Abo Taleb T. Al-Hameedi

Practical Strategies and Engineered Solutions to Minimize the Impact of Lost Circulation Problem

Lost circulation is a complicated problem to be banned or combatted during the drilling operations. Mud losses remedies are extensively used to stop or mitigate losses using remedial methods or to prevent mud losses using proactive measures. Lost circulation presents a lot of big challenges during drilling. To address these problems, a number of methods/techniques have evolved over the years. The Rumaila field in Iraq is one of the largest oilfields in the world. Wells drilled in this field are highly susceptible to lost circulation problems when drilling through the Hartha formation. Lost circulation events range from seepage losses to complete loss of the borehole and are a critical issue in field development. This paper describes a study of the lost circulation events for more than 300 wells drilled in the Rumaila field. Lost circulation events were extracted from daily drilling reports, final drilling reports, and technical reports. Key drilling parameters (e.g. ROP, SPM, RPM, WOB, bit type) and mud properties (e.g. mud weight, yield point, gel strength) at the time of each event were recorded along with the lost circulation remedies attempted, and the outcome of those remedies. These data have been analyzed to determine the best ranges of the key drilling parameters that have the greatest chance of mitigating lost circulation in the Hartha formation. nPractical field information from the Rumaila field and range of sources have been reviewed and summarized to develop an integrated methodology and flowchart for handling lost circulation events in this formation. In a related development, this paper will be extended work along with previous comprehensive statistical study and sensitivity analysis models about the Hartha formation to obtain the best field procedures for avoiding or minimizing lost circulation events in the Hartha formation. Proactive approaches have been made prior entering the Hartha formation to prevent or mitigate the occurrence of lost circulation. A unique statistical work, primitive mechanisms, typical drilling fluid properties and recommended operational drilling parameters have been evaluated to use during drilling the Hartha formation. In addition, corrective actions have been determined for each kind of the mud losses to provide effective remedies, minimize non-productive time, and reduce cost. nLost circulation strategy to the Hartha formation has been summarized depending on statistical work and economic analysis evaluation to determine the most successful remedies for each type of the losses. These treatments are classified by relying on the mud losses classifications in order to avoid unwanted consequences due to inappropriate actions. This study provides a typical compilation of information regarding traditional approaches and the latest approaches to lost circulation control. In addition, the work attempts to provide useful guidelines or references for both situations in terms preventive measures, remedial methods, and analytical economic study.

Volume loss modeling for lost circulation, Hartha formation, South Rumalia Field, Iraq

A all hydrocarbons wellbores experience multiphase flow in the form of varied combinations of gas oil and/or water fractions. The prediction of multiphase flow characteristics such as the pressure drop and phase fractions is an important requirement in the prediction of the tubing performance relationship (TPR) in these wellbores. Numerous multiphase flow models/correlations exist for these predictions but present limitations in their applicability for varied flow conditions, fluid properties and well configurations. In order to extend a range of applicability, this paper presents a new correlation derived from approximation of seven (7) flow correlations using regression analysis. A dimensionless two phase pressure gradient, flowrate and phase fraction relationships were established which is expected to present a good prediction of flow characteristics in varied flow conditions especially for bubble and slug flow regimes. The performance of this correlation was validated with field data derived from literature and compared with the existing correlations used for the approximation. The pressure gradient prediction and phase fraction Results from the comparative analysis showed an adequate +/-0.05% 2% deviation from the experimental data.

Limiting Key Drilling Parameters to Avoid or Mitigate Mud Losses in the Hartha Formation, Rumaila Field, Iraq

Wells drilled in Rumaila field are highly susceptible to lost circulation problems when drilling through the Hartha formation. This paper presents an extended statistical work and sensitivity analysis models of lost circulation events in more than 100 wells drilled in Rumaila field. Lost circulation data are extracted from daily drilling reports, final reports, and technical reports. The volume loss model is conducted to predict the mud losses in the Hartha formation. Observations that are made from the volume loss model are ECD, MW, and Yp have a significant impact on lost circulation respectively; however, SPM, RPM, and ROP have a minor effect on the mud losses. Equivalent circulation density model is obtained to estimate ECD in the Hartha zone, and from this model can be deduced that MW, ROP, and Q have a significant impact on ECD respectively; nevertheless, RPM and Yp have a minor impact on the ECD. The rate of penetration model is made to estimate ROP in the Hatha zone. It is concluded that WOB, RPM, and SPM have a significant impact on the ROP respectively. Due to the lack of published studies for the Hartha formation, this work can serve as a practical resource for drilling through this formation.