Sand Management of Ultra-High-Rate Gas Wells

Abstract

Abstract Sand production can pose a significant threat to asset integrity, hydrocarbon control and availability of production. As a result sand management is crucial to protecting commercial interest, safety and the environment. Most of the sand production problems tend to be found in relatively shallow reservoir sands that tend to be unconsolidated. The propensity for sand erosion is exacerbated in ultra high rate gas wells where fluid velocities are typically very high. The Kapok Field is such an example with reservoirs and fluid velocity that are prone to incipient sand production. Surrounding field history and an appraisal drill stem test (DST) results indicate that sand control will be a major challenge to delivering full well potential thereby maximizing the value of the field reserves. This risk was addressed in all phases of the development from appraisal drilling, to the front-end engineering design and the operation of the field. As a result, the plan of development for the Kapok field ensured that sand production was taken into consideration and therefore measures were put in place to manage sand spanning from well placement in the reservoir and well completion design, topside installation of wear monitors on all chokes, the implementation of two independent types of sand detection systems as redundancy, and managing the field through focused well operating guidelines and adhering to a reservoir surveillance plan. Kapok Field production is on plateau delivering 1.1 Bcfd of gas and approximately 10,000 barrels of condensate per day that will be exported off the Kapok unmanned satellite platform. Customers requiring this daily volume of gas need the assurance that this gas deliverability is not threatened in any way and gas suppliers need to ensure that this deliverability is not compromised such that both parties maximizes return on their investment in a cost effective manner. Introduction Trinidad's gas production has increased dramatically over the past 10 years.The gas growth has been driven by a natural increase in the local demand and the construction of a series of Liqufied Natural Gas (LNG) trains. BP Trinidad and Tobago LLC's (bpTT) share of the gas supply to the local market has grown from less than 350 Mmcfd in 1994 to over 2000 Mmcfd today with production coming from several prolific fields located off Trinidad's East coast. One of these newest gas fields for bpTT is Kapok that represents more than half of the daily contracted gas volume. The Kapok field was discovered on July 1997 where the first gas production was on July 2003. The field is located offshore the east coast of Trinidad, approximately 37 miles southeast of Galeota Point (Figure 1). The Kapok Field consist of two separate discoveries called Sparrow and Renegade. Both of which is characterised by multiple stacked gas bearing sands bounded by a major fault. The field is located in a water depth of 230 feet. bpTT is the operator with a 70% working interest where the other 30% is owned by Repsol YPF.