METHOD OF REMOTE DIVERGENCE FOR WELLS EQUIPPED WITH INTELLIGENT COMPLETION

Abstract

The present invention addresses to a remote divergence method for inhibiting or removing scaling in wells equipped with intelligent completion (IC), including sealing failures, in which a mixture of viscous gel and solid material in different granulometries is used (7) and spheres soluble in water (8) and in oil (6), aiming at maintaining the production of wells equipped with intelligent completion, as well as reducing costs in relation to operations commonly performed with rigs.

Claims

1- A METHOD OF REMOTE DIVERGENCE FOR WELLS EQUIPPED WITH INTELLIGENT COMPLETION, characterized in that it comprises the following steps: a) With the upper ICV (2) and lower ICV (4) closed, pumping the oil-soluble spheres (6), a mixture of viscous gel and solid material in different granulometries (7), and water-soluble spheres (8). Positioning the cushion inside the production string (1). The cushion must have the volume ((6)+(7)+(8)) equivalent to the space between the plug (5) and the base of the intelligent completion valve of the upper interval (2); b) Filling the production string (1) to the position above the lower interval ICV (4) and below the base of the upper ICV (2), positioning the water-soluble spheres (8) at the lower part of the string, together mixing viscous gel and solid material (7), and positioning the oil-soluble spheres (6) on upper part of the string; c) Opening the upper ICV (2) and injecting the chemical treatment in the upper interval of the reservoir; d) After completing the chemical treatment in the upper interval, opening the lower ICV (4) for cleaning and thus the lower interval must produce the material that is positioned inside the string, between the two intelligent completion valves; e) Returning to the normal production condition of the well.

2- THE METHOD OF REMOTE DIVERGENCE FOR WELLS EQUIPPED WITH INTELLIGENT COMPLETION according to claim 1, characterized in that the viscous gel is additivated by an enzymatic or peroxide breaker.

3- THE METHOD OF REMOTE DIVERGENCE FOR WELLS EQUIPPED WITH INTELLIGENT COMPLETION according to claim 1, characterized in that the solid material is a mineral, such as coarse, medium and fine calcite (calcium carbonate).

4- THE METHOD OF REMOTE DIVERGENCE FOR WELLS EQUIPPED WITH INTELLIGENT COMPLETION according to claim 1, characterized in that the soluble spheres are of water-soluble (8) and oil-soluble (6) type.

5- THE METHOD OF REMOTE DIVERGENCE FOR WELLS EQUIPPED WITH INTELLIGENT COMPLETION according to claim 1, characterized in that it is applied in wells with two or more ICVs installed inside the production string.

6- THE METHOD OF REMOTE DIVERGENCE FOR WELLS EQUIPPED WITH INTELLIGENT COMPLETION according to claim 1, characterized in that it is applied in wells that are completed with perforated casing, without intelligent completion, and that produce for more than one interval.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0013] The present invention will be described in more detail below, with reference to the attached figures, which, in a schematic form and not limiting the inventive scope, represent examples of its embodiment. In the drawings, there are:

[0014] FIG. 1 illustrating a scheme of the production string showing the upper producing interval and the lower producing interval, where there are represented: the production string (1), the upper ICV (2), the packer (3), the lower ICV (4) and the plug (5);

[0015] FIG. 2 illustrating the application of packing inside the string of oil-soluble sealant spheres, cross-linked viscous gel, solid material, and water-soluble sealant spheres, to reduce permeability and generate divergence within the production string, in order to direct the chemical treatment for the upper interval, where there are represented: the production string (1), the upper ICV (2), the packer (3), the lower ICV (4), the plug (5), the oil-soluble spheres (6), the cross-linked viscous gel and solid material (7), the water-soluble sealing spheres (8).

DETAILED DESCRIPTION OF THE INVENTION

[0016] The remote divergence method for wells equipped with intelligent completion, object of the present invention, occurs with the use of a mixture of viscous, mineral gel, such as calcite (calcium carbonate) of different granulometries, and water- and oil-soluble spheres.

[0017] The combination of these three materials is carried out as follows: a cylinder of porous medium is assembled inside the production string, with the spheres providing a main structure, while the solid material fills the voids between the spheres and the viscous gel fills the voids between the grains of solid material, as well as between them and the spheres and the string wall. In the pumping sequence, the water-soluble spheres (8) will be firstly pumped. Then, the mixture of cross-linked viscous gel and solid material (7) will be pumped, and finally the oil-soluble spheres (6) will be pumped. This sequence of positioning the spheres in the formation of the porous medium cylinder is intended to protect the cylinder during the acidification operation. At the lower part of the cylinder, due to contact with the oil in the well, there will be the water-soluble spheres (8). At the upper part of the cylinder, due to contact with acid treatment or chelating solutions, there will be oil-soluble spheres (6), naturally insoluble in water-based solutions.

[0018] In this way, there is a porous medium of low permeability by means of the mixture of soluble sealing spheres, solid material, such as calcite, in different granulometries, all these materials being involved in a high viscosity gel. The use of a mixture of soluble sealant spheres, viscous gel, and solid material to reduce permeability is presented as a robust technique to accomplish the divergence in the chemical treatment for inhibition or removal of scale in offshore oil producing wells equipped with intelligent completion.

[0019] Counteracting the loss of circulation is an operation used during the drilling and completion of oil wells in carbonate formations, as in the case of pre-salt, and sandstone formations. These operations generally use a mixture of chemical materials, such as viscous gels based on polymers and a material to cause plugging into the reservoir, such as calcite with different granulometries, and in this way generate a control of the loss of fluids to the formation.

[0020] The sealing spheres are used to promote divergence in wells with large extensions of perforations, when chemical treatments are required. These spheres are injected during the treatment, aiming at plugging the region that has the best permeability. The spheres are positioned in the hole of the perforation in the wall of the production casing, generating a blockage to the flow, which is diverted to other perforations where the injection flow was lower, and, therefore, the treatment is directed to the region that has less permeability, thus leading to the divergence of the treatment.

[0021] In the construction of the well, in the phase of equipping the well for production during the completion operations, completion pieces of equipment are installed in the well, such as the production string. Firstly, the production tail is lowered and then the packer is seated. Sometimes, after the lower well completion phase, the well is temporarily abandoned. Then, the stand valve is placed on top of the TSR (Tubing Seal Receptacle) mandrel, and then a plug of solid material, such as calcite, is placed inside the annulus over the tail, to protect the equipment at the top of the tail. Then, two cement plugs are built, in specific positions inside the annulus. When it is time to install the top completion, the two cement plugs are then removed. After fluid change and well cleaning, the solid material is removed from inside the annulus over the TSR mandrel.

[0022] The remote divergence method for wells equipped with intelligent completion, according to the present invention, is illustrated in one of its applications, but not limited to the same, in FIG. 1, comprising the following steps: [0023] a) With the upper ICV (2) and lower ICV (4) closed, pumping the oil-soluble spheres (6), a mixture of viscous gel and solid material in different granulometries (7), and water-soluble spheres (8). Positioning the cushion inside the production string (1). The cushion must have the volume ((6)+(7)+(8)) equivalent to the space between the plug (5) and the base of the intelligent completion valve of the upper interval (2). [0024] b) Filling the production string (1) to the position above the lower interval ICV (4) and below the base of the upper ICV (2), positioning the water-soluble spheres (8) at the lower part of the string, together mixing viscous gel and solid material (7), and positioning the oil-soluble spheres (6) on upper part of the string; [0025] c) Opening the upper ICV (2) and injecting the chemical treatment in the upper interval of the reservoir; [0026] d) After completing the chemical treatment in the upper interval, opening the lower ICV (4) for cleaning and thus the lower interval must produce the material that is positioned inside the string, between the two intelligent completion valves; [0027] e) Returning to the normal production condition of the well.

[0028] With the pressure drop generated by mixing oil-soluble sealing spheres (6), viscous gel and solid material (7), and water-soluble sealing spheres (8), to promote permeability reduction, the upper ICV (2) is open and the chemical treatment is injected in the upper interval.

[0029] Due to the flow passage in the plug (5) at the end of the production string (1) and through the ICV valve of the lower interval (4), the pressure drop generated by the mixture is sufficient to carry out the divergence, with the injection of treatment into the upper ICV (2).

[0030] The objective is to temporarily plug the production string (1) in the interval between the top of the plug (5) and the base of the ICV (2), so that the chemical treatment flow can be directed to the upper interval of the well. After the treatment of the upper interval is concluded, it is opened for cleaning and thus the lower interval must produce the material that is positioned inside the string between the two intelligent completion valves (2, 4). As a result, the well returns to normal production condition.

[0031] The viscous gel is mixed with the solid material in different granulometries (example: coarse, medium and fine calcite) (7), together with the oil-soluble spheres (6) and the water-soluble spheres (8), in such a way that it can be pumped and moved to the point of interest within the production string (1), in order to generate the desired blockage between the intelligent completion valves (2, 4) or plugs (5) at the end of the string (1) with loss of tightness.

[0032] The viscous gel is cross-linked, additivated by enzymatic or peroxide breaker, to generate the divergence within the production string and direct the chemical treatment to the desired interval. These types of gels are usually made up of different polymers, such as HPG and or cellosize.

[0033] Both breakers are timed. The difference is that the enzymatic breaker is normally used in the cake of horizontal injection wells to dissolve the cake at the end of completion, thus avoiding damage to the injectivity. The peroxide type is used for gels that are injected into the reservoir, in operations that involve loss of circulation or stimulation within the reservoir. However, the peroxide after a while breaks the strength of the gel and reduces its viscosity. Thus, there is no damage to the formation due to some residual gel, because when the well is produced, the gel comes out with the same.

[0034] At the end of the operation, the method of dissolution/dispersion of the material deposited in the production string can occur as follows: in the case of cross-linked viscous gel, the peroxide or enzymatic breaker itself can be used, which will act after a determined time breaking the gel, which, from then on, starts to act like a fluid. In the case of soluble sealing spheres, the production of oil from the well itself will dissolve them. However, if necessary, an appropriate organic solvent can be used to dissolve the spheres. In the case of the solid material, an acid can be used for removal.

[0035] Since the pumping of the remote operation is carried out by means of a stimulation vessel, it is necessary to carry out an operation planning, including a risk assessment, considering the circuit passage diameters from the topside to the service and production lines in relation to the diameters of the materials that are used. The risk assessment must consider that the pumping sequence must be planned in order to avoid risks as to the displacement of materials.

[0036] It should be noted that, although the present invention has been described in relation to the attached drawings, it may undergo modifications and adaptations by technicians skilled on the subject, depending on the specific situation, but provided that it is within the inventive scope defined herein.