METHOD FOR DRILLING AND FRACTURE TREATING MULTIPLE WELLBORES
A method includes completing multiple wellbores in a subsurface formation. The method includes a first wellbore having been drilled along a first selected trajectory through the subsurface formation. The first wellbore is fracture treated. A second wellbore is drilled along a second selected trajectory through the subsurface formation. The second trajectory is laterally spaced from the first trajectory. The second wellbore is fracture treated. A third wellbore is drilled along a third selected trajectory through the subsurface formation. The third trajectory is disposed between the first and second trajectories. The third wellbore is fractured treated such that a fracture network extending therefrom hydraulically connects to fracture networks extending from the first and second wellbores and hydraulically connects the first, second and third wellbores proximate an upper end thereof so that the first, second and third wellbores may all produce fluids.
This disclosure relates generally to the field of drilling and completion of multiple, highly inclined wellbores through subsurface rock formations. More specifically, the invention relates to methods for using a plurality of highly inclined wellbores to create a subsurface fracture network in a low permeability subsurface formation.
Extraction of oil and/or gas from certain subsurface formations requires creating a network of wellbores extending laterally through the formation, that is, in a direction generally along the geologic orientation of the formation. The network of wellbores increases the effective drainage capacity within such formation. For certain low permeability formations, such as gas bearing shales, extending such networks of wellbores has made possible extraction of oil and/or gas from such formations to be commercially profitable.
Hydraulic connection of the three lateral wellbores 1, 2, 3 to the pilot wellbore (vertical wellbore 4 in the illustrated example) may be performed using a “multilateral junction” of types known in the art. Such devices can be expensive to manufacture and install in a multilateral wellbore.
U.S. Pat. No. 8,490,695 issued to Bahorich et al. discloses a method for drilling and fracture treating multiple lateral wellbores in which some of the lateral wellbores are abandoned.
SUMMARYA method according to one aspect includes completing multiple wellbores in a subsurface formation. The method includes a first wellbore having been drilled along a first selected trajectory through the subsurface formation. The first wellbore is fracture treated. A second wellbore is drilled along a second selected trajectory through the subsurface formation. The second trajectory is laterally spaced from the first trajectory. The second wellbore is fracture treated. A third wellbore is drilled along a third selected trajectory through the subsurface formation. The third trajectory is disposed between the first and second trajectories. The third wellbore is fractured treated such that a fracture network extending therefrom hydraulically connects to fracture networks extending from the first and second wellbores and hydraulically connects the first, second and third wellbores proximate an upper end thereof so that the first, second and third wellbores may all produce fluids to the Earth's surface through a common pilot wellbore.
Other aspects and advantages will be apparent from the following description and the appended claims.
In
In the present example, the first lateral wellbore 1 may be fracture treated from a selected depth therein (e.g., close to the total measured depth) to a position very close (within several tens of meters) to the bend 4A from the vertical wellbore 4 to the first lateral wellbore 1. Thus, only a small distance between the fracture treated part of the first lateral wellbore 1 and the vertical wellbore 4 exists.
After plugging the first lateral wellbore 1 a second lateral wellbore 2 is drilled, which may also be drilled into another part of the target formation 10. The second lateral wellbore 2 may also generally follow the geologic structure of the target formation 10, and may laterally displaced from the first lateral wellbore 1 by a selected lateral distance and extend generally parallel to the first lateral wellbore 1. The selected lateral distance between the first wellbore 1 and the second wellbore 2 may be selected such that the fracture network 1A extending from the first wellbore 1 does not connect directly to a fracture network (explained below) that may be created in the second lateral wellbore 2. The second lateral wellbore 2 may be directionally drilled so as to create a second bend 4B in the pilot wellbore 4 if the second lateral wellbore 2 is drilled from the same pilot wellbore 4 or a different pilot wellbore (not shown).
In
In
The third lateral wellbore 3 may be drilled along the target formation 10 in a lateral position between the first and second fracture networks 1A, 2A created previously by fracture treating the first 1 and second 2 lateral wellbores, respectively. The third lateral wellbore 3 may have a bend 4C where the trajectory of the third lateral wellbore 3 is turned from the pilot wellbore 4 trajectory to the lateral trajectory in the target formation 10.
In
Any or all of the first 1, second 2 and third 3 lateral wellbores may be completed in the target formation 10 prior to hydraulic fracture treating by cementing in place therein a pipe such as a casing or liner followed by perforation of the liner or casing within the target formation 10, that is, where each lateral wellbore traverses the target formation 10. The lateral wellbores 1, 2, 3 may also be completed using a slotted pipe or liner, or may be “open hole” completed such as by filling the respective lateral wellbores 1, 2, 3 with gravel or similar material that creates a high permeability fluid conduit. As will be appreciated by those skilled in the art, the completion technique used in any particular lateral wellbore may depend on the mechanical properties of the target formation 10 and the type of fracture treatment used to create the respective fracture networks 1A, 2A, 3A
Depending on the composition and structure of the target formation 10, the first 1 and/or second 2 lateral wellbores may be hydraulically connected to equipment (not shown) at the surface for the purpose of flow back and well cleanup procedures known in the art to be associated with fracture treatment of wellbores. The timing of such flow back and cleanup procedures may be such that the first and second well plugs 5, 5A, respectively, are removed from the first 1 and/or second 2 lateral wellbores to enable such procedures. Alternatively, the first 1 and/or second 2 lateral wellbores may be flowed back and cleaned up prior to setting the plugs, 5, 5A, respectively.
In some examples, any two or all of the three lateral wellbores described above may be drilled from a common or “pilot” vertical wellbore, e.g., pilot wellbore 4 drilled to a selected depth above the target formation 10. Non-limiting example procedures and devices for drilling multiple lateral wellbores from a single pilot wellbore are described in U.S. Pat. No. 5,785,133 issued to Murray et al. and in U.S. Pat. No. 5,735,350 issued to Longbottom et al.
In the present example, and referring to
It will be appreciated by those skilled in the art that the particular order in which the lateral wells are drilled, i.e., the first, second and third lateral wellbores as described above is not required in order for the method to work. The lateral wellbores may be drilled and fracture treated in any order. It is convenient in cases where all the lateral wells are drilled from a common pilot wellbore to perform the method in the order as described above, but it is not required, just as it is not required to drill all the lateral wellbores from the same pilot wellbore. In other embodiments, for example, the first and second lateral wellbores may be pre-existing lateral wellbore that have been completed and fracture treated as explained with reference to
A method for drilling and fracture treating multiple lateral wellbores according to the present disclosure may provide production rates close to those of multiple lateral wellbores known in the art while eliminating the need to provide a multilateral junction between the multiple lateral wellbores and a pilot wellbore.
While the invention has been described with respect to a limited number of embodiments, those skilled in the art, having benefit of this disclosure, will appreciate that other embodiments can be devised which do not depart from the scope of the invention as disclosed herein. Accordingly, the scope of the invention should be limited only by the attached claims.
Claims
1. A method for drilling and completing multiple wellbores in a subsurface formation, comprising:
- fracture treating a third lateral wellbore extending from a bend in a pilot wellbore to a selected length along a third selected trajectory through the subsurface formation, the fracture treating performed such that a fracture network extending from the third lateral wellbore hydraulically connects respective fracture networks extending from a first lateral wellbore and a second lateral wellbore, the fracture network hydraulically connecting the first lateral wellbore, the second lateral wellbore and the third lateral wellbore;
- wherein the first lateral wellbore is drilled along a first selected trajectory through the subsurface formation from the pilot wellbore or a different pilot wellbore, the first lateral wellbore fracture treated to a position proximate a bend from the pilot wellbore or the different pilot wellbore to the first selected trajectory, the first wellbore being plugged;
- wherein the second lateral wellbore is drilled along a second selected trajectory through the subsurface formation from the pilot wellbore or a different pilot wellbore, the second lateral wellbore fracture treated to a position proximate a bend from the pilot wellbore or the different pilot wellbore to the first selected trajectory, the first wellbore being plugged;
- wherein the third wellbore is drilled along the third selected trajectory through the subsurface formation, the third selected trajectory disposed between the first and second trajectories.
2. The method of claim 1 wherein the first, second and third lateral wellbores are drilled from a same pilot wellbore.
3. The method of claim 1 wherein the respective trajectory of each of the first, second and third lateral wellbores substantially follows a bedding plane of the subsurface formation.
4. The method of claim 1 wherein the respective trajectory of each of the first, second and third lateral wellbores is substantially horizontal through the subsurface formation.
5. The method of claim 1 wherein the first and second lateral wellbores being plugged comprise having set a respective plug therein at a wellbore depth above the subsurface formation.
6. The method of claim 1 wherein at least one of the first and second lateral wellbores is flowed back and cleaned up after fracture treatment.
7. The method of claim 6 wherein the flow back and cleanup is performed prior to plugging.
8. The method of claim 6 wherein the flow back and cleanup is performed after plugging.
9. The method of claim 1 wherein at least one of the first lateral wellbore and the second lateral wellbore produces fluid from the subsurface formation prior to the fracture treating the third lateral wellbore.
Type: Application
Filed: Nov 20, 2014
Publication Date: Aug 31, 2017
Inventor: Michael S. Bahorich (Houston, TX)
Application Number: 15/516,674