Mohd Hatta, Siti Aishah (PETRONAS Carigali Sdn Bhd) | Zawawi, Irzee (PETRONAS Carigali Sdn Bhd) | Gupta, Anish (PETRONAS Carigali Sdn Bhd) | Ahmad Nadzri, M. Safwan (PETRONAS Carigali Sdn Bhd) | Salleh, Nurfarah Izwana (PETRONAS Carigali Sdn Bhd) | Jeffry, Suzanna Juyanty M. (PETRONAS Carigali Sdn Bhd) | Sharif, Natasha Md (PETRONAS Carigali Sdn Bhd) | Ishak, Izza Hashimah (PETRONAS Carigali Sdn Bhd) | Maoinser, M. Azuwan (Universiti Teknologi PETRONAS)
Field B is a marginal green field located offshore Sarawak, Malaysia with formation depth of less than 1000 meters. The compressional sonic transit time range is from 100 – 115 μs/ft, which immediately triggered the possibility of using active downhole sand control as this range is assumed to be unconsolidated. However, the rock mechanical strength characterization tests from sidewall core indicated contradictory result of a consolidated formation. Since the field is considered as a small field, the cost of the well especially on downhole sand control device need to be extensively optimized. Hence, sand prediction study for a small green field development using field and laboratory measurements was performed.
Several methodologies of sand prediction were utilized to evaluate the optimum sandface completion and sand control management for the field. Empirical and analytical sand prediction based on the well logs, sidewall cores analysis, and sand prediction software are employed to evaluate the likelihood of sand production and the optimum well completion design for the field development. The available data from appraisal wells of Field B is also calibrated to the nearby brown field, Field A that has been producing for more than 30 years.
This paper will discuss on the sand onset prediction results between full perforation versus oriented perforation, and pressure depletion impact on the sand production. The study shows that the formation is not prone to sand production especially in the early part of the production life with high reservoir pressure and low watercut. The expected Critical Drawdown Pressure (CDP) generated from different methods show large variation of sand onset pressure if the sandface is completed using full perforation. Oriented perforation tremendously expands the sand free drawdown limit. Based on the results of the study, expected reservoir pressure depletion and watercut, the completion of the wells adopted Oriented Perforation with no other downhole sand control equipment.
This paper is beneficial for petroleum and well completion engineers especially on sand prediction part of well completion design in development stage. This will assist in ensuring the field meets the EUR and bring forward economic value as well as well integrity assurance.
Baram field is a mature oil field in Sarawak, Malaysia and it is the largest and most structurally complex field in the Baram Delta Province. The reservoirs are thinly stacked and predominantly friable and unconsolidated requiring active sand control by gravel packing techniques being the most reliable sand control method available. Sand production in Baram wells resulted in several wells being shut-in, low oil production and costly surface maintenance to remove the sand. The drawbacks of gravel packing techniques were its high wellbore skins due to gravel carrier fluids, intermixing of gravel and fine sands, and blockage of gravel filter bed from fines migration over time resulting in lower well PIs and flow efficiencies through the gravel pack (GP) completions.
This paper reviews the gravel packing techniques applied in 47 completions in Baram South with the aim of identifying the most optimum method for gravel packing in future Baram South wells. A statistical tool called Taguchi Method for Design of Experiment and Analysis of Variance (ANOVA) were employed to analyze impact of the well deviations, gravel packing techniques and permeability variation on skin factor. It is a simple and reliable tool to analyze extensive amount of data and introduces the signal-to-noise ratio as an indication of effect each variable has on the output (skin). The statistical study concluded that the most suitable gravel packing technique for Baram South is High Rate Water Frac (HRWF). The GP technique adopted appears to be the dominant factor contributing to the skin while the type of reservoir and the deviation of the well have minimal effect.
Sand control is defined as the limitation of sand production to an acceptable level (Ott and Woods, 2003; Bellarby, 2009). It has become one of the critical parts of well completion as the impact of sand production during the well life can be detrimental and costly to operators. For a matured field, a review of sand control method applied in the field should benefit in optimizing new well completion design and cost. Lessons learnt from successes and failures of the methods applied would be an important factor towards optimum selection and application of sand control methods. This paper will focus on reviewing the sand control techniques applied in Baram South area of Baram Field and optimizing the application using Taguchi method.