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.

Description

TECHNICAL FIELD OF THE INVENTION[0001]The present invention relates generally to the recovery of subterranean resources, and more particularly to a method and system for enabling commercial production of high pressure natural gas, condensate or oil from tight subterranean zones without the use of hydraulic fracturing.BACKGROUND OF THE INVENTION[0002]Subterranean deposits of shale or tight rock that contain high pressure natural gas or oil usually require hydraulic fracturing to create sufficient ‘contact surface area’ and flow paths to enable production of commercial quantities of hydrocarbons. While the hydraulic fracturing method of completing wells in high pressure shale or tight rock formations is commonplace in many subterranean deposits, it is very capital intensive and requires copious amounts of water and proppant.[0003]The ‘contact surface area’ of hydraulically fractured wells is calculated by multiplying the ‘frac height’ by ‘frac length’ by ‘number of frac stages’ comple...

AI Technical Summary

Benefits of technology

[0011]In addition, the cost to drill 100 short laterals would be approximately $2 million, assuming one rig-day per lateral, whereas the 30 stage hydraulic fracturing would cost approximately $5 million. Thus, the present invention provides a method and system to produce comparable quantities of natural gas and oil to the hydraulically fractured well, but at a significantly lower capital cost.

[0012]Another technical advantage of the present invention includes the option to drill and complete the well with non-water based drilling and completions fluids. This eliminates the ‘reduced relative permeability’ effect water has on the rock matrix, thus maximizing the rock's capacity to flow gas and/or oil. Two examples of non-water based drilling fluids include oil-based drilling mud and foam drilling systems. The secondary technical advantage of not using water in the drilling and/or completion of the well is that the well will not produce as much water over the life of the well, which reduces the size and complexity of the surface facilities.

[0013]Another technical advantage of the present invention is to eliminate the ‘reduced conduit flow capacity’ effect of fracture cl...

Problems solved by technology

While the hydraulic fracturing method of completing wells in high pressure shale or tight rock formations is commonplace in many subterranean deposits, it is very capital intensive and requires copious amounts of water and proppant.

The effective wellbore height is somewhat difficult to measure precisely because it needs to account for near wellbore effects, including drilling stress fractures.

The main problem in producing natural gas and/or oil from shale and tight rock is the extremely low permeability of the rock, which, until now, required hydraulic fracturing to create sufficient contact surface area for the hydrocarbons to flow from the surrounding rock into the wellbore where it flows, or is pumped, up to the surface facilities.

Without hydraulic fracturing the contact surface area between the rock and the wellbore is insufficient to flow commercial quantities of hydrocarbons.

Even very long horizontal wells, drilled within the shale or rock beds themselves, have insufficient contact surface area without the additional step of hydraulic fracturing.

However, after stimulating the well with 30 separate hydraulic fracture stages along this 9000′ long wellbore the well will produce approximately 500 barrels of oil per day over the first year.

Another problem in hydraulically fracturing shale or tight rock is that the water needed to fracture the rock causes a ‘reduced relative permeability’ effect in the...

Images