Field Study Results Improve Squeeze Cementing Success

Abstract

Abstract Correlations and practices that improve squeeze-cementing success in a wide range of applications were developed from a series of field studies conducted between 1992 and 2000. The first study began with analysis of a database of 137 squeeze operations. Statistical analysis of data for successful first-attempt squeeze operations from this database identified practices and correlations that significantly improved the success rate for squeeze-cementing operations. The correlations developed from this initial data were applied in other operating areas and refined over time. Prejob injection test data can be used to select basic cement type, recommended cement volume, and cement fluid loss based upon correlations developed from these studies. Guidelines for placement procedures and pumping techniques were developed from successful field operations. While these practices have significantly improved success in a wide range of applications and geographical areas, squeeze cementing continues to defy standardization. The success of most squeeze-cementing operations is directly related to the skill and experience of those designing and executing the operation. These practices are presented as a reference point for engineering and operations staff for design and execution of squeeze-cementing operations. For those skilled in squeeze cementing, this information may be confirmed by others' experience and knowledge to improve success and increase understanding of squeeze cementing. Introduction Squeeze cementing is one of the most challenging areas of cementing. It is a multidisciplinary technology requiring knowledge and skills in grouting, geomechanics, fluid mechanics, material science and, of course, cementing. After decades of field and laboratory studies, squeeze cementing defies standardization as a general practice. The success of most squeeze-cementing operations is directly related to the skill and experience of those designing and executing the operation. This paper reports the findings from a series of field studies conducted to improve squeeze-cementing success. The first study was initiated in an aging west Texas field where many squeeze-cementing operations were performed and the squeeze-cementing success rate was low. The wells in this field averaged 5000 feet in depth and were between 30 and 50 years old. All of the wells in the field were completed in carbonate producing formations. Most wells had been acid stimulated many times over their lifetime. Some wells had been water flooded, CO2 flooded or both, and there was some type of casing damage in many wells. Despite this challenging starting point, a very good set of squeeze-cementing operations data was collected for analysis. Data analysis from this first field study produced several practical correlations that significantly improved the success rate for squeeze cementing in the west Texas field. Results from the west Texas study generated interest to do field studies in other operating areas and to evaluate the broad applicability of the correlations developed from the initial data set. The entire series of studies ran over a period of eight years beginning in 1992 and ending in 2000. The correlations and recommended practices developed from the initial west Texas data set were applied in many areas of the continental United States, in offshore operating areas of the Gulf of Mexico, and in the Sultanate of Oman. These practices and correlations improved the success rate for squeeze cementing in each of the areas where they were applied. Additional findings and refinements were made as more experience was gained. A general strategy or framework for the design and execution of squeeze-cementing operations was developed from these studies for use by engineering and operations staff. Initial Field Study Records from workover operations were collected between 1992 and 1994 for wells in a west Texas field as part of a study to determine the low success rate for squeeze-cementing operations. Data from service company treating reports and workover operations morning reports were collected and put into an electronic database. Additional data fields were added to service company treating reports and rig morning reports to gather all information essential for detailed analysis. An engineer or other knowledgeable person in workover and remedial cementing operations extracted the information and entered it into the database.