pressure force to impact the pump directly as it allows the back flow to flow to unit connections and take the cycle and flow to the surface production line again.

• Increasing Production by saving time of power interruptions and pumps failure.

• Releasing part of associated water in steam form as a result of heating.

• Provision of optional Steam Injection to the well as an initiative to Enhanced Oil Recovery (EOR) as to increase reservoir pressure.

• Utilizing some of unutilized associated gases by burning in the combustion chamber instead of flaring in the air.

• Supplying electricity for off grid wells.

• Oil Production Measurement for each well having this unit separately (as it can work as well test separator). ription of the Invention onents

eating Unit

essel

ombustion System

.1. Combustion Chamber (occupying 20% of the vessel)

.2. Pipe with holes to carry the fuel for burning .3. Burner System

.4. Diesel Fuel Small Tank

.5. Temperature Control System

.1.2.5.1. Control Valves

.1.2.5.2. Temperature Sensors

eating System

.1. Heating Chamber (occupying 80% of the vessel) .2. Thick layer of Mineral Sheet to separate

Combustion and Heating Chambers

low lines

.1. Flow lines to transfer the crude to different parts in the vessel

.2. Flow line to collect the vapors and flue gases from combustion chamber

.3. Flow line to collect the vapors from the heating chamber

.4. Connections between the three inlet lines to the vessel. 3.1.1.4.5. Connection between the main inlet header to the vessel and the crude fuel inlet to the combustion chamber

3.1.1.4.6. Optional connections for injection and

stimulation jobs.

.1.5. Control valves to control the inlet, outlet and passing flow to the vessel

.1.6. Relief valve to release the excess pressure

.1.7. Sensors and instruments for temperature, pressure, level, water cut, gas content and flow measurements

Power Generation System

.2.1. Modified Turbo charger with generator to generate electricity from vapors and flue gases

.2.2. Flow lines to generate vapors

.2.3. Tank to separate water from vapors

.2.4. Valve to control vapors pressure

.2.5. Condenser

.2.6. Pump

Flow rate measurement instruments Operation Procedure

This unit could be installed by "Hot Tapping" technology while production as to avoid production loss by two connections: one from the production line to the inlet header of the vessel and the other one is from the unit outlet header to the production line. The feeding inlet header to the vessel is distributed to 3 major lines as follows: a. A line to transfer part of the crude oil and its associated gases and water if they exist. This line is having holes in the top to evaporate part of the associated water. At the end of carrier line there is a nozzles to spray the crude oil / associated gases to be burned. The first ignition should be by diesel and then the burning continues with the sprayed crude. The evaporated water shall be collected by lines to be transferred to the electricity generation system.

b. A line to transfer part of the crude as heating medium to the heating chamber which is separated from the combustion chamber by a thick layer of mineral sheet to directly transfer the heat to the heating medium which is transferring heat itself to the third line that passing the heating chamber.

c. A line passing the heating chamber to be heated by the heating medium is to go back again to the production line to heat up the produced crude continuously.

The steam, vapors and the flue gases which produced from the combustion chamber and steam and vapors produced from the heating chamber are to be collected in one line to enter the power generation system (after the condensation of the steam through condensation and superheating) which consists of modified turbo-charger to utilize the pressure of the vapors and flue gases as to rotate the turbine wheels and the shaft which will supply the generator with the sufficient mechanical / rotational energy to transform it in form of electrical energy. This system will be acting on standby basis as it will work to generate electricity only in case of power interruptions and well stoppage. As to maximize the utilization of this system a series of compressors to be added as to accumulate the collected steam from the heating chamber to reach to the optimum pressure for steam injection jobs. Connections to be made optionally for steam injection intermittent jobs and it will be depending on each well reservoir data.

In case of any interruption to the production, the crude oil in the production line with back pressure force will be diverted to the inlet line of the vessel instead of going back directly to the well and affecting the pump sucker rod. After the stabilization of the back pressure force the power generation unit will start automatically as to supply the pump with the sufficient electricity without affecting its safety.

There are built in connections between the different lines feeding or discharging from the vessel as to ensure that this unit is suitable for any kind of crude varying from heavy to light and with different contents of water and / or gas. Following are some procedures for special types of crude:

(i) For heavy crude with high water cut content: With this type of crude the unit will be efficient in separating considerable part of free water which will be evaporated and collected from both combustion and heating chamber (the bigger amount will be from the heating chamber) after condensation and superheating processes. The inlet line to the combustion chamber which carrying the crude fuel will be closed (as it contains high water cut which will decrease the heat value) and the connection from the heating chamber (heating medium crude) to the fuel inlet header will be open (before the control valve) as to supply crude fuel with better heat value). The separated steam will be accumulated to reach the required amount, pressure and quality for intermittent injection jobs to improve the reservoir pressure. This operation will help in transporting MORE oil (as it gets rid of some water) with sufficient temperature to assure stable flow without wax accumulation. On top of all, the production measurement for the producing well is a great result given by this unit as to improve the production allocation calculations,

(ii) For light crude with excessive associated gases: In the fields that the associated gases are not being utilized and just flared in the air, this unit will save this wasted resources as the associated gases will be the fuel for the combustion chamber. The minimum values add by this unit with this type of crude is the backup power generation system and production measurement in addition to the injection jobs. ontrol Procedure

Temperature Control

.1.1. Crude Oil Heating Medium Temperature Control

i. Control of the valve in the inlet line which

transferring the medium to the heating chamber: • If the medium temp increased above 130 C, the automatic valve will open gradually.

• If the medium temp decreased below 110 C, the automatic valve will close gradually.

ii. Control of the valve in the outlet line which

transferring the medium from the heating chamber:

• If the medium temp increased above 130 C, the automatic valve will open gradually.

• If the medium temp decreased below 110 C, the automatic valve will close gradually.

iii. Control of the valve in the inlet line which

transferring the crude oil to the combustion

chamber:

• If the medium temp increased above 125 C, the automatic valve will close gradually.

• If the medium temp decreased below 115 C, the automatic valve will open gradually.

. Crude Oil (in the passing line) Temperature Control i. Control of the valve in the inlet line which transferring the passing crude to the heating chamber:

• If the passing crude temp increased above 90 C, the automatic valve will open gradually.

• If the medium temp decreased below 70 C, the automatic valve will close gradually.

ii. Control of the valve in the outlet line which

transferring the passing crude from the heating chamber: • If the passing crude temp increased above 90 C, the automatic valve will open gradually.

• If the passing crude temp decreased below 70 C, the automatic valve will close gradually.

Pressure Control inside the Heating Chamber:

In case of pressure increased inside the heating chamber to above the safety pressure, the relief valve above the heating chamber will open gradually to release the excessive pressure.

Backup Electricity Line Operation Control:

The backup electricity line will be working

automatically to supply electricity when there is any interruption.

4. Conclusion

This unit is crucially important to resolve the flow assurance issue for the heavy crude oil and minimizing the oil loss beside the utilization of the associated gases which was unutilized and some of associated water which applies technical and economical load for carrying and processing and on top of all it provides additional optional applications for steam injection and stimulation jobs.