HORIZONTAL WELL PRODUCTION METHOD WITH UNIFORM FLOW

Abstract

The invention addresses to a flow uniformization process for the entire useful life of a horizontal well, which associates the use of divergent sand containment screens or divergent liner. For the manufacture of divergent liners, flow simulations are carried out via computational fluid dynamics as a function of the dimensions of the horizontal well, outer diameter and length of the liner, static pressure, expected flow pressure, expected oil flow rate, oil viscosity, API degree, planned length for the horizontal well. These simulations simulate the area open to flow along the horizontal section. Additionally, well stimulation methods, scale removers and, optionally, sand containment are used.

Claims

1. A HORIZONTAL WELL PRODUCTION METHOD WITH UNIFORM FLOW, characterized in that there is: a) designing the production string as a function of the length and diameter of the horizontal well; b) sizing the perforation distribution of the horizontal well production string according to the production string design; c) optimizing the perforation distribution in the production string with a computational fluid dynamics (CFD) simulator; d) using holes of uniform dimensions; e) installing the production string of the horizontal open well permanently; f) using a stimulation method; g) using scale removers.

2. THE HORIZONTAL WELL PRODUCTION METHOD WITH UNIFORM FLOW according to claim 1, characterized in that the computational fluid dynamics simulator uses the horizontal well design flow rate, the gas/oil ratio, reservoir pressure, flow pressure (PWF), viscosity and API grade.

3. THE HORIZONTAL WELL PRODUCTION METHOD WITH UNIFORM FLOW according to claim 1, characterized in that all holes have the same diameter.

4. THE HORIZONTAL WELL PRODUCTION METHOD WITH UNIFORM FLOW according to claim 3, characterized in that the hole diameter has a value of 1 to 3 cm.

5. THE HORIZONTAL WELL PRODUCTION METHOD WITH UNIFORM FLOW according to claim 1, characterized in that the spacing and number of holes along the production string of the horizontal well are determined by computational fluid dynamics simulation.

6. THE HORIZONTAL WELL PRODUCTION METHOD WITH UNIFORM FLOW according to claim 1, characterized in that it is applied in sandstone, carbonate and clastic sedimentary rock type reservoirs.

7. THE HORIZONTAL WELL PRODUCTION METHOD WITH UNIFORM FLOW according to claim 1, characterized in that it uses the following stimulation methods: hydraulic fracturing, acidification and solvent injection.

8. THE HORIZONTAL WELL PRODUCTION METHOD WITH UNIFORM FLOW according 1, characterized in that it uses DTPA (ethylenetriaminepentaacetic acid) or EDTA (ethylenediaminetetraacetic acid) as scale removers.

9. THE HORIZONTAL WELL PRODUCTION METHOD WITH UNIFORM FLOW according to claim 1, characterized in that it optionally employs sand containment.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The present invention will be described in more detail below, with reference to the attached figures which, in a schematic way and not limiting the inventive scope, represent examples of its embodiment. In the drawings, there are:

[0023] FIG. 1 illustrates the scheme of the conventional gravel pack screen;

[0024] FIG. 2 illustrates the current flow distribution scheme along the horizontal length of the well;

[0025] FIG. 3 illustrates the flow distribution scheme along the horizontal extension, with flow equalization;

[0026] FIG. 4 illustrates the scheme of the divergent screen innovation proposal;

[0027] FIG. 5 illustrates well production with and without flow uniformization technology. Curve 1 represents wells without the implemented technology and curve 2 represents wells with the implemented technology.

DETAILED DESCRIPTION OF THE INVENTION

[0028] There follows below a detailed description of a preferred embodiment of the present invention, by way of example and in no way limiting. Nevertheless, it will be clear to a technician skilled on the subject, upon reading this description, possible additional embodiments of the present invention still comprised by the essential and optional features below.

[0029] The horizontal well production method with uniform flow is described and characterized by: [0030] a) designing the production string as a function of the length and diameter of the horizontal well; [0031] b) sizing the perforation distribution of the horizontal well production string according to the production string design; [0032] c) optimizing the perforation distribution in the production string with a computational fluid dynamics (CFD) simulator; [0033] d) using holes of uniform dimensions; [0034] e) installing the production string of the horizontal open well permanently; [0035] f) using a stimulation method; [0036] g) using scale removers.

[0037] The stimulation methods can be the hydraulic fracturing, acidification and solvent injection. In addition, scale removers such as DTPA (ethylenetriaminepentaacetic acid) or EDTA (ethylenediaminetetraacetic acid) can be used. Sand containment is optional. The invention can be applied in sandstone, carbonate and clastic sedimentary rock (shale) type reservoirs. The computational fluid dynamics simulator uses the horizontal well design flow rate, gas/oil ratio, reservoir pressure, flow pressure (PWF), viscosity, and API grade. The invention is also characterized by all holes having the same diameter, and the hole diameter must have values from 1 to 3 cm. The spacing and number of holes along the production string of the horizontal well are determined by computational fluid dynamics simulation.

[0038] The conventional gravel pack screens that are currently used, as shown in FIG. 1, have the disadvantage of passing the preferential flow in the initial section of the horizontal extension of the well; this flow generates problems in the reservoir recovery factor because it allows the early formation of water cone and gas cone and because it does not guarantee a uniform reservoir production profile. Another disadvantage occurs in the longevity of the equipment, with the accelerated erosion of the screens and the possibility of early clogging of the screens.

[0039] The solution achieved by the invention to avoid the formation of early gas and/or water cones during the production of wells with long horizontal extension was the use of a process with the use of completion equipment. They are designed to perform flow uniformization along the horizontal extension of the wells to reduce gas and/or water production in the wells. This solution meets the need of reducing gas production for producing wells and increasing sweep efficiency for injection wells, through a flow uniformization process in the production of horizontal wells and/or vertical or directional wells with large extensions of net pays between producing intervals. In the case of horizontal producing and injection wells, these normally produce or inject with greater flow rate in the section closest to the beginning of the horizontal extension of the well, usually the shoe of the last casing.

[0040] In this invention, a divergent screen is proposed for horizontal producing and injection wells, equipped with mechanical containment of sand. The equalization of the production or injection flow, distributed along the entire horizontal extension of the well, is the great observed advantage. This equalization will be achieved through the conjunction of two factors in the design; firstly, the distribution of the number of holes in the base tube per screen, and secondly the positioning of these screens along the horizontal section of the well. As seen in FIG. 3, where the dashed arrow indicates the bottomhole pressure and the solid arrows indicate the reservoir pressure.

[0041] FIG. 4 illustrates the proposal presented herein for the divergent screen, where it demonstrates the combination of the four types of screens (T1, T2, T3, and T4) . It is possible to see the sequence between the last casing shoe (5) and the bottom of the well (6).

[0042] There are advantages in case acidic treatments are needed to improve the productivity index of horizontal producing wells or to improve the injectivity index of horizontal injection wells. The divergent screens also have the advantage of allowing the treatment to be programmed using acidification tools equipped with a mechanical divergence mechanism, which is essential to achieve an efficient result. Thus, the divergent screens offer the advantage of being able to maintain the horizontal producing and injecting wells, contributing to the longevity of the designs.

[0043] The invention brings the advantage of equipment longevity, where it prevents the erosion of the screens and prevents the obstruction of the screens by produced particles. The invention also has the advantage of maximizing the reservoir recovery factor, where it decreases the possibility of water cone formation, decreases the possibility of gas cone formation, guarantees a flow in a uniform reservoir production profile and reduces the design development costs.

[0044] In horizontal injection wells, the advantage will be the better distribution of the sweep during the injection to pressurize the reservoir, which will also contribute to a maximization of the recoverable reserve, thus contributing to the longevity of the design.

[0045] The result obtained by the invention, at first, was measured using a PETROBRAS proprietary simulator; this simulator calculates the pressure drop distribution along the horizontal extension of the well. It is worth noting that other CFD type simulators can be used as well. The initial proposal of this simulator was to design a divergent screen, which provides flow equalization along the horizontal extension of the well. The idea is to design the divergent screen or divergent liner so that the number of holes designed per base tube of each screen and the sequence of positioning the screens along the sand containment system form an arrangement that provides a decreasing pressure drop from the beginning of the horizontal extension of the well to the bottom, practically inversely proportional to the flow rate per open area to the flow along the length of the production string (screens or liner). This pressure drop will be positioned directly proportional to the production flow, considering the static pressure of the reservoir as well as the flow pressure, in such a way that the contribution of each section of the set of screens of the gravel pack or divergent liner is equal along the horizontal extension. For example, at the beginning of the well, the pressure drop will be higher and at the end it will be lower. This divergent arrangement will allow flow equalization, thus optimizing production or injection along the horizontal length of the well.

[0046] Flow simulations are used to plan the manufacture of divergent liners based on information on the dimensions of the horizontal well, information such as the outer diameter of the liner and length, static pressure, expected flow pressure, expected oil flow rate, viscosity of oil, API grade, planned length of the horizontal well will be used to simulate the area open to flow along the horizontal section.

[0047] The invention of the flow uniformization process, which associates the use of divergent sand containment screens or divergent liner provides better production management and, therefore, better reservoir management.

EXAMPLE

[0048] As an example, we have the application of this technology in oil fields of the Amazon Basin, obtaining economicity in the development of the production in these fields through the application of this technology, as shown in FIG. 5, which illustrates the application of the technology, where curve 1 (without technology of flow uniformization) shows the lower oil production in relation to curve 2, where flow uniformization technology was used with divergent perforation and throughout the life of the well with higher oil production. In this way, the invention has technical advantages due to the adequacy of the technology to the applied scenario, as well as economic advantages due to the associated cost reduction.