Acquisition and Analysis of Data for Optimized Drilling
Authors: Lummus J.L. 
Published: December 2007

Optimized drilling means we must first keep up with what's going on down there - and continuously - and then convert our findings - persistently and - so that every next foot is drilled at the lowest possible cost. Tensed-up you might call it.

Introduction

Interest in drilling optimization has increased during the past year because of several factors. Balanced drilling programs are now being prepared and implemented that, because of better control information, are providing results very close to those predicted by the program. This has increased our confidence in the value of these programs. In addition, the introduction of new bits and an understanding of the effect of the mud environment on the interaction of the bits with the formations have led to improved implementation of optimized drilling (Op Drilling) programs. The general concept of drilling optimization was disused in detail in a previous paper" that emphasized that only a limited number of drilling variables can be handled mathematically or can be assigned values for modeling purposes, and that these selected variables interact to complicate, from a mathematical standpoint, the handling of them. A later paper discussed the important aspects of planning and implementing optimized drilling programs. planning and implementing optimized drilling programs. The over-all approach described in that paper, including the important meetings both before and after drilling, is continuing to prove effective in achieving a better understanding of optimized drilling techniques at the rig level. The objective of this article is to discuss the acquisition and analysis of data needed to plan, maintain, and appraise the drilling of a particular well. The relative efficiency of various techniques for transmitting data from a field location will be described. The equipment available for monitoring drilling data at the rig site, which is an important aspect of data acquisition, was extensively described in a recent article, and therefore will not be covered here. The data required for optimized drilling are classified as follows:

1. Data needed for computer input to calculateoptimum values for the controllable drilling conditions.

2. Data needed on a day-by-day basis to determinehow efficiently drilling optimization is beingapplied and to provide the basis for suggestedchanges in mud, hydraulics, bits, etc.

3. Data needed to evaluate the effectiveness of anOp Drilling program for a particular well andto develop definite recommendations for improvingdrilling efficiency on future wells.

The important aspects of these three categories of data will be explained, and the paper will conclude with a discussion of present trends in drilling optimization and some predictions of future trends.

Input Variables for Preparing Optimized Drilling Programs

The first step in preparing an Op Drilling program is to organize the data needed for programming into the computer. Various drilling models are then used to analyze information from control wells and to specify limits on the principal variables considered. Fig. 1 shows the drilling data needed for preparing an Op Drilling program.

JPT

P. 1285