System and methods for determining the effect of fracture interference on shale well performance

A method for building a horizontal fracture field having low cluster interference, comprising:

• determining reservoir properties of a shale layer of a geological formation of interest;
• calculating, by a computing device including electrical circuitry, a memory storing program instructions and at least one processor configured to execute the program instructions, an actual fracture surface area (ACa) of the horizontal fracture field;
• exporting, by the computing device, production data from a predetermined stimulated fracture surface area;
• conducting, by the computing device, a rate transient analysis (RTA) of the production data to estimate an effective fracture surface area (ACe) for a given number of periodic perforations in a horizontal fracturing pipe;
• calculating, by the computing device, a ratio of the effective fracture surface area (ACe) to the actual fracture surface area (ACa);
• storing, in the memory of the computing device, the ratio of the effective fracture surface area to the actual fracture surface area for the first number of periodic perforations;
• iterating, by the computing device, the calculation of the ratio for a second number of periodic perforations, wherein the second number is greater than the first number by a step amount;
• continuing, by the computing device, to iterate the calculation of the ratio by adding the step amount to each previous number of periodic perforations until the production is less than or equal to a threshold amount;
• building, by the computing device, a proxy model to estimate a percentage of interference PI between the fractures as a function of spacing distance between the number of perforations and the formation properties;
• determining, by the computing device, a net present value (NPV) from the proxy model;
• estimating, by the computing device, the number of perforations which maximizes the NPV from the proxy model while minimizing the percentage of interference PI from the RTA;
• installing perforated sections and unperforated sections of the horizontal fracturing pipe in the horizontal fracture field based on the estimated number of perforations;
• and
• stimulating the horizontal fracture field by injecting a fracturing fluid under pressure into the horizontal fracturing pipe through the number of perforations.

A method for hydraulic fracturing in a shale layer of a geological formation, comprising:

• installing a tubing in a borehole which extends between a surface of the geological formation and the shale layer;
• installing a horizontal fracturing pipe which extends perpendicularly from the borehole into the shale layer, wherein the horizontal fracturing pipe has a number of stages, each stage having at least one perforation, wherein the at least one perforation of a first stage is separated by a spacing distance from at least one perforation of a neighboring stage, wherein each spacing distance corresponds with a fracture zone in the shale layer;
• installing the tubing in the horizontal fracturing pipe;
• installing a pump at the surface of the geological formation, wherein the pump is configured to inject a fracturing fluid under pressure into the tubing, wherein the pressure of the fracturing fluid is configured to inject the fracturing fluid through the perforations and stimulate fractures in the shale layer;
• installing a pressure sensor at the surface of the geological formation, wherein the pressure sensor is configured to measure the pressure of the fracturing fluid;
• installing a fluid meter at the surface of the geological formation, wherein the fluid meter is configured to measure a volume of the fracturing fluid injected into the horizontal fracturing pipe or a volume of a material forced out of the borehole by the fracturing fluid, wherein the material is one or more of oil and natural gas;
• connecting a computing device to the pump, the pressure sensor and the water meter, wherein the computing device includes electrical circuitry, a memory storing program instructions and at least one processor configured to execute the program instructions to estimate a percentage of interference PI between fracture zones of neighboring stages, according to the formula:
• PI
• =
• 100
• *
• (
• 1
• -
• A
• C
• ⁢
• e
• A
• C
• ⁢
• a
• )
• ,
• where ACe represents an effective fracture surface area of the horizontal fracture field and ACa represents an actual fracture surface area of the horizontal fracture field;
• determining a net present value NPV for each spacing distance;
• and
• determining the spacing distance which minimizes the percentage of interference PI while maximizing the net present value NPV.