System for developing high pressure shale or tight rock formations using a profusion of open hole sinusoidal laterals

Abstract

A wellbore system to produce natural gas and/or oil from high pressure shale or tight rock formations using a profusion of open hole sinusoidal laterals to achieve comparable contact surface areas with multi-stage hydraulically fractured wellbores. The laterals are drilled in an orientation designed to intersect the dominant natural fracture system and are also drilled in a sinusoidal pattern to interconnect the individual rock facies within the targeted subterranean zone. The sequence of lateral drilling is toe to heel, with the open hole kickoff in the downward direction to facilitate easy re-entry upon drill string tripping. By drilling enough laterals to achieve comparable contact surface area with hydraulically fractured wells, the subject invention allows for comparable quantities of natural gas and/or oil to be produced from high pressure shale or tight rock formations at significantly lower capital cost.

What is claimed is: 
     
         1 . A wellbore system for surface production of natural gas and/or oil from a subterranean zone, comprising:
 a) a cased wellbore that begins on the surface and lands in the subterranean zone, and then continues to transverse the zone with a main wellbore;   b) a profusion of sinusoidal laterals drilled off the main wellbore that provide a total contact surface area, between rock and wellbore, comparable to multi-stage hydraulically fractured well systems;   c) production of commercial quantities of natural gas and/or oil comparable to hydraulically fractured well systems;   d) cost of construction lower than comparable hydraulically fractured well systems; and   e) wherein the subterranean zone comprises shale and/or tight rock beds with natural gas and/or oil present.   
     
     
         2 . The wellbore system of  claim 1 , wherein the main wellbore is an open hole wellbore, with no casing or liner, through the subterranean zone. 
     
     
         3 . The wellbore system of  claim 1 , wherein the laterals are open hole wellbores drilled off the main wellbore, each in the direction of a targeted volume of rock within the overall subterranean zone. 
     
     
         4 . The wellbore system of  claim 3 , wherein the laterals are spaced from 50′ to 500′ apart, with the potential of 200 laterals drilled along a 9000′ main wellbore. 
     
     
         5 . The wellbore system of  claim 3 , wherein each lateral is of 500′ to 2000′ in length. 
     
     
         6 . The wellbore system of  claim 3 , wherein the laterals are drilled in succession from toe to heel along the main wellbore. 
     
     
         7 . The wellbore system of  claim 3 , wherein each lateral is kicked off in a downward direction to enable easy access to the lateral in subsequent trips and re-entries. 
     
     
         8 . The wellbore system of  claim 3 , wherein the laterals are drilled with a non-damaging mud system to minimize the reduced permeability observed with water based drilling and fracturing systems. 
     
     
         9 . The wellbore system of  claim 3 , wherein once each lateral is drilled to total depth, then the drilling mud is circulated out with weighted completion fluid before proceeding to next lateral drilling operation. 
     
     
         10 . The wellbore system of  claim 1 , wherein each lateral is drilled in a sinusoidal path to optimize its contact surface area in the vertical dimension within the overall subterranean zone. 
     
     
         11 . The wellbore system of  claim 10 , wherein the degree of sinusoidal drilling is dictated by the level of vertical interlayer communication as determined by whole core analysis and other methods. 
     
     
         12 . A wellbore system of  claim 1 , wherein the laterals are drilled in an orientation to intersect the dominant nature fractures in the targeted subterranean zone. 
     
     
         13 . A wellbore system of  claim 12 , wherein the direction of the dominant fracture system is determined by wellbore petrophysical techniques and other methods. 
     
     
         14 . A wellbore system of  claim 1 , wherein the original reservoir pressure is high (at or above hydrostatic pressure).