Method and apparatus for formation damage removal

A method for treating wells, the method comprising the steps of:

• providing a tubular arrangement for installation in a well bore which produces two distinct channels for segregated fluid flow;
• the first channel providing a flow path from pumping equipment at surface to a down hole tool assembly;
• and the second channel for fluid flow from the down hole tool assembly to flow control equipment at surface;
• lowering a bottom hole assembly which has been attached to the distal end of the tubular arrangement into the well bore to the desired depth;
• isolating at least one linear segment of the well bore from the remainder of the well bore by the use of one or more well bore sealing elements or packers which form part of the down hole tool assembly;
• filling the first flow channel with fluid and opening a valve in the down hole assembly to allow the fluid in the first channel to flow into the formation adjacent to the section of the well bore which has been isolated from the remainder of the well bore;
• closing said valve in the down hole assembly;
• and
• opening a valve in the down hole assembly to allow the fluids injected into the formation, as well as fluids and solid materials from the formation to flow back into the second flow channel.

A method for removing solid materials including formation cuttings, formation fines, sand, drilling fluid suspended solids, drilling fluid filter cake, sediments, and precipitates from a well bore and from the pore spaces in the formation surrounding said well bore, such method comprising;

• providing a tubular arrangement for installation in a well bore which produces two distinct channels for segregated fluid flow;
• the first channel for fluid flow from flow control equipment at surface to a down hole tool assembly;
• and the second channel for fluid flow from the down hole tool assembly to flow control equipment at surface;
• lowering a bottom hole assembly which has been attached to the distal end of the tubular arrangement into the well bore to the desired depth;
• isolating at least one linear segment of the well bore from the remainder of the well bore by the use of one or more well bore sealing elements or packers which form part of the down hole tool assembly;
• filling the first flow channel with fluid and opening a valve in the down hole assembly to allow the fluid in the first channel to flow into the formation adjacent to the section of the well bore which has been isolated from the remainder of the well bore;
• closing said valve in the down hole assembly;
• and
• opening a valve in the down hole assembly to allow the fluids injected into the formation, as well as fluids and solid materials from the formation to flow back into the second flow channel.

A method for removing liquids, emulsions, colloidal suspensions and other multi-phase fluids from the region surrounding a well bore, such method comprising;

• providing a tubular arrangement for installation in a well bore which produces two distinct channels for segregated fluid flow;
• the first channel for fluid flow from flow control equipment at surface to a down hole tool assembly;
• and the second channel for fluid flow from the down hole tool assembly to flow control equipment at surface;
• lowering a bottom hole assembly which has been attached to the distal end of the tubular arrangement into the well bore to the desired depth;
• isolating at least one linear segment of the well bore from the remainder of the well bore by the use of one or more well bore sealing elements or packers which form part of the down hole too assembly;
• filling the first flow channel with fluid and opening a valve in the down hole assembly to allow the fluid in the first channel to flow into the formation adjacent to the section of the well bore which has been isolated from the remainder of the well bore;
• closing said valve in the down hole assembly;
• and
• opening a valve in the down hole assembly to allow the fluids injected into the formation, as well as fluids and solid materials from the formation to flow back into the second flow channel.

An apparatus for use in well treating and evaluation operations which comprises:

• a tubular arrangement for installation in a well bore which produces two distinct channels for segregated fluid flow;
• the first channel providing a flow path from pumping equipment at surface to a down hole tool assembly;
• and the second channel for fluid flow from the down hole tool assembly to flow control equipment at surface;
• a bottom hole assembly which has been attached to the distal end of the tubular arrangement;
• at least one well bore sealing element or packer which forms part of the down hole tool assembly and is used to isolate a linear segment of the well bore from the remainder of the well bore;
• and
• a fluid control valve system in the down hole assembly which allows the fluid movement through the tool and the surrounding well bore regions to be controlled from surface.

A method of operating a multiple position down hole valve which operates independent of any mechanical movement of the tubing string and independent of any pressure in the tubing string or well bore, such method comprising:

• using computer software to initiate a command in a computer or microprocessor or micro controller which is located at the surface of the well location;
• having the surface computer send that command to a second microprocessor or micro controller located in the down hole assembly near the fluid control valve;
• using the down hole microprocessor or micro controller to sense or determine the position of the valve;
• using an electrically operated motor to provide the mechanical force necessary to move the valve from one position to another position;
• using the down hole microprocessor or micro controller to switch electrical power in the appropriate polarity to the electrically operated valve control motor;
• using the down hole microprocessor or micro controller to sense when the valve has reached the required position;
• and
• using the down hole microprocessor or micro controller to switch off the electrical power to the electrically operated valve motor.

A method of operating a multiple position down hole valve which operates independent of any mechanical movement of the tubing string and independent of any pressure in the tubing string or well bore, such method comprising:

• using computer software to initiate a command in a computer or microprocessor or micro controller which is located at the surface of the well location;
• having the surface computer send that command to a second microprocessor or micro controller located in the down hole assembly near the fluid control valve;
• using the down hole microprocessor or micro controller to sense or determine the position of the valve;
• using an electrically operated motor to provide the mechanical force necessary to move the valve from one position to another-position;
• using electrically operated pressure sensing devices which are connected to the down hole microprocessor or micro controller, said pressure sensing devices measuring the pressure in one or more of the locations within the tool and well bore which might at any time during the well evaluation or treating operations be different from the pressure at any other location within the tool or well bore, such as the pressure in the tubing string, the pressure in any secondary tubing string, the pressure in any inflatable packers, the pressure in the well bore above the top packer and the pressure in the well bore below the top packer;
• using the down hole microprocessor or micro controller to use the pressure sensing data to automatically switch electrical power in the appropriate polarity to electrically operated valve control motor and to move the valve to a specified position based upon preset criteria for the pressure data;
• using the down hole microprocessor or micro controller to sense when the valve has reached the required position;
• and
• using the down hole microprocessor or micro controller to switch off the electrical power to the electrically operated valve motor.
• Claims Relating to Formation Evaluation

A method for evaluating wells which comprises:

• providing a tubular arrangement for installation in a well bore which is of a continuous nature and is spoilable on to a reel;
• lowering a bottom hole assembly that has been attached to the distal end of the coiled tubing into the well bore to the desired depth, said assembly containing inflatable well bore sealing means, electrically operable multi-position fluid control valve, electrically operable micro-controller, electrically operable pressure sensing devices, and electrically operable communication modem;
• pressurizing the coiled tubing to a pressure at the down hole assembly which is greater than the pressure in the well bore at the down hole assembly, said pressures being monitored by the sensing devices in the down hole assembly;
• opening the fluid control valve in the down hole assembly to allow the fluid in the coiled tubing to flow into the inflatable packers thereby isolating at least one linear segment of the well bore from the remainder of the well bore;
• closing said valve in the down hole assembly;
• reducing the pressure in the coiled tubing to a pressure at the down hole assembly which is less than the pressure in the well bore at the down hole assembly, said pressures being monitored by the sensing devices in the down hole assembly;
• opening the fluid control valve in the down hole assembly to allow the fluids in the section of the well bore which has been isolated, as well as fluids and solid materials from the formation adjacent to it, to flow into through the valve and into the coiled tubing;
• closing said valve in the down hole assembly and recording the pressure response in the well bore isolated from the remainder of the well bore using the pressure sensing devices in the down hole assembly;
• and
• opening the fluid control valve in the down hole assembly to allow the fluids in the inflatable packers to flow into the well bore until the pressure has been equalized and the packers have deflated.