Abstract

In an effort to increase the effectiveness of fracture treatments much work has been done and reported on fracture simulation. The literature indicates that in the last few years a substantial amount of material has been written on fracturing models. The papers, with few exceptions, have dealt entirely with the theoretical aspects of fracture modelling. Very little material exists on fracture execution, it's problems, or how the numerous variables involved in job execution can doom a job.

This paper stresses the fact that to improve fracture effectiveness as much time must be spent on fracture execution planning as is spent on fracture design. The paper delves into fracture execution in an attempt to bring forward the host of variables involved in the pumping of a fracture treatment. Methods for optimizing these variables, as well as new techniques and field procedures, are suggested as ways to improve fracture execution.

The understanding and optimization of the variables involved in fracture execution will improve the effectiveness of fracture treatments, as well as producing better and more realistic fracture designs. In this manner, the gap between design and actual results will be narrowed.

Introduction

Fracture design and fracture simulation have received a lot of attention in the last few years as methods by which one can improve the effectiveness of fracture treatments. In reviewing the literature about fracturing it is apparent that very little material exists on the subject of fracture execution.

The industry has responded to this increased interest in fracture design by requiring that service companies provide access to fracture simulators, as well as providing computer vans in the field, to enable design of better fracturing treatments.

Although more sophisticated tools are available for the design of fracturing jobs, very little attention is given to the mechanics of pumping fracture treatments. For too long the industry has assumed that the job was executed as it had been designed and programmed. Unfortunately, this perception is not entirely correct.

The fallacy of computer design is that it assumes a level of control over fracture execution variables that rarely exist in the field. Although much is said about the level of high technology fracturing in this country, this relates primarily to fracture design. It is contended that a better understanding and optimization of the variables involved in fracture execution will improve the fracture treatments, as well as producing improved and more realistic fracture designs.

Relationship Between Fracture Design and Execution

In the current fracture design process fracture simulators have become an important part of most fracture designs. These simulators are routinely made up of two parts, a fracture simulator and a reservoir simulator. Figure #1 indicates the type of information used in both simulators, as well as indicating the relationship that exists between fracture execution variables and fracture design. The reliability of these simulators and fracture design depends largely on the quality of input data and the ability to match the values of the parameters input in the fracture design.

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