Diagnosis of Excessive Water Production in Greater Diffra Oil Fields-Sudan

Abstract

The Excessive Water Production refer to the water production mechanism , and an effective strategy can be formulated to control water production. The thesis introduces the objective of the this study and Greater Diffra oil field overview. Also the thesis presents theories of high Water production from hydrocarbon reservoirs (High water Cut), and the challenges of the excessive water production problem. General techniques have been introduced to analyze the excessive water production problem and their compatibility to Greater Diffra oil field and their status in term of international application. The technical evaluation of applicable technique had conducted in order to analyze Greater Diffra problem in particular. To find out the reliable results for the diagnosis; production data have been used with other supporting data to analyze and diagnose the type of water problem by using Oil Production Manager (OFM) software. The results of the analysis were presented. The results showed that The excessive water problem can be diagnosed the general type of diagnostic for each individual sub field including the reasons of normal displacement with high water cut due to (oil saturation is less than 60%, High permeability, contact with closing contour, Edge water drive and washout below and above the perforated zone) and multilayer channeling due to (production behavior change from natural to artificial-lift (ESP pump), channeling behind casing due to bad cement bond with formation- leak of bridge block and Edge water drive and water contact movement). This chapter also introduced the recommendations of the problem solution. The recommendations consists of not using ESP pump in the wells producing natural or producing over economic limit to achieve good reservoir management. The second recommended solution is to consider re-modeling and make some seniors (new interval zones – horizontal wells) to decrease the excessive water problem. The third recommendation is to revisit the well integrity in order to solve the channeling problems at (Hamam and Diffra area ) and run the IOR screening study to choose the suitable way to eliminate the problem severity. The final recommended initiative is that Bentiu formation in some wells producing with Bottom water drive mechanism and diagnostic problem type is water contact movement , so the proper way to shut-off the water by isolating lower Bentiu formation.