Wear Analysis Of(Polycrystalline Diamond Compact)PDC Cutter While Drilling Hard Rock Formation

Predicting the wear of drill bits is essential for all oil companies to maximize drilling efficiency and reduce loss in money and time.Typically,this problem has been dealt with by evaluating the wear rate of the drill bits at drilling formation intervals.Although this technique sometimes provides a good indication of the bit wear,a number of phenomena such as bit balling and high vibration of the drill bit might give misleading results that affect the reliability of these techniques.Therefore,it is necessary to develop an effective predictive tool for the bit tooth wear rate by both modeling and theoretical approaches.A case study is presented for the evaluation of the wear of PDC bits combined with dimensionless drilling parameters method as indicating tools for monitoring the wear of the PDC bits.The results were compared with the qualitative tooth wear index of the bits and an agreement was found for limited cases.The case study did not include the mechanical properties of the materials that form the bit,therefore a wear model was needed to combine the drilling parameters with the mechanical properties of the materials forming the bit.Simulation Modeling were carried out on polycrystalline diamond compact cutters and on rock to study two different cases.The first is to do finite element analysis for hard rock cutting.To optimize the drilling process using polycrystalline diamond compact(PDC)cutters,understanding of interaction between the cutting tool and the rock is very essential.To explain the behavior of cutter rock contact,failure of rock and fragmentation ANSYS 2D-AUTODYN is used.A 2D single PDC cutter and rock were modeled to simulate the orthogonal cutting process and to observe the results of different parameters such as depth of cut(DOC)and back rake angle on granite and basalt rocks.The second case is Wear Rate of Single Polycrystalline diamond compact(PDC)bit Cutter While Drilling Hard Rock.This project aimed to investigate the effect of cutter back rake angle and the cutter size on PDC cutter wear rate in hard formation.Conventional PDC bits often failed in hard formations due to the formation abrasiveness and impact load damage causing excessive wear to the cutter.The study is focused on the single cutter test using 13 mm and 16mm PDC cutter to study the effect of back rake angle and cutter shape on hard formation(granite).The drilling operation is simulated under the constant applied force and velocity.The theoretical basis of the PDC cutter is studied using the cutter-rock interaction model and Merchant's orthogonal cutting model.A 3D simulation model of rock breaking with a single PDC cutter is carried out using ANSYS based on rock mechanics to analyze the stress beneath the cutter.The effect of back rake angle and size of PDC cutter on the cutter wear rate were analyzed using the wear model.