Cementing Technology of PRHH-X Well in Parahuacu Oilfield, Ecuador

In recent years, in order to maximize the benefits of exploration and development and reduce the issues arising from the long openhole section of the third section in the Parahuacu field in Ecuador, the second well structure of the PRHH-X well has undergone optimization and adjustment. A Φ244.5 mm casing was utilized to seal the BASE TENA oil layer and the abnormally high-pressure Caliza A limestone layer in the second section.In response to the the technical problems faced during the Φ244.5 mm casing cementing in the PRHH-X well, such as low displacement efficiency and low flushing efficiency of large annulus, low casing center degree, the weak wellbore cleaning capacity in the highly deviated section, the active edge and bottom water of the reservoir, and the susceptibility of the cement slurry to invasion by formation fluids, the following measures were adopted. Designing a multi-effect preflush system can effectively flush and dissolve the mud and mud cake in the annulus, enhancing the shear strength of the second interface of cementing. Designing high-performance pioneer fluid with good suspension stability ensures the safety of cementing operations. Analyze the reasons for the invasion of formation fluids into the cement slurry, evaluate the performance of thixotropic agents, and optimize the combination to form anti-invasion cement slurry. Indoor experiments show that compared with the clear water system, the shear strength of the second interface of the cementing in the multi-effect preflush system increased by 526% and 715% at 2 days and 7 days, respectively. The stability of the pioneer fluid is good, and the thickening time is more than 10 hours. The static gel transition time of the anti-intrusion cement slurry is 8 minutes, and the transition time from 40 Bc to 70 Bc is 6 minutes, showing strong thixotropy. 8 h The compressive strength reaches 20.6 MPa, and the SPN value is 2.2756, with good anti-gas channeling performance. Based on the above multi-effect preflush system, pioneer fluid, cement slurry and supporting technical measures (optimizing the type and quantity of centralizers, slurry column structure design, and combined flow state displacement), the cementing technology was applied in the PRHH-X well in 2024 with good results. The cementing quality was qualified, and the high-quality rate of the openhole section was over 85%, providing strong technical support for the technical casing cementing of the φ244.5 mm production layer and abnormal high-pressure gas layer in the Parahuacu oilfield, Ecuador.