Abstract
There are two major challenges in achieving perfect and durable inter/intra zonal isolation; accurate planning of cementing operations according to well specific requirement and realistic evaluation of operational performance for attainment of the objective. Prevailing practice for evaluating cementing performance, in the industries is not authentic enough to justify remedial operations planned. It just based on readings of graph while other critical aspect such as phenomenal formational response, influence of other processes which are being performed / to be performed prior to or post cementing operations like hermetical testing of casing, various activation/stimulation processes which could affect the quality of evaluation/performance are overlooked.
The objective of study is to address all the relevant aspects while interpreting the logs and develop a methodology for making precise and realistic evaluation of logs for avoiding many futile operations which ultimately affects the productivity and life of the wells.
The procedure adopted for formulation is as under Compilation / analysis of log data field wise Compilation / analysis of production trend with reference to cementing performance.
Mathematical model exhibiting impact of stresses produced during pressure testing at various stages of cementing through well completion process and its influence over logs and cement bond integrity.
Influence of formational image on sonic log graph.
Organization of all logical and mathematical data to design and develop realistic-precise methodology.
This paper provides (i) an innovative approach to the prevailing practice (ii) helps to develop a methodology which may utilize all those data presently ignored (iii) to devise a precise diagnostic tool in the form of software to reduce human error, this is under conceptual stage.
This methodology may limit its application to the development field as exploratory wells may not have sufficient quantum of data for uploading in the software for analysis.
